ISSN:
1432-1939
Keywords:
Wetlands
;
Stable carbon isotopes
;
Organic sediment
;
Salinity gradient
;
Mississippi delta plain
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
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.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00379369
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