Aragonite pteropod flux to the Somali Basin, NW Arabian Sea

Aragonite export fluxes of pteropods (>250, 150–250 and 125–150 μm) in the Somali Basin were estimated using a 9-month time-series sediment trap (MST9-E) from June 1992 to February 1993. The trap with 23 time-series sediment collectors placed at 1032 m water depth collected settling particles over a total of 249 days. Pteropods showed large seasonal variations in both the numerical and mass fluxes (>125 μm) with their maxima at the end of the SW Monsoon during September and early October. It was also observed that records of pteropod fluxes varied in different size fractions. The average numerical flux and mass flux of pteropods (>125 μm) from the 9-month record of the sediment trap was estimated to be about 1830 shells m−2 d−1 and 18 mg m−2 d−1, respectively. We estimate that about 22.5% of the total CaCO3 in the Somali Basin was contributed by aragonitic pteropods (>125 μm).