Monthly sediment trap fluxes and sea-ice cover measured at the mooring station HG-IV from 2000 to 2013. Panels (a) and (b) depict the monthly POC and terrigenous marker flux. Panel c shows the monthly average sea-ice cover over the mooring location at HG-IV. Green circles in panels (a–c) show the sequence abundance of Phaeocystis OTUs in the sediment trap samples.