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The importance of benthic macrofauna in decomposition of microalgae in a coastal marine sediment
Author(s) -
Andersen Frede Ostergaard,
Kristensen Erik
Publication year - 1992
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.1992.37.7.1392
Subject(s) - benthic zone , microcosm , sediment , organic matter , fauna , decomposition , environmental chemistry , algae , total organic carbon , environmental science , ecology , oceanography , chemistry , biology , geology , paleontology
The effectiveness of macrofauna in decomposing organic matter was studied in microcosms by adding 14 C‐labeled microalgae to undisturbed sediment cores with and without fauna. The presence of benthic macrofauna stimulated release of 14 CO 2 only briefly during the initial phase (4 d); after 21 d the total amount of 14 CO 2 released was nearly equivalent with or without fauna. The first‐order decay rate constant of the added organic matter based on the rate of 14 CO 2 production was 0.019 d −1 with fauna and 0.020 without. The release of [ 14 C]DOC from the sediment accounted for 4–5% of the total 14 C release. Only a small fraction of the 14 C added as algae was found as 14 CO 2 (max, 1.2%) or [ 14 C]DOC (max, 0.7%) in the pore water at any time during the experiment. In contrast, there was a significant increase of both sediment TCO 2 (total inorganic C) production (70%) and O 2 uptake (17%) rates in the presence of animals. The discrepancy between the effect of macrofauna on fluxes of labeled vs. unlabeled compounds indicates that the surface deposit feeders primarily affected decomposition of old and relatively refractory sediment organic matter.