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Publications

Publications from USGS science centers throughout the Southeast Region.

Filter Total Items: 10378

Bend-scale geomorphic classification and assessment of the Lower Missouri River from Sioux City, Iowa, to the Mississippi River for application to pallid sturgeon management Bend-scale geomorphic classification and assessment of the Lower Missouri River from Sioux City, Iowa, to the Mississippi River for application to pallid sturgeon management

Management actions intended to increase growth and survival of pallid sturgeon (Scaphirhynchus albus) age-0 larvae on the Lower Missouri River require a comprehensive understanding of the geomorphic habitat template of the river. The study described here had two objectives relating to where channel-reconfiguration projects should be located to optimize effectiveness. The first objective...
Authors
Robert B. Jacobson, Michael E. Colvin, Edward A. Bulliner, Darcy Pickard, Caroline M. Elliott

Water-quality observations of the San Antonio segment of the Edwards aquifer, Texas, with an emphasis on processes influencing nutrient and pesticide geochemistry and factors affecting aquifer vulnerability, 2010–16 Water-quality observations of the San Antonio segment of the Edwards aquifer, Texas, with an emphasis on processes influencing nutrient and pesticide geochemistry and factors affecting aquifer vulnerability, 2010–16

As questions regarding the influence of increasing urbanization on water quality in the Edwards aquifer are raised, a better understanding of the sources, fate, and transport of compounds of concern in the aquifer—in particular, nutrients and pesticides—is needed to improve water management decision-making capabilities. The U.S. Geological Survey, in cooperation with the San Antonio...
Authors
Stephen P. Opsahl, MaryLynn Musgrove, Barbara Mahler, Rebecca B. Lambert

Quantifying relative importance: Computing standardized effects in models with binary outcomes Quantifying relative importance: Computing standardized effects in models with binary outcomes

Scientists commonly ask questions about the relative importances of processes, and then turn to statistical models for answers. Standardized coefficients are typically used in such situations, with the goal being to compare effects on a common scale. Traditional approaches to obtaining standardized coefficients were developed with idealized Gaussian variables in mind. When responses are...
Authors
James B. Grace, Darren Johnson, Jonathan S. Lefcheck, Jarrett E. K. Byrnes

Coastal wetland adaptation to sea level rise: Quantifying potential for landward migration and coastal squeeze Coastal wetland adaptation to sea level rise: Quantifying potential for landward migration and coastal squeeze

Coastal wetland ecosystems are expected to migrate landwards in response to rising seas. However, due to differences in topography and coastal urbanization, estuaries vary in their ability to accommodate migration. Low‐lying urban areas can constrain migration and lead to wetland loss (i.e. coastal squeeze), especially where existing wetlands cannot keep pace with rising seas via...
Authors
Sinéad M. Borchert, Michael J. Osland, Nicholas M. Enwright, Kereen Griffith

Cumulative spring discharge and survey effort influence occupancy and detection of a threatened freshwater mussel, the Suwannee Moccasinshell Cumulative spring discharge and survey effort influence occupancy and detection of a threatened freshwater mussel, the Suwannee Moccasinshell

Freshwater mussels (Unionidae) are among the most imperiled groups of organisms in the world, and the lack of information regarding species distributions, life-history characteristics, and ecological and biological requirements may limit the protection of remaining mussel populations. We examined the influence of hydrologic factors on the occurrence of the Suwannee Moccasinshell...
Authors
Jordan M. Holcomb, Colin P. Shea, Nathan A. Johnson

Benthic foraminifera from the Carnarvon Ramp reveal variability in Leeuwin Current activity (Western Australia) since the Pliocene Benthic foraminifera from the Carnarvon Ramp reveal variability in Leeuwin Current activity (Western Australia) since the Pliocene

