An array of persistent chemical pollutants are present in the Arctic in both biota and abiotic compartments, including snow and ice. These chemicals include older legacy contaminants such as PCBs and DDT, well as an array of newer 'emerging' contaminants with contrasting physical-chemical properties. Rapid changes to the physical and biological environment in the Arctic are changing the pathways and fate of pollutants, making biological exposure and impact difficult to predict; indeed changes to the Arctic may be altering the biological exposure to contaminants and even exacerbating it. The purpose of this proposal is to provide a mechanistic and quantitative understanding on the role of sea ice (particularly first year sea ice - the dominant ice type in a warmer Arctic) in the accumulation and subsequent release of chemical contaminants to the base of the marine foodweb. Preliminary evidence indicates that some newer contaminants are present in sea ice at concentrations akin to temperate coastal seas and we need to know the reasons for this, plus the likely exposure to biota once contaminants are released during ice break up and melt at the end of winter. Elucidating this process and understanding the fate and behaviour of chemicals in marine ice and snow can help shape chemical management strategies at the global level, particularly if changes to the Arctic cryosphere are also altering nutirent availability in ice and surrounding seawater. The contaminant and nutrient processes to be observed in the Arctic will be supported by artificial sea ice experiments. We plan to investigate this topic using field and laboratory studies and use these to model effects on the lower marine foodweb, examining whether nutrient and contaminant availability are linked and their impact on sea ice habitat functioning.