Gulf Coast Wetland Shoreline Change
Land and seafloor slopes are generally low along the coasts in the Mid-Atlantic and Gulf Coast states, making wetlands and estuaries vulnerable to sea level change, subsidence, and extreme events (e.g., hurricanes and tropical storms). Land-use change and land loss have been mapped extensively and with increasing frequency, but the link between land loss and the processes responsible for landscape change has not been investigated in detail in many places.
CMHRP scientists study how coastal wetlands and estuaries interact on scales from years to hundreds of years. One such CMHRP effort was in Mobile Bay, Alabama. It was initiated as part of the National Gulf of Mexico project and has continued as part of the Sea-level and Storm Impacts on Estuarine Environments and Shorelines (SSIEES) project. Findings show that natural disturbances such as hurricanes strongly affect the estuary and marsh. The bayhead delta and the marshes fringing the bay were found to rely heavily on inorganic sediment flux from the adjacent river channels and the estuary, respectively. In the fringing marshes, sediment properties, stable isotopes, and timelines derived from lead and cesium isotopes indicated that hurricanes and storm surge were the main processes delivering inorganic sediment to the marshes. Using modeled marsh elevation, the CMHRP showed that without that event sedimentation, the marsh elevation might have fallen below mean sea level.
The findings from Mobile Bay highlight some of the beneficial aspects of sediment deposition during storms; however, large portions of shorelines can also be lost during storms and fair-weather conditions. To learn more about those processes, SSIEES studies have expanded into Louisiana, Mississippi, and additional regions of the Alabama shoreline (Mississippi Sound) and the surrounding bays and estuaries, as well as Chincoteague Bay (Maryland and Virginia) and Barnegat Bay (New Jersey). The efforts have integrated a wide selection of proxies (microfossils, stable isotopes, biomarkers, metals, and other sediment tracers) to better quantify marsh response laterally and vertically to storms and sea level, as well as the interactions between the two. The CMHRP partners for these efforts with the USGS Ecosystems Mission Area (National Wetlands Research Center -Lafayette), Grand Bay National Estuarine Research Reserve, the U.S. Fish and Wildlife Service through Grand Bay National Wildlife Refuge and Bon Secour National Wildlife Refuge, the National Park Service (National Seashore and Assateague Island), Chincoteague Bay National Wildlife Refuge, Maryland and Virginia state wildlife agencies, and academic colleagues at several universities.
Explore the CMHRP Decadal Strategic Plan geonarrative
The CMHRP Decadal Science Strategy 2020-2030
This geonarrative constitutes the Decadal Science Strategy of the USGS's Coastal and Marine Hazards and Resources Program for 2020 to 2030.
Sea-level and Storm Impacts on Estuarine Environments and Shorelines (SSIEES)
Land and seafloor slopes are generally low along the coasts in the Mid-Atlantic and Gulf Coast states, making wetlands and estuaries vulnerable to sea level change, subsidence, and extreme events (e.g., hurricanes and tropical storms). Land-use change and land loss have been mapped extensively and with increasing frequency, but the link between land loss and the processes responsible for landscape change has not been investigated in detail in many places.
CMHRP scientists study how coastal wetlands and estuaries interact on scales from years to hundreds of years. One such CMHRP effort was in Mobile Bay, Alabama. It was initiated as part of the National Gulf of Mexico project and has continued as part of the Sea-level and Storm Impacts on Estuarine Environments and Shorelines (SSIEES) project. Findings show that natural disturbances such as hurricanes strongly affect the estuary and marsh. The bayhead delta and the marshes fringing the bay were found to rely heavily on inorganic sediment flux from the adjacent river channels and the estuary, respectively. In the fringing marshes, sediment properties, stable isotopes, and timelines derived from lead and cesium isotopes indicated that hurricanes and storm surge were the main processes delivering inorganic sediment to the marshes. Using modeled marsh elevation, the CMHRP showed that without that event sedimentation, the marsh elevation might have fallen below mean sea level.
The findings from Mobile Bay highlight some of the beneficial aspects of sediment deposition during storms; however, large portions of shorelines can also be lost during storms and fair-weather conditions. To learn more about those processes, SSIEES studies have expanded into Louisiana, Mississippi, and additional regions of the Alabama shoreline (Mississippi Sound) and the surrounding bays and estuaries, as well as Chincoteague Bay (Maryland and Virginia) and Barnegat Bay (New Jersey). The efforts have integrated a wide selection of proxies (microfossils, stable isotopes, biomarkers, metals, and other sediment tracers) to better quantify marsh response laterally and vertically to storms and sea level, as well as the interactions between the two. The CMHRP partners for these efforts with the USGS Ecosystems Mission Area (National Wetlands Research Center -Lafayette), Grand Bay National Estuarine Research Reserve, the U.S. Fish and Wildlife Service through Grand Bay National Wildlife Refuge and Bon Secour National Wildlife Refuge, the National Park Service (National Seashore and Assateague Island), Chincoteague Bay National Wildlife Refuge, Maryland and Virginia state wildlife agencies, and academic colleagues at several universities.
Explore the CMHRP Decadal Strategic Plan geonarrative
The CMHRP Decadal Science Strategy 2020-2030
This geonarrative constitutes the Decadal Science Strategy of the USGS's Coastal and Marine Hazards and Resources Program for 2020 to 2030.