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Decomposition of 14 C‐labeled organic substances in marine sediments 1
Author(s) -
Henrichs Susan M.,
Doyle Allen P.
Publication year - 1986
Publication title -
limnology and oceanography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.7
H-Index - 197
eISSN - 1939-5590
pISSN - 0024-3590
DOI - 10.4319/lo.1986.31.4.0765
Subject(s) - microcosm , sediment , organic matter , decomposition , environmental chemistry , total organic carbon , algae , sulfate , chemistry , settling , environmental science , geology , ecology , environmental engineering , biology , organic chemistry , paleontology
The depth variation of total organic carbon (TOC), organic matter composition, and porewater composition in marine sediments suggests that different components of the organic matter undergo decomposition at widely different rates. The decomposition of 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 9 × faster than the melanoidins and 90 × faster than the natural sediment TOC. The soluble fraction of the algae was decomposed more rapidly than the particulate material.