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Full-Text Articles in Entire DC Network
The Influence Of Sublacustrine Hydrothermal Vent Fluids On The Geochemistry Of Yellowstone Lake, Laurie S. Balistrieri, Wayne C. Shanks Iii, Russell L. Cuhel, Carmen Aguilar, J. Val Klump
The Influence Of Sublacustrine Hydrothermal Vent Fluids On The Geochemistry Of Yellowstone Lake, Laurie S. Balistrieri, Wayne C. Shanks Iii, Russell L. Cuhel, Carmen Aguilar, J. Val Klump
United States Geological Survey: Publications
The geochemical composition of Yellowstone Lake water is strongly influenced by sublacustrine hydrothermal vent activity. The evidence for this conclusion is twofold. First, mass-balance calculations indicate that the outflow from Yellowstone Lake is enriched in dissolved As, B, Cl, Cs, Ge, Li, Mo, Sb, and W relative to inflowing waters. Calculations involving stable isotopes of hydrogen and oxygen (δD and δ18O, respectively) and mass-balances indicate about 13 percent evapoconcentration in the lake, which is inadequate to account for the enrichment of these elements in the water column. Second, linear relationships between the concentration of Cl and many other elements in …
Hydrothermally Altered Rock And Hot-Spring Deposits At Yellowstone National Park—Characterized Using Airborne Visible- And Infrared-Spectroscopy Data, K. Eric Livo, Fred A. Kruse, Roger N. Clark, Raymond F. Kokaly, W. C. Shanks Iii
Hydrothermally Altered Rock And Hot-Spring Deposits At Yellowstone National Park—Characterized Using Airborne Visible- And Infrared-Spectroscopy Data, K. Eric Livo, Fred A. Kruse, Roger N. Clark, Raymond F. Kokaly, W. C. Shanks Iii
United States Geological Survey: Publications
The hydrothermal system in Yellowstone National Park has created altered rock and hot-spring deposits that were mapped using AVIRIS (airborne visible and infrared imaging spectrometer) data. The mapped minerals are indicative of the geologic processes and environments that controlled their formation. Ongoing volcanic activity is expressed at the surface by geothermal features, earthquakes, and geologically recent caldera formation. Precipitated minerals such as siliceous sinter and travertine on the surface are derived from chloride-rich alkaline solutions that are leaching silica and calcite from the underlying country rock. Siliceous sinter and montmorillonite are associated with hydrothermal systems abundant in hot water, whereas …
Investigations Of The Effects Of Synthetic Chemicals On The Endocrine System Of Common Carp In Lake Mead, Nevada And Arizona, Michael R. Rosen, Steven L. Goodbred, Reynaldo Patiño, Thomas J. Leiker, Erik Orsak
Investigations Of The Effects Of Synthetic Chemicals On The Endocrine System Of Common Carp In Lake Mead, Nevada And Arizona, Michael R. Rosen, Steven L. Goodbred, Reynaldo Patiño, Thomas J. Leiker, Erik Orsak
United States Geological Survey: Publications
Lake Mead is the largest reservoir by volume in the United States and was created by the construction of the 221-meter high Hoover Dam in 1935 at Black Canyon on the lower Colorado River between Nevada and Arizona (fig. 1). Inflows of water into the lake include three rivers, Colorado, Virgin, and Muddy; as well as Las Vegas Wash, which is now perennial because of discharges from municipal wastewater treatment plants (Covay and Leiker, 1998) and urban stormwater runoff. As the population within the Las Vegas Valley began to increase in the 1940s, the treated effluent volume also has increased …
Applications Of Trace-Element And Stable-Isotope Geochemistry To Wildlife Issues, Yellowstone National Park And Vicinity, Maurice A. Chaffee, Wayne C. Shanks Iii, Robert O. Rye, Charles C. Shwartz, Monique G. Adams, Robert R. Carlson, James G. Crock, Pamela A. Gemery-Hill, Kerry A. Gunther, Cynthia L. Kester, Harley D. King, Shannon R. Podruzny
Applications Of Trace-Element And Stable-Isotope Geochemistry To Wildlife Issues, Yellowstone National Park And Vicinity, Maurice A. Chaffee, Wayne C. Shanks Iii, Robert O. Rye, Charles C. Shwartz, Monique G. Adams, Robert R. Carlson, James G. Crock, Pamela A. Gemery-Hill, Kerry A. Gunther, Cynthia L. Kester, Harley D. King, Shannon R. Podruzny
