An inventory of 13C abundances in coastal wetlands of Louisiana,USA: vegetation and sediments |
| |
Authors: | G. L. Chmura P. Aharon R. A. Socki R. Abernethy |
| |
Affiliation: | (1) Laboratory for Wetland Soils and Sediments and Dept. Marine Science, Center for Wetland Resources, Louisiana State University, 70803 Baton Rouge, LA, USA;(2) Dept. Geology and Geophysics, Louisiana State University, 70803 Baton Rouge, LA, USA;(3) Coastal Ecology Institute, Center for Wetland Resources, Louisiana State University, 70803 Baton Rouge, LA, USA;(4) Present address: Waste Management Division, US Environmental Protection Agency, 60604 Chicago, IL, USA;(5) Present address: Dept. of Conservation, Division of Forestry and Ecological Services, 701 Broadway, 37203 Nashville, TN, USA |
| |
Abstract: | Summary Organic carbon-rich sediments from the surface of fresh, intermediate, brackish and salt marshes of coastal Louisiana were sampled and analyzed for their 13C content. The average 13C from all sites within each wetland type was-27.8,-22.1,-16.9, and-16.2, for fresh, intermediate, brackish and salt marshes, respectively. Means from the fresh, intermediate and brackish marshes were significantly different at the 0.01 level. A mixing model using measurements of standing crop and 13C of plant carbon was applied to estimate the contribution of each species to the sedimentary carbon at four of the marsh sites. Sedimentary 13C values generally reflected that of the dominant species present at each site. Brackish and salt marsh samples, however, showed a negative shift of 13C with respect to whole plant carbon. We interpret these depeleted 13C values to be the result of more extensive organic matter decomposition and selective preservation of 13C-depleted refractory components in sediments from saline sites. The results of this study suggest that 13C composition of sedimentary carbon may offer a valuable tool for distinguishing subtle changes in paleohydrology of wetlands resulting from relative sea level changes. |
| |
Keywords: | Wetlands Stable carbon isotopes Organic sediment Salinity gradient Mississippi delta plain |
本文献已被 SpringerLink 等数据库收录! |
|