A closer look at water-related geologic activity on Mars
Alfred S. McEwen, C.J. Hansen, W.A. Delamere, E. M. Eliason, Kenneth E. Herkenhoff, Laszlo P. Keszthelyi, V. C. Gulick, Randolph L. Kirk, M. T. Mellon, J. A. Grant, N. Thomas, C.M. Weitz, S. W. Squyres, N.T. Bridges, S.L. Murchie, F. Seelos, K. Seelos, C.H. Okubo, M.P. Milazzo, L.L. Tornabene, W.L. Jaeger, S. Byrne, P.S. Russell, J.L. Griffes, S. Martinez-Alonso, A. Davatzes, F. C. Chuang, B.J. Thomson, K.E. Fishbaugh, C. M. Dundas, K.J. Kolb, M. E. Banks, J.J. Wray
2007, Science (317) 1706-1709
Water has supposedly marked the surface of Mars and produced characteristic landforms. To understand the history of water on Mars, we take a close look at key locations with the High-Resolution Imaging Science Experiment on board the Mars Reconnaissance Orbiter, reaching fine spatial scales of 25 to 32 centimeters per...
Meter-scale morphology of the north polar region of mars
Kenneth E. Herkenhoff, S. Byrne, P.S. Russell, K.E. Fishbaugh, A. S. McEwen
2007, Science (317) 1711-1715
Mars' north pole is covered by a dome of layered ice deposits. Detailed (∼30 centimeters per pixel) images of this region were obtained with the High-Resolution Imaging Science Experiment on board the Mars Reconnaissance Orbiter (MRO). Planum Boreum basal unit scarps reveal cross-bedding and show evidence for recent mass wasting,...
A multiple-approach radiometric age estimate for the Rotoiti and Earthquake Flat eruptions, New Zealand, with implications for the MIS 4/3 boundary
C. J. N. Wilson, D.A. Rhoades, M. A. Lanphere, A.T. Calvert, Bruce F. Houghton, S.D. Weaver, J. W. Cole
2007, Quaternary Science Reviews (26) 1861-1870
Pyroclastic fall deposits of the paired Rotoiti and Earthquake Flat eruptions from the Taupo Volcanic Zone (New Zealand) combine to form a widespread isochronous horizon over much of northern New Zealand and the southwest Pacific. This horizon is important for correlating climatic and...
Proximate composition, energetic value, and relative abundance of prey fish from the inshore eastern Bering Sea: Implications for piscivorous predators
J.R. Ball, Daniel Esler, Joel A. Schmutz
2007, Polar Biology (30) 699-708
Changing ocean conditions and subsequent shifts in forage fish communities have been linked to numerical declines of some piscivorous marine birds and mammals in the North Pacific. However, limited information about fish communities is available for some regions, including nearshore waters of the eastern Bering Sea, where many piscivores reside....
Biodegradation of PAHs and PCBs in soils and sludges
L. Liu, J.A. Tindall, M.J. Friedel
2007, Water, Air, & Soil Pollution (181) 281-296
Results from a multi-year, pilot-scale land treatment project for PAHs and PCBs biodegradation were evaluated. A mathematical model, capable of describing sorption, sequestration, and biodegradation in soil/water systems, is applied to interpret the efficacy of a sequential active-passive biotreatment process of organic chemicals on remediation sites. To account for the...
Distinguishing sources of ground water recharge by using δ2H and δ18O
Kyle W. Blasch, Jeannie R. Bryson
2007, Ground Water (45) 294-308
Stable isotope values of hydrogen and oxygen from precipitation and ground water samples were compared by using a volumetrically based mixing equation and stable isotope gradient to estimate the season and location of recharge in four basins. Stable isotopes were sampled at 11 precipitation sites of differing elevation during a...
Bioenergetic and pharmacokinetic model for exposure of common loon (Gavia immer) chicks to methylmercury
W. H. Karasov, K.P. Kenow, M.W. Meyer, F. Fournier
2007, Environmental Toxicology and Chemistry (26) 677-685
A bioenergetics model was used to predict food intake of common loon (Gavia immer) chicks as a function of body mass during development, and a pharmacokinetics model, based on first-order kinetics in a single compartment, was used to predict blood Hg level as a function of food intake rate, food...
Hydrographic characterization of two tidal creeks with implications for watershed land use, flushing times, and benthic production
C. Buzzelli, Austin F. Holland, D.M. Sanger, P.C. Conrads
2007, Estuaries and Coasts (30) 321-330
Many coastal ecosystems are undergoing anthropogenic stress from large increases in population and urbanization. In many regions changes in freshwater and material inputs to the coastal zone are altering the biogeochemical and biological capacities of ecosystems. Despite increased watershed inputs, large tidal volumes and flushing indicative of macrotidal estuaries can...