United States Geological Survey: Publications
Reconnaissance investigations have been conducted to identify how geochemical techniques can be applied to biological studies to assist wildlife management in and near Yellowstone National Park (the Park). Many elements (for example, As, B, Be, Ce, Cl, Cs, F, Hg, K, Li, Mo, Rb, S, Sb, Si, and W) are commonly enriched in (1) thermal waters in the Yellowstone area, (2) rocks altered by these waters, (3) sinter and travertine deposits, and (4) soils and stream sediments derived from these rocks. Some of these elements, such as As, F, Hg, and Mo, may be toxic to wildlife and could be …
Concentrations Of Metals In Aquatic Invertebrates From The Ozark National Scenic Riverways, Missouri, Christopher J. Schmitt, William G. Brumbaugh, John M. Besser, Thomas W. May
Concentrations Of Metals In Aquatic Invertebrates From The Ozark National Scenic Riverways, Missouri, Christopher J. Schmitt, William G. Brumbaugh, John M. Besser, Thomas W. May
United States Geological Survey: Publications
This report summarizes the findings of a study conducted as a pilot for part of a park-wide monitoring program being developed for the Ozark National Scenic Riverways (ONSR) of southeastern Missouri. The objective was to evaluate using crayfish (Orconectes spp.) and Asian clam (Corbicula fluminea) for monitoring concentrations of metals associated with lead-zinc mining. Lead-zinc mining presently (2007) occurs near the ONSR and additional mining has been proposed. Three composite samples of each type (crayfish and Asian clam), each comprising ten animals of approximately the same size, were collected during late summer and early fall of 2005 …
Hydrologic Connectivity And The Contribution Of Stream Headwaters To Ecological Integrity At Regional Scales1, Mary C. Freeman, Catherine M. Pringle, C. Rhett Jackson
Hydrologic Connectivity And The Contribution Of Stream Headwaters To Ecological Integrity At Regional Scales1, Mary C. Freeman, Catherine M. Pringle, C. Rhett Jackson
United States Geological Survey: Staff Publications
Cumulatively, headwater streams contribute to maintaining hydrologic connectivity and ecosystem integrity at regional scales. Hydrologic connectivity is the water-mediated transport of matter, energy and organisms within or between elements of the hydrologic cycle. Headwater streams compose over two-thirds of total stream length in a typical river drainage and directly connect the upland and riparian landscape to the rest of the stream ecosystem. Altering headwater streams, e.g., by channelization, diversion through pipes, impoundment and burial, modifies fluxes between uplands and downstream river segments and eliminates distinctive habitats. The large-scale ecological effects of altering headwaters are amplified by land uses that alter …
Microbial Sulfate Reduction And Metal Attenuation In Ph 4 Acid Mine Water, Clinton D. Church, Richard T. Wilkin, Charles N. Alpers, Robert O. Rye, R. Blaine Mccleskey
Microbial Sulfate Reduction And Metal Attenuation In Ph 4 Acid Mine Water, Clinton D. Church, Richard T. Wilkin, Charles N. Alpers, Robert O. Rye, R. Blaine Mccleskey
United States Geological Survey: Staff Publications
Sediments recovered from the flooded mine workings of the Penn Mine, a Cu-Zn mine abandoned since the early 1960s, were cultured for anaerobic bacteria over a range of pH (4.0 to 7.5). The molecular biology of sediments and cultures was studied to determine whether sulfate-reducing bacteria (SRB) were active in moderately acidic conditions present in the underground mine workings. Here we document multiple, independent analyses and show evidence that sulfate reduction and associated metal attenuation are occurring in the pH-4 mine environment. Waterchemistry analyses of the mine water reveal: (1) preferential complexation and precipitation by H2S of Cu …
Butterfly Responses To Prairie Restoration Through Fire And Grazing, Jennifer A. Vogel, Diane M. Debinski, Rolf R. Koford, James R. Miller
