Some lower food web organisms in the nutrition of marine harpacticoid copepods: an experimental study

Some lower food web organisms from the marine littoral environment were studied as food for harpacticoid copepods. In laboratory experiments, it could be shown that, among the ciliates, the slow-movingUronema sp. was taken up while the fast-movingEuplotes sp. was not.Asterionella glacialis, a pennate diatom with spiny projections, was unsuitable as food. The centric diatomSkeletonema costatum was ingested by all harpacticoid species tested, includingTisbe holothuriae, Paramphiascella vararensis, Amphiascoides debilis andDactylopodia vulgaris. All are epibenthic and phytal species occurring in the shallow waters of Helgoland (North Sea). The amount of ciliate and algal carbon taken up was less than that provided by bacteria under laboratory conditions. However, some diatom food may be essential for the development ofD. vulgaris.