A new comprehensive approach to characterizing carbonaceous aerosol with an application to wintertime Fresno, California PM2.5
P. Herckes, J.A. Leenheer, J.L. Collett Jr.
2007, Atmospheric Chemistry and Physics Discussions (7) 8423-8453
Fine particulate matter (PM2.5) samples were collected during a three week winter period in Fresno (CA). A composite sample was characterized by isolating several distinct fractions and characterizing them by infrared and nuclear magnetic resonance (NMR) spectroscopy. More than 80% of the organic matter in the aerosol samples was recovered...
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...
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...
Occurrence of pesticides in water, sediment, and soil from the Yolo Bypass, California
Kelly L. Smalling, James L. Orlando, Kathryn Kuivila
2007, San Francisco Estuary and Watershed Science (5)
The objective of this study was to evaluate the potential sources of pesticides to the Yolo Bypass, including those that could potentially impact critical life stages of resident fish. To assess direct inputs during inundation, pesticide concentrations were analyzed in water and suspended and bed sediment samples collected from source...
Invasion by nonnative brook trout in Panther Creek, Idaho: Roles of local habitat quality, biotic resistance, and connectivity to source habitats
Joseph R. Benjamin, Jason B. Dunham, M.R. Dare
2007, Transactions of the American Fisheries Society (136) 875-888
Theoretical models and empirical evidence suggest that the invasion of nonnative species in freshwaters is facilitated through the interaction of three factors: habitat quality, biotic resistance, and connectivity. We measured variables that represented each factor to determine which were associated with the occurrence of nonnative brook trout Salvelinus fontinalis in Panther Creek,...
Formation of tellurium nanocrystals during anaerobic growth of bacteria that use Te oxyanions as respiratory electron acceptors
Shaun M. Baesman, Thomas D. Bullen, J. Dewald, Donghui Zhang, S. Curran, F.S. Islam, T.J. Beveridge, Ronald S. Oremland
2007, Applied and Environmental Microbiology (73) 2135-2143
Certain toxic elements support the metabolism of diverse prokaryotes by serving as respiratory electron acceptors for growth. Here, we demonstrate that two anaerobes previously shown to be capable of respiring oxyanions of selenium also achieve growth by reduction of either tellurate [Te(VI)] or tellurite [Te(IV)] to elemental...
Response of the St. Joseph River to lake level changes during the last 12,000 years in the Lake Michigan basin
K.A. Kincare
2007, Journal of Paleolimnology (37) 383-394
The water level of the Lake Michigan basin is currently 177 m above sea level. Around 9,800 14C years B.P., the lake level in the Lake Michigan basin had dropped to its lowest level in prehistory, about 70 m above sea level. This low level (Lake Chippewa) had profound effects...
DOM in recharge waters of the Santa Ana River Basin
J.A. Leenheer, G. R. Aiken, G. Woodside, K. O’Connor-Patel
2007, Journal - American Water Works Association (99) 118-131
Assessment of the composition, reactivity, and potential health effects of dissolved organic matter (DOM) is an important issue in the regulation and operation of groundwater recharge projects. The composition of DOM in various natural surface waters and reclaimed waters used to recharge the alluvial aquifers of the lower Santa Ana...
Ambiguous taxa: Effects on the characterization and interpretation of invertebrate assemblages
T. F. Cuffney, Michael D. Bilger, A.M. Haigler
2007, Journal of the North American Benthological Society (26) 286-307
Damaged and immature specimens often result in macroinvertebrate data that contain ambiguous parent-child pairs (i.e., abundances associated with multiple related levels of the taxonomic hierarchy such as Baetis pluto and the associated ambiguous parent Baetis sp.). The choice of method used to resolve ambiguous parent-child pairs may have a very...
