CS39A Zooplankton - Feeding, Reproduction, Growth and Molecular Diversity
Date: Tuesday, June 11, 2002
Time: 4:30:00 PM
Location: View Royal
ThorP, Kristineberg Marine Research Station, Fiskebaeckskil, Sweden, pthor@get2net.dk
Møller, E, F, National Environmental Research Institute, Roskilde, Denmark, efm@dmu.dk
Nielsen, T, G, National Environmental Research Institute, Roskilde, Denmark, tgn@dmu.dk
DOC flux mediated by grazing of large calanoid copepods in the pelagic of the Disko bay, Western Greenland
In the Disko Bay the mesozooplankton is dominated by three large calanoid copepods species: Calanus hyperboreus, C. glacialis, and C. finmarchicus. The grazing pressure of these copepods is high, constituting about 25% of the phytoplankton biomass per day in June 2001. Much of the trophic processing of primary production was therefore mediated by these species. Recently, we have gained significant knowledge about the trophic role of calanoid copepods in the Disko Bay and arctic environments in general. However, their impact on the DOC flux is only scarcely investigated. Our study showed that, depending on species, between 20 and 60% of the organic carbon from the handled food was released as DOC due to sloppy feeding. Moreover, up to 28% of the organic carbon was released from fecal pellets within an hour. Consequently, large calanoid copepods not only acted as conveyors of carbon up through the classical food chain, but also generated vast amounts of DOC readily available for bacterioplankters. In total 20 mgC/m3/d was transformed from phytoplankters to DOC by the copepods during the post-bloom situation studied.