Released April 13, 2026 11:56 EST

2026, Open-File Report 2026-1001

Shelby A. Weiss, Matthew L. Trumper, Nathan R. De Jager, Lyle J. Guyon, Molly Van Appledorn

Preface 

In anticipation for increased funding made possible by the Water Resources Development Act of 2020, the Upper Mississippi River Restoration (UMRR) Program identified a need to conduct river-wide assessments of floodplain vegetation. In January 2025, we assembled a group of subject matter experts to perform the following tasks:

1. Review Upper Mississippi River Restoration’s current floodplain vegetation research portfolio,
2. Identify important features and goals for long-term floodplain vegetation monitoring,
3. Evaluate the suitability of existing datasets for system-wide vegetation assessments, and
4. Discuss emerging opportunities to learn about floodplain vegetation dynamics from local-scale restoration and management projects.

This document is a summarization of what occurred at the meeting and provides suggested next steps toward developing the capacity to conduct routine long-term monitoring and assessment of floodplain vegetation as part of the Upper Mississippi River Restoration Program.

Released April 13, 2026 11:50 EST

2026, Circular 1563

Adam T. Ringler, David C. Wilson, Robert Anthony, Corey I. Beutel, Andrew Holcomb, Charles R. Hutt, Tom Telesha

This circular presents a strategic outlook for the U.S. Geological Survey (USGS) Albuquerque Seismological Laboratory (ASL) for the next 10 years (2026–36). The ASL is a USGS field office in the Geological Hazards Science Center that operates portions of the Advanced National Seismic System and the Global Seismographic Network and focuses on fundamental research for instrumentation testing and data quality. The strategic outlook is categorized into two types of tasks: “Foundational Tasks” and “Aspirational Tasks.” Foundational Tasks are those that maintain the laboratory’s basic operations and services, including regional and global seismic monitoring, improving data quality, and providing instrument testing and support. A suite of Aspirational Tasks is also articulated; these can be considered priority targets of ASL that could improve ASL’s seismic monitoring capabilities and mission. Such tasks include improvements to remote stations, testing capabilities of nonseismic geophysical instruments, detection threshold monitoring, rapid aftershock deployments, and expanding seismic monitoring networks. This report was written with input from the USGS Geological Hazards Science Center, the USGS Earthquake Hazards Program (EHP), and colleagues with an interest in the work done by the ASL. Although the details of these tasks may change, this document can provide guidance on the overarching tasks at the ASL from 2026 to 2036 and an overview of the various components of the ASL and how they fit into the EHP and the Global Seismographic Network Program.

Released April 13, 2026 11:44 EST

2026, Scientific Investigations Report 2025-5093

Andrea Cecile Jaegge, Keith Bouma-Gregson, Thomas D. Byl, Kurt D. Carpenter, Victoria Christensen, Rebecca Michelle Gorney, Jennifer L. Graham, Heather A. Heckathorn, Hayley T. Olds, Pamela A. Reilly, Joshua J. Rosen, Michael D.W. Stouder

Cyanobacterial toxins (cyanotoxins) represent a substantial threat to drinking water supplies and safe recreational uses of freshwater resources in watersheds worldwide. Monitoring cyanotoxins can be difficult because toxin events are variable in both space and time, are not always persistent, can be moved easily by wind and currents, and may be degraded biotically or abiotically. Thus, monitoring programs that collect discrete samples on a monthly or even bimonthly interval can miss key events and underestimate cyanotoxin risk or if they capture a high-concentration event, can give a false impression that cyanotoxins are a widespread health hazard. The use of Solid Phase Adsorption Toxin Tracking (SPATT) samplers helps address this issue by providing a time-weighted average estimate of dissolved cyanotoxin occurrence and relative concentrations. SPATT samplers have been used as a complement to traditional monitoring programs and can help elucidate cyanotoxin dynamics. SPATT samplers have been used by six U.S. Geological Survey (USGS) Water Science Centers (New York, California, Oregon, Upper Midwest, New Jersey, and Lower Mississippi-Gulf) to monitor various cyanotoxins in waterbodies such as streams, rivers, lakes, waterfalls, estuaries, and drinking- water intakes. Despite their use across the USGS, there is little guidance available to ensure consistent approaches and data quality across the Bureau. This report summarizes best practices for SPATT deployment and analysis, synthesizes data and describes lessons learned from USGS studies, identifies priority knowledge gaps, and offers considerations for future targeted experiments to help improve data collection and interpretation.

Released April 10, 2026 13:33 EST

2017, Article

Richard B. Wanty, Andrew H. Manning, Michaela R. Johnson, Stephen J. Kalkhoff, Jessica D. Garrett, Jean M. Morrison, Stefania Da Pelo, Jeffrey L. Mauk

Released April 10, 2026 11:27 EST

2026, Scientific Investigations Report 2026-5141

Viviana Mazzei, Keith A. Loftin, Emily Karwacki, Jose V. Lopez, Lauren E. Krausfeldt, Barry H. Rosen, Hidetoshi Urakawa

The Caloosahatchee River, located in southwest Florida, is a eutrophic and colored river that flows from Lake Okeechobee westward into its estuary and the Gulf of America. Cyanobacterial harmful algal blooms (HABs) are a documented problem along this freshwater-to-marine waterway where nutrient enrichment has been identified as a key factor in bloom occurrence but has not been experimentally tested in the river. This study is the first to test the effects of inorganic nutrient loading on phytoplankton assemblages in the Caloosahatchee River and the effects of different nutrient sources on phytoplankton dynamics at different times of the year. Three independent, in situ experiments were conducted to test the effects of daily, incrementally increased ammonium, nitrate, and phosphate loading on phytoplankton at different times of the year (summer, fall, winter). Over the 72-hour enclosure period, phytoplankton abundance metrics (cell concentration, chlorophyll-a, and phycocyanin), dissolved oxygen, and pH increased, and fluorescent dissolved organic matter and turbidity decreased in all treatments and controls. Increased phytoplankton abundance metrics relative to controls were observed after 72 hours of exposure to elevated ammonium and nitrate in summer and only ammonium in winter, suggesting periodic nitrogen limitation; however, no treatment effects on phytoplankton assemblage structure in terms of resemblance and diversity metrics were found. Increases in total cell concentrations were driven by elevated growth rates of already dominant taxa but not sufficiently to form a visible bloom. Cyanobacteria consistently dominated the phytoplankton, particularly Aphanocapsa and Merismopedia, whereas the common HAB-forming Microcystis maintained consistently low abundance. This study provides new information on the ecology of phytoplankton assemblages in the Caloosahatchee River and could be used by water resources managers to evaluate strategies for controlling cyanobacterial HABs in the river.

Released April 10, 2026 09:37 EST

2026, Scientific Investigations Report 2026-5128

Rebecca Michelle Gorney, Heather A. Heckathorn, Kyle Clonan, Pamela A. Reilly, Kathryn Cahalane, Bradley William Bjorklund

Harmful algal blooms, particularly cyanobacteria harmful algal blooms (cyanoHABs), have emerged as a substantial global concern because of their detrimental effects on water quality and aquatic ecosystem health. CyanoHABs can produce cyanotoxins, which pose serious health risks to humans and wildlife, such as liver failure and respiratory distress. This is particularly concerning for water bodies that serve as drinking- water sources. Recent trends indicate an increase in the frequency and intensity of cyanoHABs globally. This study focuses on the Raritan Basin Water Supply Complex in New Jersey, where extensive monitoring was conducted from August 2020 to August 2021 to assess the presence of cyanobacteria and associated cyanotoxins. The research utilized a combination of discrete water- quality sampling, continuous monitoring, and solid phase adsorption toxin tracking (SPATT) to capture the dynamics of cyanotoxin occurrence and potential transport. Findings revealed a widespread presence of cyanobacteria and potential for cyanotoxin production, although actual cyanotoxin concentrations remained below drinking water and recreational thresholds. The study, conducted by the U.S. Geological Survey (USGS) in collaboration with the New Jersey Water Supply Authority (NJWSA) and the New Jersey Department of Environmental Protection (NJDEP), highlighted the limitations of traditional sampling methods and emphasized that continuous monitoring can support better understanding of how cyanoHAB conditions change over time and in different places. Genetic testing included quantitative polymerase chain reaction (qPCR) analyses, which demonstrated higher sensitivity, or increased findings of cyanobacteria compared to microscopy, indicating the potential for use in early warning systems. This research underscores that integrating various detection methods and hydrological data can enhance understanding of cyanotoxin dynamics in river systems.

Released April 09, 2026 15:06 EST

2026, Scientific Investigations Report 2026-5138

Matthew T. Moser, Mikaela L. Cherry, Brent M. Hall

The City of Lincoln, Nebraska, has been monitoring concentrations of arsenic in their source water and evaluating their options for treatment and removal since at least 2002. In 2022, the City of Lincoln, Nebr., with funding assistance from the Nebraska Water Sustainability Fund, began cooperating with the U.S. Geological Survey to examine arsenic concentrations in surface water and groundwater in the lower Platte River valley and the area around City of Lincoln Water System (LWS) well field. Arsenic data collected from the Platte River since 1974 were examined using the “weighted regression on time, discharge, and season” model, which compared the streamflow (also referred to as “discharge”), time of year, and season to estimate concentrations of arsenic. Annual mean arsenic concentrations modeled for more than 49 years at the Platte River at Louisville, Nebr., U.S. Geological Survey streamgage (station 06805500), indicated a significant increasing trend. Arsenic concentrations in the Platte River were seasonal, with the highest concentrations being observed during mid- to late summer. When seasonal patterns and streamflow were combined with arsenic concentrations in the Platte River during low streamflow conditions, groundwater contributions, which can have higher arsenic concentrations, make up a larger portion of the streamflow. Arsenic samples were collected from upstream rivers in 2022 and 2023 and were paired to analyze the arsenic contributions at the U.S. Geological Survey streamgage on the Platte River near Ashland, Nebr. (station 06801000), near the City of Lincoln well field. The arsenic concentrations from the streamgage on the Platte River near Ashland, Nebr., location, were higher than the U.S. Geological Survey streamgage on the Elkhorn River at Waterloo, Nebr. (station 06800500), and significantly lower than at the U.S. Geological Survey streamgage on the Platte River near Leshara, Nebr.(station 06796500), indicating that the Platte River usually contributes a higher concentration of arsenic than does the Elkhorn River as they join near Ashland, Nebr. During 1991–2023, six groundwater monitoring wells were analyzed to identify trends in arsenic concentrations. Two of the six wells had a positive trend during the 33- year period. One monitoring well did not reveal a long- term trend during this period but showed a trend during 2019–23, correlating to a period when the island in the middle of the Platte River was connected to the east bank of the river when manganese reducing conditions were present and groundwater levels were declining in the well. Across all wells the oxidation and reduction (redox) condition during the time of sampling was assessed. Mixed anoxic and (or) oxic redox condition was the most common redox process and the highest sampled arsenic concentrations in monitoring wells were observed in anoxic conditions driven by manganese reduction. Groundwater arsenic concentrations had seasonal variation around the City of Lincoln well field, with higher arsenic concentrations tending to be further south in comparison to samples collected further north. Isotope samples were collected and analyzed in surface water and groundwater around the LWS well field. The samples indicate that the proportion of surface water present in the LWS production wells can be higher in the spring and lower in the summer. With higher arsenic concentrations observed in the stream water during the summer period, the LWS source water can be affected by these elevated arsenic concentrations even though the proportion of surface water is lower.

Released April 09, 2026 12:25 EST

2026, Circular 1564

Sara Ernst

The 2024 annual report of the U.S. Geological Survey Woods Hole Coastal and Marine Science Center highlights accomplishments of 2024, includes a list of 2024 publications, and summarizes the work of the center, as well as the work of each of its science groups. This product allows readers to gain a general understanding of the focus areas of the center’s scientific research and learn more about specific projects and progress made throughout 2024, all while enjoying photographs taken in various environments and laboratories, and applicable maps and figures.

Released April 09, 2026 11:16 EST

2026, Scientific Investigations Report 2026-5134

Hayden A. Lockmiller, Victoria (Tori) Byers, Lisa R. Fogarty

Lake St. Clair Metropark Beach in Michigan has a history of closures because of elevated Escherichia coli (E. coli) concentrations in its recreational waters. To reduce closures, restoration projects were implemented in 2021 to deter waterfowl from congregating on the beach. In this study, the U.S. Geological Survey, in cooperation with the Michigan Department of the Environment, Great Lakes, and Energy and in collaboration with Huron- Clinton Metroparks and the Macomb County Health Department, monitored E. coli from 2022–23 in surface water, shallow groundwater, and sediment at Lake St. Clair Metropark Beach. Results were compared to data from a prerestoration (2018–19) study. A significant decrease in daily geometric mean E. coli concentrations in surface water was observed postrestoration, but the number of high concentration events increased. This resulted in more frequent beach closures postrestoration. Surface- sediment E. coli concentrations significantly decreased after restoration, and waterfowl populations generally decreased from 2021 to 2023, suggesting that the deterrence measures could be influencing E. coli concentrations in surface sediments and surface water. Groundwater E. coli concentrations were orders of magnitude higher than those in surface water and revealed no change correlated with restoration. Seepage measurements indicated that groundwater occasionally discharges into surface water, potentially providing a transport mechanism for E. coli to reach the lake. Continued monitoring and consideration of environmental factors could help to better understand the beach system.

Released April 09, 2026 09:40 EST

2026, Preprint

Phil Harte, Andrew L. Collins

Per- and polyfluoroalkyl substances (PFAS), including perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS), have been detected at combined concentrations above 2,000 nanograms per liter (ng/L) at groundwater seep locations near the Coakley Landfill Superfund site, in North Hampton, New Hampshire. The landfill was active from 1972 to 1985. An impermeable cap was placed on the landfill in 1998. The adjacent area to the Coakley Landfill has many water supply wells, and transport of PFAS compounds to the wells is a concern. Fracture anisotropy in the underlying bedrock aquifer complicates the understanding of PFAS transport because groundwater preferentially travels along fractures that may not align with the prevailing groundwater flow direction. In 2018, the U.S Environmental Protection Agency and the U.S. Geological Survey began an investigation of the groundwater flow from the Coakley Landfill site. This report describes the modification of a numerical groundwater-flow model for the local area around the Coakley Landfill and summarizes findings of the investigation. In addition, this report includes a brief description of PFOA and PFOS occurrence, a discussion of model construction, evaluation of model performance through calibration, and discussion of simulation results for two periods (before and after capping). Limitations are also discussed. Results show that simulated groundwater flow moves from the Coakley Landfill to the west and north. Advective transport modeling using particle tracking shows that groundwater from the landfill discharges primarily to streams to the west and north, and a small amount is transported to distal wells. Dilution of contaminants through advection and dispersion likely plays a role in whether PFAS compounds from the landfill will be detected above laboratory reporting levels at distal wells.

Released April 09, 2026 07:47 EST

2026, Circular 1566

Yellowstone Volcano Observatory

The Yellowstone Volcano Observatory (YVO) monitors volcanic and hydrothermal activity associated with the Yellowstone magmatic system, carries out research into magmatic processes occurring beneath Yellowstone Caldera, and issues timely warnings and guidance related to potential future geologic hazards. YVO is a collaborative consortium that includes the U.S. Geological Survey (USGS), Yellowstone National Park, University of Utah, University of Wyoming, Montana State University, EarthScope Consortium, Wyoming State Geological Survey, Montana Bureau of Mines and Geology, and Idaho Geological Survey. The USGS component of YVO also has the operational responsibility for monitoring volcanic activity in the Intermountain West of the United States, including Arizona, New Mexico, Utah, and Colorado. This report summarizes the activities and findings of YVO during the year 2024, focusing on the Yellowstone volcanic system.

Released April 08, 2026 09:46 EST

2026, Data Report 1224

Shannon M. Meppelink, Stephen J. Kalkhoff

The Cedar River alluvial aquifer is the source of drinking water in Cedar Rapids, Iowa. Production wells are completed in the alluvial aquifer approximately 40 to 80 feet below land surface. The City of Cedar Rapids and the U.S. Geological Survey have studied the groundwater-flow system and water quality of the aquifer in the vicinity of Cedar Rapids since 1992. Results of these studies documented hydrologic conditions, water quality, and geochemistry of the alluvial aquifer and interactions with the Cedar River. Water-quality samples were collected for studies involving well field monitoring, trends, source-water protection, groundwater geochemistry, surface-water–groundwater interaction, and pesticides in groundwater and surface water. Water quality was analyzed for dissolved major ions (boron, bromide, calcium, chloride, fluoride, iron, magnesium, manganese, potassium, silica, sodium, sulfate, and total dissolved solids), dissolved nutrients (ammonia as nitrogen, ammonia plus organic nitrogen as nitrogen, nitrite plus nitrate as nitrogen, nitrite as nitrogen, orthophosphate as phosphorus, and phosphorus), dissolved organic carbon, and selected pesticides. Physical characteristics (alkalinity, dissolved oxygen, pH, specific conductance, and water temperature) were measured on site and recorded for each water sample collected. This report presents the results of routine water-quality data-collection activities from October 2017 through September 2022. Methods of data collection, quality assurance, water-quality analyses, and statistical procedures are presented. Data include the results of water-quality analyses from quarterly sampling from monitoring wells, production wells, two water treatment plants, and the Cedar River at Blairs Ferry Road at Palo, Iowa, streamgage (U.S. Geological Survey station number 05464420), as well as monthly nutrient sampling from the Cedar River and Morgan Creek near Covington, Iowa, streamgage (U.S. Geological Survey station number 05464475).

