Publication Abstract

Food web structure  at 3 contrasting sites in the North Sea

Benjamin Kürten, S. Painting,* U. Strück and N. Polunin

Carbon and nitrogen flows through benthic and pelagic food webs at 3 hydrodynamically distinct sites in the shelf waters of the North Sea (1 southern, 2 central, see poster by Painting et al) are being investigated over an annual cycle using δ13C and δ15N stable isotope techniques. Preliminary results of POM <62µm and different zooplankton species from a cruise in February 2007 indicate contrasting pelagic food web structures between the southern and central sites. During the winter conditions prior to the onset of spring phytoplankton blooms, zooplankton such as copepods and chaetognaths appear to have been feeding at higher trophic levels in the southern bight than in the central North Sea. Analyses of Calanus species, for example, indicate that the species dominant at the southern site (C. helgolandicus) was feeding on higher trophic levels than it’s competitor, C. finmarchicus, particularly at the southern site.  More detailed analyses of samples collected throughout the spring/summer growth season will contribute towards an improved understanding of temporal and spatial changes in food web structure.

Reference

Benjamin Kürten, S. Painting,* U. Strück and N. Polunin (2007) Food web structure  at 3 contrasting sites in the North Sea. ICES Annual Science Conference in Helsinki, Finland September 2007.