期刊
AQUATIC MICROBIAL ECOLOGY
卷 53, 期 3, 页码 257-269出版社
INTER-RESEARCH
DOI: 10.3354/ame01248
关键词
Microphytobenthos; Cyanobacteria; EPS; PLFA; Biomarkers; Amino acids; Chemoautotrophy; Permeable sediment; (15)N; (13)C; Stable isotopes; Nitrate
资金
- European Union
- Netherlands Organisation for Scientific Research [PIONIER 833,02.002]
- [EVK 3-CT-2002-00076]
The pathways and fate of C and N in the microbial compartment of a coastal permeable sandy sediment in the photic zone were studied in a pulse-chase experiment, (13)C-bicarbonate and (15)N-rutrate were added to the water column on top of 5 sediment cores incubated in 4 transparent and 1 opaque laboratory chambers. After 9 b of labelling in the light and dark, stable isotope incorporation by microphytobenthos (MPB) and bacteria was quantified over a period of 4 d through the analysis of phospholipid-derived fatty acids (PLFA) and hydrolysable amino acids (HAA). (13)C was fixed by MPB, and more than 50% was directed to the production of extracellular polymeric substance (EPS). MPB (15)N incorporation was similar in the dark and in the light. Bacterial activity appeared to have 2 effects that depencled on sediment depth: at the sediment surface, there was a steady increase of label in the bacterial PLFA, suggesting metabolism of label-containing EPS; in the subsurface layers, uniform enrichment started immediately after the labelling procedure, indicating continuous incorporation of inorganic C by chemoautotrophic bacteria (Cbac). This experiment demonstrates the efficient transfer of inorganic C and N to the benthic community through the activities of photo- and chemoautotrophic microorganisms, and the role of EPS as a carrier of energy to the benthic microbial food web.
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