Released April 08, 2026 07:51 EST

2026, Journal of Volcanology and Geothermal Research (474)

Drew T. Downs, May Sas

Differentiated magmas stored in the rift zones of Kīlauea have received more attention in recent years following eruption of andesite during the early phase of 2018 lower East Rift Zone activity. Despite this growing interest, some of the most voluminous eruptions of differentiated rift zone magmas remain poorly studied. One such eruption, and the most voluminous exposed differentiated flow field at Kīlauea, is the Kamakaiʻa Hills. This eruption took place in the Southwest Rift Zone of Kīlauea, a region that is hypothesized to contain a long-lived rift zone reservoir. The Kamakaiʻa Hills flow field encompasses >250 × 10⁶ m³ of basaltic andesite and basalt compositions with a mineral assemblage of orthopyroxene + clinopyroxene + plagioclase during its early ʻaʻā phase and clinopyroxene + plagioclase + olivine during its late pāhoehoe phase. To better understand storage conditions and magma accumulation, this study focuses on major, minor, and trace elements from the mineral assemblage present within the early ʻaʻā and late pāhoehoe phases. The diversity of clinopyroxene and plagioclase compositions within the early ʻaʻā and late pāhoehoe phases, as well as diverse compositions of plagioclase and orthopyroxene within the early ʻaʻā phase, suggest multiple magma bodies and limited pre-eruption magma mixing within the broader Kamakaiʻa Hills reservoir. Oscillatory zoning patterns (particularly in clinopyroxene) imply processes such as recharge events, magma mixing or mingling, or convection within a differentially cooling, chemically stratified reservoir over protracted time intervals, whereas only limited resorbed mineral textures indicate incomplete mixing of heat and chemically distinct magmas during the dike intrusion that triggered the eruption. Mineral-mineral and mineral-melt thermobarometry indicate predominantly shallow (≤2.5 km depth) crustal storage conditions of the cooled, differentiated magma (∼1100 °C and cooler for the basaltic andesites) to hotter temperatures for the basalts (all >1100 °C). Despite the known large standard errors estimated for mineral-melt and mineral-mineral barometry (10s to >100 MPa), the calculated pressures and depths broadly correspond with earthquake swarm depths beneath the Kamakaiʻa Hills, and drill core and fluid inclusion barometry storage depths of differentiated magmas within the lower East Rift Zone. The Kamakaiʻa Hills differentiated magmas have H₂O contents (∼0.5 wt%, using plagioclase-melt hygrometry) equivalent to typical Kīlauea basalts. Our data and interpretations demonstrate a complex, long-lived rift zone storage system that consisted of multiple magma bodies and was mobilized into eruption through intrusion of a hotter and more primitive summit-derived (uprift) magma.

Released April 08, 2026 06:49 EST

2026, Scientific Investigations Report 2026-5001

Noah Schmadel, Cristiana Figueroa-Kaminsky, Daniel Wise, Jamie K. Wasielewski, Zachary Johnson, Robert W. Black

The U.S. Geological Survey and the Washington State Department of Ecology (Ecology) have developed watershed models of seasonal load estimates of total nitrogen (TN) and total phosphorus (TP) discharging into the Washington State waters of the Salish Sea from 2005 through 2020. The modeling approach used was dynamic SPARROW (SPAtially Referenced Regressions On Watershed attributes), a statistical-physical watershed modeling technique, initially applied at large spatial scales to represent long-term average stream loads throughout a stream network, refined here to estimate seasonal TN and TP loads across watersheds.

Upstream contributing sources included permitted treated wastewater facilities, crop fertilizer, animal feeding operations, septic systems, urban land and stormwater, atmospheric deposition (TN only), nitrogen fixation by Alnus rubra Bong. (red alder) trees (TN only), and background geologic material (TP only). Instream load magnitudes and their source compositions varied across watersheds, and even within each watershed, yet the largest loads typically occurred in the large rivers during winter and fall when streamflow was highest. Likewise, instream loads were typically lowest in summer during low streamflow, yet the relative instream aquatic decay was highest. The seasonal storage lag component of all nonpoint sources was estimated to contribute a quarter of the seasonal instream load during winter and fall high streamflow and sometimes half of the instream load during summer low streamflow.

Simulated seasonal loads carried by streams to a few hundred river mouth marine discharge points ranged by several orders-of-magnitude for TN and TP due to the spatial and seasonal differences in hydrologic flows, magnitude and timing of contributing sources, and instream decay. The Snohomish and Skagit Rivers discharged the largest TN and TP loads, yet the Samish River was shown to have some of the highest TN and TP yields and concentrations. Additionally, a reference scenario estimate developed of the pre-industrial local and regional TN loads suggests that red alder tree density has increased in lower riparian areas and that treated wastewater is the dominant source in some watersheds that has led to increases in TN loading to marine waters.

Released April 07, 2026 10:10 EST

2026, International Journal of Disaster Risk Reduction (139)

Nathan J. Wood, Jeff Peters

Previous efforts to characterize lahar threats posed to communities downstream of volcanoes have focused primarily on delineating hazard zones that lack information on lahar-arrival times and exposure estimates that implicitly treat threats to be the same regardless of distance from the volcano. Estimated lahar-arrival times, travel times for individuals to leave hazard zones, and possible evacuation delays related to event identification, warning dissemination, and evacuee behavior are important, but often overlooked, aspects of understanding the societal threats posed by lahars. These temporal considerations are important for unexpected lahars that could occur due to slope failure in the absence of precursory volcanic unrest or eruption. This case study examines the role of time in lahar evacuations by quantifying population exposure and evacuation potential for non-eruptive lahar hazards associated with Mount Rainier, Washington. Lahars could directly affect tens of thousands of residents and employees, thousands of students at primary and secondary schools, and hundreds of individuals at long-term residential care facilities. Geospatial path-distance modeling quantified evacuation potential for 736 scenarios that represent combinations of lahar sources, evacuation destinations, pedestrian travel speeds, and a range of departure-delay assumptions. Depending on location, some communities may have substantial loss of life in tens of minutes after lahar initiation, whereas other communities may be managing large-scale evacuations over several hours. Estimates of evacuation success based on a range of scenarios provide individuals in hazard zones and risk-reduction agencies with insights on how their actions may increase or decrease the number of people that survive future lahars.

Released April 07, 2026 08:30 EST

2026, Water Resources Research (62)

Tianxin Wang, Gabriel B. Senay, Joseph Verfaille, Daphne J. Szutu, MacKenzie Friedrichs, Jack R. Eggleston, Dennis Baldocchi

Accurate measurement of evapotranspiration (ET) is essential for sustainable water management. Standard methods such as eddy covariance (EC) are costly, while alternatives such as surface renewal are cheaper but require calibration and complex data processing. This study evaluates the utility of the Variance-Bowen Ratio (VBR) method for estimating ET across three California’s wetlands. Using data from 2023, half-hourly latent heat flux (λE) and daily/monthly ET from VBR were compared with EC at one non-tidal (site A) and two tidal (sites B and C) wetlands. λE_VBR consistently underestimated λE_EC, with root mean squared errors (RMSE) of 61.2 W m^-2 at sites A, 106.1 W m^-2 at site B, and 137.2 W m^-2 at site C, largely due to storage fluxes across sites. Temporal integration improved VBR’s performance at tidal sites, where compensating water heat storage errors yielded low daily and monthly biases (site B: RMSE = 0.78 mm/d and 12 mm/month; r = 0.93; site C: RMSE = 0.90 mm/d and 13 mm/month; r = 0.93), with reduced major axis (RMA) regression slopes of 0.98 and ~0.91. In contrast, biomass heat storage at site A caused persistent biases (RMSEs = 0.97 mm/d and 23 mm/month; daily and monthly RMA slopes ~0.75; r = 0.85). These results highlight VBR’s limitations in environments with substantial storage fluxes. Despite this, VBR is cost-effective for estimating daily and monthly ET, with sensor costs at least tenfold lower than EC and simpler setup, making it suitable for ET monitoring in resource-limited and hard-to-access regions.

Released April 07, 2026 08:04 EST

2026, Nature Reviews Earth and Environment (7) 213-215

Michael Zemp, Ethan Z. Welty, Samuel U. Nussbaumer, Jacqueline Bannwart, Isabelle Gärtner-Roer, Albin Wells, Andreas Peter Ahlstrøm, Brian Anderson, Liss Marie Andreassen, Mohd. Farooq Azam, Jamie Barnett, Carlo Baroni, Nicholas Edward Barrand, Andreas Bauder, Eric Bernard, Etienne Berthier, Giulia Bertolotti, Tobias Bolch, Mylène Bonnefoy-Demongeot, Matthias H. Braun, David Burgess, David Cappelletti, Jonathan L. Carrivick, Luca Carturan, Daniele Cat Berro, Jorge Luis Ceballos, Guillermo Cobos, Rolando Cruz, Nicolas Cullen, Bolívar Cáceres, Johanna Dahlkvist, Otgonbayar Demberel, Simon de Villiers, Roberto Dinale, Eugene Drozdov, Inés Dussaillant, Luzmila Dávila, Nelly Elagina, Hallgeir Elvehøy, Alexander Erofeev, Daniel Falaschi, Andrea Fischer, Mauro Fischer, Caitlyn Florentine, Koji Fujita, Stephan Peter Galos, Ayon Garcia, Noel Gourmelen, Federico Grosso, Afanasiy Gubanov, Andri Gunnarsson, Anne Guyez, Lea Hartl, Martin Hoelzle, Jorge Huenante, Romain Hugonnet, Matthias Huss, Bernhard Hynek, Takuro Imazu, Rodolfo Iturraspe, Livia Jakob, Sharad Joshi, Neamat Karimi, Nina Kirchner, Bjarne Kjøllmoen, Jack Kohler, Stanislav Kutuzov, Ivan Lavrentiev, James Matthew Lea, Amerigo Lendvai, Huilin Li, Shenghai Li, Zhongqin Li, Andreas Linsbauer, Sebastián Marinsek, Enrico Mattea, Christoph Mayer, Christopher McNeil, Luca Mercalli, Alexandra Messerli, Carolyn Michael, Umberto Morra di Cella, Francisco Navarro, Hofiz Navruzshoev, Anton Neureiter, Gennady Nosenko, Massimo Pecci, Mauri Pelto, Victor Popovnin, Rainer Prinz, Carla Puigdomenech, Heather Purdie, Finnur Pálsson, Alberto Rossotto, Lucas Ruiz, Louis Sass, Erik Schytt Mannerfelt, Riccardo Scotti, Donghui Shangguan, Brenda Shepherd, Delphine Six, Andrey Smirnov, Ireneusz Sobota, Markus Strudl, Shin Sugiyama, Emmanuel Thibert, Laura Thomson, Thorsteinn Thorsteinsson, Levan Tielidze, Florian Tolle, Pavel Toropov, Paolo Tuccella, Gulomjon Umirzakov, Ryskul Usubaliev, Lauren Vargo, Wei Yang, Bernhard Zagel

Glaciers lost 408 ± 132 Gt of mass during the hydrological year 2025, equivalent to 1.1 ± 0.4 mm sea-level rise. Since 1975, glacier mass loss has totalled 9,583 ± 1,211 Gt, equivalent to 26.4 ± 3.3 mm of sea-level rise, with six of the highest mass-loss years on record occurring in the past seven years.

Released April 04, 2026 09:25 EST

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

Phillip J. Goodling, Sydney Foks, Jessica Ayers

Characterizing changes to water availability for domestic, industrial, agricultural, and other uses is essential to support water management. To better quantify these changes, the U.S. Geological Survey and National Science Foundation National Center for Atmospheric Research produced two hydrologic models simulating water budget components from 1980 to 2021 over the contiguous United States (CONUS). Both hydrologic models were driven by a common atmospheric forcing dataset and aggregated to common spatial and temporal scales, which enables a novel evaluation of congruency between the models. We present annual and seasonal trends in six water budget components (precipitation, evapotranspiration, streamflow, groundwater recharge, soil saturation, and snow water equivalent) based on the Mann–Kendall test for monotonic trend and Theil-Sen slope estimate for the water year 1983–2021 period for ~86,000 catchments in CONUS. Additional components and metrics from our analysis pipeline are available in an associated published dataset, which contains more than 46 million trend results. The water budget trends showed broad agreement with prior observational and modeling studies that indicate increasing trends in the northeast and decreasing trends in southwestern CONUS. We found the seasonal variability in water budget trends was greatest in the southern, central, and northwest CONUS. These findings support integrated trend assessments when coupled with trends in water quality and use.

Released April 03, 2026 13:08 EST

2026, Data Report 1222

Suellen Lynn, Barbara E. Kus

Executive Summary 

We surveyed for Least Bell’s Vireos (Vireo bellii pusillus; vireo) and Southwestern Willow Flycatchers (Empidonax traillii extimus; flycatcher) along Big Tujunga Creek in the Hansen Dam Basin in Los Angeles County, California, in 2025. Four vireo surveys were completed between April 17 and July 2, 2025, and three flycatcher surveys were completed between May 20 and July 2, 2025. We detected 62 territorial male vireos, 51 of which were confirmed as paired, and 2 transient vireos. Additionally, we detected 32 juvenile vireos during surveys. Seventy-seven percent of vireos were detected in habitat characterized as mixed willow, and 95 percent of vireos were detected in habitat with greater than 50-percent native plant cover. Most vireo territories were dominated by Goodding’s black willow (Salix gooddingii).

On May 20, 2025, we detected 18 transient Willow Flycatchers of unknown subspecies, none of which were confirmed to be paired, and no juveniles were detected. Mixed willow habitat was used by 78 percent of Willow Flycatchers, and all Willow Flycatchers were detected in habitat with greater than 50-percent native plant cover. Most Willow Flycatchers were detected in locations dominated by Goodding’s black willow.

Released April 03, 2026 09:14 EST

2026, Groundwater

Michael J. Stephens, Bennett Eugene Hoogenboom, Lyndsay B. Ball, Will Chang

Growing concern about the quantity of available freshwater around the world has led to interest in surveying groundwater total dissolved solids (TDS) below water well depths. Deep TDS has not been systematically mapped, and there is much to learn about the distribution and controls on deeper groundwater. In sedimentary basins across the United States, groundwater resources often overlie hydrocarbon resources, providing an opportunity to use borehole geophysical data collected for hydrocarbons to characterize groundwater and pore space resources. This study adapts a recently developed subsurface geostatistical and geophysical modeling approach to continuously map groundwater TDS, porosity, and temperature in the Dakota Group of the Williston Basin—an undercharacterized regional aquifer system overlying deeper hydrocarbon reservoirs. Groundwater TDS in the Dakota Group ranges from approximately 4800 to 26,900 mg/L. TDS patterns are stratified with higher TDS in the lower and upper Dakota Group, and relatively lower TDS in the middle Dakota Group. The lower TDS in the middle zone may represent a preferential regional flow path for lower-TDS meteoric recharge from the west. The alternating pattern of TDS may also be evidence of higher-TDS inflows into the Dakota Group from underlying and potentially from overlying aquifers. Porosity is lower near the center of the Williston Basin and tends to be higher to the east, which may be related to grain size distributions. The new regional TDS and porosity modeling serves as a quantitative reference for water users and provides supporting evidence for hypotheses on Dakota Group recharge.

Released April 02, 2026 15:09 EST

2026, Open-File Report 2026-1005

Lindsey R. King, Sara L. Caldwell Eldridge, Melissa A. Schaar, Travis S. Schmidt, Thomas Chapin, Ashley M. Bussell

The U.S. Geological Survey, in cooperation with the U.S. Environmental Protection Agency, collected water-quality samples and environmental data in Lake Koocanusa (also known as “Koocanusa Reservoir”), the Kootenai River, and the Tobacco River during water years 2022–23. The transboundary Lake Koocanusa is in southeastern British Columbia, Canada, and northwestern Montana, United States. It was formed by constructing Libby Dam on the Kootenai River 26 kilometers upstream from Libby, Montana. One of the lake sites and the Kootenai River site, in the Libby Dam tailwater (the outflow of the lake flow into the Kootenai River), were equipped with automated, high-frequency ServoSipper water samplers. At the lake site, these samplers were mounted to pontoon platforms during the summer, and a submersible ServoSipper sipper was deployed with ice buoys during the winter. Samples were automatically collected from multiple depths. At the Kootenai River site, these samplers were housed in the gage house. In water year 2022, discrete water-quality samples were collected every 4–6 weeks, year round, at all four lake sites in the Kootenai River between April and November. In water year 2023, discrete water-quality samples were collected at three lake sites and the Kootenai and Tobacco River sites every 4–6 weeks. The goal of this project was to collect multidepth, high-frequency vertical and temporal water-quality samples and data to understand the limnological and biological processes that control variations and trends in selenium concentrations and loads throughout Lake Koocanusa and in the Libby Dam tailwater at the southern end of the lake. This sampling and analysis plan documents the organization, sampling and data-collection scheme and design, pre- and post-collection processes, and quality-assurance and quality-control procedures of the Koocanusa/Kootenai water-quality monitoring program during water years 2022–23.

