ABSTRACT
The flux of organic matter (OM) sinking to the bottom through oxygen deficient water columns appears to be greater than in oxic waters. Reduced attenuation coefficients for sinking organic matter have been noted for sediment traps deployed beneath OMZs off Peru (Martin et al. 1987), in the Arabian Sea (Haake et al. 1993), and off Mexico (Devol & Hartnett 2001). These are attributed to a decreased oxidation rate of material within the OMZ. Molecular characterisation of sediments underlying the Oman margin OMZ revealed little evidence of zooplankton reworking within the OMZ, but extensive benthic invertebrate reworking at the lower OMZ boundary (Smallwood & Wolff 2000). Thus, the sea bed beneath OMZs receives high inputs of organic matter from the productive overlying waters.
