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Decomposition of /sup 14/C-labeled organic substances in marine sediments

Journal Article · · Limnol. Oceanogr.; (United States)
OSTI ID:5152379
The depth variation of total organic carbon (TOC), organic matter composition and porewater composition in marine sediments suggest that different components of the organic matter undergo decomposition at widely different rates. The decomposition of /sup 14/C-labeled organic substances was followed in sediment microcosms in the laboratory. The substances used were chosen to simulate a portion of material settling to the sediment-water interface (a marine diatom) or hypothesized components of refractory sediment organic matter (melanoidins and a bacterial polymer). The microcosms were found to be good models of the sediment-water interface in terms of how well they mimicked sediment decomposition rates and processes. The decomposition of the labeled material and the natural sediment TOC were monitored over 1 month: the water overlying the sediment remained oxic, and net consumption of nitrate was small. There was no detectable sulfate reduction. The algae and the bacterial polymer were decomposed on average 9x faster than the melanoidins and 90x faster than the natural sediment TOC. The soluble fraction of the algae was decomposed more rapidly than the particulate material.
Research Organization:
Univ. of Alaska, Fairbanks
OSTI ID:
5152379
Journal Information:
Limnol. Oceanogr.; (United States), Journal Name: Limnol. Oceanogr.; (United States) Vol. 31:4; ISSN LIOCA
Country of Publication:
United States
Language:
English