Released April 02, 2026 14:40 EST

2026, Scientific Investigations Map 3544

Page C. Valentine, VeeAnn A. Cross

The U.S. Geological Survey, in cooperation with the National Marine Sanctuary Program of the National Oceanic and Atmospheric Administration, has conducted seabed mapping and related research in the Stellwagen Bank National Marine Sanctuary (SBNMS) region since 1993. The area being mapped using geophysical and geological data includes the SBNMS and the surrounding region, which totals approximately 3,700 square kilometers (km²) and is subdivided into 18 quadrangles. The seabed is a glaciated terrain that is topographically and texturally diverse. Quadrangle 3, the subject of this scientific investigations map, has a mapped area of 185 km² and has water depths that range from about 30 meters (m) on the Stellwagen Bank crest to about 135 m in a basin east of South Ninety Bank, which lies off the eastern margin of Stellwagen Bank. Seven map types, each at a scale of 1:25,000, depict seabed topography, ruggedness, backscatter intensity, distribution of geologic substrates, sediment mobility, distribution of fine- and coarse-grained sand, and substrate mud content. These maps show the distribution of geologic substrates on the southeastern part of Stellwagen Bank, on adjacent banks and basins in deeper water to the east, in the eastern part of Race Point Channel to the south of the bank, and on the northern slope of Cape Cod. Interpretations of multibeam sonar bathymetric and seabed backscatter imagery, photographs, video imagery, and grain-size analyses were used to create the geology-based maps. Data from 309 stations were analyzed, including 279 sediment samples. The geologic substrate maps of quadrangle 3 show the distribution of 21 geologic substrates that represent a wide range of textures, such as rippled sand, immobile sand, immobile muddy sand, sand that partially veneers gravel, and boulder ridges. Mapped substrates are characterized by sediment grain-size composition, surface morphology, substrate layering, the mobility or immobility of substrate surfaces, and water depth range. This scientific investigations map portrays the major geological elements (substrates, topographic features, and processes) of environments in quadrangle 3. It is intended to provide a foundation for research into present and past sediment transport processes in a complex terrain, provide insights into the ecological requirements of invertebrate and vertebrate species that use the various substrates, and support seabed management in the region.

Released April 02, 2026 14:00 EST

2026, Scientific Investigations Report 2025-5090

Jennifer L. Closson, Thomas P. Suro, Lukasz M. Niemoczynski

The Delaware River basin (DRB) provides drinking water to 15 million people in the surrounding area. Water is frequently withdrawn from the freshwater reaches of streams, above head of tide, in the DRB for use as public drinking water. During extended periods of low flow, saltwater can move upstream, which can threaten drinking-water supplies in the basin. Due to spatial patterns in bathymetry, tidal influences within the DRB, and varying weather conditions, it can be hard to predict the movement and upstream extent of the freshwater-saltwater interface, often defined as the salt-front. Although there is a relationship that predicts this location in the main stem of the Delaware River, there lacks a relationship for its tributaries, such as the Maurice and Cohansey Rivers in southwestern New Jersey. In this study, a relationship was developed between daily specific conductance (SC) at gage locations along the tidal river reaches of the Maurice and Cohansey Rivers to the daily upstream location of the salt-front. The study augmented existing real-time tide gage data with the collection of water temperature and specific conductance data to develop the relationship. Additionally, longitudinal profiles upstream of the selected tide gages were conducted during a range of high tide conditions to define the location of the salt-front. Equations were then developed that related the daily SC measured at the tide gage to the upstream location of the salt-front. The equations were used to estimate the daily upstream location of the salt-front for the period of July 15, 2021, to July 15, 2024. This work can aid in understanding the propagation of saltwater upstream, which can affect local communities and crop farmers along these tidal reaches of the DRB.

Released April 01, 2026 18:10 EST

2026, Scientific Investigations Report 2026-5122

John A. Moody, Robert H. Meade

An extreme flood on the Powder River in southeastern Montana in May 1978 inundated its valley and deposited sediment on the floodplains and terraces at multiple heights. The recurrence interval for this flood was less than 1 percent in the reach between Moorhead and Broadus, Montana. Peak discharges at the U.S. Geological Survey streamgages at Moorhead and Broadus were 779 and 711 cubic meters per second (m³/s), respectively, the difference reflecting the water and sediment stored on the valley surfaces. Bankfull discharge depended on the height of the bank at the start of the valley transect and varied from 243 to 713 m³/s. Sediment-thickness and particle-size data were collected and analyzed in the autumn of 1978 by U.S. Geological Survey scientists at about 900 sites along 20 valley transects between Moorhead and Broadus, Mont. These transects were approximately orthogonal to the floodflow across the floodplain from near the edge of the channel to the high-water mark. Estimated maximum flood depths along these transects ranged from 0.9 to 4.2 meters.

Contrary to theory and controlled laboratory experiments, the distribution of sediment thickness and particle sizes along valley transects did not decrease systematically with distance from the main channel but were affected by the distribution of vegetation. Additionally, some water and sediment—primarily muds and silts—were conveyed by subsidiary channels (often connected to the main channel downriver from the valley transect) during the early stages of the flood before water overtopped the banks at the start of the valley transect. The vegetation created natural sediment traps in the recirculation and wake zones in the lee of trees and shrubs. Sediment that accumulated in these traps formed dunes and thus an undulating surface with many local maximums and minimums in sediment thicknesses. Sediment in the traps are referred to as lee dunes, which recorded flow conditions and a predominance of coarsening-upward sequence of particle sizes (mud to silt to sands) starting at the preflood surface. These sequences were associated with the rising limb of the hydrograph, and later as the flood began to recede, the lee dunes recorded a fining-upward sequence associated with the falling limb of the hydrograph.

Released April 01, 2026 14:24 EST

2026, Scientific Investigations Map 3519

Thomas P. Miller, Christopher F. Waythomas, Margaret T. Mangan, Frank A. Trusdell, Andrew T. Calvert

Introduction 

The Emmons Lake volcanic center is a spatially clustered group of stratovolcanoes and calderas in the southwestern part of the Alaska Peninsula, Alaska. The volcanic center is characterized by several ice- and snow-clad stratovolcanoes located within and along the margins of a nested-caldera complex that includes Emmons Lake. A shieldlike ancestral edifice (ancestral Mount Emmons) is truncated by the caldera complex and forms a broad volcanic platform around the center. The main stratovolcanoes of the Emmons Lake volcanic center are Pavlof Sister, Pavlof Volcano, Little Pavlof, Double Crater, Mount Hague, and Mount Emmons. Several small unnamed cinder cones and vents also are located within Emmons Lake volcanic center and on the east flank of Pavlof Volcano. Many of these cones and vents have been the source of the young lava flows that mantle the floor of the caldera. Pavlof Volcano, in the northeastern part of the Emmons Lake volcanic center, is one of the most historically (that is, the past about 300 years) active volcanoes in Alaska, and eruptions from Pavlof Volcano pose the greatest hazards to the region.

Volcanic rocks of the Emmons Lake volcanic center overlie continental and marine sedimentary rocks of chiefly Late Jurassic to early Tertiary age. The oldest rocks in the area are those of the Naknek Formation, consisting of volcaniclastic sandstone, siltstone, and conglomerate of Late Jurassic age. The southern part of the area includes rocks of the Belkofski Formation, a thick sequence of volcaniclastic sandstone, siltstone, and conglomerate of middle Tertiary age. Lava flows, volcanic breccia, and fluvial volcaniclastic rocks of late Miocene age, which unconformably overlie the Belkofski Formation south of the Emmons Lake volcanic center, are primarily exposed on the islands just south of the Alaska Peninsula.

The Emmons Lake volcanic center was affected multiple times by glaciation associated with the glacier expansion that characterized the Quaternary. Glaciation has played a key role in shaping the present-day landscape, and much of the eruptive history of the Emmons Lake volcanic center has involved interactions with glacier ice. Thus, a brief review of the Quaternary glacial history of the area is provided to establish the physical context for Emmons Lake volcanic center eruptive activity.

Released April 01, 2026 10:18 EST

2026, Geochemistry, Geophysics, Geosystems (27)

Raphael Gottardi, Ryan J. McAleer, Gabriele Casale, Martin Wong

We investigate the microtextural, microchemical, and isotopic effects of late-stage ductile deformation in quartzite mylonites and kyanite–muscovite–quartz veins from the Raft River shear zone (Utah). Quartz microstructures record pervasive disequilibrium, expressed by unannealed features including undulatory extinction, deformation lamellae, and poorly defined fabrics, typical of waning deformation in shear zones. Microchemical disequilibrium is best preserved in kyanite quartzites, where CL-zoned kyanite records repeated fractures, overgrowth, and mineral precipitation, and in muscovite from muscovite-poor quartzite mylonites that shows minor-element zoning consistent with syn-deformational overgrowth on detrital cores. In contrast, muscovite from muscovite-rich kyanite quartzites exhibits minimal chemical zoning. These microchemical variations correlate with ⁴⁰Ar/³⁹Ar age systematics. Chemically zoned muscovite preserves variable single-step ages, including ∼150 Ma ages, reflecting retention of detrital cores. In contrast, syndeformational muscovite consistently yields Miocene ages, indicating recrystallization and new growth below argon closure temperatures that reset inherited isotopic signatures. Similar trends are observed in quartzite mylonites, where increasing quartz recrystallization and stronger crystallographic preferred orientations occur toward deeper structural levels. Together, these observations indicate increasing retrograde deformation and recrystallization with depth in the Raft River shear zone and demonstrate that strain-driven recrystallization exerts a first-order control on muscovite ages. We suggest that apparent thermochronologic gradients in retrograde shear zones may reflect recrystallization gradients rather than temperature gradients. Where cooling limits the thermal driving force for recrystallization, isotopic relics are preserved, and local deformation and fluid availability control re-equilibration. Consequently, isotopic disequilibrium—particularly in the ⁴⁰Ar/³⁹Ar system—may be the rule rather than the exception of retrograde tectonic environments.

Released April 01, 2026 09:15 EST

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

Catherine A. Chamberlin, Glenn Hodgkins

Streamflows in Massachusetts have set record lows in recent years despite generally wetter conditions than during the drought of the 1960s, and the reasons for this are not known. To analyse potential drivers of low streamflows in Massachusetts, six low-flow metrics were computed at 107 streamgages. These metrics represent low-flow magnitude, magnitude normalized to median flows, and duration. Multiple linear regressions were used to analyse the variability of low flows over space and time. Potential explanatory variables were computed using climatic, land use, water use, and basin data. For all low-flow metrics, the ratio of precipitation to potential evapotranspiration (P/PET) in July–August explained the most variability, with decreasing P/PET largely explained by lower precipitation. Water/wetland area was a significant explanatory variable in all the normalized-magnitude and duration models, with greater area associated with lower normalized magnitudes and with shorter durations of low flows. Human influence (characterized by development, population, water use, and artificial water storage) had mixed effects. Trends from 1983 to 2022 in summer P/PET and human influence have been strongest in the eastern part of the state where the strongest decreases in flows are observed. Low flows in Massachusetts seem to be driven by a combination of low summer precipitation and human effects, though the specific mechanisms of human influence on flow likely vary between basins.

Released April 01, 2026 09:01 EST

2026, Newsletter

Aaron Lien, Stephanie Anne McAfee

No abstract available.

Released April 01, 2026 08:54 EST

2026, Technical Note ERDC/EL TN-26-1

K. Jack Killgore, David Ruppel, Faucheux. Nick, W. Todd Slack, Amanda J.M. Oliver, Josey Lee Ridgway, Jesse Robert Fischer, Robin D. Calfee

A total of 41 sites along a 58 mi reach of the Lower Mississippi River (LMR) were surveyed during winter 2022 for invasive carp aggregation.* Sites consisting of scallops closest to the dike-vegetated bank interface with deeper, slow-moving water and consistent access back to the main channel were preferred. Carp avoided strong currents, and there was no trend in depth selection other than avoiding shallow (less than 20 ft) water. In January 2023, recreation-grade sonar (e.g., side-scan and down-imaging) surveys were conducted in the same reach of the LMR
to demonstrate the technology and evaluate carp population size at sites with high abundances based on previous surveys. Fish density was estimated to be 32 fish/10,000 yd³ (95% confidence interval [CI; 31–34]) using down-imaging software, which is the first estimate of assumed bigheaded carp density in the LMR. Additional fish collections are needed to confirm species composition and size abundance provided by sonar technology. Resurveying sites with high carp abundance over a range of river stages would be necessary to fully characterize habitat conditions, evaluate influence of river stage on occupancy duration, and continue to evaluate species composition and mass removal techniques as a management option in the Lower Mississippi River. 

Released April 01, 2026 00:00 EST

2026, Avian Conservation and Ecology (21)

Elsa M. Forsberg, Rose J. Swift, Larkin A. Powell, Joel G. Jorgensen, Mark P. Vrtiska

Knowledge of factors that influence nest survival can inform effective conservation management for imperiled avian species. Habitat availability and quality are common priorities of conservation efforts, and climate and interspecific associations can also affect survival rates. In the lower Platte River system of eastern Nebraska, USA, Piping Plovers (Charadrius melodus, hereafter plovers) nest on river sandbars and different types of human-created off-river sites (i.e., sand and gravel mines, housing developments, and transitional sites) that are unique within the Northern Great Plains breeding population. However, off-river habitat may not be suitable for plover nesting long-term because of reduced habitat availability on both river sandbars and off-river sites. We evaluated plover nest survival at off-river and sandbar sites using data from 2008 to 2023 (n = 285). In addition, we examined the effects of extreme temperatures, proximity to conspecific and Interior Least Tern (Sternula antillarum athalassos, hereafter tern) nests, and temporal factors on nest survival. Plover nest survival did not differ between off-river sites and sandbars or amongst different off-river site types. Daily nest survival was 0.9818 (95% CI = 0.9729–0.9878) from 2008 to 2013 (unexclosed; n = 87) and 0.9950 (0.9918–0.9970) from 2014 to 2023 (exclosed; n = 198). Nest survival increased with the proportion of above average temperature days, increased with proximity to neighboring tern nests, and decreased with later nest initiation dates. Therefore, prioritizing early season nests, recognizing the benefits terns provide to plover nest survival, and monitoring the effect of climatic trends may aid future conservation efforts. Finally, as nest survival at off-river sites is comparable to sandbars, the predicted decline of habitat provided at off-river sites may reduce the overall breeding productivity and abundance of plovers in the lower Platte River system with ramifications to broader population viability.

Released March 31, 2026 13:40 EST

2026, Professional Paper 1890-B

Jan M. Lindsay, Elaine R. Smid, Natalie Balfour, Natalia I. Deligne, Angela Doherty, Annahlise Hall, Tracy Howe, Gill Jolly, Graham Leonard, Kate Lewis, Craig A. Miller, Ema Nersezova, Ross Roberts, Richard E. Smith, Thomas Stolberger, Kelvin Tapuke, Thomas M. Wilson

The Determining Volcanic Risk in Auckland (DEVORA) Research Programme was launched in 2008 to address the challenges associated with monogenetic volcanism in an urban setting and to enhance volcanic risk management in Tāmaki Makaurau Auckland in Aotearoa New Zealand. It is a multi-agency, increasingly transdisciplinary (defined here as research that transcends traditional disciplinary boundaries by integrating diverse types of knowledge, perspectives, and methods from academic and non-academic participants to create novel solutions to complex problems), and collaborative research program jointly led by Waipapa Taumata Rau University of Auckland and Earth Sciences New Zealand (ESNZ; formerly GNS Science), with core funding from Natural Hazards Commission Toka Tū Ake (NHC; formerly the Earthquake Commission, EQC) and Te Kaunihera o Tāmaki Makaurau Auckland Council (AC). The primary research focus of DEVORA is to investigate the geologic history, volcanic hazards, and risk posed by the basaltic intraplate Auckland Volcanic Field. Disruption from ash fall and gas from other Aotearoa New Zealand volcanoes is also considered. DEVORA’s work to explore exposure and vulnerability in Tāmaki Makaurau Auckland is also useful for assessing risks from other non-volcanic natural hazards, such as seismic and tsunami hazards. The greater Tāmaki Makaurau Auckland region has an ethnically and socio-economically diverse population of approximately 1.7 million, representing about one-third of the Aotearoa New Zealand population, and hosts critical infrastructure of national significance. The size and nature of the populace, consequential economic base, and important infrastructure within Tāmaki Makaurau Auckland mean that the effects of a volcanic eruption would be felt nationally, including through the disruption of air travel to Aotearoa New Zealand. The hazards from such an eruption could potentially affect hundreds of thousands of people, businesses, and lifelines (critical infrastructure). A considerable challenge for emergency and risk managers is the monogenetic nature of the volcanic field. It is not known where or when the next eruption will occur, how much warning we may get before an eruption, nor how an eruption and its effects might unfold. In this contribution, we highlight the concept and collaborative intent of the DEVORA Programme and show how it has evolved over the 16 years since its inception. We describe how DEVORA has unified more than 100 researchers (including more than 50 graduate students) and numerous stakeholders to address key issues facing Tāmaki Makaurau Auckland and describe how research findings are being implemented into policy and communicated to stakeholder agencies and the public. We also illustrate the broader influence of the DEVORA Programme and provide some learnings that might benefit others embarking on similar integrated projects, especially those focused on distributed volcanism in and near populated areas.

