Released February 26, 2026 15:10 EST

2026, Scientific Investigations Report 2026-5118

Paul M. Thomas

The U.S. Geological Survey, with funding from the Idaho Department of Water Resources, developed a groundwater budget for the Mountain Home area in southern Idaho for irrigation year 2023 (November 1, 2022–October 31, 2023). This study focused on the water balance across the Cinder Cone Butte Critical Groundwater Area (CGWA), Mountain Home Groundwater Management Area (GWMA), and the rest of the study area (RoSA), compiling data from various sources, including precipitation records, groundwater level measurements, metered groundwater pumpage data, surface water diversions and evapotranspiration (ET) estimates derived from remote sensing satellite imagery, and ground-based reference data. Key inflow components included recharge from applied surface water irrigation (which incorporates incidental recharge from irrigation practices and conveyance losses), estimated tributary streamflow, and estimated mountain block recharge. The key outflow components were groundwater pumpage for irrigation, municipal, industrial, and domestic uses, and ET. Recharge from applied irrigation and mountain block recharge were the largest inflows, and groundwater pumpage for irrigation was the largest outflow.

The CGWA had a positive groundwater budget residual of 2,170 acre-feet (acre-ft), which contrasts with observed long-term groundwater level declines and historical trends of storage depletion. This positive residual is likely associated with unquantified outflows, including lateral groundwater flow out of the subregion, or other complexities, such as overestimated tributary contributions relative to the actual recharge for the 2023 water budget. The GWMA exhibited a positive residual of 56,563 acre-ft, primarily owing to recharge from applied surface water irrigation and areal recharge during a wetter-than-average year, which allowed irrigation entities to deliver more water from in-basin and out-of-basin reservoirs. The RoSA showed a large positive residual of 124,933 acre-ft. The interpretation of these positive residuals must account for significant uncertainties, including estimations of areal recharge, tributary streamflow (particularly losses and diversions), ET, the volume of surface water loss to the Snake River, lateral groundwater flows between subregions and across study area boundaries, and the unquantified groundwater discharge to the Snake River. These uncertainties, in combination with the complex hydrogeologic controls on water movement and limitations of remotely sensed data, directly affect the accuracy of water availability assessments.

Future data collection efforts would help reduce these uncertainties and support water resource management decisions in the Mountain Home area. Key efforts could include installing additional streamflow gaging stations (particularly to quantify tributary losses and gains and surface water losses to the Snake River), improving groundwater pumpage metering, and validating remotely sensed ET data with ground-based measurements. Furthermore, to better quantify unrepresented or highly uncertain fluxes, focused investigations on groundwater discharge to the Snake River, lateral groundwater flows between subregions and across study area boundaries, and a more robust determination of the actual influence and volume of mountain block recharge would help refine future water availability assessments for the Mountain Home area.

Released February 26, 2026 14:28 EST

2026, Techniques and Methods 18-B1

Emily Heaston, Sean Winter, Shelby Bauer, Tait Ronningen, Jason Dunham

Intersections of drainage networks and road networks represent a critical nexus between natural waterways and human infrastructure. Managing these systems involves decisions related to management of infrastructure, hydrologic and geomorphic processes, and ecological connectivity. Interactions among these systems influence multiple values, including the intactness of transportation networks, public safety, water quality, and ecosystem function that collectively amount to billions of dollars. Despite the importance of road- stream crossings, there are countless gaps in knowing where and what they are. These gaps limit the degree to which managers can inventory and assess stream and road networks to inform decisions. To address this first- level need, we developed RoadxStr (road- stream crossings): a survey tool that effectively characterizes road- stream crossings across the full stream and drainage network. This document describes the RoadxStr Field Form, available within a mobile application, which is designed for rapid and standardized data collection involving assessment of a road- stream crossing, including the road, crossing structure(s), and the nearby hydrologic channel. This document provides instructions on how to (1) access and download the RoadxStr Field Form within the mobile application service and (2) use and complete a RoadxStr Field Form survey.

Released February 26, 2026 13:00 EST

2026, Scientific Investigations Report 2025-5052

Emily M. Taylor, Margaret E. Berry, Shannon A. Mahan, Jeremy C. Havens

Centered on Fort Morgan, Colorado, this study is intended to build from previous work by adding a three-dimensional (3D) view of the subsurface to better understand the depositional history of Quaternary deposits. A 1:100,000 scale geologic map was made by combining previous geologic maps, regional soil maps, and recent field investigations. In addition to the geologic mapping, drill hole lithologic data from water wells and oil and gas exploration were compiled and lithologic units simplified to best represent the stratigraphy of the Quaternary deposits. From these subsurface data, a 3D subsurface model was constructed, trimmed at the surface by a digital elevation model, and a bedrock surface foundation gridded from drill hole data was added. The surface of the 3D model was then compared visually to the surficial geologic map. Cross sections were constructed from the 3D model and compared to site-specific drilling that was done as part of this project. Finally, the model was examined in detail to reconstruct the depositional history of the subsurface alluvial and eolian units. Alluvial and fluvial drainage basins exposed in the subsurface have a greater areal extent than the present-day narrow drainages. Older eolian sand in the subsurface tends to be interbedded with loess indicating coeval deposition. Holocene sand, both eroded from bedrock exposed at the surface north of the study area and reworked from the South Platte River, buries most of the interbedded older sand and loess.

Released February 26, 2026 09:30 EST

2026, Scientific Investigations Report 2026-5116

Ian P. Armstrong, Meghan A. McCallister, Kristina M. Hyslop, Adam J. Benthem

Acadia National Park has had increases in the frequency and magnitude of precipitation in recent years, leading to increased flood flows, stream erosion, and costly infrastructure damage. To improve infrastructure management in a changing climate, the U.S. Geological Survey, in cooperation with the National Park Service, has developed multiple datasets that can help natural resource managers identify stream reaches and stream crossings that have the highest potential for erosion and flood damage within Acadia National Park. To develop these datasets, we first created a lidar- derived hydrography based on a 1- meter digital elevation model and then estimated peak flows at stream crossings and along the stream network using regional regression equations for Maine. We assessed the erosion potential of stream reaches by computing channel morphologic and hydrologic metrics associated with erosive power, such as stream steepness, topographic openness, and percent storage in the contributing watershed. Stream crossing flood vulnerability was assessed by comparing estimated peak flows to stream crossing conveyance capacities. Our results indicate that stream reaches in the headwaters of the Acadia National Park highlands such as Sargent, Penobscot, and Cadillac Mountain, have the highest erosion potential and generally coincide with reaches that have had erosion and infrastructure damage in the past. Stream crossings with the highest flood vulnerability are distributed throughout Mount Desert Island and Acadia National Park, especially south of Jordan Pond, north of Sargent Mountain, and surrounding Eagle Lake. Over a quarter of the total stream crossings have insufficient information to compute flood vulnerability and are often on the parts of the stream with the highest potential for erosion. The datasets allow users to identify stream reaches with the highest erosion potential, stream crossings that are most vulnerable to flood damage, and to highlight areas where supplemental field assessments could most effectively be completed.

Released February 26, 2026 07:11 EST

2026, Scientific Investigations Report 2026-5120

Nicholas J. Taylor, Roy Sando

The U.S. Geological Survey, in cooperation with the Wyoming Water Development Office, developed regional regression equations based on basin characteristics and streamflow statistics for streamgages through water year 2021 (October 1, 2020, to September 30, 2021). The regression equations allow estimates of mean annual maximum, mean annual, mean seasonal, and mean monthly streamflows; frequency statistics for the 7- day mean low flows with 2- year and 10- year recurrence intervals, 14- and 30- day mean low flows with 5- year recurrence intervals, and 60- and 1- day mean high flow with 2- year and 5- year recurrence intervals, respectively; and the 0.1- , 0.2- , 0.5- , 1- , 2- , 4- , 5- , 10- , 20- , 25- , 30- , 50- , 60- , 70- , 75- , 80- , 90- , 95- , 98- , and 99- percent durations for annual streamflows and 0.1- , 0.5- , 10- , 15- , 20- , 25- , 30- , 40- , 50- , 60- , 70- , 75- , 80- , 85- , 90- , 95- , and 99- percent durations for monthly streamflows for most months for ungaged locations in Wyoming that are largely unaltered by diversions or upstream reservoirs.

Regression equations were developed for 243 streamflow statistics. Best- subset selection was used to assess explanatory variables for respective streamflow statistics. Exploratory data analyses determined that, of the 81 basin characteristics evaluated as potential explanatory variables, characteristics such as drainage area and precipitation often produced models with the highest adjusted coefficient of determination and lowest mean squared error, as determined in the best- subset selection. To address heteroskedasticity of model residuals, model variables were regionalized using fixed- effects models; the percentages of the streamgage basins in selected ecoregions were defined as interaction terms, which represent the model slope for specific ecoregions. Most models were determined to be statistically significant for probability values less than or equal to 0.1 for one or more regional explanatory variables. The final regional regression equations defined in this report are available for use in the U.S. Geological Survey’s StreamStats web application at https://streamstats.usgs.gov/ss/.

Released February 25, 2026 15:25 EST

2026, Scientific Investigations Report 2025-5110

Terence Messinger, James M. Duda, Daniel M. Wagner, Padraic S. O’Shea, James D. Scott, Chintamani Kandel

Magnitude and frequency of annual peak streamflows were computed for 813 streamgages on rural, unregulated streams with annual peak streamflow data from 1791 through the 2021 water years in and near Virginia and West Virginia. The study was done in cooperation with the Federal Emergency Management Agency, the West Virginia Department of Transportation, and the Virginia Department of Transportation.

Regression equations were developed for estimating flood frequency and magnitude. Twelve regions with homogeneous flood characteristics were identified. Generalized least squares regression equations relating logarithmic-transformed drainage area and peak streamflow were developed for the 0.5, 0.2, 0.1, 0.04, 0.02, 0.01, 0.005, and 0.002 annual exceedance probabilities (AEPs). Drainage area was the only significant variable for all equations. The range of drainage areas used to develop the equations differed for each region; the smallest drainage area in any region was 0.21 square miles (mi²) and the largest drainage area in any region is 2,966 mi². Pseudo coefficient of determination (pseudo-R²) values for regression equations ranged from 0.481 to 0.995 for all regions and AEPs. Performance metrics and diagnostic plots indicated that equations for 11 of the 12 regions showed generally good performance, with pseudo-R² values ranging from 0.762 to 0.968 for the 0.01 AEP.

The overall average change in at-site 0.01 AEP annual peak streamflows at individual streamgages was 0.5 percent compared to the most recent 2011 Virginia study and 2.3 percent compared to the most recent 2010 West Virginia study. Changes from the previous studies for estimates from regional equations for the 0.01 AEP, solved specifically for a 50 mi² basin, ranged from a 30 percent increase to a 45 percent decrease in areas where the previous regions overlapped with the current regions by 750 mi² or more.

New regional skews were developed using Bayesian weighted least-squares/Bayesian generalized least-squares regression for two skew regions that included the study area. A constant regional skew of 0.50 was computed for streams in Virginia, West Virginia, and Maryland that drain to the Atlantic Ocean. A constant regional skew of 0.048 was computed for streams that drain to the Gulf of America, including streams in Kentucky and Tennessee, most of West Virginia, far southwestern Virginia, and part of western Maryland.

About 12 percent of the 418 streamgages with 30 or more gaged peaks had statistically significant (p-value [significance level] less than or equal to 0.05) trends, with 40 of these exhibiting positive trends and 11 exhibiting negative trends. Streamgages with 30 percent or greater development were excluded from regression analyses.

A regulation index was developed that accounted for storage and drainage area of dams and drainage area at the streamgage; a value of 0.0040 or more for the regulation index indicates regulated peak streamflow. Frequency analyses were done at 86 streamgages on regulated streams.

Regression procedures developed in this study are applicable only to rural, unregulated streams within Virginia and West Virginia with drainage basins that (1) are within the range of drainage areas used to develop the equations for each region, (2) included less than 30 percent of developed area, and (3) had a regulation index less than 0.0040.

Released February 25, 2026 10:43 EST

2026, Preprint

Zeno Levy, Andrew Lee Soldavini

This study provides a comprehensive assessment of decadal changes in the quality of groundwater used for public drinking-water supply at 444 monitoring sites across California during 2004–2023. We assessed decadal step trends in groundwater quality for 145 water-quality constituents and geochemical indicators statewide and across geographic and land-use based network groups. We evaluated the statistical significance of directional changes (predominant increase or decrease of constituent concentrations) and the magnitude of those changes across all network groups.

Uranium showed the most widespread directional and high-magnitude increases of all constituents with regulatory benchmarks statewide, particularly in the agriculture-dominated Central Valley as well as urban- and desert-dominated regions of Southern California. Fluoride and perchlorate showed the most widespread directional and high-magnitude decreases of all constituents with regulatory benchmarks statewide, which were also most pronounced in Southern California. Although arsenic and nitrate did not often register significant directional changes across network groups, they showed widespread, high-magnitude changes in both directions (increase and decrease) at levels often exceeding 10 percent of respective regulatory benchmarks statewide. Triazine herbicides (atrazine and simazine) and the gasoline oxygenate methyl tert-butyl ether (MTBE) showed significant directional decreases statewide, but not at levels considered to be of high magnitude compared to respective regulatory benchmarks.

We observed significant directional and high-magnitude increases of total dissolved solids (TDS) statewide, which were most pronounced in agricultural areas. Analysis of explanatory geochemical indicators indicated that prevalent statewide increases of alkalinity and calcium were the predominant components of the observed statewide increases in TDS by mass. Widespread increases in groundwater alkalinity and calcium across agricultural and urban areas may be related, in part, to warm-season irrigation and other anthropogenic factors that have shifted soil weathering dynamics over the long term. Increasing alkalinity concentrations were related to increasing uranium concentrations, particularly in areas with aquifer materials derived from granitic rocks. Conversely, increasing calcium concentrations were related to decreasing fluoride concentrations, particularly in areas where fluoride occurred naturally at elevated concentrations. Decrease of perchlorate, triazine herbicides, and MTBE are likely related to decreased anthropogenic source inputs over time and natural attenuation in aquifers.

Released February 25, 2026 09:50 EST

2026, Fact Sheet 2026-3063

Christopher J. Schenk, Tracey J. Mercier, Janet K. Pitman, Phuong A. Le, Andrea D. Cicero, Benjamin G. Johnson, Jenny H. Lagesse, Heidi M. Leathers-Miller

Using a geology-based assessment methodology, the U.S. Geological Survey estimated undiscovered, technically recoverable mean conventional resources of 269 million barrels of oil and 14.3 trillion cubic feet of gas in the Larsen Basin, Antarctica.

Released February 24, 2026 09:53 EST

2026, Eos, American Geophysical Union

Jacob Aaron Zwart, Cameron Thompson, Hassan Moustahfid, Jessica Burnett, Michael Dietze

Ecological forecasting offers critical insights for managing natural resources and safeguarding public well-being. Despite growing demand for these forecasts, progress is hindered by fragmented systems, redundant workflows, and limited interoperability. Drawing lessons from weather forecasting and recent successes like the NEON Ecological Forecasting Challenge, shared cyberinfrastructure is important for advancing ecological prediction. By adopting common standards, open-source tools, and scalable architectures, and fostering transdisciplinary collaboration, the ecological forecasting community can overcome technical and institutional barriers. Such investments could accelerate scientific understanding, improve forecast reliability, and empower decisionmakers to anticipate environmental change and respond effectively.

Released February 24, 2026 09:23 EST

2026, Open-File Report 2026-1060

Amanda H. Bell, Sophia LaFond-Hudson, Owen M. Stefaniak, James T. Romano, Daniel J. Sullivan

Portions of Underwood Creek in Milwaukee County, Wisconsin were reconstructed beginning in 2010 to allow for improved fish habitat and better management of streamflow during storm events. Four reaches of Underwood Creek were sampled in April 2021 for fish abundance by species to evaluate the status of fish communities after reconstruction efforts were completed. A total of 25 fish species were collected during the April 2021 sampling events. Reach D, a recently restored reach, contained the most fish species (14) and individuals (391). White suckers (Catostomus commersonii) were present in three of four reaches, fulfilling one of the success metrics outlined in the Underwood Creek restoration plan. Another success metric, collection of young of year northern pike (Esox lucius), was not met in this sampling event. However, spawning steelhead (Oncorhynchus mykiss) were observed in several reaches, indicating that reconstruction allowed for suitable habitat and passage for some migratory fish.

Released February 24, 2026 09:08 EST

2026, Report

Ruth A. Harris, Michael Barall

No abstract available.