Benthic foraminiferal assemblages from a ~300 m deep core from an outer carbonate-ramp site off Western Australia (International Ocean Discovery Program Core U1460A) were examined to reconstruct the paleoceanographic evolution of the Carnarvon Ramp and the warm surficial Leeuwin Current (LC) for the last 3.54 Ma. Of the identified 179 benthic foraminiferal species, occurrences of the 15...
Authors
Christian Haller, Pamela Hallock, Albert C. Hine, Christopher G. Smith

President elect's message President elect's message

The first morning home the day after I became president of SWS at the annual meeting in Denver, I note the wilting of my garden and the grumpiness of my cats as the dawn of my new reality. The extra hours that I will spend as president of SWS will manifest itself as more cat and garden unhappiness as travel and responsibilities grow. The cats gleefully blast out of the door into the...
Authors
Beth A. Middleton

New insights on scale-dependent surface-groundwater exchange from a floating self-potential Dipole New insights on scale-dependent surface-groundwater exchange from a floating self-potential Dipole

In south-central Texas the lower Guadalupe River has incised into the outcrop of the Carrizo-Wilcox aquifer. The river and the aquifer are hydraulically connected across the outcrop, although the connectivity is obscured at the surface by alluvium and surface-water and groundwater exchange dynamics are currently poorly understood. To investigate surface-water and groundwater exchange...
Authors
Scott Ikard, Andrew P. Teeple, Jason Payne, Gregory P. Stanton, J. Ryan Banta

Environmental controls on the geochemistry of Globorotalia truncatulinoides in the Gulf of Mexico: Implications for paleoceanographic reconstructions Environmental controls on the geochemistry of Globorotalia truncatulinoides in the Gulf of Mexico: Implications for paleoceanographic reconstructions

Modern observations of planktic foraminifera from sediment trap studies help to constrain the regional ecology of paleoceanographically valuable species. Results from a weekly-resolved sediment trap time series (2008–2014) in the northern Gulf of Mexico demonstrate that 92% of Globorotalia truncatulinoides flux occurs in winter (January, February, and March), and that encrusted and non...
Authors
Caitlin E. Reynolds, Julie N. Richey, Jennifer S. Fehrenbacher, Brad E. Rosenheim, Howard J. Spero

Ecological resilience indicators for mangrove ecosystems Ecological resilience indicators for mangrove ecosystems

Mangrove ecosystems are coastal wetland ecosystems dominated by mangrove species that are typically found in the intertidal zone, characterized by frequently flooded saline soil conditions. The majority of the approximately 500,000 acres of mangrove ecosystem in the United States occurs in the NGoM, and almost all of that is in Florida, with over 90 percent in the four southern counties...
Authors
Richard H. Day, Scott T. Allen, Jorge Brenner, Kathleen Goodin, Don Faber-Langendoen, Katherine Wirt Ames

Ecological resilience indicators for salt marsh ecosystems Ecological resilience indicators for salt marsh ecosystems

Salt marshes are coastal ecosystems within the intertidal zone, characterized by hypoxic, saline, soil conditions and low biodiversity. Low diversity arises from frequent disturbance and stressful conditions (i.e., high salinity and hypoxia), where vegetative reproduction and low competition result in mostly monotypic stands, with some differences in plant community influenced by...
Authors
Scott T. Allen, Camille L. Stagg, Jorge Brenner, Kathleen L. Goodin, Don Faber-Langendoen, Christopher A. Gabler, Katherine Wirt Ames

Establishing a baseline: the amphibians of Lower Suwannee National Wildlife Refuge, Dixie and Levy counties, Florida Establishing a baseline: the amphibians of Lower Suwannee National Wildlife Refuge, Dixie and Levy counties, Florida

From 2002-2006, we used a variety of sampling techniques to survey the amphibians and water chemistry of Lower Suwannee National Wildlife Refuge in Florida’s Big Bend region. We recorded 23 amphibian species, 19 frogs and 4 salamanders. Species richness was lower than in other areas of the coastal Big Bend region to the north, perhaps due to a combination of proximity to the limits of...
Authors
C. Kenneth Dodd, William J. Barichivich, Steve A. Johnson, Margaret Gunzburger Aresco, Jennifer S. Staiger
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