Particle export and decomposition in the Amundsen Sea Polynya, 2010-12

The Amundsen Sea harbors possibly the most productive polynya in Antarctica. The Amundsen Sea Polynya International Research Expedition (ASPIRE) occupied the ASP in December-January 2010-11 to investigate the origins and fate of the high productivity. Here I discuss settling of particles from the surface to 350 meters as one route of export from the surface bloom, and bacterial vs zooplankton respiration of the particles between 50 and 350 m. Much of the seasonal net community production (NCP) was retained as organic matter in the surface layer, at least through the duration of the cruise, and the export flux was strongly attenuated in the upper 200-300 m. The particle flux was mostly derived from ungrazed phytodetritus, with an increasing contribution from zooplankton fecal pellets as the bloom progressed.