Released March 31, 2026 08:48 EST

2026, Report

Nicole M. Watson, Isabel I. Field, Jared Thomas Myers, Daniel Yule

The U.S. Geological Survey has conducted annual trawl surveys across Lake Superior since 1978 that describe trends in fish species occurrence and relative abundance to support fisheries science and management. In 2025, the Lake Superior fish community was sampled with daytime bottom and surface trawls at 72 nearshore stations in May and June and 36 offshore locations in July. Nearshore bottom trawls collected 63,005 fish represented by 30 species or morphotypes. The number of species collected at each location ranged from 1 to 13, with a median of 7.0 species. Estimated fish biomass density at individual stations ranged from <0.1 to 125.7 kg per ha with a lakewide mean of 7.6 kg per ha. Offshore bottom trawls collected 30,342 fish represented by 13 species or morphotypes. Estimated fish biomass density at individual stations ranged from 1.6 to 34.7 kg per ha with a lakewide mean of 9.1 kg per ha, which was the highest since the offshore survey began in 2011. Lakewide average numerical densities (fish per ha) of age-1 fish were 0.67 per ha for Bloater, 0.01 per ha for Cisco, 1.15 per ha for Kiyi, 0.95 per ha for Lake Whitefish, and 336.33 per ha for Rainbow Smelt. Surface trawling collected 1,562 larval Coregonus individuals which was the fewest Coregonus larvae collected in a whole lake survey since the larval fish survey began in 2014. Nearshore mean larval Coregonus numerical densities were 156 fish per ha in May and June 2025 and 21 fish per ha in July 2025. May mean surface water temperatures (6.1°C) were near the warmest for the period-of-record, while June (6.8°C) and July (10.0°C) were near average or below.  

Released March 31, 2026 08:45 EST

2026, Earth Stewardship (3)

Kinzie Cherrel Bailey, Jia Hu, Alison M. Meadow, Stephanie Anne McAfee, Alexandder Gershunov, Carolyn Armstrong Enquist, Daniel Cayan, Beth Rose MIddleton Manning, Elizabeth Fard, Geln MacDonald, Gregg M. Garfin, Michelle Baker, Nancy Huntly, Richard F. Ambroase

The southwestern United States consists of diverse ecosystems that are experiencing increasing pressures from rising temperatures, increasing aridity, and sea level rise. To prepare this region for future uncertainty, there is a need for strong partnerships among researchers and societal partners. The Southwest Climate Adaptation Science Center (SW CASC) acts to foster engaged scholarship from diverse perspectives to produce science relevant for management and policy decisions. Here, we synthesized a subset of SW CASC-funded projects and published manuscripts to illustrate how the combination of new scientific knowledge and the research and practice of engaged scholarship produce actionable science with direct societal impacts. In the SW CASC Contributions to Regional Science section, we touch on new research produced from funded projects on the most common topics: (1) Forest Ecosystems, (2) Coastal Ecosystems, (3) Hydrometeorology, and (4) Research on Engaged Scholarship. In the SW CASC Contributions to Regional Impacts section, we outline engaged scholarship activities to demonstrate how they created societal impacts: (1) the Keepers of the Flame course and workshops, (2) the Southwest Fire Climate Adaptation Partnership and the Southern California Montane Forests Project, (3) the Coastal Managers Workshop, (4) the Colorado River Basin Wiki, and (5) the Natural Resource Workforce Development Program. In the SW CASC Publications Cited in Policy section, we used a bibliometric analysis to assess the impact of the SW CASC-funded research on policy. We analyzed how often publications were used in policy documents, finding a citation rate of 27.6%. This is high compared to similar analyses that found peer-reviewed research articles cited at a rate of 3.9% in policy documents. We conclude that coproduced science makes unique and important contributions to the resilience of the Southwest, not only by generating new knowledge but by building capacity, creating lasting relationships, and informing policy and conservation and management decisions.

Released March 30, 2026 08:38 EST

2026, People and Nature

HyeJin Kim, Garry Peterson, Hyeonjeong Kim, Hanvit Lee, Miyoung Yeo, Youngcheol Cho, Paula A. Harrison, Gwanwoo Jin, Bohun Kang, Junsoo Kim, Sanha Kim, Kyung Ah Koo, Brian W. Miller, Laura M. Pereira, SoEun Ahn, Lisa Yeonjung Gwon, Jaegyun Im, Seul-gi Lee, Chunhwa Park, Jiyeon Park, Soojin Park, Yea-Yl Yoon, Yukyong Jung Yun Choe, Mijung Im, Jae Chun Choe

1.The Korean Demilitarized Zone (DMZ), a buffer between North and South Korea, holds profound historical, cultural and ecological significance, as well as exceptional potential for conservation and transformation. This study explores ecologically diverse and peaceful futures for the Korean Peninsula by envisioning the DMZ as a landscape for harmonious human–nature co-existence.

2.Using the Nature Futures Framework (NFF) and the Seeds of Good Anthropocenes (SoGA) approach, we co-developed four ‘Living in Harmony with Nature’ visions that reflect diverse values and meanings of nature for sustainable and well-being oriented futures in Korea.

3.These visions emphasize balancing human activities with ecological integrity, reimagining the DMZ as a space for peace, restoration and shared stewardship. They express citizens' perspectives on aspirational and inclusive futures, highlighting existing initiatives as levers for change and intersectoral and interdisciplinary collaboration as key enabling conditions. 

4.This visioning process demonstrates the role of the science-policy-society interface, diverse stakeholder engagement and integration of history, culture and social cohesion. This paper reflects on the lessons from this process and discusses implications for future scenario development—particularly how a whole-of-society approach can help identify policy options and societal transformations that advance nature–people-positive futures in Korea and beyond.

Released March 29, 2026 09:34 EST

2026, Environmental Science and Technology.

Mohammed Baalousha, Morgane Desmau, Roberto A. Colina-Ruiz, Antonio Lanzirotti, Sheryl A. Singerling, Michelle A. Stern, Charles N. Alpers

The increasing activity of wildland–urban interface (WUI) fires has raised concerns regarding the potential environmental and human health impacts of residual ash remaining after burning. In this study, we investigated the concentration and speciation of titanium in WUI fire ash. Total titanium concentrations in WUI fire ash ranged from 0.53 to 80 g kg^–1. Synchrotron-based macro- and microscale X-ray absorption near-edge structure (XANES and μXANES, respectively) spectroscopy were used to quantify the relative abundance of major Ti phases in the fire ash, and the results were corroborated by high resolution-transmission electron microscopy (HR-TEM) measurements. Rutile (α-TiO₂), anatase (β-TiO₂), ilmenite (FeTiO₃), and titanium(III) oxide (Ti₂O₃) were detected in all 20 ashes investigated by XANES and accounted for 0.26–0.83, 0.19–0.83, 0.33, and 0.17–0.72 of the spectral weight, respectively. Deeper analysis by μXANES of one sample demonstrated that Ti-bearing particles occurred as a mixture of rutile (α-TiO₂), anatase (β-TiO₂), ilmenite (FeTiO₃), and titanium(III) oxide Ti₂O_3, with the absence of a pure Ti₂O₃ phase. The presence of Ti₂O₃ in the WUI fire ash is ascribed to the reduction of rutile and anatase to Magnéli titania (Ti_nO_2n–1, n = 4–9), which is estimated to be the dominant phase of titanium in the 20 WUI fire ashes investigated by XANES. The occurrence of Magnéli titania was corroborated by HR-TEM. Our findings demonstrate the impact of WUI fires on titanium speciation; fires convert titanium dioxides (e.g., rutile and anatase) to reduced titanium phases (e.g., Magnéli titania). Based on HR-TEM analyses, most of the titanium-bearing particles were less than 500 nm in size. Magnéli particles have been shown to be more toxic than rutile and anatase and have been linked to reduced lung function. Therefore, this study provides critical insights into the pollution characteristics and potential health risks of WUI fire ashes and associated particles, which are currently poorly understood.

Released March 27, 2026 14:15 EST

2026, Open-File Report 2026-1068

Allan J. Ruddy, Emily E. Woodward, Gerolamo C. Casile

Supersaturation of total dissolved gases (TDG) can potentially occur in the tailrace water at the Youghiogheny River at dam outlet tunnel near Confluence, Pennsylvania (U.S. Geological Survey [USGS] streamgaging and monitoring station 03077100). The USGS, in cooperation with the U.S. Army Corps of Engineers, established methods to collect and report TDG saturation data in the tailrace below the Youghiogheny Dam. Monitoring and TDG data collection started in June 2008 and continues currently (2025). Data are collected from June 1 through November 30 of each year, and these data are used by the U.S. Army Corps of Engineers to guide management of the dam outflow. Methods used for data collection, processing, reporting, and quality assurance for TDG monitored at USGS station 03077100 are presented in this report. The TDG data are publicly available in the USGS National Water Information System database.

Released March 27, 2026 09:05 EST

2026, Environmental DNA (8)

Conor O'Kane, Nicholas S. Johnson, Kim T. Scribner, Jeannette Kanefsky, Weiming Li, Tyler Bruning, John D. Robinson

The sea lamprey (Petromyzon marinus), a non-native species in the Laurentian Great Lakes, has significantly impacted native fish communities and commercial fisheries, requiring population suppression efforts. While traditional control methods such as lampricides and barriers have reduced sea lamprey population abundance, questions remain regarding sea lamprey dietary composition given the focus of current damage assessments on economically and ecologically important host species. Recent advances in molecular technology offer promising methods of sea lamprey dietary assessment. Specifically, DNA metabarcoding enables species-specific identification of taxonomically diverse prey items from gut and fecal samples, and has proven effective in many taxa, including hematophagous species such as Arctic lamprey (Lethenteron camtschaticum) and sea lamprey. However, studies on DNA retention within digestive tracts are limited, particularly given the potential effects of environmental and dietary factors among hematophagous species. We used controlled feeding experiments to understand the effects these factors may have on DNA retention and host detectability within sea lamprey digestive tracts. Additionally, we evaluated the utility of metabarcoding for identifying multiple host species from consecutive feedings. Results indicate that host DNA can be detected up to 30 days post-feeding, with detection probability decreasing with increasing time following feeding. Temperature effects were dependent upon fasting periods, and host-switching trials indicated multiple previous host species could be detected from a single lamprey. Findings provide valuable insights for refining dietary analysis protocols for wild-caught sea lamprey within native and introduced ranges.

Released March 26, 2026 08:41 EST

2026, Remote Sensing of Environment (339)

Juliet Biggs, Nantheera Anantrasirichai, Kyle R. Anderson, Valerie Cayol, Edna W. Dualeh, Quentin Dumont, Susanna K. Ebmeier, Jean Luc Froger, Matthew Gaddes, Federico Galleto, Pablo J. Gonzales, Ian Hamling, Andrew Hooper, Milan Lazecky, Camila Novoa Lizama, Matthew E. Pritchard

Sentinel-1 has transformed how satellite radar data (SAR and InSAR) are used in volcanology. The systematic, long-term archive and open-access policy means that volcano observatories and research organisations have invested in integrating Sentinel-1 datasets into their monitoring systems. We identify 233 high priority volcanoes and estimate that Sentinel-1 data has been used in peer-reviewed publications for 90 of them. We examine a global archive of 3.3 million automatically processed Sentinel-1 interferograms of volcanoes and use machine learning methods to identify eruptions and periods of unrest. We then review the ways in which InSAR data are being used in different contexts. At frequently erupting basaltic systems in Iceland, Hawaiʻi, the Galápagos , and Piton de la Fournaise, InSAR has become an effective monitoring tool and is integrated with other datasets and models to forecast magma pathways. For large explosive eruptions, deformation measurements often remain challenging, but SAR backscatter is increasingly used to map damaging flows and measure the changing shape of ocean islands. Sentinel-1's long archive provides critical baseline measurements that are vital for measuring slow deformation, capturing new periods of unrest and providing fresh insights into subsurface dynamics. Understanding the drivers of deformation remains challenging and typically relies on integration with external datasets. Future European Space Agency missions have the potential to improve both resolution and coverage providing an even richer dataset to further enhance global volcano monitoring

Released March 25, 2026 13:50 EST

2026, Scientific Investigations Report 2026-5123

Matthew J. Kauffman, Blake Lowrey, Jennifer L. McKee, Chloe J. Beaupre, Jeffrey Beck, Jon Beckmann, Scott Bergen, Joel Berger, Regan Berkley, Nathan Borg, Peyton Carl, Michelle Cowardin, Sarah Dewey, Katie M. Dugger, Amy Ehrhart, Jessica Fort, Eric Freeman, Ian Freeman, Emily R. Gelzer, David German, Jacob Gray, Evan Greenspan, Zach Gregory, Emily Hagler, Makeda Hanson, Valerie D. Hinojoza-Rood, Pat Hnilicka, Nick Jaffe, Andrew F. Jakes, Aran Johnson, Jaron T. Kolek, Art Lawson, Zach Lockyer, Daryl Lutz, Cody McKee, Jane McKeever, Jerod Merkle, Matthew A. Mumma, Dennis Newman, Erika Peckham, Jill E. Randall, Tempe Regan, Adele K. Reinking, Robert Ritson, William J. Rudd, Brianna M. Russo, Hall Sawyer, Cody Schroeder, Brandon Scurlock, Jeff Short, Bret Stansberry, Erik Steiner, Alethea Steingisser, Tom Stephenson, Eric VanNatta, Cody F. Wallace, Brad Weinmeister, Don Whittaker, Tatjana Woody, Sean Yancey

This report, volume 6 in the “Ungulate Migrations of the Western United States” report series, showcases the migrations of 23 ungulate herds in the Western United States. The report series is produced by the Corridor Mapping Team (CMT). Led by the U.S. Geological Survey, the CMT is a collaboration among 11 State agencies, as well as regional and Federal partners, and an expanding number of Tribal wildlife agencies. The CMT was initiated in response to the U.S. Department of the Interior Secretarial Order 3362, which was signed in 2018 and provided Federal support to expand existing research efforts to study ungulate populations and conserve their migrations throughout the Western United States. Including this volume, the report series has detailed the migrations of 237 unique ungulate herds throughout the Western United States and continues to serve as a valuable resource to guide local and regional management, policy, and on-the-ground work necessary to maintain intact and functional ungulate migrations. This report highlights several guiding principles of the CMT that facilitate collaboration among the diverse set of partners and contribute to the program’s continued successes. Notably, raw global positioning system data are not shared among participating agencies and the U.S. Geological Survey, delineating migration corridors and seasonal ranges relies on empirical data, the CMT provides flexible approaches to participating State and Tribal partners, and regular CMT meetings create a framework for open communication among agency partners that supports transboundary mapping of migrations. The 237 ungulate migrations that have been included in the report series are an expanding inventory, which can help maintain ungulate migrations in perpetuity.

Released March 25, 2026 12:54 EST

2026, Forest Policy and Economics (186)

Mohammad Mashiur Rahman, James R. Meldrum, Julie M. Mueller, Christopher Huber

Forest restoration in a watershed can provide numerous ecological improvements and social benefits, including reducing the risk of extreme wildfire. Understanding the values of the accrued benefits can be used to evaluate the use of funds to support restoration. The Rio Grande watershed is a vast watershed covering approximately 335,000 mile² (867,646 km²). The Rio Grande watershed provides a host of ecosystem services and recreation opportunities and supports municipal water supplies. We estimate the non-market values of forest restoration in the Rio Grande watershed using a choice experiment (CE) approach. While the ecological benefits are established in literature, we focus on the social characteristics, capturing the human-forest system in a comprehensive manner. Our results indicate a significant willingness to pay (WTP) for improving air quality, reducing private property damage, and creating local jobs, with the highest WTP for job creation. Split-sample analysis indicates respondents residing within the watershed highly value the socio-economic attributes of the restoration, while ecological attributes are preferred more outside of the watershed. Our results provide insights into the benefits of multi-dimensional services from forest restoration activities in a watershed.

Released March 25, 2026 10:16 EST

2026, Journal of Great Lakes Research

Vindhyawasini Prasad, Henry F. Doyle, Cory Suski, P. Ryan Jackson, Amy E. George, Jesse Robert Fischer, Benjamin H. Stahlschmidt, Anne Marie Herndon, Rafael O. Tinoco

Recent evidence of invasive grass carp (Ctenopharyngodon idella) reproducing in tributaries to the Laurentian Great Lakes has highlighted the need for control efforts targeting multiple life stages. Initial attempts to control dispersal of downstream-drifting invasive carp ichthyoplankton (i.e., eggs and larvae) using an oblique bubble screen (OBS) revealed that nearly neutrally buoyant grass carp eggs and larvae enter helical-like motions driven by the OBS, preventing aggregation within a single capture location. To improve dispersal control methods for such early-life stage carp, we used a laboratory flume to investigate the efficacy of a streamwise-oriented bubble screen to facilitate their near-bank capture. Five early-life stages of grass carp were tested: live water-hardened eggs, pre- and post-gas bladder inflation larvae, dead larvae, and dead eggs (preserved in formalin solution and later rehydrated). A range of mean channel velocities (0.23, 0.45, and 0.75 m/s) was tested for all drifters. Capture percentages increased with increasing airflow. Preserved eggs, for instance, showed capture percentages up to 95 %, 87 %, and 69 % at low, medium, and high water velocities for the highest airflow rate, respectively, in contrast with the lower than 5 % capture measured for zero airflow cases. Symmetric secondary flow structures on either side of the bubble screen induced helical trajectories of drifters and facilitated their capture in net-arrays along each wall. Velocity data were used to estimate helical recirculation timescales, enabling calculation of optimal bubble diffuser and net-array lengths for desired capture rates. This study provides useful guidance for the design of effective systems to control dispersal of downstream-drifting ichthyoplankton of invasive carp in streams.