Butterfly Responses To Prairie Restoration Through Fire And Grazing, Jennifer A. Vogel, Diane M. Debinski, Rolf R. Koford, James R. Miller
United States Geological Survey: Staff Publications
The development of land for modern agriculture has resulted in losses of native prairie habitat. The small, isolated patches of prairie habitat that remain are threatened by fire suppression, overgrazing, and invasion by non-native species. We evaluated the effects of three restoration practices (grazing only, burning only, and burning and grazing) on the vegetation characteristics and butterfly communities of remnant prairies. Total butterfly abundance was highest on prairies that were managed with burning and grazing and lowest on those that were only burned. Butterfly species richness did not differ among any of the restoration practices. Butterfly species diversity was highest …
Factors Influencing Movement Probabilities Of Big Brown Bats (Eptesicus Fuscus) In Buildings, Laura E. Ellison, Thomas J. O’Shea, Daniel J. Neubaum, Richard Bowen
Factors Influencing Movement Probabilities Of Big Brown Bats (Eptesicus Fuscus) In Buildings, Laura E. Ellison, Thomas J. O’Shea, Daniel J. Neubaum, Richard Bowen
United States Geological Survey: Staff Publications
We investigated movements of female big brown bats (Eptesicus fuscus) roosting in maternity colonies in buildings in Fort Collins, Colorado (USA), during the summers of 2002, 2003, and 2005. This behavior can be of public health concern where bats that may carry diseases (e.g., rabies) move among buildings occupied by people. We used passive integrated transponders (PIT tags) to mark individual bats and hoop PIT readers at emergence points to passively monitor the use of building roosts by marked adult females on a daily basis during the lactation phase of reproduction. Multi-strata models were used to examine movements …
Evaluation And Comparison Of Gross Primary Production Estimates For The Northern Great Plains Grasslands, Li Zhang, Bruce K. Wylie, Thomas Loveland, Eugene A. Fosnight, Larry L. Tieszen, Lei Ji, Tagir G. Gilmanov
Evaluation And Comparison Of Gross Primary Production Estimates For The Northern Great Plains Grasslands, Li Zhang, Bruce K. Wylie, Thomas Loveland, Eugene A. Fosnight, Larry L. Tieszen, Lei Ji, Tagir G. Gilmanov
United States Geological Survey: Staff Publications
Two spatially-explicit estimates of gross primary production (GPP) are available for the Northern Great Plains. An empirical piecewise regression (PWR) GPP model was developed from flux tower measurements to map carbon flux across the region. The Moderate Resolution Imaging Spectrometer (MODIS) GPP model is a process-based model that uses flux tower data to calibrate its parameters. Verification and comparison of the regional PWR GPP and the global MODIS GPP are important for the modeling of grassland carbon flux. This study compared GPP estimates from PWR and MODIS models with five towers in the grasslands. Among them, PWR GPP and MODIS …
Fundulus As The Premier Teleost Model In Environmental Biology: Opportunities For New Insights Using Genomics, Karen G. Burnett, Lisa J. Bain, William S. Baldwin, Gloria V. Callard, Sarah Cohen, Richard T. Di Giulio, David H. Evans, Marta Gómez-Chiarri, Mark E. Hahn, Cindi A. Hoover, Sibel I. Karchner, Fumi Katoh, Deborah L. Maclatchy, William S. Marshall, Joel N. Meyer, Diane E. Nacci, Marjorie F. Oleksiak, Bernard B. Rees, Thomas D. Singer, John J. Stegeman, David W. Towle, Peter A. Van Veld, Wolfgang K. Vogelbein, Andrew Whitehead, Richard N. Winn, Douglas L. Crawford
Fundulus As The Premier Teleost Model In Environmental Biology: Opportunities For New Insights Using Genomics, Karen G. Burnett, Lisa J. Bain, William S. Baldwin, Gloria V. Callard, Sarah Cohen, Richard T. Di Giulio, David H. Evans, Marta Gómez-Chiarri, Mark E. Hahn, Cindi A. Hoover, Sibel I. Karchner, Fumi Katoh, Deborah L. Maclatchy, William S. Marshall, Joel N. Meyer, Diane E. Nacci, Marjorie F. Oleksiak, Bernard B. Rees, Thomas D. Singer, John J. Stegeman, David W. Towle, Peter A. Van Veld, Wolfgang K. Vogelbein, Andrew Whitehead, Richard N. Winn, Douglas L. Crawford
