An Estimation of the Potential Fluxes of Nitrogen, Phosphorus, Cadmium and Lead from Sea Ice and Snow in the Northern Baltic Sea

Abstract

The amount of nutrients (N and P) and trace elements (Cd and Pb) accumulated and incorporated into the snow and sea ice cover was assessed for the northern Baltic Sea, resulting in an estimate for the potential flux of nutrients and trace elements to underlying waters during sea ice and snow melt. From the atmosphere the sea ice and snow cover accumulate less than 3% of the annual N and P load, and about 5% of the annual Cd and Pb load to the Bothnian Bay. The atmospheric deposition of nutrients to the northern Baltic Sea has declined considerably during the last decade. The total accumulation in the snow and ice, from the atmosphere and seawater, make up to 6% of the annual nutrient and up to 40% of the annual Cd and Pb load into the Bothnian Bay. Thus sea ice plays an important, but still poorly understood role inchemical cycling, transformations, and budgets. The fate of substances accumulated and released from snow and sea ice merit further investigation, especially if sea ice is a source and a platform for transformation of accumulated substances, thus indirectly affecting their toxicity and/or bioavailability before they are released to the water column.