Publications
Publications from USGS science centers throughout the Southeast Region.
Filter Total Items: 9969
Suspended-sediment concentrations and loads in the lower Mississippi and Atchafalaya rivers decreased by half between 1980 and 2015
The Weighted Regressions on Time, Discharge, and Season (WRTDS) model was used to derive estimates of suspended-sediment concentration (SSC) and suspended-sediment load (SSL), their dependence on discharge, and their trends with confidence intervals, for one site each on the lowermost Mississippi and Atchafalaya Rivers. The WRTDS model reduces uncertainty in SSCs related to variable streamflow con
Authors
Scott Mize, Jennifer C. Murphy, Timothy H. Diehl, Dennis K. Demcheck
Variation in home range size and patterns in adult female American crocodiles Crocodylus acutus
The American crocodile Crocodylus acutus is a threatened species that uses relatively deep, open-water habitats with low salinity. Adult female American crocodiles nest on sandy coastal beaches, islands or human-made berms, assist in the hatching process, and can travel long distances to nesting habitat. We satellite-tracked 15 adult female American crocodiles in 2 hydrologically distinct areas in
Authors
Kristen M. Hart, Jeffrey S. Beauchamp, Michael S. Cherkiss, Frank Mazzotti
Sea-level rise could overwhelm coral reefs
An assessment of the capacity of coral reefs to grow fast enough to keep up with projected rises in sea level finds that most reefs will fall behind if nothing is done to restore them.
Authors
Ilsa B. Kuffner
Hydrographic surveys of rivers and lakes using a multibeam echosounder mapping system
A multibeam echosounder is a type of sound navigation and ranging device that uses sound waves to “see” through even murky waters. Unlike a single beam echosounder (also known as a depth sounder or fathometer) that releases a single sound pulse in a single, narrow beam and “listens” for the return echo, a multibeam system emits a multidirectional radial beam to obtain information within a fan-shap
Authors
Richard J. Huizinga, David C. Heimann
Flooding alters plant-mediated carbon cycling independently of elevated atmospheric CO2 concentrations
Plant‐mediated processes determine carbon (C) cycling and storage in many ecosystems; how plant‐associated processes may be altered by climate‐induced changes in environmental drivers is therefore an essential question for understanding global C cycling. In this study, we hypothesize that environmental alterations associated with near‐term climate change can exert strong control on plant‐associate
Authors
Scott F. Jones, Camille L. Stagg, Ken W. Krauss, Mark W. Hester
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 was to dev
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
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 Water System,
Authors
Stephen P. Opsahl, MaryLynn Musgrove, Barbara Mahler, Rebecca B. Lambert
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 binary, co
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 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 vertical adjustme
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
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 Medionidus walkeri
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 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 most abund
Authors
Christian Haller, Pamela Hallock, Albert C. Hine, Christopher G. Smith
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 backyard, beca
Authors
Beth A. Middleton