The Arabian Seas: a window into future oceans -physical, biogeochemical, and ecological dynamics in unique marginal environments.

Abstract

The Arabian Sea provide a sentinel system for understanding how global planetary boundary transgressions manifest through regional ocean processes. Their rapid warming, altered circulation, declining ventilation, deoxygenation, acidification, and ecological reorganization reveal interconnected regional manifestations of pressures associated with the Climate Change, Biogeochemical Flows, Ocean Acidification, and Biosphere Integrity boundaries. Regional physical and biogeochemical amplification compresses the timescale over which these pressures become ecologically consequential, exposing regional responses and increasing risks of regime shifts. Although the Arabian Seas possess distinctive environmental characteristics, the mechanisms linking planetary forcing to regional change are broadly relevant to other tropical and marginal oceans. Their present trajectory therefore provides a conditional, mechanism-based analogue for selected processes expected to intensify across future tropical open-ocean and marginal-sea environments. This illustrates how multiple global boundary transgressions may interact to weaken regional resilience and reorganize marine ecosystem function.