Essentials of iron, chromium, and calcium isotope analysis of natural materials by thermal ionization mass spectrometry
M.S. Fantle, T.D. Bullen
2009, Chemical Geology (258) 50-64
The use of isotopes to understand the behavior of metals in geological, hydrological, and biological systems has rapidly expanded in recent years. One of the mass spectrometric techniques used to analyze metal isotopes is thermal ionization mass spectrometry, or TIMS. While TIMS has been a useful analytical technique for the...
Possible sources of archaeological maize found in Chaco Canyon and Aztec Ruin, New Mexico
L. V. Benson, J.R. Stein, Howard E. Taylor
2009, Journal of Archaeological Science (36) 387-407
Maize played a major role in Chaco's interaction with outlying communities in the southern Colorado Plateau. This paper seeks to determine where archaeological corn cobs brought to Chaco Canyon were grown. Strontium-isotope and trace-metal ratios of 180 soil-water and 18 surface-water sites in the Southern Colorado Plateau have revealed possible...
Late Pleistocene to Holocene sedimentation and hydrocarbon seeps on the continental shelf of a steep, tectonically active margin, southern California, USA
Amy E. Draut, Patrick E. Hart, T.D. Lorenson, Holly F. Ryan, Florence L. Wong, Ray W. Sliter, James E. Conrad
2009, Marine Geophysical Research (30) 193-206
Small, steep, uplifting coastal watersheds are prolific sediment producers that contribute significantly to the global marine sediment budget. This study illustrates how sedimentation evolves in one such system where the continental shelf is largely sediment-starved, with most terrestrial sediment bypassing the shelf in favor of deposition in deeper basins. The...
Time budgets of Snow Geese Chen caerulescens and Ross's Geese Chen rossii in mixed flocks: Implications of body size, ambient temperature and family associations
J.E. Jonsson, A. D. Afton
2009, Ibis (151) 134-144
Body size affects foraging and forage intake rates directly via energetic processes and indirectly through interactions with social status and social behaviour. Ambient temperature has a relatively greater effect on the energetics of smaller species, which also generally are more vulnerable to predator attacks than are larger species. We examined...
Turbulent stresses and secondary currents in a tidal-forced channel with significant curvature and asymmetric bed forms
D.A. Fong, Stephen G. Monismith, M.T. Stacey, J.R. Burau
2009, Journal of Hydraulic Engineering (135) 198-208
Acoustic Doppler current profilers are deployed to measure both the mean flow and turbulent properties in a channel with significant curvature. Direct measurements of the Reynolds stress show a significant asymmetry over the tidal cycle where stresses are enhanced during the flood tide and less prominent over...
Dispersal of river sediment in the Southern California Bight
J.A. Warrick, K.L. Farnsworth
2009, Special Paper of the Geological Society of America 53-67
The rivers of Southern California deliver episodic pulses of water, sediment, nutrients, and pollutants to the region's coastal waters. Although river-sediment dispersal is observed in positively buoyant (hypopycnal) turbid plumes extending tens of kilometers from river mouths, very little of the river sediment is found in these plumes. Rather, river...
Hydrograph separation for karst watersheds using a two-domain rainfall-discharge model
Andrew J. Long
2009, Journal of Hydrology (364) 249-256
Highly parameterized, physically based models may be no more effective at simulating the relations between rainfall and outflow from karst watersheds than are simpler models. Here an antecedent rainfall and convolution model was used to separate a karst watershed hydrograph into two outflow components: one originating from focused recharge in...
Comparing wastewater chemicals, indicator bacteria concentrations, and bacterial pathogen genes as fecal pollution indicators
S.K. Haack, J.W. Duris, L.R. Fogarty, D.W. Kolpin, M. J. Focazio, E. T. Furlong, M. T. Meyer
2009, Journal of Environmental Quality (38) 248-258
The objective of this study was to compare fecal indicator bacteria (FIB) (fecal coliforms, Escherichia coli [EC], and enterococci [ENT]) concentrations with a wide array of typical organic wastewater chemicals and selected bacterial genes as indicators of fecal pollution in water samples collected at or near 18 surface water drinking water intakes....
A Mid-Late Quaternary loess-paleosol record in Simmons Farm in southern Illinois, USA
Hongfang Wang, C.C. Lundstrom, Z. Zhang, D.A. Grimley, W.L. Balsam
2009, Quaternary Science Reviews (28) 93-106
In unglaciated areas of the Mississippi Valley region, the typical full loess-paleosol succession contains the Modern Soil developed in Peoria Silt, weakly developed Farmdale Geosol developed in Roxana Silt, Sangamon Geosol developed in Loveland Silt, and Yarmouth Geosol developed in Crowley's Ridge Silt. Although a fifth loess called the Marianna...
