MEPS 524:225-239 (2015)  -  DOI:

Trophodynamics of estuarine intertidal harpacticoid copepods based on stable isotope composition and fatty acid profiles

Clio Cnudde1, Tom Moens1, Eva Werbrouck1, Gilles Lepoint2, Dirk Van Gansbeke1, Marleen De Troch1,*

1 Ghent University, Marine Biology, Krijgslaan 281/S8, 9000 Gent, Belgium
2 University of Liège, MARE Centre, Laboratory of Oceanology, Allée du 6 août B6, 4000 Liège, Belgium
*Corresponding author:

ABSTRACT: Trophic interactions at the basis of food webs, for instance between meiofauna, primary producers and bacteria, are key drivers of benthic energy fluxes. Yet both qualitative and quantitative information about meiofaunal resource utilization under in situ conditions is scant. By means of natural stable isotope ratios of carbon and nitrogen and of fatty acid (FA) profiles, we examined the variability of in situ resource utilization of a range of harpacticoid copepod species from 5 stations in an estuarine intertidal area. These stations, located in different habitats, differed in sediment granulometry, resource availability, presence/absence of vegetation and other environmental variables, as well as in copepod species composition. Our goal was to describe inter-specific differences among harpacticoid species, as well as spatio-temporal variability within species. Despite differences in resource availability between habitats, δ13C data clearly point at microphytobenthos (MPB) as the major carbon source to the harpacticoid assemblages at all 5 stations. Small differences in carbon isotopic ratios between co-occurring species indicate some degree of resource differentiation, whereas both the δ15N and FA composition suggest that several harpacticoid species obtain MPB carbon indirectly, perhaps through feeding on bacteria or ciliates. For a limited number of species, such as Paraleptastacus spinicauda, clear dietary contributions of suspended particulate matter and bacteria were found, and MPB appeared to have only a small or no contribution. Even in vegetated salt-marsh stations, Spartina anglica detritus did not appear to contribute to copepod diets. The δ13C of Cletodidae were highly depleted, reflecting a contribution of methane-derived carbon.

KEY WORDS: Harpacticoid copepods · Intertidal · Fatty acids · Stable isotopes · Feeding ecology · Seasonal variability · Scheldt estuary

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Cite this article as: Cnudde C, Moens T, Werbrouck E, Lepoint G, Van Gansbeke D, De Troch M (2015) Trophodynamics of estuarine intertidal harpacticoid copepods based on stable isotope composition and fatty acid profiles. Mar Ecol Prog Ser 524:225-239.

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