Released February 24, 2026 08:13 EST

2026, Ecological Indicators (183)

Saira M. Haider, Craig van der Heiden, Marcel Bozas, Stephanie S. Romañach

Tree islands are patchy upland forested habitats in Florida's Everglades that face degradation and disappearance due to altered hydrologic patterns. The U.S. Geological Survey coordinated with the Miccosukee Tribe of Indians of Florida and the Seminole Tribe of Florida to co-develop a decision-support tool based on tree-island hydrologic conditions. Everglades managers can use this tool to help with restoration planning and water operations decisions that affect tree-island conditions. After a series of organized workshops and meetings, a list of hydrologic metrics was selected as indicators of tree-island health, including hydroperiod, number of days since last dry, and maximum water depth at the head of the island. As a result, a web application tool, called ETree, has been developed and is publicly available online. This web application provides data on daily metrics for the current Everglades water year and annual summaries for past years, beginning in 2000.

Released February 24, 2026 07:50 EST

2026, Limnology and Oceanography Methods

Natalie C. Hall, Adam C. Mumford, Aaron M. Goldfain, David W. Allen, E. Terrence Slonecker, Alisa Shtabnoy, Carl J. Legleiter, Sarah A. Spaulding

Cyanobacterial and other algal blooms are an environmental concern in waterbodies worldwide. While these blooms are a nuisance for recreational activities, they can also be harmful to human and wildlife health when the algae produce and release toxins. Algal community composition can be monitored and analyzed by acquiring hyperspectral images that provide information on various photosynthetic and accessory pigments. Validated, traceable measurements are needed to compare data collected by different hyperspectral instruments. In this proof-of-concept study, we detail the development and validation of a custom hyperspectral microscopy imaging system and assess whether this technology can differentiate between cyanobacteria genera based on differences in their reflectance characteristics. As not all cyanobacteria produce toxins, the ability to distinguish among taxa could be used to identify potential toxin-producers and guide field sampling and further research. Spectral characterization of these taxa contributes to remote sensing efforts to characterize and identify cyanobacterial genera at larger spatial scales.

Released February 23, 2026 13:24 EST

2026, Techniques and Methods 8-D3

Alden T. Tilley, Peter C. Esselman, Christopher Roussi, Ben Hart, Aaron Lyons, Anthony J. Arnold, Jeremy Childress, Charley Weller

Lake and seabed environments are home to fisheries and other biota that are important to ecosystems and economies, yet these environments and the species that use them are difficult to accurately assess and monitor. Traditional benthic survey techniques, like bottom trawling used by the U.S. Geological Survey, are limited by substrate constraints, poor spatial resolution and precision, and operational depth limits, hindering accurate assessment of benthic species and habitats. In response to these limitations, the U.S. Geological Survey developed the Autonomous Benthic Imaging and Surveying System, a camera system integrated into underwater vehicles, to capture high- resolution images of the lakebed. The system uses color and stereo cameras to collect imagery, which can be analyzed using computational methods to detect organisms and (or) characterize habitat features, such as geologic substrate types. The system has been integrated into autonomous underwater vehicles and into an underwater housing used by self- contained underwater breathing apparatus (SCUBA) divers. Although the engineering of the system was motivated by the need for data collection in the Great Lakes, it has potential to collect high quality data in any aqueous setting with sufficient water clarity and safe operating conditions. The Autonomous Benthic Imaging and Surveying System can operate across diverse depths and light conditions to map and quantify ecological patterns that were difficult or impossible to assess using traditional methods. The Autonomous Benthic Imaging and Surveying System offers the potential for accurate and precise monitoring and assessment of native benthic biota, invasive species, and habitat, potentially providing natural resource managers with improved information to support decision making about benthic resource management.

Released February 23, 2026 09:23 EST

2026, Forest Ecology and Management (609)

Richard D. Inman, Bradley James Udell, Amy Kristine Wray, Bethany R. Straw, Andrea Nichole Schuhmann, Helen Trice Davis, Sarah C. Sawyer, Brian E. Reichert

Coordinated, regional strategies to guide effective management and conservation of forests can be used to balance conservation with management for other objectives such as timber, scenic viewsheds, and fire. A key part of these regional strategies is incorporating knowledge of how management actions may affect certain species, especially those that are sensitive or are of concern. However, knowledge of how management actions may affect species is inferred from studies conducted across small areas where the species’ behavior and forest conditions are easily assessed. Here, we examine how occupancy of four bat species responds to forest management across the eastern United States at regional scales. We used range-wide capture and stationary acoustic surveys from the North American Bat Monitoring Program from 2010 to 2020 to estimate yearly summer occupancy for four bat species of conservation concern identified in the U.S. Department of Agriculture Forest Service (USFS) Southern and Eastern Regions Bat Conservation Strategy: little brown bat (Myotis lucifugus), northern long-eared bat (Myotis septentrionalis), Indiana bat (Myotis sodalis), and tricolored bat (Perimyotis subflavus), and assessed the degree to which occupancy of each species changed after different vegetation management actions were implemented on USFS lands. We identified 78 different management actions that were hypothesized to influence summer bat occupancy at two spatial scales (5-km and 10-km) across the eastern United States from the Forest Service Activity Tracking System and grouped these management actions into four vegetation management types: clear-cutting, fire, thinning, and ground vegetation management. To evaluate potential effects of these vegetation management types on bat occupancy, we created a yearly management metric representing the average number of years that had passed since any one of the included management actions in each management type had been implemented in each 5-km or 10-km grid cell, weighted by the proportion of the grid cell covered by the management treatment history. We chose these metrics to ask if more management or management done recently had a larger effect on bat occupancy than less management or management done long-ago. We then fit Bayesian hierarchical multi-scale occupancy models for each species to assess how occupancy changed in response to the amount and time since implementation of each vegetation management type. Using the estimated relationships between the yearly metrics of management and bat occupancy, we created predictions for how bat occupancy responded at 1- and 5- years after implementation. We found substantial differences in the response of the four species to the four vegetation management types. Ground vegetation management provided the greatest increase in expected occupancy at 1 year after implementation for little brown bat, long-eared bat, and tricolored bat, while fire provided the greatest increase in expected occupancy for Indiana bat. Thinning provided increases for all species at 1 year after implementation, but even greater increases at 5 years after implementation. Clear-cutting, on the other hand, tended to result in decreased occupancy at both 1- and 5-years after implementation for each species and had the greatest effect on tricolored bat at 1 year after implementation. Clear evidence for how management types like these may be affecting bat populations can be used at regional scales to help private and public forest managers achieve their strategic goals.

Released February 23, 2026 08:23 EST

2026, Earthquake Spectra (42)

Rashid Shams, Chukwuebuka C. Nweke, Grace Alexandra Parker

Site response in sedimentary basins is influenced by complex three-dimensional (3D) features, including trapping of seismic waves, focusing of seismic energy and basin resonance. Current ground motion models (GMMs) incorporate basin effects using one-dimensional parameters like V_S30 and shear wave velocity isosurface depths, which are limited in capturing lateral and 3D effects. To address these limitations, we develop seismic site response models based on novel parameters that represent multi-dimensional properties of the Los Angeles Basin (LAB) geometry and shear wave velocity. We define a basin shape for the LAB using depth to subsurface geologic interfaces associated with the oldest sedimentary deposits (depth to a particular shear wave velocity horizon, i.e., 1.5 km/s - z_1.5) and the depth to the crystalline basement (z_cb) which are determined using geologic cross sections and community seismic velocity model profiles. We explore a suite of geometric descriptors computed for the LAB and southern California, from which three parameters with the greatest predictive potential are selected and evaluated using empirical ground motion residual analyses in combination with the Boore et al. GMM. The results demonstrate that the zonal heterogeneity index (), standard deviation of the absolute difference between z_1.5 and z_cb () and standard deviation of z_cb () each provide a reduction in site-to-site variability (ϕ_S2S) of empirical GMMs. The reduction in ϕ_S2S is period-dependent, with average decreases of 3%, 26% and 6% for , , and , respectively. Although these reductions are modest from an engineering application perspective, they are statistically significant, underscoring the inherent difficulty in fully characterising complex basin effects. Collectively, these findings indicate that the inclusion of basin-specific geometric parameters yields measurable, albeit incremental, improvements in site response prediction and establishes a framework for the progressive refinement of seismic hazard characterisation within sedimentary basins.

Released February 23, 2026 07:42 EST

2026, Seismological Research Letters

Dara Elyse Goldberg, Heather Elizabeth Hunsinger, Pablo Koch, Kirstie Lafon Haynie, Diego Melgar, Sebastian Riquelme

Models of the spatiotemporal evolution of earthquake slip, termed finite-fault models, are a critical component of rapid earthquake and tsunami response, earthquake forecasting, seismic ground-motion estimates, and studies of earthquake kinematics. Here, we detail a newly released finite-fault modeling software, Wavelet Inversion for SliP (WISP), in use at the U.S. Geological Survey’s National Earthquake Information Center (NEIC) and available to the public. WISP version 1.1.0 allows inversion of teleseismic body and surface waves, as well as local strong-motion, static and dynamic Global Navigation Satellite System, and satellite imagery (e.g., Interferometric Synthetic Aperture Radar) observations on single or multiple planar fault segments. The software is used in NEIC rapid response of earthquakes M_w ≥ 7, generally resulting in a published model within the first few hours after the event origin time. The rupture location and dimensions are then used as inputs to downstream products to estimate earthquake shaking, predict loss, and model the likelihood of secondary hazards, namely landslides and liquefaction. WISP is also used in research studies to evaluate the characteristics of complex ruptures including multifault ruptures and earthquake doublets, among others. The WISP version 1.1.0 software release is composed of Python-wrapped FORTRAN code to accomplish the inversion procedure. A simple command line interface facilitates ease of use even for those with only a cursory knowledge of Python scripting. WISP version 1.1.0 includes a Jupyter Notebook tutorial demonstrating use of the software for modeling the 2015 M_w 8.3 Illapel, Chile, earthquake. In parallel with the tutorial, we demonstrate the typical usage of the WISP software using the M_w 8.3 Illapel earthquake example here.

Released February 22, 2026 10:08 EST

2026, Limnology and Oceanography Letters (11)

Scott D. Ducar, Tyler V. King, Michael Frederick Meyer, Stephen A. Hundt, Grady P. Ball, Konrad C. Hafen, Dulcinea Marie Avouris, Brendan Flynn Wakefield, Victoria G. Stengel, Quinten Vanhellemont

Satellite-based earth observation is a robust tool for tracking change in ecosystems. While terrestrially focused applications of remote sensing have empowered wide adoption for research and management, remote sensing of inland aquatic ecosystems remains comparably nascent. This divergence, in part, stems from the lack of standardized, accessible, and near real-time remotely sensed surface reflectance, atmospherically corrected for aquatic environments. To date, surface reflectance products at national scales and with minimal latency are typically designed exclusively for terrestrial environments. Rectifying this situation can be accomplished by applying aquatic-focused atmospheric correction algorithms independent of those used for terrestrial ecosystems. As a first step to filling this data gap, we present the first national scale, dynamically updated, analysis-ready, aquatic reflectance dataset for inland water derived from Sentinel-2 for the conterminous United States.

Released February 20, 2026 09:47 EST

2026, Current Forestry Reports (19)

Daniel A. Friess, Maria F. Adame, Jeffrey Kelleway, Ken W. Krauss, Gregory B. Noe

Purpose of Review

Blue carbon is an important concept for environmental policy. Blue carbon strategies (conservation and restoration for carbon gain) have been primarily implemented with mangroves, though are likely to be suitable for other tidal forested wetlands. Here, we discuss the expanding definition of blue carbon encompassing all tidal forested wetlands, synthesize ecological and carbon sink knowledge of tidal forested wetlands, and reflect on key actions in mangrove blue carbon research and implementation that could be applied to other tidal forested wetlands.

Recent Findings

Conceptually, the blue carbon concept has now expanded beyond traditional coastal vegetated ecosystems to include all tidal wetlands, including tidal forested wetlands. Emerging data on carbon sequestration, emissions, and budgets from around the world now show that many tidal forested wetland ecosystems are carbon sinks at a magnitude similar to mangroves. At the global scale, mangroves have become incorporated into blue carbon strategies rapidly compared to other tidal forested wetlands, facilitated by agenda-setting papers, adequate data addressing concerns on emissions and permanence, the availability of global maps, a clear ecosystem definition, clear accounting and policy frameworks, and international stakeholders who acted as high profile ecosystem advocates, alongside long-term capacity building efforts. This provides a roadmap for implementation in other tidal forested wetlands.

Summary

Tidal forested wetlands other than mangroves have high potential for blue carbon management. Many tidal forested wetlands share biophysical similarities with mangroves, carbon stocks can be similar, and methane emissions are often no higher. An increasing evidence base, challenging assumptions around greenhouse gas fluxes, and robust engagement with policy actors and frameworks, could increase the use of blue carbon for tidal forested wetland conservation and restoration.

Released February 20, 2026 09:44 EST

2026, Report

Catherine S. Jarnevich, Peder Engelstad, Shelby K. LeClare, Richard D. Inman, Ian Pfingsten, Wesley Daniel

As environmental conditions change, land managers are increasingly concerned about the potential for new aquatic invasive species to move into their jurisdictions. Because managers may have limited resources, detecting invasive species early is important as prevention is more effective and less costly than ongoing mitigation of established populations. Tools built to assist early detection efforts often use information on pathways of spread (how species move through a landscape) and maps of suitability (where habitat allows a species to live and reproduce). While each is useful, information on pathways or suitability alone provides only a part of the story of invasion risk. To better anticipate the risk of invasive species expanding their ranges into the Northeast U.S., there is a need to improve the way we combine and use pathways and suitability information, especially across large areas (e.g., states, regions). To fill this need, we took a new approach that combines estimates of current and future suitability with a diverse variety of pathways that gives us invasion risk scores for more than 100 freshwater invaders (fishes, plants, and invertebrates) across the Northeast U.S. In this report, we provide an overview of our methodology, results, and a description of the ongoing work to make the data publicly available. This work can be used to aid early detection efforts and associated management activities at state and local levels, including the identification of invasion risk hotspots and ranking of individual species risk to help anticipate and prevent invader establishment.

Released February 19, 2026 11:16 EST

2026, Ecosphere (17)

Paige E. Howell, Abigail Jean Lawson, Davis Kristin P., Guthrie S. Zimmerman, Orin J. Robinson, Matthew A. Boggie, Mitchell J. Eaton, Fitsum Abadi, Jessi L. Brown, Julie A. Heath, John A. Smallwood, Karen Steenhof, Ted Swem, Brian W. Rolek, Christopher J.W. McClure, Jean-Francois Therrien, Karl E. Miller, Brian A. Milsap

The American kestrel (Falco sparverius, hereafter referred to as kestrel) has declined across much of its North American range since at least the mid-1960s. Kestrel population dynamics have been explored through a multitude of local studies and two broad reviews of available data. Across large geographic extents, however, the demographic cause(s) of kestrel population declines remain(s) largely unknown. As part of a collaborative effort to elucidate the drivers of kestrel population declines, we developed a continental-scale integrated population model using band-recovery data, productivity data, and Breeding Bird Survey indices from 1986 to 2019 to estimate indices of annual population sizes, survival, and productivity rates across the continental United States. We detected a decline in population size of ~1%–2% per year. Overall estimates of population growth from 1986 to 2019 suggest a 29% decline in population size (95% CI = −34% to −23%). There was little evidence of a trend in brood size. However, survival of juvenile birds (mean = −0.015, SD = 0.008 and mean = −0.024, SD = 0.010 for females and males, respectively) and adult males (mean = −0.016, SD = 0.010) in the summer declined, suggesting that these vital rates could be contributing to declines in populations over time. Winter adult survival rates (mean = −0.004, SD = 0.009 and mean = −0.009, SD = 0.010 for females and males, respectively) also declined but to a lesser extent than summer survival. For juvenile birds, winter survival increased (mean = 0.006, SD = 0.008 and mean = 0.002, SD = 0.009 for females and males, respectively); however, this was not enough to offset declines in summer survival and annual survival rates declined over the time series. Annual adult survival was also low relative to previous research on kestrel survival rates. Given the importance of survival to population trends, our findings provide support for several previously proposed broad classes of factors potentially contributing to observed population declines: declines in arthropod prey, second-generation rodenticides, neonicotinoid insecticides, and predation.

Released February 18, 2026 17:15 EST

2026, Circular 1562

Janice M. Gordon, Alison P. Appling, Alfredo Aretxabaleta, John F. Bechtell, Thomas E. Burley, Janet M. Carter, Peter C. Esselman, Jason C. Fisher, Graham W. Lederer, James M. Mitchell, Neal J. Pastick, Jake Weltzin, Tim Woods

Artificial intelligence (AI) can offer opportunities to enhance the science, science delivery, and business operations of the U.S. Geological Survey (USGS). Although USGS staff have proactively adopted AI into our workflows for many years, a comprehensive USGS strategy for AI has not previously been developed. The strategy described here is motivated by the acceleration of AI technological development, the benefits of increased AI adoption to USGS mission delivery as anticipated by USGS staff, rising public concern about the implications and trustworthiness of AI, and emerging Federal directives and guidance about AI. The USGS vision is to continue integrating AI to deliver valuable science for the public good while maintaining high ethical standards, scientific quality and integrity, and compliance with Federal and U.S. Department of the Interior requirements. To realize this vision, the USGS can take steps to (1) develop a strong AI workforce, (2) adapt our organizational approaches to include AI governance and communication, (3) ensure responsible and trustworthy use of AI, (4) modernize our computing and data infrastructure to support AI, and (5) accelerate AI adoption and innovation in the Bureau.

