PLANKTONIC SARCODINES (ACANTHARIA, RADIOLARIA, FORAMINIFERA) IN SURFACE WATERS NEAR BERMUDA - ABUNDANCE, BIOMASS AND VERTICAL FLUX

The abundance, biomass and vertical flux of large planktonic Foraminiferal Acantharia and polycystine Radiolaria were determined in surface waters of the Sargasso Sea southeast of Bermuda. On average, Acantharia were the most abundant group (similar to 10(6) m(-2) integrated over the upper 150 m). Foraminifera were present at abundances approximately one order of magnitude less than the Acantharia, while Radiolaria (primarily colonial species) were too sparse to allow accurate abundance estimates. Nevertheless, the average integrated biomass of Radiolaria in the upper 150 m was approximately equal to the biomass of Acantharia (2.6 versus 2.8 mg C m(-2)). Averaged integrated biomass of planktonic Foraminifera was approximately one-half of the values for Acantharia and Radiolaria (1.4 mg C m(-2)). Sarcodine fluxes averaged 15.5% of the total carbon flux. Acantharia were consistently a few percent of the sinking material caught in sediment traps deployed at 150 m. Radiolaria and Foraminifera had higher average contributions than Acantharia, but both of these averages were dominated by data from a few cruises with extremely high fluxes. Observed fluxes of Radiolaria were highly variable because of their coloniality and patchy distribution. When present in trap material, however, they constituted a significant fraction of the material caught in short-term trap deployments.