Parameterizing ice-edge biological productivity in a changing Arctic: Growth factors associated with specific ice provenances

Abstract:

Sea ice plays a significant role in the ecology of polar seas and a significant portion of the biological production in the Arctic occurs at ice edges. These environments are inherently variable in space and time and subject to climate variation as the summer ice extent changes. Recent field results from the northern Bering Sea suggest that the parameterization of ice edge production in coupled physical-biological models that ignore processes specific to the ice-melt environment will be insufficient to describe the variability and intensity of Arctic production. In addition to the stabilizing the surface layer, ice may contribute phytoplankton growth factors such as trace metals that have been derived from the regions of ice formation as well as aeolian deposition. Results of an analysis of sea ice formation, flow and melt suggests regions that are likely to receive trace metals from ice and has been validated with regions of known ice edge productivity in the Bering Sea. A similar analysis for the Chukchi Sea compared the likely ice-edge productivity regions between pre-2000 ice conditions and those in the more recent period of reduced summer ice cover. Changes are predicted in both the timing and distribution of these regions in proportion to the variations in the dominant ice flow patterns. Ways in which the non-local processes important to elevated ice edge productivity can be incorporated into couple arctic models will be discussed.