United States Environmental Protection Agency: Publications
A strong foundation of basic and applied research documents that the estuarine fish Fundulus heteroclitus and related species are unique laboratory and field models for understanding how individuals and populations interact with their environment. In this paper we summarize an extensive body of work examining the adaptive responses of Fundulus species to environmental conditions, and describe how this research has contributed importantly to our understanding of physiology, gene regulation, toxicology, and ecological and evolutionary genetics of teleosts and other vertebrates. These explorations have reached a critical juncture at which advancement is hindered by the lack of genomic resources for these …
Developing A Rapid Method For Assessing The Physical Stability Of Streams In Minnesota's Agassiz Beach Ridges, Abigail V. Franklund
Developing A Rapid Method For Assessing The Physical Stability Of Streams In Minnesota's Agassiz Beach Ridges, Abigail V. Franklund
Theses and Dissertations
This thesis assessed the physical characteristics and stability of selected western Minnesota streams that cross the eastern beach ridges of glacial Lake Agassiz. Stream and river channels in this area host unusually diverse aquatic habitat and biodiversity, but incompatible land use along channels and in watersheds impair their quality and function. Previous rapid assessment protocols have been developed for stream attributes and stability, but these methods have been developed elsewhere in the United States and are not necessarily appropriate for western Minnesota’s unique geology and landscape.
A rapid reconnaissance method was developed to assess stream conditions using an integrated numerical …
Chemical Analyses In Support Of Yucca Mountain Studies, Harry Reid Center For Environmental Studies, University Of Nevada, Las Vegas
Chemical Analyses In Support Of Yucca Mountain Studies, Harry Reid Center For Environmental Studies, University Of Nevada, Las Vegas
Publications (YM)
Research Objectives: Provide preparation of injectates, sorption studies and analyses for tracer tests Provide REE, trace metals, majors and field measurement data from wells of the Nye County Early Warning Drilling Program (NCEWDP)and Inyo County Other laboratory needs as they arise
Trampling, Peeling And Nibbling Mussels: An Experimental Assessment Of Mechanical And Predatory Damage To Shells Of Mytilus Trossulus (Mollusca: Mytilidae), Carlos E. Cintra-Buenrostro
Trampling, Peeling And Nibbling Mussels: An Experimental Assessment Of Mechanical And Predatory Damage To Shells Of Mytilus Trossulus (Mollusca: Mytilidae), Carlos E. Cintra-Buenrostro
School of Earth, Environmental, & Marine Sciences Faculty Publications
Shell damage, if properly recognized, can provide information about biotic interactions between molluscs and their predators. However, it can be difficult to distinguish predatory damage from mechanical breakage, thus making interpretation of damaged modern and fossil shells problematic. To establish a clear-cut distinction between antemortem predatory crab damage and ante- and postmortem mechanical damage in Mytilus trossulus shells, a combined field and experimental approach was used. Mussels were exposed to predation by crabs, tumbled-live, tumbled-dead, and trampled. After 100 h of tumbling, live-collected mussel shells were abraded and disarticulated but not otherwise damaged. Eight percent of the dead-collected shells were …
Simulations Of Phytoplankton Species And Carbon Production In The Equatorial Pacific Ocean 2. Effects Of Physical And Biogeochemical Processes, Baris Salihoglu, Eileen E. Hofmann
Simulations Of Phytoplankton Species And Carbon Production In The Equatorial Pacific Ocean 2. Effects Of Physical And Biogeochemical Processes, Baris Salihoglu, Eileen E. Hofmann
CCPO Publications