Released March 25, 2026 09:41 EST

2026, International Journal of Coal Science & Technology (13)

Bridget R. Scanlon, Robert C. Reedy, Brent A. Elliott, James C. Hower, J. Richard Kyle, Marek Locmelis, Nolan Theaker, Peter D. Warwick

United States heavy reliance on imports of critical minerals (CMs), including rare earth elements (REEs), underscores the importance of development of domestic sources. The study objective was to quantify CM and REE concentrations in coal and coal ash in the US Gulf Coast region. CM and REE concentrations were measured for 118 samples from outcrops and 14 mines in the Gulf Coast. Results show that total REE + Yttrium (REY) concentrations (dry coal basis) are comparable to those of the upper continental crust (UCC) with localized hot spots, such as the Texas Gibbons Creek mine (REY ≤ ~ 2860 ppm). When normalized to UCC REY concentration (169 ppm, dry coal basis), REY to UCC ratios for Gulf Coast coal samples range from 0.1 to 17 (median ratio 0.6). REE extractability from lignites is high (median: 63%–93%) using environmentally benign weak acid. In addition to raw coal, coal ash from power plants could also serve as an REE source with a median ratio of REY in ash relative to coal of 4; however, extractability from coal ash is generally much lower (≤ 5% using the same weak acid as in coal). The median basket price for extracted REY as oxides from coal, assuming 70% extractability, is $3.2 per tonne of coal and $186 billion based on 58 billion metric tonnes of dry coal in the Gulf Coast. REEs important for magnets (Pr + Nd + Tb + Dy) account for ~ 80% of the total value. The corresponding median basket price for extracted REY as oxides from coal ash, assuming ~ 30% extractability, is ~$4.4 per tonne of ash and $1.2 billion based on 258 million tonnes of ash. REE production from coal would likely require co-products, such as activated carbon or humic acids, to attain economic viability. Production of REEs from coal ash could offset remediation costs related to potential water contamination. This reconnaissance study shows the potential for REE production from coal and coal ash in the Gulf Coast; however, carbon coproducts and/or societal benefits would likely be required for socioeconomic viability.

Released March 25, 2026 08:20 EST

2026, Water (18)

Elijah I. Ohimain, Robert Eugene Turner, Beth A. Middleton

Mangroves are crucial for biodiversity conservation, coastal protection, and supporting local livelihoods. Mangroves may also protect coasts from storms and rising sea levels and can play a major role in climate mitigation. Threats to their health include activities such as infrastructural development, urban encroachment, aquaculture and crop farming, and oil and gas exploration. We review the threats and opportunities for the restoration of mangrove ecosystems on the coasts of Africa, which are highly impacted by oil spills. The most important challenge for mangrove restoration identified in this review is the restoration of appropriate hydrologic and salinity regimes prior to natural recruitment or the active planting of propagules.

Released March 25, 2026 07:49 EST

2026, Landscape Ecology (41)

Miguel L. Villarreal, Tara B. Bishop, Temuulen Ts. Sankey, William K. Smith

Landscape ecologists have long depended on satellite and aerial remote sensing to address questions about landscape pattern and process, structure, and change (Foody 2023). Unoccupied aerial systems/vehicles (UAS/UAV, a.k.a. drones) technology is becoming an increasingly popular research tool in environmental sciences allowing scientists to generate low-cost, high-quality, and high-resolution imagery on demand that can be tailored to specific research questions. While satellite data are of a fixed resolution and temporal interval, UAS offer researchers control and flexibility to design studies and collect data at resolutions and scales that provide ecologically relevant information at finer spatial resolutions (e.g., < 30 cm) than what is currently available from satellite platforms (typically > 3m), thus helping capture objects such as individual plant canopies, micro-topography, and individual animals. Unlike satellites with fixed orbits, UAS can be deployed at more optimal temporal frequencies for ecological monitoring.

We organized the special collection “Advances and Applications of Unoccupied Aerial Systems (UAS) Research in Landscape Ecology” to showcase the many ways that UAS tools and technologies are currently applied to advance landscape ecological research. When we announced the collection in 2023, only 11 papers published in the journal Landscape Ecology used UAS data, which was a notably small number compared to many other general ecology, environmental science and remote sensing journals. In an attempt to understand why UAS were not more widely used in landscape ecology and provide possible solutions, we published a review article (Villarreal et al. 2025) that identified the challenges, knowledge gaps, and obstacles for the adoption of UAS technologies in landscape ecology research. The main issues we identified include: (1) an abundance of UAS methods papers in the existing literature, with comparatively few studies demonstrating how UAS can be applied to address ecological questions; (2) a perceived scale mismatch between the geographic extent of UAS data collection (local) compared to larger study areas (landscapes) and a need to design robust scaling approaches to connect fine-scale UAS data with broader ecological patterns; and (3) a need for improved integration of UAS data with other commonly used remote sensing datasets including historical high resolution aerial imagery. Additionally, researchers new to UAS remote sensing may be discouraged or overwhelmed by the general lack of scientific consensus and standardized protocols for typical tasks such as data collection, vegetation classification, and change detection, as well as restrictive and/or confusing policy, regulatory, and legal issues surrounding UAS operations (Villarreal et al. 2025).

Released March 25, 2026 07:00 EST

2026, Data Report 1218

Scarlett L. Howell, Barbara E. Kus

Executive Summary 

We surveyed for Least Bell’s Vireos (Vireo bellii pusillus; vireo) and Southwestern Willow Flycatchers (Empidonax traillii extimus; flycatcher) at the Mojave River Dam study area near Hesperia, California, in 2025. Four vireo surveys were completed between April 23 and June 26, 2025, and three flycatcher surveys were completed between May 16 and June 26, 2025.

We detected two territorial male vireos, both of which were paired, and one transient vireo. No juvenile vireos were observed during surveys. Vireos were reported in two habitat types: riparian scrub dominated by narrowleaf willow (Salix exigua) or mule fat (Baccharis salicifolia) and willow-cottonwood dominated by red or arroyo willow (Salix laevigata or lasiolepis). One transient willow flycatcher of unknown subspecies was observed in willow-cottonwood habitat dominated by Fremont cottonwood (Populus fremontii).

Released March 23, 2026 13:03 EST

2026, Journal of Geophysical Research: Earth Surface (131)

Liam Toney, Michael E. West, Ezgi Karasözen, Denny M Capps, Elaine A. Collins, Kate E. Allstadt, Jana Pursley, Heather McFarlin, Anne Mangeney, David Fee, Dennis M. Staley, Matthew M. Haney, John J. Lyons, John Bellini

Large, rapid landslides are a global hazard that can occur in remote, mountainous areas. Eyewitness reports of landslides and satellite imagery can often be limited or delayed, particularly during inclement weather. However, landslide-generated seismic and infrasound (low-frequency atmospheric sound) waves can be remotely detected in near real-time. This information can significantly expedite characterization and possible landslide response activities. Here, we highlight these capabilities using a > 4 million m³ ice–rock avalanche in Denali National Park and Preserve (Alaska). This event was detected via a landslide-specific seismic location and volume estimation algorithm deployed in Alaska, and — notably — by standard earthquake monitoring systems. Following rapid detection of this event, we combined its seismic and infrasound dataset with optical, synthetic aperture radar, and oblique aerial imagery, multitemporal digital elevation models, and a numerical flow model to reconstruct its failure timeline and dynamics. We apply array processing to infrasound signals traveling > 250 km and find that two precursory events occurred minutes prior to the main failure. We use long-period seismic signals to infer the force exerted by the landslide on the Earth and constrain the rheological parameters of our numerical flow simulation with this result and deposit morphology. The main failure produced a steeply-dipping impulsive initial downward force and reached speeds exceeding 60 m/s. This impulsive force generated relatively strong seismic body waves, which contributed to the earthquake system detection. This large, remote Alaska landslide underscores the key value of seismic and infrasound analysis for rapid landslide assessment and motivates efforts to further operationalize these approaches.

Released March 23, 2026 08:53 EST

2026, Geophysical Research Letters (53)

Bryant C. Jurgens, Zeno F. Levy

Groundwater age offers important insight into recharge, storage, and contamination risk. Although models predict age changes can be driven by pumping and climate variability, direct observational evidence remains limited. Here, we analyzed paired environmental tracer suites (tritium, carbon-14, and tritiogenic helium-3) collected a decade apart from 268 wells across California to assess the prevalence of groundwater age transience. Travel-time distribution models and statistical tests indicated age transience at 29% of sites, occurring most often in agricultural regions, such as the San Joaquin Valley and Southern Coast Ranges, where large carbon-14 changes coincided with substantial nitrate and chloride shifts. Sites with tritiogenic helium-3 data showed more frequent age transience, underscoring the value of multi-tracer data sets. These results provide the first regional evidence of widespread groundwater age change and a method for detecting changing water balances with implications for groundwater sustainability and water quality.

Released March 23, 2026 08:29 EST

2026, Conservation Biology

Autumn-Lynn Harrison, Candace Stenzel, Alexandra Anderson, Jessica Howell, Richard B. Lanctot, Marley Aikens, Joaquín Aldabe, Liam A. Berigan, Joël Bêty, Erik Blomberg, Juliana Bosi de Almeida, Andy J. Boyce, David W. Bradley, Stephen C. Brown, Jay D. Carlisle, Edward Cheskey, Katherine Christie, Sylvain Christin, Rob Clay, Ashley A. Dayer, Jill L. Deppe, Willow B. English, Scott A. Flemming, Olivier Gilg, Christine Gilroy, Susan Heath, Jason M. Hill, J. Mark Hipfner, James A. Johnson, Luanne Johnson, Bart Kempenaers, Paul Knaga, Eunbi Kwon, Benjamin J. Lagassé, Jean-François Lamarre, Christopher Latty, Don-Jean Léandri-Breton, Nicolas Lecomte, Pam Loring, Laura Anne McDuffie, Rebecca L McGuire, Scott Moorhead, Juan G. Navedo, David Newstead, Erica Nol, Alina Olalla-Kerstupp, Bridget Olson, Elizabeth Olson, Julie Paquet, Allison K. Pierce, Jennie Rausch, Kevin Regan, Matthew E. Reiter, Amber M. Roth, Mike Russell, Daniel R. Ruthrauff, Sarah T. Saalfeld, Amy L. Scarpignato, Shiloh Schulte, Nathan R. Senner, Joseph A.M. Smith, Paul A. Smith, Zach Spector, Kelly Srigley Werner, Michelle L. Stantial, Audrey R. Taylor, T. Lee Tibbitts, Mihai Valcu, Nils Warnock, Walter Wehtje, Brad Winn, Michael B. Wunder

Addressing urgent conservation issues, such as the drastic declines of North American migratory birds, requires creative, evidence-based, efficient, and collaborative approaches. The abundance of over 50% of monitored North American shorebird populations has declined by over 50% since 1980. To address these declines, we developed a partnership of scientists and practitioners called the Shorebird Science and Conservation Collective (hereafter the collective). The collective was founded to translate the combined findings of shorebird tracking data into on-the-ground conservation action. With advice from an advisory group, the collective acts as an intermediary whereby dedicated staff collate and analyze data contributions from scientists to support knowledge requests from conservation practitioners. In its first three years, data contributions from 75 organizations include over 7.1 million shorebird observations forming movement paths of 3420 individuals representing 36 species tracked across the Americas and have informed 18 conservation projects spanning education, land and species management, land conservation, and policy requests. Others engaged in translational science from big data could consider similar knowledge-sharing models that prioritize usable data products, foster collaborative engagement between science experts and practitioners, build focused communities around topics or taxonomic groups, and employ a proof-of-concept phase to develop scalable solutions while making progress toward long-term funding to sustain impact. As the volume of scientific data continues to grow, intermediaries, such as the collective, can be vital liaisons to rapidly integrate and interpret research to support conservation action. Dedicated to the memory of Shiloh Schulte and his conservation achievements for shorebirds.

Released March 22, 2026 09:32 EST

2026, Journal of Environmental Quality (55)

Tucker R. Burch, Joel P. Stokdyk, Joe Heffron, Sarah A. Opelt, Aaron D. Firnstahl

Private wells supply drinking water for many households, and their contamination by fecal microbes presents a risk of acute gastrointestinal illness (AGI). Risk is thought to vary by contaminating fecal source, but specific associations with fecal source are unknown for most private wells in the United States. This study characterizes AGI risk in Grant, Iowa, and Lafayette counties in southwestern Wisconsin. AGI risk was assessed for 10 viral, bacterial, and protozoan pathogens detected in private wells using quantitative microbial risk assessment. Exposure assessment was based on sampling 138 private wells in the study area, and risk was associated with fecal source by microbial source tracking (MST). Median Monte Carlo estimates indicated 4450 AGI cases/year in the study area associated with drinking water from contaminated private wells (95% confidence interval: 90–37,990). Most annual cases were associated with detection of human MST markers, including median estimates of 2550 associated with only human markers and 880 with human and livestock MST markers detected together. Note that 50 AGI cases/year were associated with detection of only livestock markers, and nearly 1000 cases were estimated to occur in the absence of detectable MST markers. This study characterizes AGI risk for households served by private wells in southwestern Wisconsin. It illustrates that human fecal sources can predominate risk associated with drinking water from private wells, even in a rural region characterized by substantial agricultural activity. MST can characterize the relationship between risk and fecal source; contributions of fecal sources to risk cannot be assumed from land use.

Released March 21, 2026 10:00 EST

2026, Global Biogeochemical Cycles (40)

K. Sharma, Soren Brothers, S. Bernal, Núria Catalán, P. Keller, M. Koschorreck, S. Kosten, C. Leigh, D. von Schiller, A. Pastor, A. Larrañaga, A. Ari, A. Camacho-Santamans, A. Grinham, A. Lupon, A. Linkhorst, A. Elosegi, B. Obrador, B. D. Eyre, C. Trochine, C. C. Muniz, C. Feijoo, C. Duvert, E. Moreno-Ostos, E. Jacqueline Garcia, E. S. Oliveria, F. Cuassolo, H. R. Fernandez, J. Yeo, J. Oakes, J. R. Paranaíba, J. Pegg, J. Anselmo, J. J. Montes-Perez, L. van den Heuvel, L. Ran, L. L. Wilkinson, L. Gomez-Gener, M. Arroita, M. Shanafield, M. L. Gultemirian, M. I. Arce, M. Cobo, M. M. Sanchez-Montoya, N. Barros, N. Wells, N. Karakaya, P. Erturk Ari, Q. Struik, R. Aben, R. Rimas, S. Kumar, Sheel Bansal, S. Sarkar, S. Rodriguez-Gomez, T. Huang, T. Silverthorn, T. Datry, V. Diaz Villanueva, R. Marce

Many inland waters are shrinking due to shifts in climate and water diversion for human uses. As they dry out, their exposed sediments emit large amounts of carbon dioxide (CO₂) to the atmosphere. However, current global estimates of CO₂ emissions from dry inland waters are derived exclusively from bare sediment dark-chamber measurements that do not account for the colonization of desiccated areas by vegetation. To understand the impact of vegetation on CO₂ emissions from dry sediments, we analyzed 164 dry inland water bodies across five climatic regions and five inland water body types (lakes, ponds, reservoirs, streams and wetlands). On average, within vegetated zones, vegetation occupied 47 ± 35% in measured biomass quadrants. Light-induced decreases in instantaneous CO₂ emissions in vegetated dry sediments were lower (mean ± SD = −3.7 ± 12.9 mmol CO₂ m⁻² hr⁻¹) than increases during dark conditions (14.7 ± 20.1 mmol CO₂ m⁻² hr⁻¹). Diel (24-hr) CO₂ emissions from dry, vegetated sediments (mean ± SD = 100 ± 261 mmol CO₂ m⁻² d⁻¹) were 25% lower than in bare sediments (133 ± 245 mmol CO₂ m⁻² d⁻¹). These results indicate that vegetation can partially off-set sediment respiration, although the magnitude of this effect is insufficient to switch dry beds from net sources to net sinks of carbon.

