Production of DOC by Calanus finmarchicus, C-glacialis and C-hyperboreus through sloppy feeding and leakage from fecal pellets

Using C-14-labeled phytoplankton as tracer, we investigated 2 mechanisms of immediate dissolved organic carbon (DOC) release during grazing activity of Calanus spp. - sloppy feeding and leakage from newly expelled fecal pellets. Half of the carbon cleared by Calanus spp. was released as DOC through sloppy feeding. Freshly expelled fecal pellets lost more than 20% of their carbon content within the first hour, corresponding to 6% of the carbon cleared. Thus, copepods should not only be considered as an essential link to higher trophic levels, but also as a feedback link to the microbial food web.