Discriminating assimilants and decoupling deep- vs. shallow-level crystal records at Mount Adams using 238U-230Th disequilibria and Os isotopes
Brian R. Jicha, Clark M. Johnson, Wes Hildreth, Brian L. Beard, Garret L. Hart, Steven B. Shirey, Brad S. Singer
2009, Earth and Planetary Science Letters (277) 38-49
A suite of 23 basaltic to dacitic lavas erupted over the last 350 kyr from the Mount Adams volcanic field has been analyzed for U–Th isotope compositions to evaluate the roles of mantle versus crustal components during magma genesis. All of the lavas have (230Th/238U) > 1 and span a large range...
In situ video observations of two manefishes (perciformes: Caristiidae) in the mesopelagic zone of the northern Gulf of Mexico
M.C. Benfield, John H. Caruso, K. J. Sulak
2009, Copeia (4) 637-641
This paper describes direct video observations of two manefishes, likely Paracaristius sp., from the mesopelagic waters of the north-central Gulf of Mexico. One fish was observed with a remotely operated vehicle at a depth of 829 m by an industrial ROV as part of the SERPENT Project. The second was...
Interactive effects of fire, soil climate, and moss on CO2 fluxes in black spruce ecosystems of interior Alaska
Jonathan A. O’Donnell, Merritt R. Turetsky, Jennifer W. Harden, Kristen L. Manies, L.E. Pruett, Gordon Shetler, Jason C. Neff
2009, Ecosystems (12) 57-72
Fire is an important control on the carbon (C) balance of the boreal forest region. Here, we present findings from two complementary studies that examine how fire modifies soil organic matter properties, and how these modifications influence rates of decomposition and C exchange in black spruce (Picea mariana)...
Effect of species rarity on the accuracy of species distribution models for reptiles and amphibians in southern California
J. Franklin, K.E. Wejnert, S.A. Hathaway, C.J. Rochester, Robert N. Fisher
2009, Diversity and Distributions (15) 167-177
Aim: Several studies have found that more accurate predictive models of species' occurrences can be developed for rarer species; however, one recent study found the relationship between range size and model performance to be an artefact of sample prevalence, that is, the proportion of presence versus absence observations in the...
A shift in the dominant toxin-producing algal species in central California alters phycotoxins in food webs
R. Jester, K. Lefebvre, G. Langlois, V. Vigilant, K. Baugh, M.W. Silver
2009, Harmful Algae (8) 291-298
In California, the toxic algal species of primary concern are the dinoflagellate Alexandrium catenella and members of the pennate diatom genus Pseudo-nitzschia, both producers of potent neurotoxins that are capable of sickening and killing marine life and humans. During the summer of 2004 in Monterey Bay, we observed a change...
Simulating and understanding sand wave variation: A case study of the Golden Gate sand waves
F. Sterlini, S.J.M.H. Hulscher, D.M. Hanes
2009, Journal of Geophysical Research F: Earth Surface (114)
In this paper we present a detailed comparison between measured features of the Golden Gate sand wave field and the results of a nonlinear sand wave model. Because the Golden Gate sand waves exhibit large variation in their characteristics and in their environmental physics, this area gives us the opportunity...
Forecasting the combined effects of urbanization and climate change on stream ecosystems: from impacts to management options
Karen C. Nelson, Margaret A. Palmer, James E. Pizzuto, Glenn E. Moglen, Paul L. Angermeier, Robert H. Hilderbrand, Mike Dettinger, Katharine Hayhoe
2009, Journal of Applied Ecology (46) 154-163
Streams collect runoff, heat, and sediment from their watersheds, making them highly vulnerable to anthropogenic disturbances such as urbanization and climate change. Forecasting the effects of these disturbances using process-based models is critical to identifying the form and magnitude of likely impacts. Here, we integrate a new biotic model with...
Shallow water processes govern system-wide phytoplankton bloom dynamics: A modeling study
L.V. Lucas, Jeffrey R. Koseff, Stephen G. Monismith, J.K. Thompson
2009, Journal of Marine Systems (75) 70-86
A pseudo-two-dimensional numerical model of estuarine phytoplankton growth and consumption, vertical turbulent mixing, and idealized cross-estuary transport was developed and applied to South San Francisco Bay. This estuary has two bathymetrically distinct habitat types (deep channel, shallow shoal) and associated differences in local net rates of phytoplankton growth and consumption,...