Released February 18, 2026 12:45 EST

2026, Scientific Investigations Report 2026-5114

Dina Saleh, Lorraine E. Flint, Michelle A. Stern

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Released February 18, 2026 09:13 EST

2026, Remote Sensing (18)

Natalie K. Day, Tyler V. King, Adam R. Mosbrucker

Monitoring suspended-sediment concentration (SSC) is essential to better understand how sediment transport could adversely affect water availability for human communities and ecosystems. Aquatic remote sensing methods are increasingly utilized to estimate SSC and turbidity in rivers; however, an evaluation of their quantitative performance is limited. This study evaluates the performance of three multispectral sensors, which vary in resolution and ease of deployment, to estimate turbidity in the Colorado River: the Multispectral Instrument (MSI) on board the European Space Agency’s Sentinel-2 satellite, an industrial-grade 10-band dual camera system mounted on a cable car, and a consumer-grade 6-band dual camera system positioned on the riverbank. We use multivariate linear regression to compare in situ turbidity measurements with concurrent spectral reflectance data from each sensor. Models for all three sensors selected similar spectral information and resulted in mean errors <35% in predicting turbidity. A cross-sensor comparison showed that little accuracy is lost when applying models developed for satellite-based systems to ground-based systems, and vice versa. Transferability of satellite-based models to ground-based systems could support continuous water-quality monitoring between satellite overpasses and avoid issues associated with cloud interference. Conversely, continuously operating ground-based systems could be used to rapidly establish datasets and models for application in satellite imagery, thus accelerating remote sensing applications. The encouraging performance of the consumer-grade system indicates that SSC could be monitored for low cost.

Released February 18, 2026 08:45 EST

2026, Scientific Investigations Report 2025-5113

Michelle M. Lorah, Emily H. Majcher, Adam C. Mumford, Ellie P. Foss, Trevor P. Needham, Andrew W. Psoras, Colin T. Livdahl, Jared J. Trost, Andrew M. Berg, Bridgette F. Polite, Denise M. Akob, Isabelle M. Cozzarelli

Executive Summary 

Chlorinated solvents, including trichloroethene (TCE) and other chlorinated volatile organic compounds (cVOCs), are widespread contaminants that can be treated by bioremediation approaches that enhance anaerobic reductive dechlorination. Reductive dechlorination can be enhanced either through the addition of an electron donor (biostimulation) or the addition of a known dechlorinating culture (bioaugmentation) along with an electron donor. Although bioremediation has been applied at many TCE- contaminated groundwater sites, application in source zones at sites where residual dense nonaqueous phase liquid (DNAPL) is present is more limited. In this study, laboratory and field treatability tests were completed to evaluate the potential application of anaerobic bioremediation for a shallow groundwater plume containing TCE in a perched alluvial aquifer at Site K, former Twin Cities Army Ammunition Plant, Arden Hills, Minnesota, which was on the National Priorities List as the New Brighton/Arden Hills Superfund site until 2019. In addition to the presence of residual DNAPL at the site, temporal variability in groundwater flow directions and input of oxygenated recharge were possible complicating factors for the application of enhanced anaerobic biodegradation in the shallow plume. The Site K plume extends beneath the footprint of Building 103, which was demolished in 2006, and soil excavations to a maximum depth of 6 feet (ft) below ground surface in 2014 were known to leave some deeper contaminated soil in place in the TCE source area. Groundwater treatment at the site, formalized as part of the 1997 Record of Decision, has been in operation since 1986 and consists of an extraction trench at the downgradient edge of the plume to collect groundwater, which is then pumped to an on- site air stripper. Groundwater concentrations in the plume have been relatively stable since treatment began, indicating a continued source of TCE in the aquifer. The desire for a destructive remedy that would enhance the removal of cVOCs in the aquifer at Site K and shorten the remediation timeframe led the U.S. Army to request that the U.S. Geological Survey conduct a groundwater treatability study to assess bioremediation. This report describes the U.S. Geological Survey bioremediation treatability study conducted during 2020–22, including pre- design site characterization to assist in formulating the bioremediation approach, laboratory experiments to support the design of the field pilot test, and implementation and 1-year performance monitoring results for the pilot test.

Pre- design site characterization included the collection of soil cores for cVOC analysis and lithologic descriptions and the re- installment of three wells to obtain hydrologic measurements and initial groundwater chemistry. Relatively flat head gradients were measured at the site, and substantial decreases in water- level elevations occurred from spring to summer (May–July 2021). Continuous water- level monitoring indicated a rapid response to precipitation. Groundwater flow velocities were consistently less than 0.5 foot per day, and the pilot bioremediation test was therefore designed with short lateral distances (about 5 ft) between injection and individual monitoring points. Soil analyses confirmed that high volatile organic compound contamination was left in place in the source area. The highest concentrations were near or in clay at the base of the perched aquifer. Concentrations of cVOCs measured in the replaced wells were consistent with historical data and had a maximum TCE concentration of 57,700 micrograms per liter (μg/L), indicative of nearby residual DNAPL based on the general rule of observed concentrations exceeding 1 percent of solubility. The primary TCE daughter product detected was 1,2- cis- dichloroethene (cisDCE), which indicated limited reductive dechlorination in the plume. Groundwater in both the source and downgradient areas was relatively reducing during the pre- design characterization, particularly in the source area where methane concentrations greater than 400 μg/L were measured.

Initial laboratory tests conducted using native aquifer microorganisms from the three replacement wells showed that anaerobic TCE biodegradation rates were low when biostimulated with the addition of sodium lactate as an electron donor, also known as a carbon donor, and resulted in the production of only cisDCE. Addition of a known dechlorinating culture, WBC- 2, however, resulted in rapid biodegradation and production of ethene, verifying complete reductive dechlorination of TCE. Microcosms constructed with aquifer soil collected from the site were used to evaluate other electron donors besides lactate to support reductive dechlorination by WBC- 2, including corn syrup as an alternative fast- release compound and whey, soy- based vegetable oil, and 3- D Microemulsion (Regenesis, San Clemente, California) as slow-release compounds. First- order rate constants for total organic chlorine removal in these WBC- 2 amended microcosms were greatest with either lactate or vegetable oil as the donor, ranging between 0.061 and 0.047 per day or corresponding half- lives of 11–15 days. Testing of commercial products in other WBC- 2- bioaugmented microcosms led to selection for the field pilot test of an emulsified vegetable oil product that also contained some sodium lactate as a fast- release donor. Delaying the addition of WBC- 2 relative to the donor in the microcosms resulted in the most rapid overall biodegradation rates.

The selected design for the pilot test utilized three separate test plots, each about 30-ft wide and 60-ft long: plots GS1 and GS2 in the source area of the plume and plot GS3 in the downgradient area of the plume near the excavation trench. Each test plot had one injection well, one monitoring well upgradient from the injection point, and 12 surrounding monitoring wells in a grid to capture variable groundwater flow directions. Donor injections, which included a bromide tracer, were completed in October 2021, immediately following baseline sampling, and the WBC- 2 culture was injected about 40 days later, between November 30 and December 2, 2021. Performance monitoring conducted until December 2022 included hydrologic measurements and analyses of cVOCs, redox- sensitive constituents, dissolved organic carbon, bromide, volatile fatty acids, compound- specific carbon isotopes, and microbial communities.

The biogeochemical data collected during the pilot tests in the three treatment plots showed that enhanced, complete reductive dechlorination of cVOCs in the groundwater was achieved in the GS1 and GS3 plots. In contrast, evidence of distribution of the injected amendments and subsequent biodegradation was limited in GS2, which was in an area of more heterogeneous soil lithology and low water table elevations. The molar composition of volatile organic compounds in the GS1 and GS3 plots was dominated by ethene in wells that were reached by the injected amendments by the end of the monitoring period. In the GS1 and GS3 plots, similar patterns were observed of cVOC concentrations decreasing to near detection levels, or below, at some wells sampled in July and October 2022, whereas ethene became dominant and indicated sustained complete reductive dechlorination. Baseline cVOC concentrations were more than a factor of 10 higher in the groundwater in the GS1 plot than in GS3, but no apparent inhibition of complete dechlorination occurred. As expected from the initial pre- design site data and the laboratory experiments, enhanced dissolution of residual DNAPL coupled to biodegradation was evident in the GS1 plot, where a marked increase in dichloroethene (DCE) above the initial baseline and upgradient TCE and DCE concentrations occurred. DCE concentrations subsequently declined where DNAPL dissolution was evident, concurrent with production of vinyl chloride and then predominantly ethene. Thus, overall biodegradation rates outpaced the DNAPL dissolution and desorption and DCE production in the source area. This success in complete degradation to predominantly ethene was achieved even in areas where the DCE concentrations reached a maximum of about 30,000 μg/L. Compound specific isotope analysis of carbon in TCE, cisDCE, trans- 1,2- dichloroethene, and vinyl chloride was conducted to provide another line of evidence of the occurrence and extent of anaerobic biodegradation. Along a flow path in each plot that was affected by the injected amendments, carbon isotopes in the TCE and daughter cVOCs in the groundwater became isotopically heavier, indicating biodegradation.

Enhanced biodegradation rates calculated from the field tests in GS1 and GS3 showed half- lives of 36.9–75.3 days for DCE degradation and 9.48–38.5 days for ethene production. Notably, these ethene production rates calculated from the field tests are consistent with the results of WBC- 2- bioaugmented microcosms amended with either lactate or vegetable oil, which had half- lives for total organic chlorine removal that ranged from 11 to 15 days. These rates indicated rapid enhanced biodegradation, which is promising for application of a full- scale bioremediation remedy. Ultimately, however, the mass of residual or sorbed TCE in the aquifer that remains accessible for dissolution and biodegradation would likely control the time required for a full- scale bioremediation effort to achieve performance goals for TCE and cisDCE specified in the Record of Decision for Site K.

The field pilot tests showed that the relatively low hydraulic head gradients and temporal changes in groundwater flow directions in the shallow aquifer would add complexity to a full- scale bioremediation effort. The radius of influence (ROI) at GS1 and GS3 (16.3 ft and 12.7 ft, respectively) were close to the design ROI of 15 ft. The estimated ROI at GS2 was about four times the design ROI, but may be less reliable at this location owing to groundwater flow direction. In addition, the low temperatures following WBC- 2 injection in late November to early December 2021, in combination with the low hydraulic head gradients, were probably major factors in the delay observed before the onset of enhanced biodegradation following injection of the culture. Additional test injections could be beneficial to optimize the timing of donor and culture injections with the variable temperatures and hydraulic head in the shallow aquifer.

Released February 18, 2026 08:33 EST

2026, Canadian Journal of Fisheries and Aquatic Sciences (83) 1-9

Nicole Lynn Berry, David B. Bunnell, Thomas J. Fisher, Erin P. Overholt, Elizabeth M. Mette, Todd Howell, Craig E. Williamson

Little is understood of lake browning (due to increased dissolved organic carbon; DOC) in large lakes such as the Laurentian Great Lakes. Lake browning can alter whole lake ecosystems, including decreasing exposure to damaging ultraviolet radiation (UV-B) which is strongly and selectively attenuated by DOC more so than photosynthetically active radiation (PAR). We compared the changes in UV-B and PAR transparency to DOC data collected during the ice-free seasons from 62 nearshore sites in four of the five Great Lakes from 2002 to 2022 using linear mixed effects regression models based on backwards selected Bayesian information criteria. Regionally, DOC significantly increased from 2002 to 2022 by 0.5% per year on average. DOC strongly and inversely explained the variability of UV-B and PAR transparencies, as did seasons and offshore influence on these habitats. We provide regional evidence of lake browning within the nearshore habitats of the Great Lakes as a strong contrast to the well-documented increased offshore water transparency associated with the spread of invasive dreissenid mussels.

Released February 18, 2026 07:59 EST

2026, ESA Bulletin

Nicole K. Ward, Kelly G. Guilbeau, Amanda L. Sesser, Abigail J. Lynch

The increasing uncertainty with global change often stifles action and results in calls for more data before moving beyond status quo environmental decisions (Mahapatra & Ratha 2017; Ripple et al. 2017; Montefalcone et al. 2025). Advancing science and collecting more data is crucial; however, science alone (i.e., “western” or “positivist” science, as described in Fuller, 2001; Reid et al. 2020) may be insufficient to reduce uncertainty to a comfortable level for decision making. Therefore, increasing personal and collective capacity to make proactive decisions may require decision makers to recognize that their own understanding of the world, and therefore interpretation of scientific data, is influenced by all Four Realms of human perception: Physical, Mental, Emotional, and Transcendental (Wolf 2017; Dukes et al. 2021; Clifford et al. 2022). In the ESA Special Session, Action in Uncertainty, we introduced four questions to help participants increase cognitive awareness of how all Four Realms may affect their understanding in uncertain environmental decision contexts: 1. Physical: How do I observe uncertainty through the five senses (feel, see, hear, taste, smell)? The physical realm is what people observe, including ecological data observations and experimentation. 2. Mental: How do I think about uncertainty using logic, reason, and language-based understanding? The mental realm is how people think about the world, including scientific theory, modeling, and decision frameworks. 3. Emotional: How do I feel in uncertainty? The emotional realm is a person’s subjective emotional state, such as fear, curiosity, defensiveness, and awe. 4. Transcendental: How do I connect to something greater than myself in uncertainty? The transcendental realm includes people’s sense of purpose, responsibility for others, or moral code.

Released February 18, 2026 07:44 EST

2026, Nature 629-635

Kelley R. Bassett, Stefan F. Hupperts, Sandra Jämtgård, Lars Östlund, Jonas Fridman, Steven S. Perakis, Michael J. Gundale

Anthropogenic nitrogen (N) pollution has been emphasized as a cause of eutrophication globally. However, several recent datasets have suggested widespread oligotrophication may be occurring in some ecosystems, which is suggested to be a response to rising atmospheric carbon dioxide (eCO₂). Plant δ¹⁵N chronologies have served as primary evidence for oligotrophication, however, there has been wide disagreement whether eCO₂ or temporal changes in N deposition explain these patterns. We constructed δ¹⁵N tree ring chronologies across Sweden’s 23.5 million hectare productive forest area from the 1950s to 2010s. The study area spans a 1500 km latitudinal distance where N deposition varies four-fold, but where eCO₂ is spatially uniform. Our data revealed negative δ¹⁵N chronologies throughout Sweden, including forests in the far north where atmospheric N deposition rates are very low. Linear mixed effects models showed that eCO₂ was by far the strongest predictor of δ¹⁵N values, whereas N deposition variables, temperature, and forest basal area had much lower explanatory power. Our results clarify debates on the interpretation of previous δ¹⁵N chronologies, and provide clear evidence that eCO₂ is causing oligotrophication in boreal forests, which has implications for predicting their future role as sinks in the global carbon cycle.

Released February 17, 2026 13:05 EST

2026, Open-File Report 2026-1062

Peter M. Valley, Mercer Parker, Gregory J. Walsh, Randall C. Orndorff, Matt S. Walton Jr., E. Allen Crider, Jr.

Introduction 

The bedrock geology of the 7.5-minute Port Henry quadrangle consists of deformed and metamorphosed Mesoproterozoic gneisses of the Adirondack Highlands unconformably overlain by weakly deformed lower Paleozoic sedimentary rocks of the Champlain Valley. The Mesoproterozoic rocks occur on the eastern edge of the Adirondack Highlands and represent an extension of the Grenville Province of Laurentia. Mesoproterozoic paragneiss, marble, and amphibolite hosted the emplacement of an anorthosite-mangerite-charnockite-granite (AMCG) suite, now exposed mostly as orthogneiss, at approximately 1.18–1.15 Ga (giga-annum). In the Port Henry quadrangle, the AMCG metaigneous rocks (Yhg, Ygb, Yanw) intruded older, mostly metasedimentary rocks of the Grenville Complex during the middle to late Shawinigan orogeny (~1,160–1,150 Ma [mega-annum]). All rocks were subsequently metamorphosed to upper amphibolite to granulite facies conditions during the 1,080–1,050 Ma Ottawan orogeny. New mapping reveals four periods of deformation: (1) D1 produced rarely preserved isoclinal folds in the paragneiss and marble and predates AMCG magmatism. (2) Subsequent D2 deformation produced the dominant gneissic fabric preserved in the rock, recumbent folding, and deformed all the Proterozoic units in the map area. Syn- to late-D2 felsic magmatism resulted in the regionally extensive Lyon Mountain Granite Gneiss, which hosts numerous magnetite ore bodies. (3) Mylonitic extensional shear zones and core complex formation marked the beginning of D3 deformation. Protracted D3 deformation resulted in F3 upright folding, dome and basin formation, pegmatite intrusion, reactivation of the S2 foliation, partial melting, metamorphism, metasomatism, iron-ore remobilization, and intrusion of magnetite-bearing pegmatite both as layer-parallel sills and crosscutting dikes. (4) D4 created northeast- and northwest-trending local high-grade ductile shear zones and boudinage, northwest-trending regional kilometer (km)-wide ductile shear zones, and crosscutting granitic pegmatite dikes. The development of the late-stage regional shear zones (D4) was likely due to the continuation of extensional doming and uplift from upper amphibolite facies conditions at the end of the Ottawan orogeny. The majority of iron-ore deposits in the Port Henry and adjacent Witherbee quadrangles are in the hanging wall of these extensional shear zones. In the Port Henry quadrangle, the km-wide Cheney Mountain shear zone is the result of D4 deformation. Kilometer-scale lineaments readily observed in lidar data are Ediacaran mafic dikes and Phanerozoic brittle faults. The Paleozoic rocks are part of the Early Cambrian to Late Ordovician carbonate bank on the ancient margin of Laurentia. The approximately 1-km-thick Cambrian to Ordovician stratigraphy records a transition from synrift clastics to passive-margin peritidal carbonate buildups to gradually deeper-water subtidal- to shelf-carbonates during foreland basin development associated with the Taconic orogeny. The Paleozoic rocks are weakly folded and block faulted. Large areas of the Champlain Valley are covered by undifferentiated glacial deposits, some of which contain mapped landslides. The map also shows waste rock piles and tailings from historical mining operations.

