Carbon processing at the deep-sea floor of the Arabian Sea oxygen minimum zone: A tracer approach

► Our approach involved an on-deck incubation of sedimentary cores sampled from both inside and outside the OMZ. ► We added a different dose of C (400 and 100 mg C m-2) to the cores of the two stations. ► Duplicate cores were incubated for 7 days both under oxic and suboxic conditions. ► Freshly deposited OM was assimilated and respired quickly, the standing stock was capable of carrying out metabolic processes. ► OM quality and not oxygen concentration or low biomass is the factor for the Arabian Sea OMZ sediment OM maximum.