Flux and age of dissolved organic carbon exported to the Arctic Ocean: A carbon isotopic study of the five largest arctic rivers
P.A. Raymond, J.W. McClelland, R.M. Holmes, A.V. Zhulidov, K. Mull, B. J. Peterson, Robert G. Striegl, G. R. Aiken, T.Y. Gurtovaya
2007, Global Biogeochemical Cycles (21)
The export and Δ14C-age of dissolved organic carbon (DOC) was determined for the Yenisey, Lena, Ob', Mackenzie, and Yukon rivers for 2004–2005. Concentrations of DOC elevate significantly with increasing discharge in these rivers, causing approximately 60% of the annual export to occur during a 2-month period following spring ice breakup....
Egg flotation estimates nest age for Pacific and Red-throated Loons
Daniel Rizzolo, Joel A. Schmutz
2007, Waterbirds (30) 207-213
We used Pacific Loon (Gavia pacifica) and Red-throated Loon (G. stellata) nests with known ages to gauge the efficacy of egg flotation for determining nest age in coastal Alaska. Egg flotation accurately estimated nest age for both species; the mean ± 1SD difference between known age and age determined with egg...
High-resolution sequence stratigraphy of lower Paleozoic sheet sandstones in central North America: The role of special conditions of cratonic interiors in development of stratal architecture
Anthony C. Runkel, J.F. Miller, R.M. McKay, A. R. Palmer, John F. Taylor
2007, Geological Society of America Bulletin (119) 860-881
Well-known difficulties in applying sequence stratigraphic concepts to deposits that accumulated across slowly subsiding cratonic interior regions have limited our ability to interpret the history of continental-scale tectonism, oceanographic dynamics of epeiric seas, and eustasy. We used a multi-disciplinary approach to construct a high-resolution stratigraphic framework for lower Paleozoic strata...
Understanding shallow gas occurrences in the Gulf of Lions
Ana Garcia-Garcia, Tommaso Tesi, Daniel L. Orange, T. Lorenson, Stefano Miserocchi, L. Langone, I. Herbert, J. Dougherty
2007, Geo-Marine Letters (27) 143-154
New coring data have been acquired along the western Gulf of Lions showing anomalous concentrations of methane (up to 95,700 ppm) off the Rhône prodelta and the head of the southern canyons Lacaze-Duthiers and Cap de Creus. Sediment cores were acquired with box and kasten cores during...
An evaluation of petrogenic hydrocarbons in northern Gulf of Alaska continental shelf sediments - The role of coastal oil seep inputs
J.W. Short, J.J. Kolak, J. R. Payne, G. K. Van Kooten
2007, Organic Geochemistry (38) 643-670
We compared hydrocarbons in water, suspended particulate matter (SPM), and riparian sediment collected from coastal watersheds along the Yakataga foreland with corresponding hydrocarbons in Gulf of Alaska benthic sediments. This comparison allows an evaluation of hydrocarbon contributions to marine sediments from natural oil seeps, coal and organic matter (e.g., kerogen)...
Cosmogenic 10Be and 36Cl geochronology of offset alluvial fans along the northern Death Valley fault zone: Implications for transient strain in the eastern California shear zone
K.L. Frankel, K.S. Brantley, J.F. Dolan, R.C. Finkel, R.E. Klinger, J.R. Knott, M. N. Machette, L.A. Owen, F. M. Phillips, J. L. Slate, B.P. Wernicke
2007, Journal of Geophysical Research B: Solid Earth (112)
The northern Death Valley fault zone (NDVFZ) has long been recognized as a major right-lateral strike-slip fault in the eastern California shear zone (ECSZ). However, its geologic slip rate has been difficult to determine. Using high-resolution digital topographic imagery and terrestrial cosmogenic nuclide dating, we present the first geochronologically determined...
Dating young geomorphic surfaces using age of colonizing Douglas fir in southwestern Washington and northwestern Oregon, USA
T.C. Pierson
2007, Earth Surface Processes and Landforms (32) 811-831
Dating of dynamic, young (<500 years) geomorphic landforms, particularly volcanofluvial features, requires higher precision than is possible with radiocarbon dating. Minimum ages of recently created landforms have long been obtained from tree-ring ages of the oldest trees growing on new surfaces. But to estimate the year of landform creation requires...
