ABSTRACT
The Arabian Sea makes contributions to global biogeochemical cycles that are far in excess of what might be expected from its modest size. The landmass that limits the poleward expanse of the northern Indian Ocean to just about 25° N latitude profoundly affects physical processes in the Arabian Sea. The mesopelagic zone of the Arabian Sea is renewed at a surprisingly rapid rate. The highly variable physical forcing and the resultant hydrographic changes in the Arabian Sea are expected to give rise to widely differing phytoplankton assemblages in both space and time. The most striking feature of the composition of Arabian Sea sediments is the unusually high organic carbon accumulation – among the highest in the world – occurring along the continental margins. The suboxic/anoxic conditions prevailing in marginal sediments of the Arabian Sea appear to affect, to a very substantial extent, cycling and global budgets of phosphorus, nitrogen and sulphur and of redox sensitive metals.