Released March 21, 2026 08:44 EST

2026, Mineralium Deposita

Erin Kay Benson, Kathryn E. Watts, Michael J. Pribil, Jay M. Thompson, Heather A. Lowers

The Mountain Pass carbonatite stock hosts a world-class rare earth element deposit and may be classified as a carbonate-sulfate igneous rock, as it contains on average > 50 volume percent carbonate minerals and 20 to 30 volume percent sulfate minerals. The sulfates range in composition from barite to celestine and locally occur with sparse sulfide minerals. We investigate the origin of sulfur enrichment and the occurrence of sulfur-bearing minerals in the Mountain Pass carbonatite with in-situ sulfur isotope and mineral chemistry. Barite cores with δ³⁴S of 1 to 3‰ do not coexist with sulfides, whereas celestine rims with δ³⁴S of > 3‰ are associated with sulfides with δ³⁴S < -10‰. We propose a model in which sulfur-bearing sediments were subducted during episodes of plate convergence in the Mojave Province that preceded Mountain Pass magmatism. Metasomatism of the overlying mantle by melts derived from the subducted sediments generated an unusually carbon- and sulfur-rich source to yield carbonatite magmas. Sulfur from primary carbonatite magmas and ~ 1 to 7% sulfur from subducted sediment melts yielded a slightly enriched δ³⁴S composition (relative to depleted mantle δ³⁴S of -1‰) for early crystallizing barite. Celestine rims on magmatic barite cores formed at low, hydrothermal temperatures (< 350 °C) based on S isotope thermometry for equilibrium celestine-galena and celestine-pyrite pairs. The sparse sulfides in the carbonatite stock are not in equilibrium with the primary barite cores and therefore do not permit S isotope thermometry estimates of magmatic temperatures. The S/Se ratios of sulfide minerals (> 3,400) typically exceed primitive mantle values (S/Se of 3,340), also consistent with their derivation from hydrothermal fluids. Trace occurrences of sulfide and sulfate minerals in alkaline silicate stocks related to the carbonatite stock have similar δ³⁴S compositions and yield similarly low formation temperatures, suggesting regionally extensive and chemically similar sulfur-bearing hydrothermal fluids that imparted lithologically diverse rocks with a consistent sulfur isotope fingerprint.

Released March 20, 2026 12:25 EST

2026, Scientific Investigations Report 2026-5126

Alexander O. Headman, Oscar A. Wilkerson, Christopher A. Curran, Andrew S. Gendaszek

The Enloe Dam was built in 1920 for hydropower generation and impounds a steep-banked, narrow reach of the Similkameen River in north-central Washington. During the subsequent century, sediment from the Similkameen River watershed, which includes historical mining operations, accumulated within Enloe Dam’s impoundment. Enloe Dam ceased hydropower production in 1958 and is currently under consideration for removal, but there are concerns that the remobilization of sediments may have harmful impacts on downstream water quality. To complement previously published analyses of heavy metal concentrations within sediments and assess the total volume that may be transported following dam removal, this report presents estimates of the volume of sediment trapped behind Enloe Dam which was measured in 2020. The volume of sediment was estimated by comparing a bathymetric survey, collected using an acoustic Doppler continuous profiler, and a survey of the bedrock-sediment interface, collected using a continuous resistivity profiler.

The study area spanned a 2.6-kilometer reach of the Similkameen River upstream from Enloe Dam. The volume of impounded sediment was calculated in 2020 by subtracting the elevation of the bedrock-sediment interface measured using the continuous resistivity profiler from a bathymetric surface measured by the acoustic Doppler current profiler. In 2020, the estimated volume of sediment impounded by Enloe Dam was 2.17±0.04 million cubic meters (Mm³) compared to 1.37 Mm³ measured in 1971. This equates to a deposition rate of approximately 16,300 cubic meters per year from 1971 to 2020. Continuous resistivity profiles revealed that bedrock within Enloe Dam’s impoundment was deepest (about 20 m) in the southern, downstream end of the profiles and shallowest (less than 5 m) in the northern upstream end of the profiles.

Released March 20, 2026 10:12 EST

2026, Chemical Geology (709)

Philip L. Verplanck, Cameron Mark Mercer, Jay M. Thompson, Martin Danišík, Heather A. Lowers, Leah E. Morgan, Ganesh Bhat

Pervasive chemical weathering on stable cratons may form thick regoliths and elemental enrichment, but constraining the age of regolith formation is challenging. In this study we utilize multiple geochronological techniques on different minerals from the world-class Mount Weld rare earth element (REE) deposit, formed by lateritic weathering of a carbonatite, to constrain the age of formation and provide insight into landscape evolution. The oldest dates, ca. 100 to 38 Ma, are from Lu-Hf dating of churchite [HREE(PO₄)·2(H₂O)], a heavy REE phosphate mineral. Growth bands on individual minerals show a younging outwards. ⁴⁰Ar/³⁹Ar geochronology of cryptomelane [K(Mn⁴⁺,Mn²⁺)₈O₁₆] yielded dates from ca. 40 to 27 Ma. Similarly, (U-Th)/He geochronology of goethite [FeO(OH)] yielded dates ranging from ca. 45 to 19 Ma.

Integrating results into regional constraints, suggests 1) churchite formed by mineral saturation in a karst-like setting below the water table from ca. 100 to 40 Ma, 2) with minor uplift and erosion, cryptomelane and goethite formed at or near the water table between ca. 45 and 19 Ma, 3) after ca. 15 to 10 Ma chemical weathering within the profile had ended. Other studies document that the region experienced minimal uplift and a wet, warm climate from ca. 100 Ma to 15 Ma. These conditions and the high carbonate content of the carbonatite promote extensive chemical weathering, a deep weathering profile, and the preservation of the weathered section. This study highlights the use of multiple geochronological techniques utilizing different minerals to provide insight into how laterites form and to constrain the timing and history of the formation of this important mineral deposit.

Released March 20, 2026 10:01 EST

2026, Environmental Research: Water (2)

Edward G. Stets, Matthew J. Cashman, Olivia L. Miller, Kathryn Powlen, Anthony J. Martinez, Julie Padilla, Althea A. Archer

Consistent, large-scale estimates of water availability are needed to identify and avoid potential conflicts among human and ecosystem uses of water. We present an assessment of water limitation, defined as the monthly balance (difference) between water supply (ws) and human consumptive water use (wc), for the conterminous United States (CONUS) during water years 2010–2020. We estimate that 26.7 million Americans, 8% of CONUS population, live in areas with chronic high or severe water limitation. Although ws greatly exceeds wc at the CONUS scale, water is limited locally or regionally due to spatial and temporal patterns in climate and wc. Our water limitation metric, the monthly supply and use index (SUI), peaked in 2012 during a widespread drought when 38% of the CONUS land area experienced elevated water stress. The central and Southwestern U.S. experienced the highest SUI due to the combination of low ws and high wc, especially for irrigation. Spatial overlays of SUI and fish habitat ranges, including those of conservation concern, revealed that several species had notable proportions of their habitat exposed to high or severe water limitation during spawning season over the modeled time period, especially the Arkansas River shiner. ws was calculated from two CONUS, physically-based, hydrologic models while wc was calculated from three CONUS models of water use for crop irrigation, thermoelectric power generation, and public supply. The ws and wc values were routed through a stream network and compared to calculate water limitation and SUI for human populations and fish species at the scale of 12-digit hydrologic unit codes. Evaluation of water availability at higher spatial and temporal resolution promotes more comprehensive analyses of the drivers of water availability and can be combined with complementary studies of water quality and water limiting thresholds to better understand the limitations on water availability.

Released March 20, 2026 09:41 EST

2026, Journal of Environmental Management (404)

Kristin Jaeger, Susan Wherry, Malia H. Scott, Audrey Marie Martinez, Roy Sando, Evan A. Thaler

The objective of this study is to provide a framework to reconcile streamflow permanence products that provide information on whether a stream is perennial or nonperennial. Accurate classification of streams as perennial or nonperennial is important for a variety of land and water resource management decisions. However, resource managers are challenged with how to reconcile different streamflow permanence information to determine if it is sufficient to avoid field verification, which can be prohibitively costly and time consuming. The study evaluates two datasets for the Pacific Northwest Region, U.S., the National Hydrography Dataset Plus High Resolution (NHDPlus HR) hydrographic classification and the PRObability of Streamflow PERmanence (PROSPER) model output, which differ in structure, output type, and temporal and spatial resolution. The framework includes a two-level evaluation that involves assessing agreement between the two datasets and evaluating the reliability of the two datasets. Summarized at a regional scale, the two datasets agree for 68% of flowlines with higher agreement for nonperennial streams. PROSPER nonperennial stream classifications may be considered generally reliable in arid regions relative to other ecoregions within the Pacific Northwest study area but less reliable for high elevation mountain regions and larger streams and rivers. More than 75% of NHDPlusHR classifications may be considered reliable when evaluating reliability based on approximate climate conditions associated with the year that the NHDPlus HR classification was assigned. The decision procedure is reproducible, flexible to varying criteria of end user applications, and is intended to help provide cost saving opportunities for land managers by providing information for more strategic field verification of streamflow class determination based on available yet imperfect data sources.

Released March 20, 2026 09:41 EST

2026, Global Change Biology Communications (1)

Holly Susan Embke, Karen M Alofs, David Bunnell, Christy M. Caudill, Cindy Chu, Corey Garland Dunn, Kaelyn Fogelman, Spencer T. Gardner, Tomas O Hook, Scott A. Jackson, Matthew Keefer, Scott T Koenigbauer, Olivia E. LeDee, Stuart A. Ludsin, Abigail Lynch, Bonnie Myers, Elizabeth A. Nyboer, Travis Seaborn, Cory Suski, Lindsey Thurman, Annika W. Walters, Jacob Thomas Westhoff

Freshwater species are increasingly threatened by climate change, yet our ability to assess their vulnerability remains incomplete. Typically, climate change vulnerability assessments (CCVAs) evaluate three components: exposure, sensitivity, and adaptive capacity. Adaptive capacity, defined as the ability of a species to adjust to changing conditions, provides critical insight into how species may persist under future scenarios and can strengthen conservation planning by highlighting opportunities for resilience and targeted management strategies. Trait-based approaches offer a promising path for managers to operationalize adaptive capacity by identifying measurable biological and ecological traits that influence climate change response strategies. However, these insights are rarely integrated into broader vulnerability frameworks that support conservation decision making. We build on previous research to synthesize current understanding of adaptive capacity for three freshwater taxa in North America: fishes, mussels, and crayfishes. Our objectives were to: (1) assess the relevance of adaptive capacity factors for fishes, mussels, and crayfishes; (2) identify key opportunities and gaps in linking trait-based information into adaptive capacity assessments; and (3) illustrate how incorporating adaptive capacity can enhance management decisions for freshwater species under climate change. We used an expert workshop, literature review, and case studies to identify relevant adaptive capacity factors, assess available information, and evaluate inclusion in management contexts. We found that all three taxa had sufficient information to inform adaptive capacity assessments. In addition to existing adaptive capacity factors, we identified Morphology as an important yet underutilized cross-cutting diagnostic category when information was limited. By explicitly linking trait-based approaches with adaptive capacity frameworks, we offer practical guidance for improving climate adaptation strategies and prioritizing management actions for freshwater biodiversity under accelerating global change.

Released March 20, 2026 07:27 EST

2026, Data Report 1219

Lisa D. Allen, Barbara E. Kus

Executive Summary 

We surveyed for Least Bell’s Vireos (Vireo bellii pusillus; vireo) and Southwestern Willow Flycatchers (Empidonax traillii extimus; flycatcher) along Bull Creek, Haskell Creek, and the Los Angeles River (Sepulveda Dam project area) in Los Angeles County, California, in 2025. Four vireo surveys were completed between April 16 and July 2, 2025, and three flycatcher surveys were completed between May 21 and July 2, 2025. We found 11 territorial male vireos, 4 of which were confirmed as paired, and 3 transient vireos. Of the 11 territorial vireos, 6 were detected along the Los Angeles River, 3 along Haskell Creek, and 2 along Bull Creek. Forty-three percent of vireos were detected in habitat characterized as mixed willow riparian, and most vireos were detected in habitat with greater than 50-percent native plant cover. No flycatchers were observed in the Sepulveda Dam project area in 2025.

Released March 19, 2026 14:49 EST

2026, Data Report 1223

Lisa D. Allen, Barbara E. Kus

Executive Summary 

We surveyed for Southwestern Willow Flycatchers (Empidonax traillii extimus; flycatcher) at five survey areas within the City of Carlsbad Preserve, Carlsbad, California, in 2025. Three flycatcher surveys were completed between May 16 and June 30, 2025. One transient flycatcher was observed at the Lake Calavera survey area in the City of Carlsbad Preserve in 2025.

Released March 19, 2026 14:48 EST

2026, Data Report 1221

Scarlett L. Howell, Barbara E. Kus

Executive Summary 

We surveyed for Least Bell’s Vireos (Vireo bellii pusillus; vireo), Southwestern Willow Flycatchers (Empidonax traillii extimus; flycatcher), and Coastal California Gnatcatchers (Polioptila californica californica; gnatcatcher) at the Carbon Canyon Dam study area near Brea, California, in 2025. Four gnatcatcher and vireo surveys were completed between April 22 and June 25, 2025, and three flycatcher surveys were completed between May 15 and June 25, 2025.

We detected 14 territorial male vireos, 12 of which were paired. We also detected a transient vireo. Juvenile vireos were observed in two territories during surveys. Of the five vireo nests incidentally located during surveys, three were parasitized by Brown-headed Cowbirds (Molothrus ater). Vireos were reported in four habitat types: (1) mixed willow riparian, (2) riparian scrub, (3) upland, and (4) non-native vegetation. The dominant tree species in vireo territories was Goodding’s black willow (Salix gooddingii). Most vireo territories (12) were in habitat with greater than 50-percent native vegetation. The most common exotic species in vireo territories was poison hemlock (Conium maculatum). No flycatchers or gnatcatchers were observed during surveys.

Released March 19, 2026 10:34 EST

2026, Elementa: Science of the Anthropocene (14)

Margaret Scholer, Kathleen R. Hall, Thomas S. Weber, Marc L. Buursink, Mingzhe Zhu, Alexander C. Ihle, Devin Hencmann, Andrew M. Smith, Katey W. Anthony, Vasilii V. Petrenko

Methane is a potent greenhouse gas that plays an important role in atmospheric chemistry and global warming. The current global methane budget has large uncertainties, and a better understanding of the budget would help to guide strategies for reducing anthropogenic emissions to fight climate change. Natural geologic methane emissions are a particularly poorly constrained source, with top-down estimates from ¹⁴C in ice cores suggesting much lower geologic emissions than bottom-up scaling of direct flux measurements. Our study aims to contribute to resolving this discrepancy through improved bottom-up characterization of geologic methane seepage in the San Juan Basin in southwestern Colorado and northwestern New Mexico, USA. We performed 983 new flux chamber measurements in this basin during summer 2022 and winter 2023 field campaigns. Our results, in combination with prior measurements, suggest that natural seepage in the San Juan Basin only occurs on or near the Fruitland coal outcrop. Specifically, our new measurements confirm previous measurements of seepage along the northwestern exposure of the Fruitland outcrop in Colorado (a known hydrodynamic overpressure region) and for the first time, identified seepage locations along the southernmost Fruitland outcrop exposure in New Mexico, in association with a coal cleat and a fault. Overall, seepage along the Fruitland coal outcrop is heterogeneously distributed, with both positive and negative (interpreted as microbial soil sink) methane fluxes. Features that are hypothesized to be predictive of seepage (e.g., faults) were not associated with positive methane fluxes in areas outside of the Fruitland outcrop. Our best estimate for total geologic methane seepage in the San Juan Basin from spatial interpolation and statistical upscaling is approximately 0.14 Tg CH₄/yr, with a range from 0.029 to 0.48 Tg CH₄/yr. This best-estimate value is lower than a previous bottom-up estimate from a gridded seepage inventory, but higher than a previous top-down estimate.

Released March 19, 2026 10:24 EST

2026, Bulletin of the Seismological Society of America

Xiaofeng Meng, Robert Graves, Christine A Goulet

The purpose of this study is to use ground‐motion simulations to investigate ways in which source and path effects for large‐magnitude earthquakes can be represented in nonergodic ground‐motion models (GMMs). To achieve this, we designed a ground‐motion study in the San Francisco Bay Area that includes earthquakes with a broad range of magnitudes distributed uniformly on a fault plane, and sites covering a large range of rupture distances and azimuths. After running a large suite of kinematic simulations (magnitude 4–7), we then develop a nonergodic GMM with the simulated data. We find that trends in the within‐site residuals are affected significantly by the earthquake radiation pattern, rupture directivity, and slip patterns. Next, we modify an existing rupture directivity model to fit and remove the observed radiation pattern and rupture directivity from the residuals. We also minimize the contributions of slip patterns by averaging the within‐site residuals among multiple source realizations. Finally, after removing the source effects from the within‐site residuals, we compare the path effects computed with different magnitude groups using two approaches. The first approach only considers the small events that have the same shortest path to a site as the large events, whereas the second approach considers all small events on the fault plane. The results indicate that it is difficult to satisfactorily approximate the path effects of large events with those of small events using either approach, at least in the case of simulations.

Released March 19, 2026 10:00 EST

2026, Open-File Report 2026-1067

Nadia Carmosini, Justin R. Schueller, Courtney A. Kirkeeng, Anne M. Wood, Lori A. Criger, James A. Luoma

Petromyzon marinus (sea lamprey) is a parasitic, invasive fish of the Laurentian Great Lakes. Since the late 1950s, the Great Lakes Fishery Commission has implemented an integrated Sea Lamprey Control Program (SLCP) that relies on two lampricidal chemicals: 3-(trifluoromethyl)-4-nitrophenol (TFM) and niclosamide. Niclosamide is applied using a bayluscide 20-percent emulsifiable concentrate; however, a solvent in this formulation, N-methyl-2-pyrrolidone, has been linked with worker safety concerns and has contributed to equipment degradation and clogging. To address these limitations, the U.S. Geological Survey, in collaboration with Battelle UK, developed a bayluscide 20-percent suspension concentrate (SC) as a potential alternative formulation.

