Marine Science Faculty Publications
Document Type
Article
Publication Date
2015
Keywords
organic carbon cycling, paleoreconstruction, dam reservoirs, biomarker proxies
Digital Object Identifier (DOI)
https://doi.org/10.1002/2015GL065595
Abstract
We use a dated sediment core from Lake Whittington (USA) in the lower Mississippi River to reconstruct linkages in the carbon cycling and fluvial sediment dynamics over the past 80 years. Organic carbon (OC) sources were characterized using bulk (δ13C, ramped pyrolysis-oxidation (PyrOx) 14C, δ15N, and TN:OC ratios) and compound-specific (lignin phenols and fatty acids, including δ13C and 14C of the fatty acids) analyses. Damming of the Missouri River in the 1950s, other hydrological modifications to the river, and soil conservation measures resulted in reduced net OC export, in spite of increasing OC concentrations. Decreasing δ13C values coincided with increases in δ15N, TN:OC ratios, long-chain fatty acids, and lignin-phenol concentrations, suggesting increased inputs of soil-derived OC dominated by C3 vegetation, mainly resulting from changes in farming practices and crop distribution. However, ramped PyrOx 14C showed no discernible differences downcore in thermochemical stability, indicating a limited impact on soil OC turnover.
Rights Information
Was this content written or created while at USF?
Yes
Citation / Publisher Attribution
Geophysical Research Letters, v. 42, issue 19, p. 7983-7991
©2015. American Geophysical Union. All Rights Reserved.
Scholar Commons Citation
Bianchi, Thomas S.; Galy, Valier; Rosenheim, Brad E.; Shields, Michael; Cui, Xingqian; and Van Metre, Peter, "Paleoreconstruction of Organic Carbon Inputs to an Oxbow Lake in the Mississippi River Watershed: Effects of Dam Construction and Land use Change on Regional Inputs" (2015). Marine Science Faculty Publications. 2432.
https://digitalcommons.usf.edu/msc_facpub/2432
Figure S1
