Gregg Snedden, Ph.D.
Gregg Snedden is a research ecologist with the Wetland and Aquatic Research Center.
Gregg is broadly trained in aquatic ecology, fisheries, wetland plant ecology, and coastal physical oceanography. Gregg’s research interests include fluvial and physical oceanographic drivers of coastal wetland hydrology, impacts of hydrology to wetland plant performance and soil dynamics, effects of Mississippi River diversions on receiving basin wetlands, and most recently, teleconnections between coastal sea-level variability and global-scale climate dynamics and the implications these linkages may impart to coastal wetland landscape sustainability.
EDUCATION
Ph.D., Oceanography and Coastal Sciences, Louisiana State University, 2006
M.S., Fisheries Science, Louisiana State University, 1997
B.S., Aquatic Ecology, University of Illinois, 1993
BACKGROUND
2007 - Present, Research Ecologist, USGS Wetland and Aquatic Research Center (formerly National Wetlands Research Center)
2005 - 2007, Post-Doctoral Research Fellow, UNC-Wilmington Center for Marine Science
2000 - 2005, Research Associate, Coastal Ecology Institute, Louisiana State University
1993 - 1997, Research Assistant, School of Forestry, Wildlife and Fisheries, Louisiana State University
Science and Products
Filter Total Items: 15
Quantifying Restoration Impacts of Wetland Ecosystem Health and Carbon Export
USGS is investigating the impact of restoration on Louisiana's coastal wetlands' carbon dynamics.
Identifying and Projecting Water Quality Outcomes of Canal Backfilling Restoration at Jean Lafitte National Historical Park and Preserve
USGS researchers and their partners will develop a coupled hydrodynamic and water quality modeling system; calibrate and validate the models; assess and predict outcomes of a canal backfilling restoration project on key water quality attributes; and run the modeling system under a suite of climate change scenarios.
Nekton References and Targets: Assessing the Abundance and Density of Fish and Invertebrates Associated with Louisiana’s Marsh Habitat
The National Oceanic and Atmospheric Administration (NOAA) is leading a Monitoring and Adaptive Management (MAM) activity with USGS collaborators to establish reference ranges and restoration targets, assess data gaps for focal nekton species and/or guilds associated with Louisiana’s estuarine and coastal habitats, implement the fixed-area sampling strategy to quantify fishes and invertebrates...
Quantifying Changes in Wetland Area and Habitat Types in the Deepwater Horizon Louisiana Restoration Area 1985-Present with Remote Sensing
USGS researchers will quantify wetland change and wetland vegetation community type change through the analyses of aerial vegetation survey data and investigate potential relationships between Normalized Difference Vegetation Index (NDVI) and marsh elevation change.
Delivery of Strategically Placed Sediment through Tidal Creeks to Adjacent Coastal Wetlands
In the summer of 2021, instrumented platforms were deployed at Seven Mile Island Living Laboratory, New Jersey to conduct time series measurements of tidal velocity, turbidity, surface elevation, sediment concentration, and suspended sediment characteristics. The collected data will be used to provide decision support to the U.S. Army Corps of Engineers as they plan dredging activities in the Gulf...
Model Improvements for Louisiana’s 2023 Coastal Master Plan
The Louisiana Coastal Protection and Restoration Authority’s Coastal Master Plan is a blueprint for responding to environmental changes. As part of the agency’s continued engagement, USGS supports model developments and improvements for the 2023 Coastal Master Plan.
Collecting Ecological Data and Models of Living Shoreline Restoration Projects
Developing effective living shoreline restoration projects that can withstand hurricanes and storms requires a better understanding of how restoration structures reduce the impact of wave and current energy on marsh edges in estuaries and bays. Without this knowledge, existing living shoreline projects and adaptive management measures are more likely to fail, decreasing the possibility for long...
Dynamics and Fluxes of Nutrients along Environmental Gradients in the Florida Everglades, USA
USGS research in the Florida Everglades will provide information on how environmental conditions and disturbances impact carbon storage in mangrove systems.
Influence of Sea-Level Rise on Wetland Vegetation Community Structure, Primary Productivity, Organic Matter Decomposition and Carbon Storage
This study will employ a space for time substitution to show long-term effects of rising sea-level and increasing salinity on vegetation community structure, primary production and decomposition. Productivity and decomposition rates will be estimated for four wetland plant community types defined by salinity zones and dominant plant species.
Soil Properties and Geochronology in Barataria Basin, Louisiana
Will wetland vertical accretion rates be enough to keep up with the predicted rates of sea level rise? USGS looks at soil properties and geochronology in Louisiana wetlands.
