Heterotrophic flagellates and other protists associated with oceanic detritus throughout the water column in the mid North Atlantic

Abstract

Heterotrophic protists, mostly flagellates, encountered in association with marine detritus from various collections in the mid North Atlantic are described. About 40 species have been identified and are reported. Taxa reported here for the first time are: Caecitellus gen. nov. (Protista incertae sedis) and Ministeria marisola gen. nov., sp. nov. (Protista incertae sedis). The flagellates form a subset of the community of heterotrophic marine flagellates encountered in more productive marine sites. Most species are bacterivorous and small. The community extends to the ocean floor but the diversity is reduced in samples taken from greater depths. The decline in species diversity is linked also to a decline in numbers of individuals. We discuss these changes in relation to food supply and pressure effects.