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

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