Carbon contribution of sea ice floes in the Arctic Ocean

To estimate detailed contributions of particulate organic carbon (POC) as a potential food source in various environments of the Arctic sea ice floes, intensive investigations were executed at two different types of sea ice stations (ST 1 and ST 2) in the northern Chukchi Sea during the summer period in 2011. The average uptake rates of carbon and nitrogen in melt ponds from this study were within the range measured previously. The surface ice of melt ponds at ST 1 had the highest POC concentration with a mean of 148.0 mg C m−3 (S.D.=±86.0 mg C m−3), followed by sea ice cores at ST 2 (mean±S.D.=125.7±128.2 mg C m−3). The POC concentrations in melt ponds ranged between 90.0 mg C m−3 (S.D.=±12.7 mg C m−3) and 103.9 mg C m−3 (S.D.=±47.7 mg C m−3) at ST 1 and ST 2, respectively. Major POC contributors to melt ponds were diatoms with a mean biovolume contribution of 48.7% (S.D.=±39.1%) which was strongly related to in situ salinity. Although the total POC concentration of entire sea ice floes ranged from 2.8% to 5.3% of the POC concentration within the euphotic water column at the study locations, the carbon contribution of sea ice floes could be important to higher trophic levels because of the concentrated POC within sea ice floes.