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Stable isotopes' as trophic tracers: combining field sampling and manipulative labelling of food resources for macrobenthos

Herman, P.M.J. and Middelburg, J.J. and Widdows, J. and Lucas, C.M. and Heip, C.H.R. (2000) Stable isotopes' as trophic tracers: combining field sampling and manipulative labelling of food resources for macrobenthos. Marine Ecology Progress Series, 204, 79-92. ISSN 0171-8630.

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Official URL: http://dx.doi.org/10.3354/meps204079

Abstract

We combined 3 different approaches to determine the relative importance of microphytobenthos production as food for intertidal macrobenthic animals: (1) the natural abundance of stable-isotope ratios of carbon and nitrogen, (2) an in situ deliberate tracer addition of C-13-bicarbonate, which was transferred through the benthic food chain after its incorporation by benthic algae, and (3) a dual labelling experiment in a flume, where pelagic and benthic algae were labelled with N-15 and C-13, respectively. The results of the 3 approaches confirmed the high importance of microphytobenthos as a food source for (surface) deposit feeders. Despite the clearly demonstrated resuspension of benthic algae at high current velocities, suspension feeders appeared to depend almost exclusively on pelagic algae (and possibly detrital carbon) as a food source. Based on the results of the experiments, we determined an approximate degree of dependence on microphytobenthos for different species of intertidal macrobenthos. The macrobenthic biomass at 5 study locations, when weighted by these coefficients, correlated very well with measured productivity of the microphytobenthos. [KEYWORDS: food web; microphytobenthos; deposit feeding; suspension feeding; westerscheldeflume Marennes-oleron bay; westerschelde estuary; benthic invertebrates; arenicola-marina; carbon; nitrogen; gut; microphytobenthos; sediments; matter]

Item Type:Article
Institutes:Nederlands Instituut voor Ecologie (NIOO)
ID Code:10870
Deposited On:24 Nov 2011 01:00
Last Modified:14 Oct 2013 11:19

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