St. Petersburg Coastal and Marine Science Center
Wetland losses in the northern Gulf Coast region of the United States are so extensive they represent critical concerns to government environmental agencies and natural resource managers. In coastal Louisiana, wetland loss has been such an important environmental and economic issue that decades of scientific research have been dedicated to the topic. Since the trend was first recognized in the late 1960s, billions of dollars in state and federal funding have been earmarked for coastal restoration projects intended to compensate for some of the historical wetland losses. In support of that effort, research (2000 - 2011) at the St. Petersburg Coastal and Marine Science Center (SPCMSC) focused on better understanding the physical processes and human activities that contributed to historical wetland loss in coastal Louisiana and the spatial and temporal trends of that loss.
The physical processes (land-surface subsidence and sediment erosion) responsible for historical wetland loss were quantified by comparing marsh-surface elevations, water depths, and vertical displacements of stratigraphic contacts that were correlated between short sediment cores at 10 study areas in the Mississippi River delta plain and six sites at Sabine National Wildlife Refuge (SNWR) in the western chenier plain. The sequential development and two-dimensional extent of land loss at the study areas were described by comparing historical maps, aerial photographs, and satellite imagery; and the temporal and spatial trends of historical wetland loss were compared with historical subsidence rates and hydrocarbon production trends for the same period. The total three-dimensional accommodation space that formed as the result of historical wetland loss was estimated by integrating the spatial data with emergent-marsh elevations and bathymetry from the study areas.