A one-dimensional multi-component lower trophic level ecosystem model that includes detailed algal physiology is used to investigate the response of phytoplankton community and carbon production and export to variations in physical and biochemical processes in the Cold Tongue region of the equatorial Pacific Ocean at ON, 140W. Results show that high-frequency variability in vertical advection and temperature is an important mechanism driving the carbon export. Filtering out low frequency physical forcing results in a 30% increase in primary production and dominance of high-light adapted Prochlorococcus and autotrophic eukaryotes. Sensitivity studies show that iron availability is the primary control on carbon …
Assessment Of Skill And Portability In Regional Marine Biogeochemical Models: Role Of Multiple Planktonic Groups, Marjorie A. M. Friedrichs, Jeffery A. Dusenberry, Laurence A. Anderson, Robert A. Armstrong, Fei Chai, James R. Christian, Scott C. Doney, John Dunne, Masahiko Fujii, Jerry D. Wiggert
Assessment Of Skill And Portability In Regional Marine Biogeochemical Models: Role Of Multiple Planktonic Groups, Marjorie A. M. Friedrichs, Jeffery A. Dusenberry, Laurence A. Anderson, Robert A. Armstrong, Fei Chai, James R. Christian, Scott C. Doney, John Dunne, Masahiko Fujii, Jerry D. Wiggert
CCPO Publications
[1] Application of biogeochemical models to the study of marine ecosystems is pervasive, yet objective quantification of these models' performance is rare. Here, 12 lower trophic level models of varying complexity are objectively assessed in two distinct regions (equatorial Pacific and Arabian Sea). Each model was run within an identical one-dimensional physical framework. A consistent variational adjoint implementation assimilating chlorophyll-a, nitrate, export, and primary productivity was applied and the same metrics were used to assess model skill. Experiments were performed in which data were assimilated from each site individually and from both sites simultaneously. A cross-validation experiment was also conducted …
Analysis Of Miocene Stratigraphy And Sedimentology In The Ross Sea, Antarctica: A First Order Test Of Proxy Based Climate Interpretations, Samuel Gray
LSU Master's Theses
During the Cenozoic, the climate progressed from global warmth into an icehouse world. This study investigates the links between the development of the climate and cryosphere using sediment flux and stratal geometries. The current polar conditions are characterized by dry basal conditions, which due to minimal melt water produce significantly less sediment than their temperate counterparts. Therefore, the transition from temperate to polar conditions should have resulted in marked decrease in sediment flux and change in stratal geometries in adjacent marine margins. Regional seismic stratigraphic evidence clearly suggests that ice has been intermittently grounded on the Ross Sea outer continental …
Paleosalinity History Of Middle Holocene Lagoonal And Lacustrine Deposits In The Enriquillo Valley, Dominican Republic Based On Pore Morphometrics And Isotope Geochemistry Of Ostracoda, Pamela Medley, Neil E. Tibert, William P. Patterson, H. Allen Curran, Lisa Greer, Jean-Paul Colin
Paleosalinity History Of Middle Holocene Lagoonal And Lacustrine Deposits In The Enriquillo Valley, Dominican Republic Based On Pore Morphometrics And Isotope Geochemistry Of Ostracoda, Pamela Medley, Neil E. Tibert, William P. Patterson, H. Allen Curran, Lisa Greer, Jean-Paul Colin
Geosciences: Faculty Publications
The southwestern region of the Dominican Republic (Enriquillo Valley) contains exceptionally well-preserved, relict marine and saline lake deposits of mid-Holocne age. Abundant euryhaline ostracodes found in this deposit include Cyprideis salebrosa, C. mexicana, C. similis, and C. edentata. Morphometric and geochemical analyses performed on Cyprideis spp. provide high δ18O and δ13C values that are coincident with relative abundances of irregularly shaped pores that permeate the ostracode carapace. We recognize three stratigraphic intervals with distinct ostracode pore shape and stable isotope trends: (I) a 4.5-5.0m interval that contains ostracodes with highly irregular shaped pores (multiradiate) and …
