Nutrient status of snow cover and sea ice in the southern Sea of Okhotsk

Samples of sea ice and snow cover on sea ice were collected with the icebreaker P/V Soya in early February 2007 in the southern Sea of Okhotsk in order to evaluate the amount of nutrients in the sea ice and snow. The concentration of nitrate + nitrite, phosphate and silicic acid in the samples was measured in conjunction with such physical parameters as temperature, salinity, oxygen isotopic ratio and ice texture. Sea ice was categorized into three types: snow-ice, granular ice and columnar ice, based on the oxygen isotopic ratio and ice texture. A higher nitrate + nitrite concentration up to 13.5 μmol L was found in the snow and snow-ice, implying the deposition from the atmosphere, occurring as snowfall. Phosphate and silicic acid concentrations up to 14.3 μmol L and 32.7 μmol L, respectively, were highest in granular ice. These results indicate the incorporation of organisms and/or sediment from under-ice water and subsequent remineralization reactions in sea ice.