Surface Water Hydrology and Nitrate Dynamics in Delta Islands of Prograding Wax Lake Delta, Louisiana
The Wax Lake Delta is an ideal ecosystem to study the effects of a large-scale river diversion on the biogeochemistry of coastal wetlands, and the capacity of these wetlands to assimilate nutrients delivered by these diversions. USGS works to develop a better understanding of surface water hydrology and nitrate dynamics in this area.
Sediment and Nutrient Retention by Wetlands Receiving Inflows from a Mississippi River Diversion: A Mass Balance Approach
Diversions are currently used in the Mississippi River to stimulate delta growth via increased sediment supply. This technique may also help to reduce nutrient loads before its discharged into the ocean. Scientists at USGS assess how wetlands retain the sediment and nutrients that come from these diversions.
Science and Products
Filter Total Items: 15
Quantifying Restoration Impacts of Wetland Ecosystem Health and Carbon Export
USGS is investigating the impact of restoration on Louisiana's coastal wetlands' carbon dynamics.
Identifying and Projecting Water Quality Outcomes of Canal Backfilling Restoration at Jean Lafitte National Historical Park and Preserve
USGS researchers and their partners will develop a coupled hydrodynamic and water quality modeling system; calibrate and validate the models; assess and predict outcomes of a canal backfilling restoration project on key water quality attributes; and run the modeling system under a suite of climate change scenarios.
Nekton References and Targets: Assessing the Abundance and Density of Fish and Invertebrates Associated with Louisiana’s Marsh Habitat
The National Oceanic and Atmospheric Administration (NOAA) is leading a Monitoring and Adaptive Management (MAM) activity with USGS collaborators to establish reference ranges and restoration targets, assess data gaps for focal nekton species and/or guilds associated with Louisiana’s estuarine and coastal habitats, implement the fixed-area sampling strategy to quantify fishes and invertebrates...
Quantifying Changes in Wetland Area and Habitat Types in the Deepwater Horizon Louisiana Restoration Area 1985-Present with Remote Sensing
USGS researchers will quantify wetland change and wetland vegetation community type change through the analyses of aerial vegetation survey data and investigate potential relationships between Normalized Difference Vegetation Index (NDVI) and marsh elevation change.
Delivery of Strategically Placed Sediment through Tidal Creeks to Adjacent Coastal Wetlands
In the summer of 2021, instrumented platforms were deployed at Seven Mile Island Living Laboratory, New Jersey to conduct time series measurements of tidal velocity, turbidity, surface elevation, sediment concentration, and suspended sediment characteristics. The collected data will be used to provide decision support to the U.S. Army Corps of Engineers as they plan dredging activities in the Gulf...
Model Improvements for Louisiana’s 2023 Coastal Master Plan
The Louisiana Coastal Protection and Restoration Authority’s Coastal Master Plan is a blueprint for responding to environmental changes. As part of the agency’s continued engagement, USGS supports model developments and improvements for the 2023 Coastal Master Plan.
Collecting Ecological Data and Models of Living Shoreline Restoration Projects
Developing effective living shoreline restoration projects that can withstand hurricanes and storms requires a better understanding of how restoration structures reduce the impact of wave and current energy on marsh edges in estuaries and bays. Without this knowledge, existing living shoreline projects and adaptive management measures are more likely to fail, decreasing the possibility for long...
Dynamics and Fluxes of Nutrients along Environmental Gradients in the Florida Everglades, USA
USGS research in the Florida Everglades will provide information on how environmental conditions and disturbances impact carbon storage in mangrove systems.
Influence of Sea-Level Rise on Wetland Vegetation Community Structure, Primary Productivity, Organic Matter Decomposition and Carbon Storage
This study will employ a space for time substitution to show long-term effects of rising sea-level and increasing salinity on vegetation community structure, primary production and decomposition. Productivity and decomposition rates will be estimated for four wetland plant community types defined by salinity zones and dominant plant species.
Soil Properties and Geochronology in Barataria Basin, Louisiana
Will wetland vertical accretion rates be enough to keep up with the predicted rates of sea level rise? USGS looks at soil properties and geochronology in Louisiana wetlands.
Surface Water Hydrology and Nitrate Dynamics in Delta Islands of Prograding Wax Lake Delta, Louisiana
The Wax Lake Delta is an ideal ecosystem to study the effects of a large-scale river diversion on the biogeochemistry of coastal wetlands, and the capacity of these wetlands to assimilate nutrients delivered by these diversions. USGS works to develop a better understanding of surface water hydrology and nitrate dynamics in this area.
Sediment and Nutrient Retention by Wetlands Receiving Inflows from a Mississippi River Diversion: A Mass Balance Approach
Diversions are currently used in the Mississippi River to stimulate delta growth via increased sediment supply. This technique may also help to reduce nutrient loads before its discharged into the ocean. Scientists at USGS assess how wetlands retain the sediment and nutrients that come from these diversions.