ENHANCED ARCTIC PRIMARY PRODUCTIVITY FOLLOWING SEA ICE RAPID DECLINE

Satellite sea ice data from 1978 to the present reveal that the perennial ice (or ice that survives the summer) has been rapidly declining at almost 10% per decade. Warming due to increases in greenhouse gases in the atmosphere is now also being reflected in winter with drastic reductions in the maximum extent observed in 2005 and 2006. The retreat of the perennial ice also exposes more open water and has revealed an asymmetric distribution of chlorophyll a pigment concentration in the Arctic basin. Phytoplankton blooms are most dominant at high latitudes, partly on account of sea ice, but in the Arctic basin, it appears that pigment concentrations in the Eastern (Laptev Sea) Region are on the average three times higher than those in the Western (Beaufort Sea) Region. Such asymmetry suggests that despite favorable conditions provided by the melt of sea ice, there are other factors that affects the productivity of the region. The asymmetry is likely associated with much wider shelf areas in the East than in the West, with sea ice processes that inhibits the availability of nutrients near the surface in deep water regions, and river run-off that affects nutrient availability. The primary productivity in the pan-Arctic region have been estimated using the pigment concentrations and PAR derived from SeaWiFS data and the results show large seasonal as well as interannual variability during the 1998 to 2005 period. The data points towards increasing productivity for later years but with only 9 years of data it is too early to tell the overall effect of the sea ice retreat.