Microzooplankton in Lancaster Sound (eastern Canadian Arctic) in summer: biomass and distribution

Abstract

Numerical abundance, taxonomic- and size-composition and organic carbon biomass of microzooplankton (organisms >35 μm and <200 μm size in this study) in the upper 100 m at 18 stations in six transects across Lancaster Sound, Barrow Strait and Baffin Bay (eastern Canadian Arctic) were studied in summer 1980. Numerically Protozoa contributed 72% to the total numbers, ranging from 36% (Barrow Strait) to 95% (Cape Warrender) but contributed only 2–22% to carbon biomass. Mean integrated carbon biomass at various stations ranged from 1.33 to 8.88 μg l −1, with pronounced subsurface maxima in excess of 10 μg l −1 at most stations. These maxima occurred near the chlorophyll maxima but did not necessarily coincide with it. Microzooplankton biomass was probably underestimated due to concentration procedures used to collect samples. Even then the absolute values of microzooplankton carbon and ratio of microzooplankton to macrozooplankton were similar to values reported for other arctic, subarctic, temperate and tropical oceanic waters. The microzooplankton community in the Arctic probably plays a similar dynamic role in consumption of phytoplankton and regeneration of nutrients as has been postulated for temperate and tropical oceanic waters.