This study was undertaken to improve our understanding of the bedrock geology in the Adirondack Highlands, establish a modern framework for 1:24,000-scale bedrock geologic mapping in the Adirondacks, provide a context for historical iron mines in the eastern Adirondacks, and update the stratigraphy of the Champlain Valley in New York and Vermont. This Open-File Report includes a bedrock geologic map; a description of map units; a correlation of map units; and a geographic information system database that includes bedrock geologic units, faults, outcrops, and structural geologic information.

Released February 17, 2026 10:28 EST

2026, New Zealand Journal of Geology and Geophysics (69)

Leighton Watson, Aubrey Miller, Jacob F. Anderson, Liam Toney, Alberto Ardid

Snow avalanches pose considerable hazards to people and infrastructure in alpine environments. Traditional avalanche monitoring relies on meteorological data and visual observations, which can be limited in scope and timeliness. Infrasound offers a promising complementary monitoring tool by detecting the low-frequency sound waves generated by avalanches. Here, we present infrasound and camera observations during a 50-day field campaign in the Hooker Valley of Aoraki/Mount Cook National Park, New Zealand. Our study detected seven avalanches with the cameras, whereas the infrasound system identified only one of these events, which was the largest and occurred under conditions that likely favoured infrasound propagation. The infrasound system recorded numerous other events not captured by the cameras, indicating the benefit of further investigation to determine their sources. These findings highlight the potential of infrasound technology for detecting avalanches and providing broad spatial coverage, capturing events in areas not monitored by cameras, while also showcasing limitations in infrasound capabilities. The limited detection of smaller avalanches underscores the opportunity for further research to enhance detection capabilities and understand environmental influences such as snow cover and wind noise. Overall, this study emphasises the utility of multidisciplinary monitoring techniques to improve avalanche detection in alpine environments.

Released February 17, 2026 09:31 EST

2026, Journal of Biogeography (53)

Christopher D Cousins, Deanna H Olson, Lindsay S Millward, Michael J. Adams, Christopher Pearl, Jennifer Rowe, Tiffany S Garcia

Aim

Aims of the study are to examine patterns of range-wide genetic differentiation and population structure in a headwater obligate salamander living in a geologically rich region, to identify genetically distinct populations and areas of gene flow between them.

Location

Oregon and Washington in the Pacific Northwest, United States of America.

Time Period

Tissue samples were collected in 2022 and 2023.

Major Taxa Studied

The Cascade torrent salamander Rhyacotriton cascadae.

Methods

Utilisation of a genome-wide single nucleotide polymorphism (SNP) dataset from across the species range to conduct a principal components analysis (PCA), Bayesian model of population structure, co-ancestry matrix, phylogenetic tree and estimate genetic diversity.

Results

There are extensive levels of population structure within R. cascadae, including a previously unknown and highly differentiated clade. Structure is characterised by an island-like pattern wherein the species is comprised of six populations that function as independent demographic units, with gene flow largely constrained within populations.

Main Conclusions

Our findings reveal cryptic population structure within R. cascadae, identifying six distinct populations across the range. The northernmost population in the northwest of the species range in Washington is surprisingly highly divergent from the other five populations, and the divergence was not previously known to science. While major rivers act as phylogeographic boundaries between some populations, these boundaries appear to not always be complete.

Released February 17, 2026 07:57 EST

2026, Environmental Research Letters (21)

Ryan Matthew Riggs, Jesse E. Dickinson, Craig B. Brinkerhoff, Md. Safat Sikder, Jida Wang, Huilin Gao, George H. Allen

Due to a lack of management operations data, hydrological models may represent reservoirs as natural lakes, leading to poor discharge predictions in regulated basins. To parse seasonal operational signatures, we compare the dynamics of natural lake and reservoir systems across North America using Surface Water and Ocean Topography (SWOT) satellite observations and derived discharge estimates. Overall, reservoirs and their adjacent river reaches exhibit significantly greater variability (in standard deviation) than their natural counterparts across almost all SWOT observed (e.g. water surface elevation) and inferred (e.g. discharge) variables. Natural lakes show strong same-day correlations between inflow and outflow discharge (median Spearman R = 0.8), whereas 76% of reservoirs exhibit maximum correlation when outflow is lagged, suggesting operations buffer seasonal flow variability. Our findings indicate operations not only affect reservoir dynamics themselves but also have upstream and downstream consequences, which, when integrated into models, will offer more realistic hydrologic conditions.

Released February 16, 2026 08:34 EST

2026, Coral Reefs

Karen L. Neely, Christina A. Kellogg, Julie Jenice Voelschow, Allison R. Cauvin, Sydney A.M. Reed, Ewelina Rubin, Julie L. Meyer

The decimation of reefs from stony coral tissue loss disease prompted the use of a topical amoxicillin treatment to prevent coral mortality. Application of this treatment led to concerns about unintentional impacts such as potential alteration of the coral microbiome and possible spread of antibiotic resistance. We used three different methodologies—microbial RNA sequencing, 16S rRNA amplicon surveys, and microbial qPCR array—to assess these concerns and to establish a baseline of antibiotic resistance genes (ARGs) in untreated coral microbes. We conducted microbial RNA sequencing on wild Montastraea cavernosa coral mucus samples collected before and 24 h after amoxicillin application. While diverse antibiotic resistance genes (ARGs) were expressed, no differences in ARG expression were detected after amoxicillin treatment. Additionally, there were no notable changes in the microbial communities between the before and after samples. In a separate experiment, a microbial qPCR array was used to assess differences in ARGs over longer timescales using cores from wild Colpophyllia natans, comparing never-treated corals with ones treated a single time seven months prior and with those treated multiple times seven months and more prior. No clinically relevant ARGs were detected across any samples. A small number of above-detection reads (4 in the never-treated corals, 2 in the once-treated corals, and 0 in the multi-treated corals) may indicate weak amplification of similar environmental (non-anthropogenic) ARGs in the corals. Results indicate that the localized topical application of amoxicillin to prevent mortality of SCTLD-affected corals does not: (1) significantly disrupt microbiomes, (2) increase ARG expression in adjacent tissues of these species within 24 h, nor (3) increase abundance of clinically relevant ARGs over a 7 month time period.

Released February 14, 2026 09:59 EST

2026, Harmful Algae (154)

Daniel Killam, Keith Bouma-Gregson, Martha Sutula, Raphael Kudela, James Hagy, Stephanie Anderson, David Senn

Harmful Algal Blooms (HABs) are a hazard for coastal environments worldwide; identifying screening thresholds of chlorophyll-a (chl-a) associated with increased risk of HABs is a management priority. Molecular surveillance of coastal phytoplankton and bivalve biotoxins could be used to link chl-a with HAB risk, but requires an understanding of whether the HAB risks increase uniformly as chl-a rises, or whether some taxa are disproportionately favored, and if these relationships vary by season. In this study, we present a novel use of molecular abundance data to investigate the scientific bases for estuarine chl-a thresholds protective against HABs. In San Francisco Bay (SFB), California, the relationship between molecular relative abundance (as measured by 18S metabarcoding) of nine different HAB taxa, absolute quantitative polymerase chain reaction (qPCR) abundance, and mussel toxin concentrations of a subset of the taxa were investigated for thresholds as a function of increasing chl-a. Our results show most HAB taxa did not increase in absolute or relative abundance during SFB’s spring bloom interval, when chl-a levels were highest (>10 µg/L) but the assemblage was dominated by non-harmful diatoms. However, several flagellated, mixotrophic taxa did increase above their molecular baseline in fall, and the combined probability of any HAB occurring above baseline was elevated when chl-a reached ∼4.6 µg/L in the fall. This work demonstrates the promise of molecular approaches in disentangling the seasonally complex interplay between stressors and phytoplankton/HAB community responses and has the potential to provide clearer, more cost-effective monitoring and mitigation strategies for managers.

Released February 13, 2026 11:09 EST

2026, Scientific Investigations Report 2026-5124

Richard J. Huizinga, Benjamin C. Rivers

Bathymetric and velocimetric data were collected by the U.S. Geological Survey, in cooperation with the Missouri Department of Transportation, near 8 bridge crossings of the Missouri River near Kansas City, Missouri, on August 8–9, 2023. A multibeam echosounder mapping system was used to obtain channel- bed elevations for river reaches that extended about 1,550 to 1,640 feet longitudinally and generally extended laterally across the active channel from bank to bank during low floodflow to nonflood conditions. These surveys provided the channel geometry and hydraulic conditions of the river at the time of the surveys and provided characteristics of scour holes, which may be useful in developing or verifying predictive guidelines or equations for computing potential scour depth. The data collected from the surveys may also be useful to the Missouri Department of Transportation as a record of low floodflow conditions in regards to the stability and integrity of the bridges with respect to bridge scour. Bathymetric data were collected around every in- channel pier. Scour holes were at most piers where bathymetry could be obtained, except for those piers on banks or surrounded by riprap. All the bridge sites in this study were surveyed and documented in previous studies.

The average difference between the bathymetric surfaces ranged from 0.07 to 4.16 feet higher in 2023 than 2019, which indicates overall deposition between the survey dates, as might be expected based purely on streamflow at the time of the survey. However, the average difference between the bathymetric surfaces ranged from 1.44 feet higher to 1.88 feet lower in 2023 than 2015, which indicates a dynamic equilibrium of scour and deposition overall between those surveys, despite the lower flow conditions in 2023. Similarly, the average difference between the bathymetric surfaces ranged from 3.18 feet higher to 5.19 feet lower in 2023 than 2011, which indicates a relative equilibrium between scour and deposition overall, albeit the trend was toward scour as might be expected because of the substantial flood event in 2011.

Riprap blankets and alignment to flow had a substantial effect on the size of the scour hole for a given pier. Piers that were partially or fully surrounded by riprap blankets had scour holes that were substantially smaller (to nonexistent) compared to piers with no rock or riprap and effectively mitigated the scour holes historically observed at these piers. Several of the structures had piers that were skewed to primary approach flow. At most of the structures, the scour hole was deeper and longer on the side of the pier with impinging flow than the leeward side, with some amount of deposition on the leeward side, as typically observed at piers skewed to approach flow.

Released February 13, 2026 09:08 EST

2026, Preprint

John R Mullaney, Janet R. Barclay, Jennifer S. Stanton, Carl S Carlson, Madeleine Holland

Hydrologic models for the Wards Brook valley near Fryeburg, Maine were developed for historical (2016 – 2021) and hypothetical future conditions (2046 – 2065 and 2080 – 2099) to understand the effects of groundwater withdrawals for bottled water and municipal use on hydrologic conditions (stream base flows and groundwater levels). Analyses showed that the simulated base flows in Wards Brook were reduced because of pumping for both municipal water supplies and for water bottling, and about half of the total pumping impact on the base flows in Wards Brook was from the bottled water extraction. Simulated flows were greater than the minimum recommended streamflow of 2,180 cubic meters per day (400 gallons per minute) throughout the historical period. Simulated groundwater levels at two of three nearby ponds (Round Pond and Davis Pond) were minimally affected by pumping conditions, and effects were primarily from the municipal well closest to the ponds.

Several estimates of future projected recharge were used to understand the potential effects of groundwater withdrawals on hydrologic conditions under multiple hypothetical climate conditions. Annual projected recharge rates in the mid- and late-21st century from two climate scenarios (stabilized greenhouse-gas emissions and high greenhouse-gas emissions) were similar to rates for 2016 – 2021. However, monthly recharge patterns for the future periods shifted toward more recharge in the winter months (December, January, and February) and less recharge in April, May, and October relative to 2016 – 2021.

The lowest mean monthly base flows from the future emission scenarios all remain larger than the minimum recommended streamflow and indicate no long-term declines in flow relative to historical conditions. However, simulated base flows during hypothetical 3-year drought scenarios declined below minimum recommended streamflow during the summer months in the stabilized- and high-emission scenarios in the mid-21st century. Although water is generally plentiful in the Wards Brook valley, reduced pumping may be needed to maintain streamflows in Wards Brook under future climate conditions similar to modeled drought scenarios.

Released February 12, 2026 11:03 EST

2026, Ecology and Evolution (16)

Lara S. Katz, Stephen M. Coghlan Jr., Matthew A. Carpenter, Michael T. Kinnison, Joseph D. Zydlewski

We sought to assess bridle shiner (Notropis bifrenatus) habitat associations at local and regional scales across southern Maine and New Hampshire. We used local habitat data at 95 Maine sites to predict occupancy with classification and regression trees (CART). We then used ensemble species distribution models (SDMs) to model the historical (1898–2008) and current (2009–2022) ranges of the species. We used the BIOMOD platform to model the association between 35 environmental variables and bridle shiner presence during both time periods and at fine (pseudo-HUC14) and coarse (HUC12) spatial scales. We then calculated the change in predicted occupied drainages to estimate the change in the species' distribution at both scales. Within a site, bridle shiners were associated with submerged aquatic vegetation, organic substrate, and watermilfoil (Myriophyllum spp.). SDMs revealed an association with Appalachian (Hemlock-)Northern Hardwood Forest, sand substrate, and low-elevation terrain (at both spatial scales). Ensemble fine-scale SDMs suggest a substantial loss of historical bridle shiner habitat in both Maine (36% of drainages) and New Hampshire (16%), with comparable described losses (of 21% and 14%) at a coarse scale. Our local and regional models may be used to focus surveys on areas with high predicted habitat suitability or to inform habitat restoration efforts.

Released February 12, 2026 09:51 EST

2026, Geoenergy Science and Engineering (260)

C. Ozgen Karacan, Emil Attanasi, Sean T. Brennan, Peter D. Warwick

Released February 12, 2026 08:12 EST

2026, PLOS Water (5)

Jennifer S. Stanton, Michael J. Stephens, Matthew K. Landon, David H. Shimabukuro, Andrew G. Hunt, Justin T. Kulongoski, Isabelle M. Cozzarelli, Theron A. Sowers

Alluvial valley aquifers are important sources of water supply in many areas but effects of co-located oil and gas development on these resources have not been widely reported, especially in settings where recharge is dominated by stream infiltration. Interpreting the presence of geochemical indicators in the context of hydrology, geology, and other factors provides a more complete understanding of the relations between groundwater and sources of oil-field fluids and aids in identifying risks associated with oil and gas development. Groundwater and Salinas River water samples were collected in an alluvial valley near the San Ardo Oil Field in Monterey County, California and analyzed for a wide range of dissolved chemical, gas, and isotopic constituents to determine if oil-field fluids (water and gas from oil-producing and non-producing zones) have mixed with fresh groundwater used for supply. Hydraulic gradients, age-dating tracers, and other geochemical indicators show that recharge from the Salinas River has the potential to dilute oil-field fluids that might migrate or seep into the aquifer. Groundwater and Salinas River water collected downgradient of the San Ardo Oil Field showed little or no evidence of mixing with oil-field fluids. Some samples within the oil field contained trace amounts of hydrocarbons or elevated temperatures, indicating that any potential effects from oil-field activities are minor or have been diluted by recharge from the Salinas River. The two samples with the most geochemical evidence of potential mixing with oil-field fluids (SP-18 and GW-17) were collected west of or along the Los Lobos fault, where naturally occurring hydrocarbons are near the land surface. Those samples are also near active or inactive oil-field wells, and so anthropogenic activities and pathways cannot be ruled out as a cause of trace detections of hydrocarbons and elevated temperatures in the aquifer.