In this study, we evaluated the field performance of SC on the Indian River in Schoolcraft County, Michigan. The objective was to assess the formulation’s compatibility with SLCP application procedures and equipment, and to determine its ability to deliver precise lampricide concentrations in a timely manner. SC was found to dilute easily with stream water and readily combined with TFM. As a result, target lampricide concentrations in the stream were achieved within 1 hour of initiating delivery. Moreover, concentrations remained within 9 percent of target values, with less than 2 percent variation across the width of the stream, demonstrating consistent and uniform distribution. These findings indicate that SC can support accurate and timely lampricide applications. When considered alongside previous research highlighting its favorable selectivity for sea lamprey and improved environmental safety, the results support the pursuit of registration and adoption of SC as a new tool for controlling invasive sea lamprey.

Released March 18, 2026 17:05 EST

2026, Scientific Investigations Report 2026-5127

Leland R. Spangler

This report presents a new three-dimensional geologic framework model (GFM) of the northern Great Plains region, encompassing parts of Montana, North Dakota, South Dakota, and Wyoming. The model provides a regionally consistent, geographic information system (GIS)-ready representation of Phanerozoic sedimentary strata, major fault systems, and Precambrian basement geometry across two sedimentary basins and adjacent uplifts. More than 300,000 geologic and geophysical data inputs were synthesized to model 41 stratigraphic horizons and 47 faults, yielding an internally coherent, sealed-volume interpretation of the subsurface. The modeling workflow developed for this study demonstrates an efficient and scalable approach for constructing basin-to regional-scale GFMs in geologically complex and data-variable settings. Although model fidelity varies with data density and quality, the resulting geometry is broadly consistent with 1:500,000-scale geologic mapping and highlights areas where additional geologic study is most needed. The three-dimensional GFM provides a foundational framework to support groundwater, energy, and mineral resource assessments, and offers a transferable methodology for potential future U.S. Geological Survey efforts to build large-area subsurface models in underexplored regions of the United States.

Released March 18, 2026 12:36 EST

2026, Proceedings of the National Academy of Sciences (123)

Seulgi Moon, Giuseppe Formetta, Justin T. Higa, Riccardo Busti, Dino G. Bellugi, David G. Milledge, Brian A. Ebel, William E. Dietrich

The deep critical zone (CZ) has long been recognized for its importance in influencing shallow landslides but was not considered feasible to include in slope stability models at the watershed scale. In this study, we demonstrate that simple approximations of the CZ in a fully coupled hydrologic and soil slope stability model can effectively capture the location, timing, and likely size of shallow landslides. To achieve this, we use coupled, process-based models that incorporate the effects of 1) deep CZ structures, 2) three-dimensional transient hydrology, and 3) multidimensional slope stability, calibrated with data from an intensively monitored field site. Our results show that the hydrologically active deep CZ guides groundwater flow, influencing where it drains from or exfiltrates to the soil mantle, producing distinct patterns of soil saturation and seepage forces at the soil-bedrock boundary. Deep conductive weathered critical zone drains the soil mantle, reducing the likelihood of destabilizing pore pressures, while the downslope thinning of the CZ forces groundwater to the surface. This creates localized instability and a tendency for similar-sized landslides across the landscape. In contrast, the absence of conductive weathered bedrock results in more widespread destabilizing pore pressures, leading to larger landslides and the likelihood of landslides earlier in a storm than in landscapes underlain by a deep CZ. Our findings suggest that first-order variations of deep CZ can provide physical explanations for variations observed in the susceptibility, magnitude, and timing of shallow landslides, and that CZ structure may be inferred from patterns and timing of landsliding.

Released March 18, 2026 12:21 EST

2026, Scientific Investigations Report 2026-5143

William R. Selbig, James Romano

Urban runoff from streets and parking lots carries pollutants that degrade receiving waters. Green infrastructure, such as biofilters, is increasingly used to treat this runoff by mimicking natural hydrologic processes. The U.S. Geological Survey, in cooperation with the Milwaukee Metropolitan Sewerage District, evaluated a biofilter receiving roadway runoff from an industrial area in Milwaukee, Wisconsin, over a 3-year period (2022–24). Paired inlet and outlet samples were analyzed for changes in runoff volume, peak discharge, and concentrations of solids, nutrients, major ions, and metals. The biofilter reduced runoff volume by 86 percent and peak discharge by 92 percent, with substantial reductions in total suspended solids (99 percent), total phosphorus (86 percent), and particulate metals (greater than 80 percent for most analytes). However, dissolved constituents showed variable performance; dissolved phosphorus and several metals exhibited net export, likely influenced by media composition, redox conditions, and winter road salt inputs. Sodium export, despite stable chloride loads, suggests cation exchange and seasonal release dynamics. These findings highlight limitations of conventional biofilter designs for dissolved pollutants and underscore the need for improved media, vegetation management, and consideration of winter deicing practices.

Released March 18, 2026 11:18 EST

2026, Scientific Investigations Report 2026-5131

Scott D. George, Thomas R. Sadekoski, Michael J. Darling, Barry P. Baldigo, Scott M. Wells, David B. Erway, Andrea L. Conine, Jesse C. Becker, Kristen J. Dieterle

Little is known about the natural resources in the natural channel sections of the Mohawk River between Rome and Frankfort, New York, where the river channel runs separately from and parallel to the Erie Canal. This river section runs through multiple locations that are listed as active remediation sites under New York’s Inactive Hazardous Waste Disposal Site Program and has negligible public or commercial access. As a result, there is minimal recreational usage of this river section, and efforts to conduct biological sampling have been limited. To better understand the composition of fish communities and contaminant concentrations in the natural channel of the Mohawk River, the U.S. Geological Survey, in cooperation with the New York State Department of Environmental Conservation, sampled resident fish in the 34- kilometer section from the mouth of Oriskany Creek downstream to Frankfort. Fish communities were sampled using boat electrofishing during 2021, 2023, and 2024 across multiple reaches within this section. These data were used to estimate species richness (number of species), relative abundance and biomass (catch rates), population size structure (distribution of lengths), and fish condition (a proxy for health). Some gamefish specimens were also analyzed to determine contaminant concentrations in fish tissue.

A total of 1,531 individual fish and 38 fish species were captured across all surveys. Seventeen of the 38 (45 percent) species were classified as native to the Mohawk River watershed, whereas 21 of the 38 (55 percent) species were classified as nonnative. Some popular gamefish species such as largemouth bass (Micropterus salmoides) and smallmouth bass (Micropterus dolomieu) were abundant in most reaches, whereas others such as walleye (Sander vitreus) and northern pike (Esox lucius) were found sporadically. Only one round goby (Neogobius melanostomus) was captured, indicating that this high- profile invasive species remains uncommon in this habitat. A backwater reach had the greatest relative abundance and condition of many species. This indicates connected lentic habitats such as oxbows and backwaters may be important nursery and refuge areas in the aquatic ecosystem.

Polychlorinated biphenyl (PCB) concentrations in fish tissue were highly elevated relative to the New York State Department of Health (NYSDOH) fish consumption “don’t eat” advisory guideline. Some specimens exceeded the guideline by an order of magnitude or more, particularly those from a localized area downstream from the Utica Harbor Dam. Concentrations of perfluorooctanesulfonic acid (PFOS) often approached the NYSDOH “don’t eat” consumption guideline but only one sample exceeded the guideline. Concentrations of other contaminants such as mercury and pesticides were consistently measured at less than the “don’t eat” consumption guidelines. These data indicate PCBs remain the primary contaminant of concern in the natural channel of the Mohawk River and are readily bioaccumulating in aquatic organisms despite prior remediation measures. Taken together, the findings in this report are intended to inform future decisions related to fisheries management, public access, recreational usage, and fish consumption advisories.

Released March 18, 2026 10:09 EST

2026, Marine Policy (189)

Melissa E. Flye, Carly C. Sponarski, Danielle Frechette, Joseph D. Zydlewski

Collaborative governance structures (CGS) have been increasingly adopted to address joint-jurisdictional management challenges. While the establishment of CGSs has been widely studied, their practical development has remained a conspicuous gap. CGSs are variable systems with several developmental stages (activation, collectivity, and institutionalization) which eventually lead to stabilization, decline, re-creation, or re-orientation. CGSs in decline may need to revisit earlier developmental stages if members choose to re-create or re-orient the structure. The Atlantic Salmon Recovery Framework (ASRF) was the CGS responsible for managing the Gulf of Maine Distinct Population Segment of Atlantic Salmon (Salmo salar) from 2011 until 2019 when it was replaced by the Collaborative Management Strategy (CMS) pilot program. The CMS was designed to address concerns identified in the ASRF; 1. slow and ineffective decision-making, 2. confusion surrounding leadership, and 3. low adaptive capacity. Building upon a previous evaluation of the ASRF, we used a parallel design to compare the structural components and participant perceptions of the two structures using a comparative case study methodology. The changes that occurred between the ASRF and the CMS constitute a re-creation, providing a unique opportunity to study this developmental phase of a CGS. The issues observed in the CMS may result from a misalignment between participant expectations and the current developmental stage of the re-created CGS. The CMS reorganized ASRF members and created roles for participants without direct management jurisdiction. The implementation of the CMS addressed many concerns identified in the ASRF while others remained (i.e., high membership uncertainty and confusion surrounding decision-making procedures). Formal leadership roles have created more equal representation, but participants still reported uncertainty regarding status and formalization of non-leadership roles.

Released March 18, 2026 09:53 EST

2026, Nature Communications

Victoria J. Bakker, Daniel F. Doak, Alacia Welch, L. Joseph Burnett, María C. Porras Peña, Joseph Brandt, Sharon A. Poessel, Steve Kirkland, Rachel Wolstenholme, Daniel Ryan, Mike Stake, Arianna Punzalan, Nacho Vilchis, Melissa A. Braham, Myra E. Finkelstein

A fundamental challenge in conservation is assessing the efficacy of recovery actions to optimize endangered species management. Considerable recent attention has focused on effective measures to counter the endangerment of avian scavengers, which have declined worldwide, primarily due to poisoning. One iconic example is efforts to recover the critically endangered California condor (Gymnogyps californianus), whose leading cause of death is poisoning from ingesting lead-based ammunition in carcasses. Despite enormous resources expended in California, USA, including implementation of public outreach campaigns and two legislative bans on lead ammunition, lead-related mortality of condors has increased. Here we show that two types of behavioral shifts explain the observed increases in condor lead exposure: wilder foraging and ranging by condors and increased shooting of wild pigs (Sus scrofa) by humans. After accounting for these trends, we show that both lead ammunition bans and public outreach efforts have significantly reduced condor blood lead levels in California, lowering mortality. Our analyses uncover a dynamic in which changing ecological conditions mask the true efficacy of legislation and outreach. Given rapid global change, such dynamics are likely operating in many settings, underscoring the importance of comprehensive evaluations of recovery actions, which can be obscured by shifting behaviors and threats.

Released March 18, 2026 09:46 EST

2026, Environmental Research: Health (4)

Peter Christian Ibsen, Melissa R. McHale, Priyanka deSouza, Logan Steinharter, Carl Green Jr., James E. Diffendorfer, Travis Warziniak

Examining urban thermal environments has become a critical area of research spanning epidemiology, urban planning, and ecology. While traditional metrics like air temperature (T_air) and satellite-derived surface temperature dominate urban heat studies, these measures often fail to reflect how people actually experience thermal exposure intensity. More human-oriented metrics, such as mean radiant temperature (MRT), and the wet bulb globe temperature (WBGT), better capture this lived experience, particularly at locations where people are likely to encounter outdoor heat, such as bus stops. Human demographics further complicate heat exposure, as access to cooling resources like trees and greenspaces can vary by neighborhood income. Our study addresses these complications by collecting thermal data across 60 commuting locations in Denver, Colorado in the summer. We evaluate (1) the extent to which more human-oriented metrics capture thermal exposure compared to T_air and LST, and (2) how heat exposure varies by neighborhood income levels. We observed that bus stops in low-income neighborhoods had an MRT increase 2.8 °C compared wealthier neighborhoods, and that income-driven differences in MRT and WBGT strongly depended on bus stop aspect. After accounting for solar orientation, differences in MRT increased to as much as 6.3 °C at north-facing stops. Our results suggest tree canopy shade explains some observed heat exposure patterns, with south facing bus stops seeing a MRT and WBGT decrease of 0.42 °C and 0.11 °C from a percent increase in tree canopy. Interestingly, depending on bus stop aspect, nearby buildings can increase MRT and WBGT (facing east), or decrease MRT and WBGT (facing south) If planners aim to address this issue, consideration of bus stops, and land covers configuration may help.

Released March 18, 2026 08:08 EST

2026, Remote Sensing Applications: Society and Environment (42)

Roy E. Petrakis, Laura M. Norman, Maryann McGraw, Steve Carson, Craig Sponholtz, Cameron Weber, Bill D. Zeedyk

Alluvial wetland ecosystems are vital as biodiversity hotspots but are increasingly threatened by anthropogenic stressors and drought. These pressures are especially acute in arid and semi-arid regions, where eco-hydrologic connectivity is fragile and recovery is slow. This study quantifies the efficacy of nature-based solutions, particularly the ‘Zeedyk approach,’ which employs low-tech Natural Infrastructure in Dryland Streams (NIDS)—including rock detention structures—to slow surface water, raise groundwater tables, and restore wetland function at a spring-fed wetland in Cebolla Canyon, New Mexico, U.S.A. Our results depict a Restoration Feedback Loop that captures stages of change from a healthy wetland in 1935, altered by 20th-century agriculture and grazing, to the re-establishment of the historical flow regime by 2024 documented through an 89-year archive of aerial imagery (1935–2024). By the end of our study period, the Spring-Fed Wetland had expanded by roughly 229% of the original 1935 area, to 4.13 ha. Using 40 years of satellite data, we assess changes in vegetation and hydrology with remote sensing indices. Spatial and temporal analyses reveal significant increases in vegetation greenness and wetness, particularly in an Expanded Wetland subregion, which exhibited ∼3.5x higher wetness and ∼1.5x higher greenness trends compared to adjacent areas. Monthly metrics highlight seasonal variability, with increases in greenness linked to monsoonal rainfall and lateral water redistribution, indicating that restoration impacts extend beyond the primary wetland. This study demonstrates the utility of cloud-based platforms like Google Earth Engine and USGS EarthExplorer for long-term monitoring of wetland restoration, while quantifying the efficacy of the ‘Zeedyk approach’ and demonstrating its potential as a scalable method to restore and conserve wetland meadows in other arid and semi-arid landscapes.

Released March 17, 2026 09:51 EST

2026, Global Change Biology (32)

Yuwan Wang, Ted R. Feldpausch, Graeme T. Swindles, Patrick Moss, Hamish A. McGowan, Thomas G. Sim, Paul J. Morris, Adam Benfield, Colin Courtney-Mustaphi, David Wahl, Encarni Montoya, Esther N. Githumbi, Euridice N. Honorio Coronado, Femke Augustijns, Gert Verstraeten, Jess O'Donnell, John Tibby, Juan C. Benavides, K. Anggi Hapsari, Karsten Schittek, Khairun Nisha Mohamed Ramdzan, Kunshan Bao, Lydia E. Cole, Lysanna Anderson, Mariusz Galka, Orijemie Emuobosa Akpo, Paul Strobel, Prabhakaran Ramya Bala, Rene Dommain, Rob Marchant, Raman Sukumar, Sakonvan Chawchai, Sarath Pullyottum Kavil, Scott Mooney, Thomas J. Kelly, Yang Gao, Apostolos Voulgarakis, Arnoud Boom, Chantelle Burton, Juan Carlos Berrio, Kelly Ribeiro, Liana O. Anderson, Mark Hardiman, Molly Spater, Susan E. Page, Angela Gallego-Sala

Tropical peatland wildfire incidence has risen in recent decades, driven by drainage for land use and intensified by severe droughts with global climate change. These disturbances have altered vegetation structure, disrupted ecosystem functioning, and increased carbon emissions, particularly in Southeast Asia. However, the long-term history and characteristics of wildfires in tropical peatlands remain largely unknown. Here, we compiled fifty-eight macro-charcoal records from peatlands across the tropics, ranging from lowland forested to montane peatlands, to assess millennia-scale changes and controlling factors of tropical peatland burning. We divided the datasets into four main sub-regions: Neotropical, Afrotropical, Indomalayan and Australasian ecoregions to explore regional variability. Tropical peatlands had high burning levels between 0 and 850 ce, followed by a relatively low and stable period until a marked increase during the 20th century. The general trend in tropical peatland burning follows changes in global temperature, and climate variables that control the length and severity of drought events have a notable influence on peat burning before 1900 ce. During the 20th century, regional differences were observed, with declining fire trends in the Neotropical and Afrotropical regions and increasing fire trends in the Indomalayan and Australasian regions. This difference is likely attributable to human activities, and such intervention is also evident in palm swamps and hardwood swamps under similar wet, weakly seasonal climates. With the increase in anthropogenic pressures on peatlands and greater climate variability, future wildfires in peatlands are likely to become more frequent and widespread across all tropical ecoregions. Conservation and sustainable land-use practices could be used to mitigate and control peatland burning and protect these carbon-rich sinks.

