Percolomonas cosmopolitus(Ruinen) n.gen., a new type of filter feeding flagellate from marine plankton

INTRODUCTION The ecological significance of heterotrophic micro-flagellates in marine plankton has recently drawn considerable interest among biological oceanographers (Anderson & Fenchel, 1985; Haas & Webb, 1979; Fenchel, 1985 and references therein). Such organisms have been shown to be numerous, occurring in densities of 5 x 102to 2 x 103per ml in surface coastal and oceanic waters. Their grazing activities are believed to account for virtually all of the turnover of populations of suspended bacteria.