Zaphrentis and the Zaphrentidae (Devonian; anthozoa, rugosa)
W. A. Oliver Jr.
2007, Bulletins of American Paleontology (2007) 5-24
Zaphrentis is one of the most widely used names in Paleozoic coral paleontology. Species of "Zaphrentis" have been named from every Paleozoic System except the Cambrian. Variants of the word, such as zaphrentoid, are widely used with varied meanings. Nomenclatural spinoffs are numerous: Neozaphrentis and Heterophrentis are obvious examples, but...
The influence of river regulation and land use on floodplain forest regeneration in the semi-arid upper Colorado River Basin, USA
K. Northcott, D.C. Andersen, D.J. Cooper
2007, River Research and Applications (23) 565-577
Flow regulation effects on floodplain forests in the semi-arid western United States are moderately well understood, whereas effects associated with changes in floodplain land use are poorly documented. We mapped land cover patterns from recent aerial photos and applied a classification scheme to mainstem alluvial floodplains in 10 subjectively selected...
Close temporal correspondence between geomagnetic anomalies and earthquakes during the 2002-2003 eruption of Etna volcano
G. Currenti, Negro C. Del, M. Johnston, Y. Sasai
2007, Journal of Geophysical Research B: Solid Earth (112)
The early stages of the 2002-2003 lateral eruption at Mount Etna were accompanied by slow changes (over some hours) and some rapid step offsets in the local magnetic field. At five monitoring locations, the total magnetic field intensity has been measured using continuously operating Overhauser magnetometers at a sampling rate...
Stochastic uncertainty analysis for solute transport in randomly heterogeneous media using a Karhunen‐Loève‐based moment equation approach
Gaisheng Liu, Zhiming Lu, Dongxiao Zhang
2007, Water Resources Research (43)
A new approach has been developed for solving solute transport problems in randomly heterogeneous media using the Karhunen‐Loève‐based moment equation (KLME) technique proposed by Zhang and Lu (2004). The KLME approach combines the Karhunen‐Loève decomposition of the underlying random conductivity field and the perturbative and polynomial expansions of dependent variables...
Using biodynamic models to reconcile differences between laboratory toxicity tests and field biomonitoring with aquatic insects
D.B. Buchwalter, Daniel J. Cain, W.H. Clements, S. N. Luoma
2007, Environmental Science & Technology (41) 4821-4828
Aquatic insects often dominate lotic ecosystems, yet these organisms are under-represented in trace metal toxicity databases. Furthermore, toxicity data for aquatic insects do not appear to reflect their actual sensitivities to metals in nature, because the concentrations required to elicit toxicity...
Using simulated historical time series to prioritize fuel treatments on landscapes across the United States: The LANDFIRE prototype project
Robert E. Keane, Matthew Rollins, Zhi-Liang Zhu
2007, Ecological Modelling (204) 485-502
Canopy and surface fuels in many fire-prone forests of the United States have increased over the last 70 years as a result of modern fire exclusion policies, grazing, and other land management activities. The Healthy Forest Restoration Act and National Fire Plan establish a national commitment to reduce fire hazard...
Land cover variation and West Nile virus prevalence: Patterns, processes, and implications for disease control
V.O. Ezenwa, L.E. Milheim, M.F. Coffey, M.S. Godsey, R.J. King, S.C. Guptill
2007, Vector-Borne and Zoonotic Diseases (7) 173-180
Identifying links between environmental variables and infectious disease risk is essential to understanding how human-induced environmental changes will effect the dynamics of human and wildlife diseases. Although land cover change has often been tied to spatial variation in disease occurrence, the underlying factors driving the correlations are often unknown, limiting...
Effects of management and climate on elk brucellosis in the Greater Yellowstone Ecosystem
P.C. Cross, W.H. Edwards, B.M. Scurlock, E.J. Maichak, J.D. Rogerson
2007, Ecological Applications (17) 957-964
Every winter, government agencies feed ∼6000 metric tons (6 × 106 kg) of hay to elk in the southern Greater Yellowstone Ecosystem (GYE) to limit transmission of Brucella abortus, the causative agent of brucellosis, from elk to cattle. Supplemental feeding, however, is likely to increase the transmission of brucellosis in...
