The role of zooplankton communities in carbon recycling in the Ocean: the case of the Southern Ocean

Basin-scale carbon recycling estimates were obtained by combining high-resolution data on zooplankton taxonomic and functional composition with species-specific respiration rates. Datasets were collected in the Atlantic and Indian sectors of the Southern Ocean during four cruises covering spring, mid-summer, autumn and late winter between 1993 and 1998. Carbon recycling by Antarctic meso-and macrozooplankton represented a significant (44-62%) fraction of the primary production, which is at the higher end of previous estimates. Assessment based on detailed community structure appeared to be more realistic than previous estimates and showed that carbon dioxide recycling at the global scale is not a mere function of temperature and abundance of zooplankton. Both species and functional diversity influence current estimates at the community level through trophic type and developmental stage composition. In addition, a regional spatial heterogeneity linked to hydrodynamic features (frontal zones) is also important. The Southern Ocean zooplankton community respiration is assessed to be similar to 0.6 GtC year(-1).