Released March 17, 2026 08:03 EST

2026, Engineering Geology (366)

Jeffrey A. Coe, Nikita N. Avdievitch, Kate E. Allstadt, Elaine A. Collins, Erin K. Jensen, Olivia J. Hoch, Lauren N. Schaefer, Chester A. Ruleman, Jonathan W. Godt, Vince Matthews III

Slow gravitational failures of mountain peaks and ridges are poorly understood. Herein, we report on 50 years of studies at a slowly spreading castellate ridge in the Sawatch Range in central Colorado. The orientations of geomorphic-structural features indicate that the fractured Precambrian granitic rock underlying the ridge has extended and spread northwestward toward the formerly glacier-covered Busk Creek valley. Results from surveying, field-based geomorphic-structural mapping using lidar, rock mass quality measurements, a passive seismic survey, and satellite radar provide a major update to research started by U.S. Geological Survey researchers in the 1970s and 1980s. New insights include a recognition that the entire ridge has slowly moved by concurrent sliding along an inferred northwest dipping, compound basal-slip surface (or zone), and through the formation of multiple grabens by normal faulting and flexural toppling along sets of pre-existing fractures that dip moderately (∼45°) to the southeast. We were unable to distinguish the presence of a sudden and strong contrast in seismic velocity across the inferred slip surface. Movement during the 50-year study period has been episodic and gradually decreasing, in correspondence with decreasing cumulative annual precipitation and increasing mean annual air temperatures. The fastest moving area, just upslope from the glacier trimline, had an average horizontal velocity of 3–4 mm/yr. Evidence suggests that movement started as a paraglacial response mechanism, but because of the site’s proximity to the Rio Grande Rift, we cannot exclude earthquake shaking as a mechanism for initiation or enhancement of slope movement. An estimate of longer-term horizontal movement from the exposed basal-slip surface at the uphill side of the ridgetop graben is ∼1.1 mm/yr for the 13–14 ky post-glacial period.

Broad implications of our work are that: (1) long-term measurements (decades or longer) of slope movement can add insights into how sackungen form and evolve through time; (2) the identification of thrust faults and toes in zones of compression near valley bottoms can be crucial for interpreting sackung failure mechanisms, and (3) the use of passive-seismic techniques to identify the depth to a slip surface may not be successful in granitic terrain dominated by planar fractures and subtle changes in rock-mass characteristics.

Released March 17, 2026 07:53 EST

2026, Knowledge and Management of Aquatic Ecosystems

Grace C. Henderson, Peder Engelstad, Cameron J. Reimer, Shelby K. LeClare, Linnea S. Fraser, Demetra A. Williams, Keana S. Shadwell, Wesley M. Daniel, Ian A. Pfingsten, Catherine S. Jarnevich

To address increasing demand for ecological models of aquatic species that can inform the management of national freshwater resources, we leveraged manager input to develop suites of environmental data layers characterizing freshwater habitats for the contiguous United States. Using the National Hydrography Dataset, these new data cover lentic and lotic systems under current and near-future environmental conditions. The data include a variety of covariate categories including climate, soil chemistry, land use and land cover, and human modification of the surrounding landscape. The predictor resolution for atmospheric climate predictors was the lake (wetland) or stream reach, and, for the terrestrial proxies, the subwatershed (HUC12) surrounding the lake or stream reach was chosen to capture the relevant land features surrounding the habitat. Future land use, land cover and streamflow predictions were included from present to mid-century. These data are available for the development of freshwater ecological models in the contiguous United States for a variety of applications, including species distribution modeling and exploring change in spatially diverse aquatic systems in time.

Released March 16, 2026 11:48 EST

2026, Geophysical Research Letters (53)

Julia Guimond, Aaron Mohammed, Barret L. Kurylyk, Michelle A. Walvoord, Victor F. Bense

Saltwater is migrating into freshwater aquifers globally with water quality and biogeochemical implications, yet saltwater intrusion in glaciated regions is sparsely investigated. Field observations suggest that groundwater head in glaciated systems is influenced by ice sheet forcings and provides evidence that seawater infiltrated into offshore aquifers during past deglaciation events. To understand links between ice sheet dynamics, groundwater head, and saltwater intrusion, we use numerical models to explore the effects of deglaciation on nearshore head and salinity distributions. We find that ice sheet thinning diminishes groundwater head, and the resulting shift in subsurface pressure gradients drives rapid landward movement of the subsurface freshwater-saltwater interface up to 4.0 km or 1.3 m per m ice sheet loss. Results highlight an overlooked saltwater intrusion mechanism that aligns with field observations and affects glaciated coastlines undergoing ice sheet retreat, underscoring the need to consider this mechanism in studies of contemporary coastal water quality.

Released March 16, 2026 10:54 EST

2026, Bulletin of Volcanology (88)

Drew T. Downs, Kendra J. Lynn, Heather Brianne Winslow, Steven P. Lundblad, Meghann F.I. Decker

Kīlauea volcano underwent dramatic morphological changes in 2018. That year recorded the end of the 35-year-long eruption of Puʻuʻōʻō (1983–2018) and 10-year-long (2008–2018) Halemaʻumaʻu lava lake and emplacement of the ~4-month-long lower East Rift Zone lava flows that coincided with ~500 m of summit caldera collapse. Starting on December 20, 2020, eruptions resumed at Kīlauea’s summit. There were five summit eruptions between December 2020 and September 2023, which ranged in duration from more than a year to as short as a week. Following these summit eruptions, seismicity and deformation increased in the upper Southwest Rift Zone in 2024, culminating in a ~8.5-h-long eruption in this region on June 3, 2024. Increased seismicity and deformation then shifted to the upper and middle East Rift Zone and after several months culminated in an eruption just west of, and within, Nāpau Crater in the middle East Rift Zone from September 15 to 20, 2024. Despite vast morphological changes at Kīlauea’s summit, the geochemical compositions (i.e., whole rock and glass) that erupted from December 2020 to September 2023 are all remarkably similar to each other. Whole-rock compositions appear distinct from the preceding 2008–2018 Halemaʻumaʻu lava lake and phase 3 (i.e., summit or uprift-derived mafic lavas) of the 2018 lower East Rift Zone lava flows, although glass compositions appear to have more overlap with 2018 lower East Rift Zone glasses. The June 3, 2024, upper Southwest Rift Zone spatter and lava flows exhibit a dramatic enrichment in whole-rock MgO that is not recorded in glass, which reflects accumulation of olivine (e.g., antecrysts or xenocrysts) during dike emplacement, and is consistent with the abundance of olivine in the lava flows (5–10%). June 2024 Southwest Rift Zone whole-rock and glass compositions overlap with those erupted at the summit from December 2020 to September 2023, whereas some whole-rock trace (i.e., Sc, Sr, and Zr) and major elements (i.e., CaO) are suggestive of mixing with a magmatic component that had fractionated plagioclase and pyroxene and/or a new parental magma influencing the summit reservoir system. The September 15–20, 2024, eruption at Nāpau Crater in the middle East Rift Zone involved the most differentiated magma since eruptive activity resumed in December 2020, with its magma fractionating olivine + plagioclase + pyroxene. The September 15–20, 2024, composition resembles Puʻuʻōʻō lava flows that erupted in, or near, Nāpau Crater in 1983 (episode 1), 1997 (episode 54), and 2011 (episode 59), with episode 59 having a compositional cluster that is most similar to that of the September 2024 lava flows. The data presented and provided herein open new research perspectives for long-term analyses of geochemical variations following caldera collapse at Kīlauea volcano and facilitate comparisons with other basaltic caldera systems worldwide.

Released March 16, 2026 10:41 EST

2026, Bulletin of the Seismological Society of America

Kevin Ross Milner, Alexandra Elise Hatem, Richard W. Briggs, Jessica Ann Thompson Jobe, Andrea L. Llenos, Andrew J. Michael, Allison Shumway, Edward H. Field, Kirstie Lafon Haynie

We present the 2025 U.S. Geological Survey Puerto Rico and U.S. Virgin Islands (PRVI) time‐independent earthquake rupture forecast (ERF), developed for the 2025 update to the National Seismic Hazard Model (NSHM) for PRVI. The updated ERF improves upon a prior model from 2003, including an expanded fault inventory with slip‐rate estimates, updated seismicity catalogs, and refined subduction zone geometries and deformation models. It applies the fault‐system inversion methodology to solve for rates of ruptures on modeled faults, adapted from the 2023 NSHM (NSHM23) for the western United States, including the first application of the inversion to model rates on a U.S. subduction interface. Off‐fault and intraslab seismicity are constrained by observed seismicity and use updated methods developed for NSHM23. Uncertainties in model components are substantial, and the ERF represents epistemic uncertainties through a comprehensive logic tree consisting of 1.7 billion logic‐tree branches combined across all sources.

Released March 16, 2026 10:28 EST

2026, Basin Research (38)

Sandra Juárez-Zúñiga, Daniel F. Stockli, Benjamin G. Johnson, Timothy F. Lawton

The Marfa Basin in West Texas is a late Palaeozoic synorogenic depocenter associated with regional deformation linked to the Ancestral Rocky Mountains (ARM) and Ouachita–Marathon–Sonora (OMS) orogenies in southwestern Laurentia. Basin strata range in age from Middle Pennsylvanian to the middle Permian and include the Cieneguita, Alta, Pinto Canyon, Rose Mine and Mina Grande Formations. Sandstone petrography and detrital zircon (DZ) U–Pb and (U–Th)/He double dating data from these strata reveal three tectonically driven sedimentation stages: syntectonic ARM deposition, progressive OMS foredeep deposition and an orogenic transition. The Cieneguita and lower part of the Alta Formations exhibit a Mesoproterozoic DZ age signature (~1318 and ~1076 Ma age peaks) and quartzo-feldspathic sandstone compositions sourced from the adjacent ARM-related Diablo Platform basement uplift in the Middle Pennsylvanian to earliest Permian. In contrast, the upper part of the Alta Formation, as well as the Pinto Canyon and Rose Mine Formations, have peri-Gondwanan DZ age signatures, with Mesoproterozoic (~1069–1036 Ma age peaks), Neoproterozoic–Cambrian (~700–490 Ma) and Palaeozoic (~490–300 Ma) age modes and litho-quartzose sandstone compositions derived from the OMS fold-and-thrust belt and orogenic hinterland during the early to middle Permian. The lower to middle parts of the Alta Formation have alternating DZ age signatures and sandstone compositions from both ARM and OMS sources, revealing that the transition in the sediment supply occurred during the middle Wolfcampian. This transition was not characterised by source mixing, but rather by sediment interfingering alternately sourced from the Diablo Platform uplift and the advancing OMS belt. These observations are confirmed by the DZ He ages, which reveal distinct cooling histories for both source terranes. These results document a switch from ARM- to OMS-related syntectonic deposition in southwestern Laurentia during the early Permian, demonstrating that ARM-driven deformation largely preceded the continental collision along the Marathon segment of the OMS orogen.

Released March 16, 2026 09:27 EST

2026, Journal of Wildlife Management

Andrea S. Carlson, Kristin H. Berry, Jeremy S. Mack

We retrospectively compiled a database of 6,727 live, wild Agassiz's desert tortoises (Gopherus agassizii) and evaluated them for clinical signs of trauma to shell and limbs at 50 sites in the Mojave and Colorado (western Sonoran) deserts of California, USA, spanning the years 1977–2006. Our objectives were to 1) identify tortoises with severe trauma to shell, limbs, and gular horns typically seen in attacks from dogs (Canis familiaris); 2) identify locations where severe injuries occurred; and 3) develop a risk model based on distances of tortoises from settlements, towns, or cities. Our models identified multiple variables of importance for tortoises with severe damage to shells, limbs, and gular horns: relative age and sex of tortoises, decades of occurrence, and location. Females and very old tortoises were more vulnerable to attacks than other tortoises. In the decades between the 1970s and 2000s, the risk of severe overall trauma to shell and limbs increased 4 times and to gular horns 16.5 times. Compared to previous decades, by the early 2000s the percent of tortoises with severe trauma increased exponentially the closer a tortoise site was to a settlement; the exponential increase began at approximately 12 km from a settlement. We suggest that the risks may be higher now because of the growth of human populations within the geographic range of the tortoise. The threats to tortoises from dogs are based on whether dogs are off-leash in the Mojave and Colorado deserts.

Released March 16, 2026 09:16 EST

2026, Fire Ecology

Austin L. Nash, Brianne E. Brussee, Cali L. Weise, Douglas J. Shinneman, Susan K. McIlroy, Sarah C. Webster, Steven R. Mathews, Seth J. Dettenmaier, Lea A. Condon, Michele R. Crist, Cameron L. Aldridge, Julie A. Heinrichs, Mark A. Ricca, Shawn T. O’Neil, Peter S. Coates

Background

Wildfire is an increasingly important driver of changes within sagebrush (Artemisia spp. L.) ecosystems of the western USA, often resulting in increased spread of exotic annual grasses, such as cheatgrass (Bromus tectorum L.), and subsequent losses of native vegetation and wildlife habitat. Fuel breaks— areas of land treated to reduce or redistribute fuel loads — are widely implemented to help prevent the spread of wildfires and provide areas to facilitate firefighting efforts. However, localized installation and maintenance of fuel breaks directly reduce or remove vegetation and may propagate the spread of exotic annual grasses into fuel break boundaries and surrounding areas, inadvertently weakening ecological resilience to disturbance. To investigate if exotic annual grass cover was associated with mowed or green strip fuel breaks across the sagebrush biome, we combined multiple data sources and methodologies. We used targeted field surveys and land-management agency monitoring data within a space-for-time substitution framework coupled with a progressive-change before-after control-impact (PC BACI) study design using historical remotely sensed vegetation cover data which allowed us to account for potential confounding effects of roads on annual grass cover.

Results

Models using both field collected and remotely sensed vegetation indices estimated increases in exotic annual grass cover over time following mowed fuel break installation, and higher exotic annual grass cover closer to mowed fuel breaks. These increases in exotic annual grass occurred within, at 500 m and at 1000 m from mowed fuel breaks. However, we found variable patterns of exotic annual grass after green strip fuel break installation depending on the data source. No increase in exotic annual grass were indicated by either analysis at distances greater than 500 m from green strip fuel breaks. However, our and field data analyses disagreed on the direction of the association of exotic annual grass cover and green strip fuel breaks.

Conclusions

Although fuel breaks are an important tool in managing wildland fire, our analysis underscores the importance of planting fire-resistant vegetation, rather than mowing alone, to reduce invasion by annual grasses within and around fuel breaks in sagebrush ecosystems. In addition, site characteristics that hinder the proliferation of exotic annual grasses could be evaluated when installing fuel breaks to minimize unintended effects of exotic annual grass on surrounding sagebrush habitat.

Released March 15, 2026 09:52 EST

2026, Alaska Park Science (24) 72-79

Sarah Beth Traiger, Brenda Ballachey, Heather Coletti, Daniel Esler

Nearshore ecosystems are highly productive zones with strong connections to both terrestrial and open ocean ecosystems. The rocky intertidal is a highly dynamic ecosystem and changes over a variety of spatial and temporal scales depending on the factors contributing to the change. Here we summarize how nearshore communities and species responded to several perturbations to intertidal communities within Alaska’s coastal national parks.

Released March 15, 2026 09:45 EST

2026, Alaska Park Science (24) 46-55

Sarah M. Laske, Krista K. Bartz, Daniel Young

Mercury contamination can pose threats to fish, wildlife, and people. Methylmercury, found in fish, can be particularly detrimental, especially to children. This study explores the sources and concentrations of mercury and proposes how people can become aware and limit their exposure.

Released March 15, 2026 09:06 EST

2026, Quaternary Science Reviews (376)

Savvas Paradeisis-Stathis, Matthew N. Waters, Debra A. Willard, Richard S. Vachula

Ecological pressures on aquatic ecosystems have increased over recent centuries due to human activities and climate change. However, contextualizing ecosystem deterioration is often challenging due to limited knowledge of environmental changes over millennial timescales. Subtropical Carolina bays in North Carolina, USA, have remained unglaciated, preserving paleolimnological records that extend back to the last glacial period. Here, we analyzed a sediment core from the ecologically rich Lake Waccamaw spanning more than 28,000 years for aquatic proxies of nutrients, photosynthetic pigments, cyanotoxins, carbon isotopes, and terrestrial proxies of pollen and charcoal. The study explored paleolimnological changes in the aquatic environment connected to land changes and climate during the late Quaternary in the southeastern Atlantic Coastal Plain. Results reveal that while current levels of colonial cyanobacteria are high, past levels of cyanobacteria, other primary producers, and cyanotoxins were higher under natural climate variability. Abrupt ecosystem responses to increasing trophic conditions during Interstadial 3 (27.8–26.4 cal ka BP) and the early Holocene (11.4–7 cal ka BP) were marked by increases in primary producer abundance, deciduous vegetation expansion, and fire activity. Cyanobacteria remained dominant throughout the record, with colonial forms prevailing during the Holocene. Increases in pigment concentrations aligned with Quercus and were primarily driven by hydroclimatic variability and nutrient stoichiometry. Transitions between Pinus and Quercus pollen matched stadials and interstadials in the δ¹⁸Ο record from the North Greenland Ice Core Project (NGRIP). This study highlights the value of multi-proxy millennial-scale paleolimnological records for understanding aquatic ecosystem responses to climate conditions during the late Pleistocene.