Improved wetland remote sensing in Yellowstone National Park using classification trees to combine TM imagery and ancillary environmental data
C. Wright, Alisa L. Gallant
2007, Remote Sensing of Environment (107) 582-605
The U.S. Fish and Wildlife Service uses the term palustrine wetland to describe vegetated wetlands traditionally identified as marsh, bog, fen, swamp, or wet meadow. Landsat TM imagery was combined with image texture and ancillary environmental data to model probabilities of palustrine wetland occurrence in Yellowstone National Park using classification...
Estimation of evapotranspiration by reed canarygrass using field observations and model simulations
K. E. Schilling, James R. Kiniry
2007, Journal of Hydrology (337) 356-363
Reed canarygrass (Phalaris arundinacea) commonly invades meadow wetlands, effectively dominating water use and outcompeting native plants. Objectives of this study were to (i) estimate daily, seasonal and annual water use by reed canarygrass using shallow water table fluctuations; and (ii) calibrate the ALMANAC (Agricultural Land Management Alternative with Numerical Assessment...
Species richness and soil properties in Pinus ponderosa forests: A structural equation modeling analysis
D.C. Laughlin, S.R. Abella, W.W. Covington, J.B. Grace
2007, Journal of Vegetation Science (18) 231-242
Question: How are the effects of mineral soil properties on understory plant species richness propagated through a network of processes involving the forest overstory, soil organic matter, soil nitrogen, and understory plant abundance? Location: North-central Arizona, USA. Methods: We sampled 75 0.05-ha plots across a broad soil gradient in a...
A simple model for the spatially-variable coastal response to hurricanes
H.F. Stockdon, A. H. Sallenger Jr., R.A. Holman, P.A. Howd
2007, Marine Geology (238) 1-20
The vulnerability of a beach to extreme coastal change during a hurricane can be estimated by comparing the relative elevations of storm-induced water levels to those of the dune or berm. A simple model that defines the coastal response based on these elevations was used to hindcast the potential impact...
Rapid plant diversity assessment using a pixel nested plot design: A case study in Beaver Meadows, Rocky Mountain National Park, Colorado, USA
M. A. Kalkhan, E.J. Stafford, T.J. Stohlgren
2007, Diversity and Distributions (13) 379-388
Geospatial statistical modelling and thematic maps have recently emerged as effective tools for the management of natural areas at the landscape scale. Traditional methods for the collection of field data pertaining to questions of landscape were developed without consideration for the parameters of these applications. We introduce an alternative field...
Environmental and ecological conditions surrounding the production of large year classes of walleye (Sander vitreus) in Saginaw Bay, Lake Huron
D.G. Fielder, J.S. Schaeffer, M.V. Thomas
2007, Journal of Great Lakes Research (33) 118-132
The Saginaw Bay walleye population (Sander vitreus) has not fully recovered from a collapse that began in the 1940s and has been dependent on stocking with only limited natural reproduction. Beginning in 2003, and through at least 2005, reproductive success of walleye surged to unprecedented levels. The increase was concurrent...
Suspended sediment transport in an ephemeral stream following wildfire
D.V. Malmon, Steven L. Reneau, D. Katzman, A. Lavine, J. Lyman
2007, Journal of Geophysical Research F: Earth Surface (112)
We examine the impacts of a stand-clearing wildfire on the characteristics and magnitude of suspended sediment transport in ephemeral streams draining the burn area. We report the results of a monitoring program that includes 2 years of data prior to the Cerro Grande fire in...
Structure of the California Coast Ranges and San Andreas Fault at SAFOD from seismic waveform inversion and reflection imaging
F. Bleibinhaus, J.A. Hole, T. Ryberg, G. S. Fuis
2007, Journal of Geophysical Research B: Solid Earth (112)
[1] A seismic reflection and refraction survey across the San Andreas Fault (SAF) near Parkfield provides a detailed characterization of crustal structure across the location of the San Andreas Fault Observatory at Depth (SAFOD). Steep-dip prestack migration and frequency domain acoustic waveform tomography were applied to...
Coseismic source model of the 2003 Mw 6.8 Chengkung earthquake, Taiwan, determined from GPS measurements
K.-E. Ching, R.-J. Rau, Y. Zeng
2007, Journal of Geophysical Research B: Solid Earth (112)
A coseismic source model of the 2003 Mw 6.8 Chengkung, Taiwan, earthquake was well determined with 213 GPS stations, providing a unique opportunity to study the characteristics of coseismic displacements of a high-angle buried reverse fault. Horizontal coseismic displacements show fault-normal shortening across the fault trace. Displacements on the hanging...
