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The trophic significance of bacterial carbon in a marine intertidal sediment: Results of an in situ stable isotope labeling study
Author(s) -
Oevelen Dick,
Moodley Leon,
Soetaert Karline,
Middelburg Jack J.
Publication year - 2006
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.2006.51.5.2349
Subject(s) - meiobenthos , benthic zone , intertidal zone , trophic level , macrobenthos , carbon fibers , isotopes of carbon , total organic carbon , sediment , environmental chemistry , ecology , biology , oceanography , chemistry , geology , paleontology , materials science , composite number , composite material
We report the results of an in situ tracer experiment in an intertidal sediment, where bacterial carbon was tagged with stable carbon‐isotope label, after the injection of 13 C‐glucose. The appearance of label in bacteria (based on label incorporation in bacteria‐specific, phospholipid‐derived fatty acids) and subsequent transfer to meiobenthos (group level) and macrobenthos (species level) was followed for 36 days. The label dynamics of benthic taxa were either fitted with a simple‐isotope model or evaluated against enrichment in bacteria, to derive the importance of bacterially derived carbon for the meiobenthos and macrobenthos. Although selective uptake of bacteria was evident, as 2.4 times more bacterial carbon was grazed as expected from indiscriminate feeding, bacterial carbon accounted on average for only 0.08 and 0.11 of the carbon requirements of meiobenthic and macrobenthic taxa, respectively. Additionally, the contribution of bacterial carbon to total carbon requirements did not depend on the living/feeding depth in the sediment or organism size (evaluated over a size range of four orders of magnitude). The observed overall low contribution of bacterial carbon implies that most intertidal benthic fauna depend primarily on other carbon resources that may assert a stronger control on the structure of intertidal‐sediment communities.