Biogeochemical Processes And Seasonal Effects In Flow-Through Mesocosm Reactors Simulating Constructed Wetlands, Sarah J. Tritschler
Biogeochemical Processes And Seasonal Effects In Flow-Through Mesocosm Reactors Simulating Constructed Wetlands, Sarah J. Tritschler
Browse all Theses and Dissertations
Due to their distinctive environments, constructed wetlands are utilized to remediate groundwater that has been contaminated with chlorinated ethenes (i.e. perchloroethene) and other such contaminants. This research focuses on vertical flow mesocosm reactors housed in a greenhouse at Wright State University, which simulate a constructed wetland on Wright-Patterson Air Force Base. These reactors were studied to investigate the effects of vegetation and seasonal changes on the redox parameters present. Water samples were collected from six different reactors from late September/early October 2006 until August 2007. The reactors were sampled three days in a row and this sampling was done once …
Seasonal Variation In The Redox Zones And Biogeochemical Processes Within The Constructed Wetland, Yussuf Mohamud
Seasonal Variation In The Redox Zones And Biogeochemical Processes Within The Constructed Wetland, Yussuf Mohamud
Browse all Theses and Dissertations
This research investigation focuses on the vertical distribution of dissolved inorganic species in the pore-water affected by redox processes and seasonal changes within a small constructed wetland located at the Wright-Patterson Air Force Base. This is a follow up study to an earlier investigation (Lach, 2004) at this site in 2003. Water samples were collected from influent, effluent and three layers of the constructed wetland through a network of nested piezometers in the vertical flow wetland from June 2005 to June 2006. Onsite analysis of temperature, pH and conductivity were carried out onsite. Major anions and cations were measured by …
Impact Of Land Use On Water Quality In The Indian Lake Watershed: An Integrated Geographic Information Systems Approach, Michael Belke
Impact Of Land Use On Water Quality In The Indian Lake Watershed: An Integrated Geographic Information Systems Approach, Michael Belke
Browse all Theses and Dissertations
Geology and land use and land cover are the most important factors that influence water quality. The purpose of this study is to investigate how these factors operate in a rural watershed. Specifically, this thesis tests the feasibility of a proposed formula to relate how land use affects surface water quality and to infer hydrogeochemical reactions that control water chemistry through hydrogeochemical speciation and mineral stability relationships. Samples were collected from Indian Lake and its watershed in West-Central Ohio. BASINS, produced by the USEPA, was then used to delineate sub-watersheds and find the land use areas of these watersheds. The …
Evaluation Of The Streambed Leakage Concept In Analytical Models Using Data From Three Pumping Tests, Sefan J. Kollet, Vitaly A. Zlotnik
Evaluation Of The Streambed Leakage Concept In Analytical Models Using Data From Three Pumping Tests, Sefan J. Kollet, Vitaly A. Zlotnik
Department of Earth and Atmospheric Sciences: Faculty Publications
Two-dimensional analytical models of pumping induced drawdown and stream depletion account for the streambed properties and stream geometry. Using data from three pumping tests performed under various hydrologic conditions, the following hypotheses were tested: (1) a partially penetrating stream at a certain distance from the pumping well can be represented by the streambed leakage term in the analytical models; (2) in the streambed leakage term, the streambed conductance coefficient λ=(WK′)/m′ accounts for the average stream width W, the streambed thickness m′, and hydraulic conductivity K′. The first hypothesis was tested by comparing results from tests under flow and no-flow stream …
Airborne Dust Transport To The Eastern Pacific Ocean Off Southern California: Evidence From San Clemente Island, Daniel R. Muhs, James Budahn, Marith Reheis, Jossh Beann, Gary Skipp, Eric Fisher