Released February 12, 2026 07:35 EST

2026, Ecological Informatics (94)

Charles J. Labuzzetta, Arnold (Contractor) Johnsen, Amber Andress, Teresa Bohner, Alejandro Grajal-Puche, Megan Seymour, Bethany R. Straw, Wayne E. Thogmartin, Bradley James Udell, Ashton M. Wiens, James Diffendorfer

Bats provide critical ecosystem services, but bat fatalities due to wind energy development may imperil some bat populations. Statistical models are used to estimate the total fatalities that occur based on carcasses observed during monitoring surveys. Current models often estimate fatalities aggregated across species, time, and/or turbines, but fall short of reliably informing siting and operational collision mitigation strategies that account for species-specific fatality patterns on a fine spatiotemporal scale. We developed a hierarchical mixture model for estimating species-specific covariate effects and total fatalities per species at each turbine on weekly intervals. We applied the model to a high-resolution dataset of bat carcasses found during turbine searches across nineteen wind facilities in Iowa over two years. Our model explains species-specific variation in bat fatalities at individual wind turbines according to turbine proximity to bat habitat, turbine design specifications, seasonal trends, and weather conditions such as nightly air temperature, air pressure, and wind speed. Turbines located on the edge of wind facilities had higher fatalities, and proximity to roosting and foraging habitat accounted for variation in species-specific fatality estimates. These insights into turbine placement effects can inform siting strategies. We also discovered species-specific relationships with average nightly wind speed and air temperature, among other weather conditions, that could inform operational mitigation strategies such as smart curtailment. Our model can transform observations of carcasses found during turbine searches across multiple facilities, years, and variable search efforts into estimates of total fatalities per species associated with species-specific spatial, temporal, and environmental covariate effects.

Released February 11, 2026 11:50 EST

2026, Fact Sheet 2026-3062

Christopher J. Schenk, Sarah E. Gelman, Jane S. Hearon, Tracey J. Mercier, Phuong A. Le, Andrea D. Cicero, Benjamin G. Johnson, Jenny H. Lagesse, Heidi M. Leathers-Miller

Using a geology-based assessment methodology, the U.S. Geological Survey estimated undiscovered, technically recoverable mean conventional resources of 10.4 billion barrels of oil and 53.3 trillion cubic feet of gas in the Santos Basin, Campos Basin, and Espírito Santo Basin provinces of Brazil.

Released February 11, 2026 08:33 EST

2026, Journal of Soils and Sediments (26)

Gregory D. Clark, Michael W. Suplee, Haylie M. Brown, Molly A. Moloney, Rodney R. Caldwell

Purpose

Eutrophication and nuisance filamentous algal blooms (i.e. Cladophora) are increasingly common occurrences throughout much of the western United States. Wildfire may be contributing to the frequency and magnitude of algal blooms through excess sediment and nutrient loading to streams and rivers. Our objective was to evaluate the effects the 2021 Woods Creek Fire had on sediment yields and phosphorus (total and bioavailable) partitioning in Camas Creek, a major tributary to the Smith River in Montana where Cladophora are now consistently reaching nuisance levels.

Methods

We collected water quality samples during snowmelt pulsing events as well as fixed interval sampling using an established U.S. Geological Survey stream gage instrumented with a continuous water quality sonde and an automatic peristaltic pump sampler. Water samples were processed for total phosphorus (TP), sediment-bound bioavailable phosphorus (S-BioP), soluble reactive phosphorus (SRP), and suspended sediment concentrations and were evaluated using linear regression and other nonparametric statistical tests. Continuous turbidity and streamflow were evaluated using hysteresis analysis to determine sediment sourcing and connectivity.

Results

We found that the Woods Creek Fire did not significantly influence TP and S-BioP in Camas Creek. However, there was a significant increase in SRP and turbidity in both postfire years (2022 and 2023). Hysteresis analysis of 91 delineated events indicated positive (clockwise) hysteresis was the dominant event pattern during the snowmelt period. This may indicate a lower hillslope to channel connectivity, with the major sediment supply originating from the channel and/or riparian areas.

Conclusion

Results from this study demonstrate the benefits of combining discrete water quality samples with high-frequency turbidity sensors to characterize postfire sediment and phosphorus dynamics. While a lack of postfire response in TP and S-BioP is contrary to many other studies, our findings highlight the role climate and catchment morphology play in attenuating a disturbance effect.

Released February 11, 2026 08:10 EST

2026, Nature Communications (17)

Carol Wilson, Tracy Quirk, Donald R. Cahoon, Gregg A. Snedden, Leigh Anne Sharp

No abstract available. 

Released February 11, 2026 08:04 EST

2026, Fisheries Management and Ecology

Justin M. Sturtz, Benjamin J. Schall, Matthew J. Ward, Cody E. Treft, Steven R. Chipps, Christopher A. Cheek

Isotope values in fish eye lenses may be useful in differentiating rearing origins. We compared eye lens isotopic values of fall fingerling age-0 walleye (Sander vitreus) reared in a hatchery pond, a recirculating aquaculture system (RAS), and a natural lake. Using 10 fish per rearing source, we delaminated layers from one eye lens per fish to assess temporal changes in carbon (δ¹³C) and nitrogen (δ¹⁵N) and pulverized the whole second eye lens for δ¹³C, δ¹⁵N, and sulfur (δ³⁴S). RAS-reared walleye values exhibited high precision among individuals and were δ³⁴S enriched. Pond-reared walleye had lower δ¹³C and δ¹⁵N core values compared to other rearing sources. For δ¹³C and δ¹⁵N, values remained consistent among layers for RAS-reared walleye, δ¹⁵N slightly increased for pond-reared and lake-reared walleye, and δ¹³C increased substantially among subsequent layers in pond-reared walleye. Bayesian 95% ellipses did not overlap among rearing sources. These results demonstrate that eye lens stable isotope analysis may be a useful tool for differentiating hatchery-reared and wild large fingerling walleye, specifically from RAS- and pond-reared sources.

Released February 10, 2026 08:00 EST

2026, Scientific Investigations Report 2025-5018-A

Christine D. Miller Hesed, Heather M. Yocum, editor(s)

Understanding how climate change and variability will impact grassland ecosystems is crucial for successful grasslands management in the future. In 2020, the North Central Climate Adaptation Science Center began a project to establish a baseline of information to best serve grassland managers (that is, those individuals who develop grassland management plans, implement those plans on the ground, or both) at Federal, State, and Tribal agencies; nongovernmental organizations; and partnerships to help meet regional grassland management goals. This chapter presents the main findings from the review and synthesis of 183 grassland management-related documents relevant to the North Central region. Specifically, this chapter describes the methods by which grassland management-related documents were identified, reviewed, and synthesized; defines five North Central Grassland Ecoregions; provides a synthesis of regional grassland management goals and challenges; identifies information needs relevant to grassland management in a changing climate; and summarizes grassland management issues by ecoregion. 

Released February 10, 2026 07:58 EST

2026, Conservation Science and Practice

Shane Flinn, Andrew M. Muir, Kelly Filer Robinson

Dams have dramatically altered rivers and are a major contributor to native fish population declines. However, many dams serve important ecological, social, and economic functions, such as flood control, invasive species control, and provision of recreational opportunities. Therefore, dam removal is often contentious among stakeholders and involves making tradeoffs among multiple competing objectives. This research uses structured decision making to evaluate the ecological, social, and economic consequences and tradeoffs of enhancing connectivity for migratory fishes in the Boardman River, Michigan. We describe efforts to engage a diverse group of stakeholders to elicit their objectives under various fish passage alternatives. We used multi-attribute tradeoff methods to help stakeholders weigh the costs and benefits of enhancing connectivity for several fish species with varying life history traits and initial distributions. We found that the optimal alternative was passage of native fishes only; however, the optimal alternative varied based on the weight stakeholders might place on each objective. We created four objective weighting scenarios to evaluate the sensitivity of the optimal alternative to changes in objective weights. This research will help inform decision-makers on fish passage alternatives that are preferred by stakeholders and that are likely to achieve their objectives.

Released February 10, 2026 07:54 EST

2026, Seismological Research Letters (97) 619-625

Trevor I. Allen, Susan E. Hough, Oliver S. Boyd, Felix Waldhauser, Marcelo Assumpcao

More than a half century after plate tectonics provided an overarching framework to explain earthquakes along active plate boundaries, numerous theories have been proposed to explain where, why, and how often earthquakes occur well away from active plate boundaries, but a paradigm remains elusive. Even the classification of earthquakes away from active plate boundaries as "intraplate" raises issues, with potentially important distinctions between Stable Continental Regions and more actively deforming regions including passive margins and failed rifts. Some of the largest known intraplate earthquakes themselves remain enigmatic, having occurred before the modern instrumental era. Hazard assessments are often data-limited: low fault-slip rates relative to landscape modification rates result in poor discoverability of fault sources, challenging the characterization of source zones and earthquake recurrence; the completeness and homogenization of instrumental earthquake catalogs using uncertain magnitude conversions can lead to uncertainties in earthquake recurrence; and, limited strong-motion observations for large-magnitude events at near-source distances leads to uncertainties in the selection and development of ground-motion models for seismic hazard studies. Data from recent intraplate earthquakes around the world—from the moment magnitude M 7.7 2001 Bhuj, India, earthquake 25 years ago to the 2024 M 4.8 Tewksbury, New Jersey earthquake—have yielded both new insights and new questions. The papers in this special focus discuss many of the long-standing challenges involved with intraplate earthquake investigations and provide a snapshot of the state of the art with current research to advance our understanding.

Released February 10, 2026 07:28 EST

2026, Environmental Research: Water

Sara Wall, Jana E. Compton, Ashley A. Coble, Beth M. Haley, Jiajia Lin, Allison Myers-Pigg, Justin Kevin Reale, Katie Wampler, Allison Swartz, Kevan Moffett, Kevin D. Bladon, Kurt Carpenter, Heejun Chang, Junjie Chen, David Donahue, Chris S. Eckley, Amanda K. Hohner, Peter M. Kiffney, Lorrayne Miralha, Peter Regier, Joshua Seeds, Mark River

An increase in the occurrence of large, high severity wildfires in the western Pacific Northwest (PNW), USA, has created an urgent need for science to better inform forest management and policy decisions to maintain source water quality in the region. The western PNW faces similar challenges to other regions with shifting wildfire regimes and large population centers reliant on surface water from forested catchments. However, the uniquely wet and highly seasonal climate of the western PNW suggests that findings from other, more frequently burned regions may not be directly applicable. To identify science, monitoring, and management gaps and opportunities in the western PNW, this review was collaboratively undertaken by academics, non-government and industry representatives, and local, state, and federal government entities who have been working together since the 2020 Labor Day fires in Oregon. Focusing on Oregon and Washington, we found that monitoring networks for continuous water quantity and quality cover much of the state with greater representation in western U.S. ecoregions, but few studies have analyzed and published these data to capture and communicate the post-wildfire response. Approximately half of the streamgages in Oregon and Washington record major water quality parameters, and hundreds of sites in the area have discrete sampling for a wide range of water quality constituents. Still, numerous gaps exist in understanding the short- and long-term impacts of wildfire on hydrology, water chemistry, including pH and dissolved oxygen, mobilization of metals, aquatic ecosystems, and downstream drinking water treatment. Collective action to further collect, analyze, interpret, and publish the key data could help improve our understanding of post-wildfire water quality impacts in this and other increasingly wildfire-affected regions.

Released February 09, 2026 12:30 EST

2026, Fact Sheet 2025-3051

Grant D. Colip

Introduction 

At the Bascom Laser Diffraction Sedimentology Laboratory, which is located in the Florence Bascom Geoscience Center at U.S. Geological Survey (USGS) headquarters in Reston, Virginia, scientists use physical sedimentology and particle characterization techniques to conduct detailed sediment characterization. Scientists address research problems in collaboration with other USGS science centers, State geological surveys, commercial industry, universities, and other partners. Laboratory capabilities include laser diffractometry for quantitative particle-size analysis, portable x-ray fluorescence (XRF) analysis for determining elemental abundances in rock or sediment samples, petrographic analysis of geologic media, and mechanical sieve analysis. These methods are used to analyze soil and sediment core material from terrestrial, marine, and lacustrine environments, surface sediments from coastal regions, and calcareous materials. Work done by the laboratory supports geologic mapping, resource assessments, land change studies, and geohazard analyses.

Released February 09, 2026 07:57 EST

2026, Journal of Volcanology and Geothermal Research (472)

Amanda L. Hughes, Joaquín A. Cortès, Dave McGarvie, Richard J. Moscati, Valerie Olive

In this work we revisit Þingmúli volcano (Þ = Th), a classic locality known as an example of a complete tholeiitic differentiation. Þingmúli is a ~ 9.5 Ma extinct central volcano located in the East Fjords of Iceland, in which the whole compositional spectrum from basalt to rhyolites have erupted. These volcanic products have been previously considered as petrogenetically related by an ideal fractionation trend, regardless any temporal relationship or volumetric considerations.

Here we report new whole-rock geochemistry, mineral chemistry, isotope analyses, estimation of residence times of the different eruptive deposits, and an update of the original petrogenetic model. Our results highlight that an enriched source, likely spinel lherzolites, generated transitional-alkaline basaltic melts after 15–20% of partial melting at depths of 40–45 km. Many of these basaltic melts erupted at various stages of the volcano's history, while others remained longer in the volcanic plumbing system. These evolved by fractional crystallisation into basaltic andesite magmas with a residence time of ~5 years based on the crystal size distribution of the plagioclase population. Isotopic differences between the basalts/basaltic andesites (⁸⁷Sr/⁸⁶Sr ~ 0.7034; ¹⁴³Nd/¹⁴⁴Nd ~ 0.51315) and the erupted rhyolites (⁸⁷Sr/⁸⁶Sr ~ 0.7037; ¹⁴³Nd/¹⁴⁴Nd ~ 0.51304) indicate that the latter are not petrogenetically related to the former. Therefore, instead of a fractional crystallisation mechanism to generate the rhyolites, we propose the partial melting of ignimbrite layers located beneath the volcano. The broad range of trace element concentrations in andesites and dacites and their different isotopic values compared to the basalts strongly suggest that these magmas have been generated by magma mixing between basaltic and rhyolitic melts, similar to modern day Icelandic volcanoes such as Hekla. These results highlight the need to revisit previously studied Icelandic classic localities and reassess their traditionally proposed petrogenetic models.

Released February 08, 2026 07:49 EST

2026, Global Sustainability (9)

Daniel Ospina, Paula Mirazo, Richard P. Allan, Smriti Basnett, Ana Bastos, Nishan Bhattarai, Wendy Broadgate, Derik J. Broekhoff, Mercedes Bustamante, Deliang Chen, Yeonju Choi, Peter Cox, Luiz A. Domeignoz-Horta, Krislie Ebi, Pierre Friedlingstein, Thomas L. Frölicher, Sabine Fuss, Helge F. Goessling, Nicolas Gruber, Qingyou He, Sophie R. Hebden, Nadja Hedrich, Adrian Heilemann, Marina Hirota, Øivind Hodnebrog, Gustaf Hugelius, Santiago Izquierdo-Tort, Sirkku Juhola, Fumiko Kasuga, Piyu Ke, Douglas I. Kelley, Şiir Kilkiș, Maximilian Kotz, Nilushi Kumarasinghe, William F. Lamb, Shih-Yu Lee, Junguo Liu, Cara N. Maesano, Maria A. Martin, Guilherme G. Mazzochini, Christopher J. Merchant, Akira S. Mori, Jennifer Morris, Åsa Persson, Hans-Otto Pörtner, Benedict S. Probst, Justine Ramage, Estelle Razanatsoa, Aaron Redman, Johan Rockström, Regina Rodrigues, Sophie Ruehr, Sadie J. Ryan, Carl-Friedrich Schleussner, Peter Schlosser, William A. Scott, Jan C. Semenza, Hansjörg Seybold, Drew T. Shindell, Giles B. Sioen, Kathryn E. Smith, Youba Sokona, Annika H. Stechemesser, Thomas F. Stocker, Sophie H.L. Su, Djiby Thiam, Gregory Trencher, Anna-Maria Virkkala, Lila Warszawski, Sarah R. Weiskopf, Henry Wu, Shupeng Zhu

Interdisciplinary understanding is vital for delivering sound climate policy advice. However, navigating the ever-growing and increasingly diverse scholarly literature on climate change is challenging for any individual researcher. This annual synthesis highlights and explains recent advances across a variety of fields of climate change research. This year, the 10 insights focus on: (1) the record-warmth of 2023/2024 and the elevated Earth energy imbalance; (2) acceleration of ocean warming and intensifying marine heatwaves; (3) northern land carbon sinks under strain; (4) reinforcing feedback between biodiversity loss and climate change; (5) accelerated depletion of groundwater; (6) global dengue incidence; (7) global income losses and labour productivity declines; (8) strategic scaling of CDR; (9) integrity challenges in carbon credit markets and emerging responses; and (10) effective policy mixes for emissions reductions. The insights have been written to be accessible to researchers from different fields, serving as entry-points to specific topics, as well as providing an overview of the evolving landscape of climate change research. In the final section, the insights are used to develop overarching policy-relevant messages. This paper provides the basis for a science-policy report that was shared with all Party delegations ahead of COP30 in Belém, Brazil.