Using a coupled eco-hydrodynamic model to predict habitat for target species following dam removal
C.A. Tomsic, T.C. Granata, R.P. Murphy, C.J. Livchak
2007, Ecological Engineering (30) 215-230
A habitat suitability index (HSI) model was developed for a water quality sensitive fish (Greater Redhorse) and macroinvertebrate (Plecoptera) species to determine the restoration success of the St. John Dam removal for the Sandusky River (Ohio). An ArcGIS?? model was created for pre- and post-dam removal scenarios. Inputs to the...
Tracking environmental dynamics and agricultural intensification in southern Mali
G. Gray Tappan, M. McGahuey
2007, Agricultural Systems (94) 38-51
The Office de la Haute Vallée du Fleuve Niger (OHVN) zone in southern Mali is a small but important agricultural production region. Against a background of environmental degradation including decades of declining rainfall, soil erosion, and human pressure on forest resources, numerous farming communities stand out through the use of...
A new, large, late pleistocene demosponge from Southeastern Florida
J.K. Rigby, K.J. Cunningham
2007, Journal of Paleontology (81) 788-793
[No abstract available]...
Variable role of aquatic macroinvertebrates in initial breakdown of seasonal leaf litter inputs to a cold-desert river
S. M. Nelson, D.C. Andersen
2007, Southwestern Naturalist (52) 219-228
We used coarse-mesh and fine-mesh leafpacks to examine the importance of aquatic macroinvertebrates in the breakdown of floodplain tree leaf litter that seasonally entered a sand-bedded reach of the sixth-order Yampa River in semiarid Colorado. Leafpacks were positioned off the easily mobilized channel bed, mimicking litter trapped in debris piles....
Law of the sea, the continental shelf, and marine research
Deborah R. Hutchinson, Robert W. Rowland
2007, Eos, Transactions, American Geophysical Union (88) 237-240
The question of the amount of seabed to which a coastal nation is entitled is addressed in the United Nations Convention on the Law of the Sea (UNCLOS). This treaty, ratified by 153 nations and in force since 1994, specifies national obligations, rights, and jurisdiction in the oceans, and it...
Large-scale causes of variation in the serpentine vegetation of California
J.B. Grace, H.D. Safford, S. Harrison
2007, Conference Paper, Plant and Soil
Serpentine vegetation in California ranges from forest to shrubland and grassland, harbors many rare and endemic species, and is only moderately altered by invasive exotic species at the present time. To better understand the factors regulating the distribution of common/representative species, endemic/rare species, and the threat of exotics in this...
Eutrophication study at the Panjiakou-Daheiting Reservoir system, northern Hebei Province, People's Republic of China: Chlorophyll-a model and sources of phosphorus and nitrogen
Joseph L. Domagalski, Chao Lin, Yang Luo, Jie Kang, Shaoming Wang, Larry R. Brown, Mark D. Munn
2007, Agricultural Water Management (94) 43-53
Concentrations, loads, and sources of nitrate and total phosphorus were investigated at the Panjiakou and Daheiting Reservoir system in northern Hebei Province, People's Republic of China. The Luan He River is the primary source of water to these reservoirs, and the upstream watershed has a mix of land uses including...
Mountaintop island age determines species richness of boreal mammals in the American Southwest
J.K. Frey, M.A. Bogan, Terry L. Yates
2007, Ecography (30) 231-240
Models that describe the mechanisms responsible for insular patterns of species richness include the equilibrium theory of island biogeography and the nonequilibrium vicariance model. The relative importance of dispersal or vicariance in structuring insular distribution patterns can be inferred from these models. Predictions of the alternative models were tested for...
Occurrence and nest survival of four thrush species on a managed central Appalachian forest
R.L. Dellinger, P.B. Wood, P.D. Keyser
2007, Forest Ecology and Management (243) 248-258
The wood thrush (Hylocichla mustelina Gmelin) is a species of concern in the central Appalachians, and is sympatric there with three related species, the American robin (Turdus migratorius Linnaeus), hermit thrush (Catharus guttatus Pallas), and veery (Catharus fuscescens Stephens). Our objectives were to quantify use of mature forests and areas...
