Early diagenetic processes in relation to river discharge and coastal upwelling in the Aru Sea, Indonesia

► Early diagenesis in Aru Sea muds is dominated by metal reduction and aerobic respiration. ► Precipitation of authigenic carbonate minerals is a significant process. ► Benthic metabolism peaks where upwelling enhances phytoplankton and fisheries production. ► Aru Sea sediments are incinerators of organic carbon.