Released February 07, 2026 10:57 EST

2026, Conservation Biology

Brian D. Erickson, Megan Siobhan Jones

In the western United States, conservation practitioners are increasingly working with private landowners to restore habitat for North American beavers (Castor canadensis) and to use nonlethal mitigation techniques when beavers damage crops and infrastructure. Effective communication is critical for promoting coexistence, yet on-the-ground conservation messaging seldom links to behavior change theories. We conducted 23 semistructured interviews with practitioners to examine the approaches they used to communicate with private landowners about beaver coexistence in Oregon (USA). Although we did not set out to interview practitioners about their messages targeting capability, opportunity, and motivation (elements of the COM-B model of behavior), we used the COM-B model to synthesize the primary dimensions of practitioners’ complex, real-world communication about human–wildlife coexistence. We found that practitioners used multiple communication channels to listen for and respond to landowners’ capability, opportunity, and motivation. They tailored messages to affirm and enhance knowledge and skills, identify and address site-specific and social contexts, and align beaver impacts with landowner goals. Our findings suggest the COM-B model can go beyond guiding audience analysis and behavioral intervention design to help practitioners tailor real-time communication with landowners about coexistence behavior. The model, based on our use of COM-B to analyze existing communication, could be used to provide practitioners with techniques for making sense of their existing communication efforts, for identifying gaps, and for dynamically tailoring their communication.

Released February 07, 2026 08:37 EST

2026, Scientific Reports (16)

Matthew S. Varonka, Aaron M. Jubb, Bonnie McDevitt, Jenna L. Shelton, Elliott P. Barnhart, Denise M. Akob, Isabelle M. Cozzarelli

Use of per- and polyfluoroalkyl substances (PFAS) in the petroleum industry could be a cause for concern due to the large volumes of produced water (PW) generated during oil and gas extraction, the reuse of these wastes in water-stressed regions, and adverse health outcomes related to PFAS exposures. However, PW PFAS characterization is nearly absent in the literature, and hydraulic fracturing (HF) chemical disclosures often omit the identities of additives as proprietary. Here we evaluate PFAS in PW samples from three petroleum wells in the Denver Basin during their first year of production. Total concentrations of targeted PFAS (Σ₄₀PFAS) were < 35 ng/L in PW samples, with short-chain PFAS like perfluorobutanoic acid persisting throughout the sampled duration. Analysis of freshwater inputs for hydraulic fracturing (Σ₄₀PFAS ~ 113 ng/L) and mixed fracture fluid (Σ₄₀PFAS ~ 69 ng/L) indicated much of the targeted PFAS content was derived from the input water, and not from HF additives, however samples subjected to oxidation indicated the presence of PFAS precursors that would not be detected by targeted analysis. This study highlights that while PFAS content is low in the studied PWs, the potential for redistribution of PFAS in the environment may be a consideration for reuse applications.

Released February 06, 2026 11:55 EST

2026, Mineral Commodity Summaries 2026

U.S. Geological Survey

Introduction 

Each mineral commodity chapter of the 2026 edition of the U.S. Geological Survey (USGS) Mineral Commodity Summaries (MCS) includes information on events, trends, and issues for each mineral commodity as well as discussions and tabular presentations on domestic industry structure, Government programs, tariffs, 5-year salient statistics, and world production, reserves, and resources. The MCS is the earliest comprehensive source of 2025 mineral production data for the world. More than 90 individual minerals and materials are covered by two-page synopses.

Abbreviations and units of measure and definitions of selected terms used in the report are in Appendix A and Appendix B, respectively. Reserves and resources information is in Appendix C, which includes “Part A—Resource and Reserve Classification for Minerals” and “Part B—Sources of Reserves Data.” A directory of USGS minerals information country specialists and their responsibilities is in Appendix D.

The USGS continually strives to improve the value of its publications to users. Constructive comments and suggestions by readers of the 2026 MCS are welcomed.

Released February 06, 2026 09:07 EST

2026, Wind Energy (29)

Joseph Rand, Louisa Kramer, Ben Hoen, James Diffendorfer, Christopher Garrity

A growing number of wind turbines (WTs) across the globe are now reaching or exceeding their expected service lifetime; WT decommissioning is on the rise. Accordingly, questions pertaining to WT end-of-life have risen in importance in policy and practice. Yet, research on the various factors relating to WT decommissioning is relatively sparse. Moreover, the key assumptions underpinning that prior research (e.g., the lifespan of WTs, characteristics of WTs being decommissioned, and whether the site is repowered with new WTs) have never been empirically tested across a large set of decommissioned WTs. Leveraging a uniquely comprehensive and spatially explicit dataset of decommissioned WTs in the United States, this research analyzes spatial, technological, and temporal trends in WT decommissioning and develops a novel predictive model for WT decommissioning. Our analysis pinpoints more than 12,400 WTs that have been fully decommissioned in the United States., the majority of which have been relatively old (> 30 years) and small (< 200 kW). While a WT's age alone is a good predictor of the likelihood of decommissioning, other factors such as the size of the WT and recent performance are also important and significant predictors. Most sites where decommissioning has occurred have seen subsequent repowering, with repowered plants featuring substantially fewer WTs (−86 on average) and higher rated plant capacity (+62 MW on average). Many existing WTs in the U.S. are approaching the end of their expected life with roughly 7500 being 20 or more years old. Findings can help policymakers and stakeholders begin preparing for this potential wave of future decommissioning and repowering.

Released February 06, 2026 08:20 EST

2026, Data Science in Science (5)

Emil Attanasi, Bonnie McDevitt, Philip A. Freeman, Timothy Coburn

Recently, the demand for battery-grade lithium has substantially increased, largely due to electrification of the transportation sector. The search for new lithium sources has turned to produced waters (frequently brines), a large-volume wastewater by-product of oil and gas extraction. Geochemical analysis indicates the presence of varying concentrations of lithium from produced water samples collected across the United States and represented in the U.S. Geological Survey’s National Produced Water Geochemical Database, as well as mixtures of Marcellus Shale produced water included in the Pennsylvania Department of Environmental Protection’s Oil and Gas Well Waste Reports. We first examined whether the geochemical signature of the lithium-bearing produced waters is sufficiently distinct so that machine learning (ML) can be used to correctly classify samples to the formation of origin. The produced water sample data used to assess classification accuracy were from the Marcellus Shale, Utica Shale and Point Pleasant Formation (Utica), and Smackover Formation oil and gas wells. Further, we evaluated the potential for ML to accurately classify Marcellus Shale produced water spatially (i.e., northeast versus southwest Pennsylvania). We then investigated whether ML algorithms applied to a suite of geochemical concentration data (i.e. Ba, Br, Cl, K, Mg, Sr) may be used to predict the lithium concentration of an unknown sample. Finally, we applied an estimated economic lithium grade cutoff of 150 milligrams per liter (mg/l) and assessed the utility of ML to predict whether a produced water sample would fall above or below the grade cutoff based on the suite of geochemical parameters. Four machine learning algorithms—Random Forest (RF), Gradient Boosting Trees (GBT), Extreme Boosting (XGBoost), and Deep Neural Networks (DNN) were assessed. This study successfully demonstrates that all four machine learning methods can precisely and accurately estimate lithium concentrations and geologic formation classification. The products of this study contribute to the growing body of knowledge aimed at expanding the lithium resource base within the United States.

Released February 06, 2026 08:03 EST

2026, Nature Ecology and Evolution

Soroor Rahmanian, Nico Eisenhauer, Yuanyuan Huang, Martin Hejda, Petr Pyšek, Hannes Feilhauer, David J. Eldridge, Nicholas Gross, Yoann Le Bagousse-Pinguet, Hugo Saiz, Manuel Delgado-Baquerizo, Miguel Berdugo, Victoria Ochoa, Beatriz Gozalo, Sergio Asensio, Emilio Guirado, Enrique Valencia, Miguel García-Gómez, Juan J. Gaitán, Betty J. Mendoza, César Plaza, Paloma Díaz-Martínez, Jaime Martínez-Valderrama, Mehdi Abedi, Negar Ahmadian, Rodrigo J. Ahumada, Fateh Amghar, Thiago Araújo, Antonio I. Arroyo, Farah Ben Salem, Niels Blaum, Enkhjargal Boldbat, Bazartseren Boldgiv, Matthew A. Bowker, Liesbeth van den Brink, Chongfeng Bu, Rafaella Canessa, Andrea P. Castillo-Monroy, Helena Castro, Patricio Castro-Quezada, Ghassen Chaieb, Roukaya Chibani, Abel A. Conceição, Yvonne C. Davila, Balázs Deák, David A. Donoso, Andrew David Dougill, Carlos Iván Espinosa, Alex Fajardo, Mohammad Farzam, Daniela Ferrante, Jorgelina Franzese, Lauchlan H. Fraser, Erika L. Geiger, Sofia Laura Gonzalez, Elizabeth Gusman Montalván, Robert Hering, Eugene Marais, Rosa Mary Hernández, Sandra Daniela Hernández-Valdez, Norbert Hölzel, Elisabeth Huber-Sannwald, Oswaldo Jadán, Anke Jentsch, Liana Kindermann, Melanie Köbel, Peter C. le Roux, Cintia V. Leder, Xinhao Li, Pierre Liancourt, Anja Linstädter, Jushan Liu, Michelle A. Louw, Gillian Maggs-Kölling, Thulani P. Makhalanyane, Oumarou Malam Issa, Antonio J. Manzaneda, Pierre Margerie, Raphaël Martin, Mitchel P. McClaran, João Vitor S. Messeder, Juan P. Mora, Gerardo Moreno, Seth M. Munson, Girish R. Nair, Alice Nunes, Gabriel Oliva, Salza Palpurina, Guadalupe Peter, Yolanda Pueyo, Emiliano Quiroga, Sasha C. Reed, Pedro J. Rey, Alexandra Rodríguez, Victor Rolo, Jan C. Ruppert, Ayman Salah, Shlomo Sarig, Brajesh K. Singh, Anthony M. Swemmer, Alberto L. Teixido, Andrew D. Thomas, Katja Tielbörger, Samantha K. Travers, Orsolya Valkó, Wanyoike Wamiti, Deli Wang, Lixin Wang, Glenda M. Wardle, Peter Wolff, Laura Yahdjian, Gastón R. Oñatibia, Reza Yari, Eli Zaady, Yuanming Zhang, Xiaobing Zhou, Fernando T. Maestre

Drivers of non-native plant success in drylands are poorly understood. Here we identify functional differences between dryland native and non-native perennial plants and assess how biotic, abiotic and anthropogenic factors shape the success of the latter. On the basis of plant community and functional trait data from 98 sites across 25 countries, we report a total of 41 non-native plant species at 31 sites. Non-natives tend towards faster growth strategies than natives. Non-native plant richness is higher at sites with greater grazing pressure and under environmental conditions associated with higher soil fertility, decomposition and fungal richness—conditions that tend to occur in less arid regions—and lower where native plant and herbivore richness are greater. Non-native plant cover correlates positively with grazing pressure and negatively with native plant richness. Taken together, our results suggest that non-native plant success in drylands is facilitated when high grazing pressure coincides with elevated resource availability. Such context-dependence of non-native plant success and linkages with native plant and herbivore diversity highlight the need for managing grazing and conserving biodiversity across the world’s drylands.

Released February 05, 2026 08:41 EST

2026, Scientific Investigations Report 2025-5104

Daniel M. Wagner, David E. Ladd

In 2024, the U.S. Geological Survey, in cooperation with the Tennessee Department of Transportation, updated the methods for predicting the magnitude and frequency of floods at ungaged locations on streams in urban areas in Tennessee. The study area included 136 streamgages in urban areas in Tennessee, Mississippi, Alabama, Georgia, South Carolina, and North Carolina that had at least 10 percent developed imperviousness in their basins as indicated by data from the 2011 National Land Cover Database. Regression equations were developed to predict streamflows corresponding to the 50-​, 20-​, 10-​, 4-​, 2-​, 1-​, 0.5-​, and 0.2-​percent annual exceedance probabilities (AEPs) and were incorporated into the StreamStats application. In generalized least-​squares regression, the base-​10 logarithm of drainage area, the percentages of the streamgage basins in developed land use, and the percentages of the streamgage basins in the Piedmont and Ridge and Valley Level 3 ecoregions were statistically significant in explaining the variability in annual peak streamflows in the study area. Drainage areas ranged from 0.164 to 93.4 square miles, the percentage of the streamgage basins in developed land use ranged from 26 to 100 percent, and the percentage of the streamgage basins in Piedmont and Ridge and Valley Level 3 ecoregions ranged from 0 to 100 percent. Pseudo R-​squared values for the regression equations ranged from 0.86, or 86 percent, for the 50-​ and 20-​percent AEPs (2-​ and 5-​year floods) to 0.71, or 71 percent, for the 0.2-​percent AEP (500-​year flood). The average variance of prediction (in log base-​10 units) ranged from 0.023 for the 20-​ and 10-​percent AEPs to 0.05 for the 0.2-​percent AEP. The average variance of prediction can be reported as a percentage of the predicted value, known as the standard error of prediction, which ranged from 35.8 percent for the 20-​percent AEP (5-​year flood) to 55.4 percent for the 0.2-​percent AEP (500-​year flood). Methods are presented for estimating annual peak streamflows for gaged locations, ungaged locations on gaged streams, and locations on ungaged streams.

Released February 05, 2026 07:57 EST

2026, Hydrological Processes (40)

Emily C. Palmquist, Pamela Nagler, Kiona Ogle, Claudia DiMartini, Jeffrey R. Kennedy, Joel B. Sankey

Assessing riparian ecosystem water use, particularly transpiration from vegetation and evaporation from soils (‘plant water use’, hereafter), is key to developing sound water management approaches. In western North America, a multidecadal drought is reducing water availability and increasing the use of detailed water budgets. Questions related to both removal of vegetation for water salvage and budgeting water to maintain valuable riparian areas have led to a wealth of studies on riparian plant water use across dryland river systems in North America. Towards evaluating broad patterns in riparian plant water use, we synthesise results from over two decades of research, with the goal of informing water management policies and planning. This study asks: (1) Do some riparian plant communities exhibit lower plant water use than others? (2) Do riparian plant communities have higher water use under hotter climates? (3) Can statistical models based on existing data, plant communities and climate data be used to predict water use for unmeasured locations? Using hierarchical Bayesian models to synthesise data on annual and daily-scale plant water use, we show that marshes, cottonwood-willow stands and tamarisk not impacted by biocontrol use larger amounts of water at the annual scale than other vegetation communities. All plant communities have higher annual water use in hotter climates, which is likely related to a longer growing season and higher evaporative demand. Statistical models based on existing water-use data, plant communities and climate provide bounds on plant water use that can be applied to unmeasured locations and used to evaluate the effects of plant community change on water use. This synthesis produces the most complete summary of riparian plant water use in North American drylands to date and provides water use predictions across different climate and community scenarios that can be used for current and future conditions.

Released February 04, 2026 15:25 EST

2026, Scientific Investigations Report 2025-5112

Chad J. Ostheimer, Legna M. Torres-Garcia, Julieta M. Gomez-Fragoso

Digital flood- inundation maps for a 2.7- mile reach of Río Grande De Loíza in Caguas, Puerto Rico, were created by the U.S. Geological Survey. Water- surface profiles were computed for the stream reach by using a one- dimensional, steady- state, step- backwater model. The model was calibrated to the current (2025) stage- streamflow relation (rating curve) for the U.S. Geological Survey streamgage 50055000, Río Grande De Loíza, Puerto Rico. The resulting hydraulic model was then used to compute 16 water- surface profiles for water levels (flood stages) ranging from 19.00 to 34.00 feet at the streamgage; these flood stages range from “moderate flood stage” to above “major flood stage” as defined by the National Weather Service. The 34.00- foot stage exceeds the historical maximum peak stage of 33.20 feet, recorded at the streamgage in 1945. The simulated water- surface profiles were used in combination with a digital elevation model derived from light detection and ranging (lidar) data to map the inundated areas associated with each flood profile.

The flood- inundation maps and the supporting hydraulic model produced by this study can be used by emergency managers and local officials to assess flood- mitigation strategies and to define flood- hazard areas to help protect life and property, to coordinate flood- response activities such as evacuations and road closures, and to aid post- flood recovery efforts.