How processing digital elevation models can affect simulated water budgets
E. L. Kuniansky, M.A. Lowery, B. G. Campbell
2009, Ground Water (47) 97-107
For regional models, the shallow water table surface is often used as a source/sink boundary condition, as model grid scale precludes simulation of the water table aquifer. This approach is appropriate when the water table surface is relatively stationary. Since water table surface maps are not readily available, the elevation...
Bacterial succession within an ephemeral hypereutrophic mojave desert playa lake
J.B. Navarro, D.P. Moser, A. Flores, C. Ross, Michael R. Rosen, H. Dong, G. Zhang, B.P. Hedlund
2009, Microbial Ecology (57) 307-320
Ephemerally wet playas are conspicuous features of arid landscapes worldwide; however, they have not been well studied as habitats for microorganisms. We tracked the geochemistry and microbial community in Silver Lake playa, California, over one flooding/desiccation cycle following the unusually wet winter of 2004-2005. Over the course of the study,...
Elevated CO2 enhances biological contributions to elevation change in coastal wetlands by offsetting stressors associated with sea-level rise
J. A. Cherry, K.L. McKee, J.B. Grace
2009, Journal of Ecology (97) 67-77
1. Sea-level rise, one indirect consequence of increasing atmospheric CO2, poses a major challenge to long-term stability of coastal wetlands. An important question is whether direct effects of elevated CO 2 on the capacity of marsh plants to accrete organic material and to maintain surface elevations outweigh indirect negative effects...
Relatedness and social organization of coypus in the Argentinean pampas
J.I. Tunez, M.L. Guichon, D. Centron, A.P. Henderson, C. Callahan, M.H. Cassini
2009, Molecular Ecology (18) 147-155
Behavioural and trapping studies of the social organization of coypus have suggested the occurrence of kin groups and a polygynous mating system. We used 16 microsatellite markers to analyse parentage and relatedness relationships in two populations (J??uregui and Villa Ruiz) in the Argentinean Pampas. At J??uregui, a dominant male monopolized...
Flow and geochemistry of groundwater beneath a back-barrier lagoon: The subterranean estuary at Chincoteague Bay, Maryland, USA
J.F. Bratton, J.K. Böhlke, D.E. Krantz, C.R. Tobias
2009, Marine Chemistry (113) 78-92
To better understand large-scale interactions between fresh and saline groundwater beneath an Atlantic coastal estuary, an offshore drilling and sampling study was performed in a large barrier-bounded lagoon, Chincoteague Bay, Maryland, USA. Groundwater that was significantly fresher than overlying bay water was found in shallow plumes up to 8 m thick...
Effects of rodent community diversity and composition on prevalence of an endemic bacterial pathogen - Bartonella
Y. Bai, M.Y. Kosoy, C.H. Calisher, J.F. Cully Jr., S.K. Collinge
2009, Biodiversity (10) 3-11
By studying Bartonella prevalence in rodent communities from 23 geographic sites in the western United States and one site in northern Mexico, the present study focused on the effects of rodent community diversity (measured by richness and Shannon index) and composition on prevalence of Bartonella infections. The analysis showed negative correlations of Bartonella prevalence with rodent...
Impacts of weathered tire debris on the development of Rana sylvatica larvae
K.M. Camponelli, R.E. Casey, J.W. Snodgrass, S.M. Lev, E. R. Landa
2009, Chemosphere (74) 717-722
Highway runoff has the potential to negatively impact receiving systems including stormwater retention ponds where highway particulate matter can accumulate following runoff events. Tire wear particles, which contain about 1% Zn by mass, make up approximately one-third of the vehicle derived particulates in highway runoff and therefore may serve as...
Geologic columns for the ICDP-USGS Eyreville B core, Chesapeake Bay impact structure: Impactites and crystalline rocks, 1766 to 1096 m depth
J. Wright Horton Jr., R.L. Gibson, W.U. Reimold, A. Wittmann, Gregory Gohn, Lucy E. Edwards
2009, Special Paper of the Geological Society of America 21-49
The International Continental Scientific Drilling Program (ICDP)-U.S. Geological Survey (USGS) Eyreville drill cores from the Chesapeake Bay impact structure provide one of the most complete geologic sections ever obtained from an impact structure. This paper presents a series of geologic columns and descriptive lithologic information for the lower impactite and...