Airborne Dust Transport To The Eastern Pacific Ocean Off Southern California: Evidence From San Clemente Island, Daniel R. Muhs, James Budahn, Marith Reheis, Jossh Beann, Gary Skipp, Eric Fisher
United States Geological Survey: Staff Publications
Islands are natural dust traps, and San Clemente Island, California, is a good example. Soils on marine terraces cut into Miocene andesite on this island are clay-rich Vertisols or Alfisols with vertic properties. These soils are overlain by silt-rich mantles, 5–20 cm thick, that contrast sharply with the underlying clay-rich subsoils. The silt mantles have a mineralogy that is distinct from the island bedrock. Silt mantles are rich in quartz, which is rare in the island andesite. The clay fraction of the silt mantles is dominated by mica, also absent from local andesite, and contrasts with the subsoils, dominated by …
Passive Aerobic Treatment Of Net-Alkaline, Iron-Laden Drainage From A Flooded Underground Anthracite Mine, Pennsylvania, Usa, Charles A. Cravotta Iii
Passive Aerobic Treatment Of Net-Alkaline, Iron-Laden Drainage From A Flooded Underground Anthracite Mine, Pennsylvania, Usa, Charles A. Cravotta Iii
United States Geological Survey: Staff Publications
This report evaluates the results of a continuous 4.5-day laboratory aeration experiment and the first year of passive, aerobic treatment of abandoned mine drainage (AMD) from a typical flooded underground anthracite mine in eastern Pennsylvania, USA. During 1991–2006, the AMD source, locally known as the Otto Discharge, had flows from 20 to 270 L/s (median 92 L/s) and water quality that was consistently suboxic (median 0.9 mg/L O2) and circumneutral (pH ~ 6.0; net alkalinity >10) with moderate concentrations of dissolved iron and manganese and low concentrations of dissolved aluminum (medians of 11, 2.2, and <0.2 mg/L, respectively). In 2001, the laboratory aeration experiment demonstrated rapid oxidation of ferrous iron (Fe2+) without …0.2>
Late Cenozoic Climate Changes In China’S Western Interior: A Review Of Research On Lake Qinghai And Comparison With Other Records, Steven M. Colman, Shi-Yong Yua, Zhisheng Anc, Ji Shend, A.C.G. Henderson
Late Cenozoic Climate Changes In China’S Western Interior: A Review Of Research On Lake Qinghai And Comparison With Other Records, Steven M. Colman, Shi-Yong Yua, Zhisheng Anc, Ji Shend, A.C.G. Henderson
United States Geological Survey: Staff Publications
We review Late Cenozoic climate and environment changes in the western interior of China with an emphasis on lacustrine records from Lake Qinghai. Widespread deposition of red clay in the marginal basins of the Tibetan Plateau indicates that the Asian monsoon system was initially established by ~8 Ma, when the plateau reached a threshold altitude. Subsequent strengthening of the winter monsoon, along with the establishment of the Northern Hemisphere ice sheets, reflects a long-term trend of global cooling. The few cores from the Tibetan Plateau that reach back a million years suggest that they record the mid-Pleistocene transition from glacial …
Sexual Selection Drives Speciation In An Amazonian Frog, Kathryn E. Boul, W. Chris Funk, Catherine R. Darst, David C. Cannatella, Michael J. Ryan
Sexual Selection Drives Speciation In An Amazonian Frog, Kathryn E. Boul, W. Chris Funk, Catherine R. Darst, David C. Cannatella, Michael J. Ryan
United States Geological Survey: Staff Publications
One proposed mechanism of speciation is divergent sexual selection, whereby divergence in female preferences and male signals results in behavioural isolation. Despite the appeal of this hypothesis, evidence for it remains inconclusive. Here, we present several lines of evidence that sexual selection is driving behavioural isolation and speciation among populations of an Amazonian frog (Physalaemus petersi). First, sexual selection has promoted divergence in male mating calls and female preferences for calls between neighbouring populations, resulting in strong behavioural isolation. Second, phylogenetic analysis indicates that populations have become fixed for alternative call types several times throughout the species’ range, …