Released February 04, 2026 09:17 EST

2026, Canadian Journal of Fisheries and Aquatic Sciences

Vanessa R. von Biela, Amy M. Regish, Stephen D. McCormick, Joseph Spaeder, Kevin Whitworth, Justin Leon, Daniel Gillikin, Zachary Liller, Renae Ivanoff, Jenefer Bell, Sean D. Larson, Michael P. Carey, Christian E. Zimmerman

Chinook salmon population declines span their geographic range with climate hypothesized as a major driver. Concerns of warming freshwater temperatures in their northern range gained urgency during 2019 when a heatwave coincided with premature mortality. This study examined heat stress during the 2019 heatwave compared to subsequent years and described water temperatures in western Alaska to understand the degree to which freshwater temperatures may be a stressor. Heat stress was prevalent among Chinook salmon captured in the 2019 heatwave (Kuskokwim tributaries: 90% in Kwethluk and 63% Takotna river), and variable in subsequent years (∼8% to 60% across Kuskokwim tributaries and Norton Sound rivers). A review of water temperature data indicated that potentially stressful temperatures (≥18 °C) were most common and prolonged in the Yukon River, moderately common and prolonged in the Kuskokwim River, and relatively rare in the Norton Sound region. Water temperatures in 2019 broke several records for overall maximum and frequency of temperatures ≥ 18 °C. Migration water temperatures and heat stress in northern Pacific salmon habitats vary more widely than previously recognized (up to 25 °C).

Released February 04, 2026 09:07 EST

2026, Scientific Investigations Report 2025-5098

Darwin J. Ockerman, Namjeong Choi

The U.S. Geological Survey, in cooperation with the City of Brownsville, Texas, configured and calibrated a set of hydrologic models for a 217-square-mile study area in Cameron County in south Texas during 2022–23. The models were used for estimating runoff and quantities of water diverted from the Rio Grande/Rio Bravo del Norte (hereinafter referred to as the “Rio Grande”) to maintain water-surface elevations in the canals and resacas (former distributary channels cut off from the main channel of the Rio Grande). Resacas provide habitat to aquatic species and help reduce the effects of flooding.

Because of the large size of the study area and diversity of hydrologic conditions, the study area was divided into 11 watersheds, and separate hydrologic models were developed for 9 of the watersheds. Six of the nine modeled watersheds are drained mostly by canals (canal watersheds), and three of the modeled watersheds drain to resacas (resaca watersheds). The Hydrological Simulation Program—FORTRAN was selected for modeling the study area watersheds because it is flexible in simulating a wide variety of watershed conditions.

The models were calibrated with streamflow data collected during 2022–23. The calibrated models were used to simulate water budgets (streamflow, evapotranspiration, water-storage volumes, and water diversions and withdrawals) during 2022–23. Model simulations showed that the resaca watersheds required more diversions from the Rio Grande and released less runoff than did the canal watersheds. Management practices maintaining resaca water levels constrained their runoff.

Released February 04, 2026 08:29 EST

2026, Quaternary Research

John R. "Jack" Wood, Shannon A. Mahan, Amy E. East, Eric Leland Bilderback, Emma Taylor Krolczyk, Brian A. Rasmussen, Karina S. Zyatitsky, Leticia (Contractor) Hallas

Understanding the local to regional history of extreme events such as debris flows and floods provides context to plan for and mitigate these hazards to life, property, and infrastructure. The Klamath Mountains of northwestern California have experienced both debris flows and devastating wildfires. Whiskeytown National Recreation Area (WHIS) is at the heart of this range and has a wealth of debris flow–related landforms. Gaining an understanding of prehistoric flows and their relationship with fire or other potential triggers can help mitigate future problems. Optically stimulated luminescence and radiocarbon analyses from sediment and entrained organics in undisturbed facies, including beneath partially buried boulders, establishes a chronology of paleo-events in WHIS. The levee deposits indicate a repetition of debris flows during the latest Holocene, every 125–150 years, since 850 yr. Larger flows occurred, with a record elucidated from debris-flow deposits along Clear Creek, with Middle Holocene ages, ca. 2600 to 5500 yr, most of which have sufficient concentrations of charcoal to indicate origins as postfire debris flows. Deposits at higher elevations show events from the latest Pleistocene ca. 13,000 yr. This geochronology indicates that these are not singular events but are relatively common and inherent to the geomorphic processes shaping this landscape.

Released February 04, 2026 08:23 EST

2026, Journal of the American Water Resources Association (62)

Michael N. Fienen, Andrew J. Long, Katherine H. Markovich, Adel E. Haj, Matthew Irwin Barker

History matching of large hydrologic models is challenging due to data sparsity and non-unique process combinations (and associated parameters) that can produce similar model predictions. We develop an ensemble-based history matching (and uncertainty quantification) approach using an iterative ensemble smoother (iES) method for three cutouts of the National Hydrologic Model (NHM) and qualitatively compare the results and performance to the stepwise history matching approach. In the latter approach, subsets of parameters and observations were sequentially calibrated to a diverse range of observations to mitigate non-uniqueness and local minima. In iES, localization simulates the same causal connections between parameters and observations without the need (and computational cost) of sequential history matching steps. iES uses a weighted sum-of-squared-errors objective function which allows differential weighting of multiple data sources. Formal adoption of range observation also pushes results to within ranges of observation values rather than discrete values. Overall, the ensemble approach performs similarly to the stepwise approach. Both approaches performed poorly for the cutout representing a snowmelt-dominated watershed, indicating a structural issue in the process representation of the model. The main advantage of iES is quantification of uncertainty in both the history matching and the predictions of interest.

Released February 04, 2026 08:07 EST

2026, FEBS Letters

Cheyenne R. Smith, Laura Burattin, Nuria Ruiz Iglesias, Roisin Sullivan, Charles D. Rice, Helmut Segner, Lluis Tort

Understanding how environmental changes affect the health of organisms and ecosystems is complex, but recent interdisciplinary advances and the recognition of immune function as a dynamic mediator offer exciting progress. Environmental immunotoxicology in teleost fishes is evolving beyond cataloguing stressors towards a mechanistic, integrative framework that leverages omics, in vivo tracking and cross-disciplinary modelling. However, knowledge gaps in immune mechanisms, toxicokinetics and multi-stressor interactions remain. The present work highlights these gaps, advocating for immune function as both a mechanistic lens and an integrative health indicator. Such a framework can improve predictive risk assessments, management strategies and our understanding of contaminant effects on resilience, disease susceptibility and population viability. While challenges remain, the field is poised for significant growth through collaborative innovation and advancing technology.

Released February 03, 2026 09:07 EST

2026, Water Resources Research (62)

G. Sun, Z. Bian, K. Khand, P. V. Caldwell, J. Boggs, C. Wang, Y. Chen, N. Liu, Y. Zhang, X. Chen, Gabriel Senay, S. G. McNulty

Urban forests and other green infrastructures have been viewed as part of the “Nature-based Solutions” (NbS) to mitigate emerging urban environmental change. This study focuses on the role of evapotranspiration (ET) in regulating water balances of small watersheds in the eastern United States. We compared streamflow and ET patterns at daily, monthly and annual scales and linked these hydrological variables to the physical properties of 11 paired watersheds dominated by forests (FW) or urban (UW) land covers. The annual precipitation ranged from 1028 mm to 1683 mm and potential ET (PET) from 815 mm to 1450 mm. The mean annual flow/precipitation (Q/P) ratios were 0.26 ± 0.13 and 0.41 ± 0.1 for FW and UW, respectively. Overall, UW had lower annual ET (772 mm in UW vs. 947 mm in FW), but higher mean annual and (∼58% higher), monthly water yield (17%–186% higher), and peakflow rates (up to 100 times higher) than FW. The streamflow differences between FW and UW were most pronounced during the growing season and early winter (June-November). The mean Q/P ratios for 30 large hurricane events (2016–2021) were 0.12 ± 0.11 and 0.38 ± 0.23 for FW and UW, respectively. The flow rates in the dormant season (around December-May) in UW were similar or lower than FW. We developed conceptual models to explain the seasonal and storm event streamflow differences using background climate (PET), ET, and land surface characteristics. Urban NbS designs should factor in strategies that maximize ET while minimizing impervious surfaces enhancing watershed “sponge” and “pump” functions.

Released February 03, 2026 07:54 EST

2026, Animal Microbiome (8)

Sergei V. Drovetski, Brian P. Bourke, Michelle L. Hladik, Carolina F. Ferreira, Koray Ergunay, Yvonne-Marie Linton, Dana W. Kolpin, Gary Voelker

Although a few studies have focused on avian gut virome variation in response to environmental stressors, none have assessed virome in relation to the production of chemically intensive crop-based agriculture that alters food resources and detrimentally affects various aspects of avian health and fitness. In this study, we used shotgun metatranscriptomics to assess whether exposure to cotton (Gossypium spp.) production had a deleterious effect on the ileal virome of sedentary northern mockingbirds (Mimus polyglottos) sampled from two cotton-producing areas (16 birds in total) and one uncultivated area (7 birds) in Texas, USA. We recovered 43 viruses representing 13 virus families, which included two viruses that appear to be potential vertebrate pathogens. Individual sample richness varied from 25 to 33 viruses. Both virome richness (Adj. r² = 0.247, F_{(2, 20)} = 4.615, P = 0.022) and composition (r² = 0.370, F_{(2, 20)} = 5.883, P = 0.001) differed among three sampling regions. Cotton production was associated with the increase of virome richness (Adj. r² = 0.283, df = 22, P = 0.005). Pesticide occurrence data collected using silicone bands at the three sites suggest that virome compositional changes are not only associated with total pesticide exposure but are also particularly sensitive to the pesticide combinations detected at each location.

Released February 02, 2026 08:37 EST

2026, Earth System Science Data (18) 779-800

Benjamin Page, Christopher J. Crawford, Saeed Arab, Gail Schmidt, Christopher Barnes, Danika F. Wellington

In April 2020, the U.S. Geological Survey (USGS) Earth Resources Observation and Science (EROS) Center introduced a Level 2 provisional Aquatic Reflectance (AR) product for the Landsat 8 Operational Land Imager (OLI), marking the initial phase in developing a standardized global product for Landsat-derived surface water measurements. The goal of USGS EROS aquatic product research and development is to prepare for an operational processing architecture for Landsat Collection 3 in the late 2020s that will enable use of quality-controlled data for emerging Landsat aquatic science applications. To achieve this, we released a subset of the Landsat 8/9 provisional AR products (Crawford et al., 2025, https://doi.org/10.5066/P14MBBRM) and examined its general performance through the Science Algorithms to Operations (SATO) framework alongside quantitative assessment using community made inland water data records (GLObal Reflectance community dataset for Imaging and optical sensing of Aquatic environments, GLORIA) and radiometric coastal validation platforms (NASA’s Ocean Color component of the Aerosol Robotic Network, AERONET-OC). Variability within the validation datasets indicate that the performance of the Landsat 8/9 provisional AR retrieval is highly context-dependent; errors are minimal in optically simple waters (e.g., clear to moderately turbid coastal waters) but increase considerably in optically complex waters where factors such as elevated levels of turbidity, chlorophyll (Chl a) concentrations, or colored dissolved organic matter (CDOM) dominate the water column. Additionally, this paper examines key algorithmic considerations for atmospheric correction, highlighting factors that influence accuracy, scalability, and computational efficiency necessary for collection processing in the operational Landsat Product Generation System (LPGS). This paper is intended to communicate with aquatic scientists, satellite oceanographers, and the broader Earth observation community on the origins, requirements, challenges, successes, and future objectives for operationalizing global AR data products for Landsat satellite missions.

Released February 02, 2026 08:14 EST

2026, Environmental Biology of Fishes (109)

Jon M. Flinders, Daniel D. Magoulick

Assimilation efficiency is a critical assumption of stable isotope mixing models and bioenergetics models, yet few studies examine how assimilation efficiency influences modeling inferences. We conducted laboratory experiments to determine rainbow trout (Oncorhynchus mykiss) assimilation efficiencies. Assimilation efficiency averaged 55.8% (SE ± 0.90) and 64.5% (SE ± 1.98) at the 10% and 25% ration levels, respectively, and did not differ significantly. Caloric energy egested in feces was not significantly different between ration levels. Caloric energy excreted in ammonia and urea was significantly different between the ration levels, with a higher amount at the 25% ration level. Absorption efficiency was significantly greater at a higher ration level. Percent energy egested in feces was significantly greater at lower ration levels. Percent energy excreted as ammonia and urea was high compared to previous studies and did not differ significantly by ration level. Our estimates of assimilation efficiency of rainbow trout (56% and 65%) were lower than some previously reported estimates, and our estimates of energy losses (feces and ammonia) were higher than some previous estimates. As knowledge of species-specific assimilation efficiencies increases, our ability to draw strong inferences and improve the accuracy of model predictions will improve.

Released February 02, 2026 08:07 EST

2026, Current Biology (36) 799-808

Anna C. Ortega, Tayler N. LaSharr, Patrick W. Burke, Patrick Lionberger, Miguel Valdez, Kevin L. Monteith, Matthew J. Kauffman

Although migration is widespread among ungulates, the fitness benefits associated with different migratory tactics have rarely been documented. Here, we evaluated a 9-year dataset on a migratory population of mule deer to test the hypothesis that long-distance migration provides access to seasonal forage which translates into demographic benefits. Mule deer that migrated long (>130 km) and medium distances (50–130 km) accessed higher forage quality and thus gained 1.3–2.7 times more fat over the growing season compared to mule deer that remained year-round as residents within a desert ecosystem. Elevated levels of fat translated to ∼20% higher probability of adult annual survival than residents. Mule deer that remained year-round in the desert portion of the study area were so resource-limited that they raised fawns at the expense of their own survival. Due to their higher levels of fat, annual survival, and fetal rates, migrants showed more robust population growth (λ = 1.03) compared to residents, which exhibited projected declines in population size over time (λ = 0.95). These results support the notion that migration translates into demographic benefits and highlight the urgent conservation work necessary to sustain diverse ungulate migrations amid habitat alteration due to climate change and an expanding web of linear barriers to movement.

Released February 02, 2026 08:05 EST

2026, Ecosphere (17)

Calvin A. Farris, Ellis Q. Margolis, Jose Iniguez, D.A. Falk, K. Gerow, C.H. Baisan, C.D. Allen, T.W. Swetnam

Climate change, expanding human ignitions, and increased fuels from fire exclusion are driving increases in area burned and fire severity in dry conifer forests of the western United States. Increasing area burned is occurring against the backdrop of a large fire deficit caused by over a century of fire exclusion. A key land management question is whether historically frequent fire regimes can be restored. Accurate estimates of historical annual area burned (prior to circa 1900) are necessary to evaluate modern area burned (after circa 1900), but are difficult to derive, and have rarely been calibrated or validated against modern fires, leaving their accuracy uncertain. We developed new methods to use tree-ring fire scars to reconstruct historical annual area burned and compare it to modern annual area burned. We focused on two southwestern US wilderness areas—Saguaro National Park (SAGU) and the Gila Wilderness (GILA)—that have a long history of using prescribed and managed fires. The abundant modern low- and moderate-severity fires allowed us to (1) calibrate and validate the fire-scar models against mapped fires to derive the first uncertainty estimates of reconstructed annual area burned and (2) test whether active fire management can help restore annual area burned to historical levels. A multi-model ensemble consisting of 10 individual member models accurately estimated area burned of mapped modern fires with no consistent biases. Each member model had distinct strengths and assumptions that made them suitable for specific applications (e.g., the synchrony model is easily applied, and Thiessen polygons provide spatially explicit area burned estimates). The accurate reconstruction of modern area burned from relatively sparse fire-scar data at GILA suggests that dense grids may not be necessary for accurate reconstructions. Our findings reveal that despite the near absence of fire in the early 20th century, both annual and 20-year sums of area burned in recent decades are back within historical levels at GILA, and trending toward historical levels at SAGU. These results demonstrate that fire management can help restore the historically prevalent, ecologically important process of widespread, frequent, low-to-moderate-severity fire in dry conifer forests.

Released February 02, 2026 07:53 EST

2026, Journal of Earthquake Engineering (JEE)

Shaghayegh Karimzadeh, S.M. Sajad Hussaini, Daniel Caicedo, Alexandra Carvalho, Sanaz Rezaeian, Paulo B. Lourenco

Building on a previously developed bedrock dataset, this study extends the Azores Plateau ground motion simulations to include soil-amplified records and introduces a comprehensive validation framework. Soil amplification is modeled using one-dimensional soil profiles. A stochastic source-based approach is employed to generate the dataset, incorporating randomization of input-model parameters to account for the aleatory uncertainty in seismic activity. The accuracy of the dataset is verified through a comprehensive validation framework, showing that the randomization effectively captures variance and inter-period correlation observed in records. This work provides a robust dataset for advancing seismic hazard and risk assessment in the Azores Plateau.

Released February 02, 2026 07:45 EST

2026, Earth-Science Reviews (275)

Kate Andrzejewski, Julia A. McIntosh, Erik L. Gulbranson, Daniel Ibarra

Fossilized soils, or paleosols, contain soil-formed phyllosilicates whose stable isotopic compositions may be used to calculate paleotemperature and thus reconstruct ancient terrestrial environments. Though paleosols are common in the geologic record, the use of phyllosilicates as paleotemperature proxies is limited in the literature owing to difficulties with selecting optimal paleosols, isolation from non-clay minerals and organic materials, mixtures of phyllosilicates in natural samples, wide variations of chemical compositions for phyllosilicates, and limited to undefined equilibrium fractionation factors between phyllosilicates-water. Here, we address these challenges by examining and comparing methods used for sample selection, mineral isolation, pretreatments, mineral identification, conventional and developing methods for oxygen and hydrogen isotopic analyses, and determination of phyllosilicate-water equilibrium fractionation factors, concluding with recommendations for best approaches for paleotemperature estimation. Additionally, we discuss how to identify and avoid detrital phyllosilicates, the impacts of diagenesis, comparison of stable isotope and non-isotope paleosol paleotemperature proxies, and challenges and opportunities for broadly using paleosols as paleoclimate archives. With ongoing efforts to refine this multi-faceted paleotemperature approach, the stable isotope geochemistry of soil-formed phyllosilicates continues to be an invaluable proxy system, enhancing our understanding of terrestrial paleoenvironments and paleoclimate.

