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Tracing carbon and nitrogen incorporation and pathways in the microbial community of a photic subtidal sand

Evrard, V.P.E. and Cook, P. and Veuger, B. and Huettel, M. and Middelburg, J.J. (2008) Tracing carbon and nitrogen incorporation and pathways in the microbial community of a photic subtidal sand. Aquatic Microbial Ecology, 53, 257-269. ISSN 0948-3055.

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Official URL: http://dx.doi.org/10.3354/ame01248

Abstract

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. 13C-bicarbonate and 15N-nitrate were added to the water column on top of 5 sediment cores incubated in 4 transparent and 1 opaque laboratory chambers. After 9 h 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). 13C was fixed by MPB, and more than 50% was directed to the production of extracellular polymeric substance (EPS). MPB 15N incorporation was similar in the dark and in the light. Bacterial activity appeared to have 2 effects that depended 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.

Item Type:Article
Institutes:Nederlands Instituut voor Ecologie (NIOO)
ID Code:4753
Deposited On:29 Sep 2009 02:00
Last Modified:26 Nov 2012 04:00

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