Microsatellite Loci For Distinguishing Spotted Owls (Strix Occidentalis), Barred Owls (Strix Varia), And Their Hybrids, W. Chris Funk, Thomas D. Mullins, Eric D. Forsman, Susan M. Haig
Microsatellite Loci For Distinguishing Spotted Owls (Strix Occidentalis), Barred Owls (Strix Varia), And Their Hybrids, W. Chris Funk, Thomas D. Mullins, Eric D. Forsman, Susan M. Haig
United States Geological Survey: Staff Publications
We identified four diagnostic microsatellite loci that distinguish spotted owls (Strix occidentalis), barred owls (Strix varia), F1 hybrids and backcrosses. Thirty-four out of 52 loci tested (65.4%) successfully amplified, and four of these loci (11.8%) had allele sizes that did not overlap between spotted and barred owls. The probability of correctly identifying a backcross with these four loci is 0.875. Genotyping potential hybrid owls with these markers revealed that field identifications were often wrong. Given the difficulty of identifying hybrids in the field, these markers will be useful for hybrid identification, law enforcement and spotted …
New Insights Into Marine Migration And Winter Habitat Of Gulf Sturgeon, Randy E. Edwards, Frank M. Parauka, Kenneth J. Sulak
New Insights Into Marine Migration And Winter Habitat Of Gulf Sturgeon, Randy E. Edwards, Frank M. Parauka, Kenneth J. Sulak
United States Geological Survey: Staff Publications
Migrations and movements of Gulf sturgeon Acipenser oxyrinchus desotoi were determined using satellite pop-up archival transmitting (PAT) tags and acoustic telemetry. Adult Gulf sturgeon from four rivers in northwestern Florida were caught with gill nets and were tagged with PAT and acoustic tags in the fall of 2001 and 2002. PAT tags were programmed to release in early February 2002 and 2003 to provide information about location of late-winter marine habitats. However, only 5 of 25 provided meaningful location information. Three of the PAT-tagged fish were relocated acoustically near the PAT tag pop-up locations, one of which was in Choctawhatchee …
Hydrologic Connectivity And The Contribution Of Stream Headwaters To Ecological Integrity At Regional Scales, Mary C. Freeman, Catherine M. Pringle, C. Rhett Jackson
Hydrologic Connectivity And The Contribution Of Stream Headwaters To Ecological Integrity At Regional Scales, Mary C. Freeman, Catherine M. Pringle, C. Rhett Jackson
United States Geological Survey: Staff Publications
Cumulatively, headwater streams contribute to maintaining hydrologic connectivity and ecosystem integrity at regional scales. Hydrologic connectivity is the water-mediated transport of matter, energy and organisms within or between elements of the hydrologic cycle. Headwater streams compose over two-thirds of total stream length in a typical river drainage and directly connect the upland and riparian landscape to the rest of the stream ecosystem. Altering headwater streams, e.g., by channelization, diversion through pipes, impoundment and burial, modifies fluxes between uplands and downstream river segments and eliminates distinctive habitats. The large-scale ecological effects of altering headwaters are amplified by land uses that alter …
Species Richness And Soil Properties In Pinus Ponderosa Forests: A Structural Equation Modeling Analysis, Daniel C. Laughlin, Scott R. Abella, W. Wallace Covington, James B. Grace
Species Richness And Soil Properties In Pinus Ponderosa Forests: A Structural Equation Modeling Analysis, Daniel C. Laughlin, Scott R. Abella, W. Wallace Covington, James B. Grace
Public Policy and Leadership Faculty Research
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 Pinus ponderosa (ponderosa pine) forest ecosystem. We evaluated multivariate models of plant species richness using structural equation modeling. Results: Richness was highest at intermediate levels of understory plant cover, suggesting that both colonization success and competitive exclusion can limit richness in this system. We did not detect a reciprocal positive …