Released February 01, 2026 09:58 EST

2026, Ecological Applications (36)

Teagan A. Hayes, Aaron N. Johnston, L. Embere Hall, Jill Randall, Matthew J. Kauffman, Christopher Keefe, Kevin Monteith, Tabitha A. Graves

Wildlife and their habitats face profound challenges from climate and landscape-scale changes that extend beyond the influence and time horizon of most biologists and land managers. In this changing environment, long-term datasets can enhance assessments of how demographic trends respond to interactions among local (e.g., habitat restoration decisions) and broad extent drivers, including energy development, to shape wildlife populations. Although many studies evaluate habitat selection or demographics for a single population, our multipopulation, multiscale study quantifies the influence of local management actions given broader environmental forces using both immediate and lagged effects. This approach may be particularly important for species with high site fidelity that may have less adaptive capacity, including mule deer (Odocoileus hemionus), which are experiencing widespread population declines. We analyzed a 40-year (1980–2019) dataset for 37 mule deer populations across Wyoming, USA, to test hypotheses about and quantify the relative influence of conditions within winter use areas on annual rates of juvenile recruitment. Recruitment has been strongly affected by multiple factors largely beyond the control of managers. Land cover (agriculture and shrubland) had the largest positive effects on recruitment, with estimates more than twice the magnitude of other variables, but also had limited presence in some winter use areas. The next strongest effect sizes were shared by energy developments (including oil/gas and wind energy) and climatic conditions, which, except for wind turbines, had broad distributions across winter use areas. Recruitment increased with higher mean winter temperatures and summer precipitation, but declined with wind, oil and gas developments, cumulative drought, and wildfire. Expected increases in drought and decreases in summer precipitation may constrain options to sustain mule deer populations. Although mule deer recruitment may sometimes be enhanced through habitat restoration, effects varied with treatment type, habitat type, and time since treatment. Given large constraining effects of temperature and drought, supporting drought resiliency for important habitat may be useful. Our results can be used to weigh the relative strength of threats and the value of restoration actions, interpret historic demographic change, prioritize populations for conservation, and optimize options for wildlife habitat management.

Released February 01, 2026 09:56 EST

2026, Science Report NPS/SR—2026/381

Adam Sepulveda, Susanna Theroux

The U.S. Geological Survey (USGS) and Southern California Coastal Water Research Project supported Channel Islands National Park, The Nature Conservancy’s (TNC) Santa Cruz Island Preserve, and University of California San Diego (UCSD) researchers in using environmental DNA sampling to monitor for invasive Argentine ant (Linepithema humile) and to describe spatial biodiversity patterns in a freshwater stream on Santa Cruz Island that is colloquially known as Cañada del Puerto Creek (hydrologic unit code 12 number 180600140201). An eDNA autosampler was deployed May 27–June 02, 2025, which filtered and preserved four 2-L water samples every 12 hours (n = 48 samples). These samples were extracted by USGS and shipped to UCSD for targeted eDNA analyses of Argentine ant. Environmental DNA sampling kits were used to filter and preserve water samples at four sites along the creek spanning ~ 5 km of stream distance. Six 1-L samples were collected at each site May 27–28 and samples were analyzed for eDNA metabarcoding using a comprehensive panel, which encompasses species across the tree of life. In these samples, eDNA from 2,134 unique taxa spanning 30 taxonomic groups (e.g., amoebas, insects, plants) were found. These sampling efforts demonstrated how eDNA autonomous and manual sampling approaches can be applied by National Park Service, TNC, and partners at scale to provide otherwise difficult and expensive to acquire information about biological threats and biodiversity.

Released February 01, 2026 08:48 EST

2026, Research Note RMRS-RN-111

James Meldrum, Colleen Donovan, Suzanne Wittenbrink, Porfirio Chavarria, Patricia A. Champ, Hannah Brenkert-Smith, Christopher M. Barth, Carolyn Wagner

Community wildfire readiness includes homeowner wildfire risk mitigation and wildfire evacuation preparedness. This report presents results from a household survey distributed to homeowners in the study area around Santa Fe, New Mexico in 2024 which was a follow-up to a previous survey of homeowners of the same residences, consisting of mostly identical questions, that was conducted in 2021. This follow-up survey was motivated by the nearby 2022 Hermit’s Peak/Calf Canyon Fire. Comparison of results indicates general stability in the aggregated responses to most survey questions. As found previously, 2024 results indicate that Santa Fe survey respondents are engaged in preparing for wildfire, yet more could be done to reduce risk in study communities. Despite decreases between 2021 and 2024 in the acceptability of fuels treatment methods that concern the use of fire, respondents generally support multiple types of programs intended to reduce wildfire risk to the city, including most but not all types of fuels treatments on public lands.

Released February 01, 2026 08:48 EST

2026, Remote Sensing (18)

Selena Anne-Marie Johnson, David G. Zawada, Kimberly Yates, Connor Monroe Jenkins

Coral reefs provide immense ecosystem and economic value, supporting biodiversity, fisheries, tourism, and coastal protection worth billions annually. However, widespread degradation from thermal stress, storms, disease, and human impacts has caused significant coral cover and reef structure loss, increasing coastal vulnerability and economic risks. While coral loss is well-documented, degradation of underlying reef infrastructure and surrounding seafloor changes remain poorly understood. This study addresses this knowledge gap by quantifying seafloor elevation and volume changes across 234.2 km² of the Upper Florida Keys (UFK) reef tract using historical bathymetric and modern lidar (light detection and ranging) data collected from two periods with distinctly different disturbance regimes: 1935–2002 (frequent storms and major coral loss) and 2002–2016 (few storms and persistently low coral cover). Analysis of over 25,000 data points revealed substantial elevation and volume loss during 1935–2002 (−0.1 ± 0.8 m; 13.6 × 10⁶ m³ net loss), shifting to minimal gains by 2002–2016 (0.0 ± 0.3 m; 1.6 × 10⁶ m³ net gain). Despite this shift, benthic cover data showed continued declines in stony coral, with increases in macroalgae and octocorals, indicating that limited reef accretion persists even with reduced storm activity. Spatial analyses highlighted variable accretion and erosion patterns across habitats and subregions, underscoring the limitations of localized measurements for ecosystem-wide assessments. Our findings demonstrate the value of integrating historical and modern datasets for regional reef monitoring, establishing baselines for restoration planning, and emphasizing the need for continued high-resolution monitoring to guide adaptive management amid ongoing environmental change.

Released January 31, 2026 09:19 EST

2026, Book chapter, Probabilistic tsunami hazard and risk analysis

Natalia Zamora, Anita Grezio, Maria Papathoma-Kohle, Fatemeh Jalayer, Dimitra Salmanidou, Thomas E. Parsons, Eric L. Geist, Jacopo Selva, Mathilde B. Sørensen, Irina Rafliana

Mathilde B. Sørensen, Jorn Behrens, Fatemeh Jalayer, Finn Løvholt, Stefano Lorito, Irina Rafliana, Mario A. Salgado-Gálvez, Jacopo Selva, editor(s)

Tsunamis are multiscale phenomena resulting from a water column displacement that may be induced by multiple sources, and range from local scale inundation processes to ocean-wide scale wave propagation. Different strategies may be required to model tsunami evolution at different scales and to characterize various intensity measures. Research in tsunami hazard and risk has focused mostly on the tsunami effects such as the wave heights or flow depths. This chapter reviews the evolution of tsunami hazard and risk assessment methodologies, with particular emphasis on the development of probabilistic approaches. Building on advances in numerical modeling and uncertainty analysis, two main frameworks for Probabilistic Tsunami Hazard and Risk Analysis (PTHA/PTRA) are described. Framework 1 (FW1) focuses on quantitative methods, including fully simulation-based assessments (FW1A), integration of hazard with vulnerability and loss models (FW1B), consideration of dynamic processes such as tidal and sea-level variations (FW1C), and approaches using limited scenario sets (FW1D). Framework 2 (FW2) complements this by incorporating indicator-based vulnerability assessments, both physical (FW2A) and social, multi-dimensional (FW2B).

Released January 31, 2026 08:03 EST

2026, Palaeogeography, Palaeoclimatology, Palaeoecology (687)

Neil Patrick Griffis, Marieke Dechesne, Tyson Michael Smith, Mark R. Hudson, Charles M. Henderson, Roland Mundil, Mikel Shinn, Justin E. Birdwell, Laura Pianowski, Brandon Michael Lutz, Cameron Mark Mercer, Leah E. Morgan, Leland Robson Spangler

Cyclothems are defined by the repeat juxtaposition of littoral and open marine successions over short stratigraphic distances (meters to 10's of meters) and are interpreted to be driven by glacioeustatic forcing of sea level during the late Paleozoic Ice Age. The concept of cyclothems was defined in the Midcontinent region of the United States. However, correlating the Midcontinent region to other cyclic successions is difficult, which is the result of no geochronologic control for the Midcontinent biostratigraphic framework. We present the first high-resolution UPb zircon CA-ID-TIMS and feldspar ⁴⁰Ar/³⁹Ar age control for the onset of Midcontinent cyclothem deposition in the Arkoma Basin, Arkansas USA. Geochronologic control is obtained from a volcaniclastic unit preserved in the newly recovered Dare Creek #1 core. We integrate these data with biostratigraphic, lithostratigraphic and trace element analyses to investigate the timing, stratigraphic and geochemical response to late Paleozoic climate forcing. The lowermost Atoka Formation is associated with the onset of five high frequency transgressive-regressive cycles, which are defined by nearshore sandstones juxtaposed on top of offshore marine mudstones and are associated with changes in salinity and redox conditions. The Trace Creek Member of the lower Atoka Formation hosts a thick, organic-rich black shale, which defines the last and maximum transgression of the lower Atoka Formation in the Arkoma Basin, in the latest Bashkirian. Base-level records from time equivalent stratigraphic successions from Arrow Canyon, Nevada, U.S.A. and the Donets Basin, Ukraine also record a maximum transgression in the latest Bashkirian. The synchroneity of maximum flooding events from multiple basins which span the low latitudes in the latest Bashkirian support that cyclothem deposition was controlled by allostratigraphic forcing mechanisms, likely glacioeustatic forcing resulting from dynamic glaciation in high-latitude Gondwana.

Released January 30, 2026 08:43 EST

2026, Biogeosciences (23) 851-865

Mona Huyzentruyt, Maarten Wens, Gregory S. Fivash, David Walters, Steven Bouillon, Joel Carr, Glenn Guntenspergen, Matt L. Kirwan, Stijn Temmerman

Tidal marshes are considered one of the world's most efficient ecosystems for belowground organic carbon sequestration and hence climate mitigation. Marsh systems are however also vulnerable to degradation due to climate-induced sea level rise, whereby marsh vegetation conversion to open water often follows distinct spatial patterns: levees (i.e. marsh zones < 10 m from tidal creeks) show lower vulnerability of vegetation conversion to open water than basins (i.e. interior marsh zones > 30 m from creeks). Here, we use sediment cores to investigate spatial variations in organic carbon accumulation rates (OCAR) in a microtidal system (Blackwater marshes, Maryland, USA): (1) across a gradient of marsh zones with increasing marsh degradation, assessed as increasing ratio of unvegetated versus vegetated marsh area and (2) by comparing levees versus basins. We show that OCAR is up to four times higher on marsh levees than in adjacent basins. The data suggest that this is caused by spatial variation in three processes: sediment accretion rate, vegetation productivity, and sediment compaction, which are all higher on levees. Additionally, OCAR was observed to increase with increasing degree of marsh degradation in response to sea level rise. We hypothesize this may be due to more soil waterlogging in more degraded marsh zones, which may decrease carbon decomposition. Our results highlight that tidal marsh levees, in a microtidal system, are among the fastest soil organic carbon sequestration systems on Earth, and that both levees and basins sustain their carbon accumulation rate along gradients of increasing marsh degradation in response to sea level rise.

Released January 29, 2026 16:30 EST

2026, Scientific Investigations Report 2026-5115

Kelli M. Palko, Cory A. Russell, Nicholas J. Pieseski

Water users in Elbert County, Colorado, rely on groundwater from bedrock aquifers in the Denver Basin aquifer system (upper Dawson, lower Dawson, Denver, Arapahoe, and Laramie-Fox Hills aquifers) for approximately half of their water uses. Withdrawals from the bedrocks aquifers have increased to meet the water use needs of expanding regional population growth and development. The U.S. Geological Survey, in cooperation with the Elbert County Board of County Commissioners, began a study in 2015 to monitor groundwater levels within Elbert County. The primary purpose of this report is to present a summary of groundwater levels measured during the study period (2015–23) and present results from statistical analyses of changes in groundwater-level elevations through time.

Discrete groundwater levels were measured at 36 wells within Elbert County. Seven of those wells contained equipment to make and record continuous groundwater-level measurements at hourly intervals. All aquifers, except the lower Dawson aquifer, had only declining groundwater-level elevations in discrete measurements for wells with statistically significant trends. Of the eight statistically significant trends in the lower Dawson aquifer, two wells indicated increasing groundwater-level elevation from discrete measurements. The groundwater-level elevation trend medians in the upper Dawson, lower Dawson, Denver, Arapahoe, and Laramie-Fox Hills aquifers were −0.23, −0.66, −0.64, −0.39, and −0.63 feet per year, respectively, for discrete groundwater-level elevation measurements. Trends in continuous groundwater-level elevations were in agreement with statistically significant trends in discrete groundwater-level elevations for all wells. The groundwater-level elevation trend medians in this study, compared to the overall trends in a 2015−2018 study, both indicated declining groundwater-level elevations except in the upper Dawson aquifer, where the trend direction was opposite, a positive trend from 2015 to 2018 and a negative trend (declining groundwater elevations) from 2015 to 2023. The change in trends within the upper Dawson aquifer may be affected by differences in the study period and the trend analysis applied. Trends during the 2015–23 study period were compared to departures from the median 2015 groundwater-level elevation for each site in each aquifer. In general, the departures from the 2015 median supported trends observed at each site and correlated spatially with greater departures near the western border of Elbert County. Additionally, 30-year precipitation data showing wet and dry periods were overlaid with the departure from the 2015 median to assess groundwater-level patterns in wells in the five aquifers. Departures from the 2015 median groundwater-level elevations appeared greatest during the dry period between 2020 and 2023. Potentiometric-surface maps of the upper and lower Dawson aquifers created from static April 2023 groundwater elevations indicated groundwater-flow direction is generally from the south to the north. Results of this study could be used to guide additional groundwater monitoring in Elbert County and could aid in long-term planning of water resources.

Released January 29, 2026 15:35 EST

2026, Ecological Applications (36)

Sarah R. Weiskopf, Toni Lyn Morelli, Tina G. Mozelewski, Alexey N. Shiklomanov, Susannah B. Lerman

Ecological restoration is essential to meeting global biodiversity conservation goals. Given limited conservation budgets, deciding where to restore habitat is a key challenge for the coming decade. We developed a spatially explicit framework to optimize ecological restoration site selection by integrating land use history, species distributions, and economic costs. The framework includes the following steps: identify potential restoration area based on relevant environmental measures like land use; identify species of interest; calculate restoration benefits by modeling habitat and climate suitability and estimating reduced extinction risk associated with restoring a particular land parcel based on a modified species–area relationship; aggregate benefits across species; and compare to parcel-level land acquisition costs. We applied linear programming to maximize conservation benefit/restoration cost ratios to identify optimized restoration sites. We illustrate this approach using a case study for highly threatened grassland ecosystems in the Great Plains region of Kansas, USA. We selected five grassland animal species (greater prairie chickens [Tympanuchus cupido], lesser prairie chickens [Tympanuchus pallidicinctus], swift fox [Vulpes velox], pronghorn [Antilocapra americana], and regal fritillary [Speyeria idalia]) as indicators of restoration benefit across taxa. For the indicator species that we chose, shortgrass and mixed-grass prairies had the highest conservation benefit to cost ratio. Setting a minimum restoration threshold for each habitat type allowed us to identify high-priority tallgrass prairie sites. Despite increasing interest in ecological restoration, optimizing restoration site selection is challenging because one must consider habitat features that do not currently exist. The modeling approach described here is flexible and can be updated for different ecosystems, species, and conservation priorities. We outline potential alterations that can be made in future analyses, depending on desired restoration goals.