MORPHOLOGIES AND TRANSFORMATIONS OF CELESTITE IN SEAWATER - THE ROLE OF ACANTHARIANS IN STRONTIUM AND BARIUM GEOCHEMISTRY

Free-drifting sediment traps deployed at 400, 1500, and 3200 m were used to collect particles near the US JGOFS Time-Series Station (31-degrees-49,5'N and 64-degrees-08.2'W) in the Atlantic Ocean. Acantharian specimens isolated from our samples were abundant at the 400-m depth horizon and were rare to non-existent in our 1500-m traps. No specimens were detected in the 3200-m traps. This trend parallels those noted for the Pacific and has been linked to the oceans' Sr/Cl profiles. Our collections revealed the presence of myriad, heretofore undocumented, minute SrSO4 particles. These particles are most likely related to the acantharian reproductive cycle. The extreme abundance of acantharians and acantharian-derived particles may have implications beyond the oceans' Sr budgets. Barium/strontium molar ratios in acantharian-derived celestite on the order of 3 X 10(-3) indicate that acantharians may play an important role in oceanic Ba cycling.