The Role of non-phytoplankton food for zooplankton in the North Sea

During the phytoplankton spring bloom, zooplankton abundance is low, however it reaches high abundances after the decline of the phytoplankton bloom. This high zooplankton biomass is maintained for a considerable period of time.

It has therefore been speculated that zooplankton might feed on non-phytoplankton food sources during this period. Recent findings on the occurrence of 'micro-particles' such as transparent exopolymer particles and spontaneous aggregation of dissolved organic matter in the sea further support the hypothesis that zooplankton cover their carbon and energy demands to a considerable extent from these sources. Moreover, distinct plumes of silt and clay originating from the English Coast are transported towards the Frisian Front, which is characterized by high primary production and a rich benthic community.