607 Modeling study on the response of lower trophic level production to climate change

The project aims to establish a coupled ice-ocean ecosystem model including both pelagic and sea ice habitats. The model will be based on the existing pelagic ecosystem model (Jin et al. 2006b) for the southeastern Bering Sea and the ice-ocean ecosystem model (Jin et al. 2006a) for offshore Barrow. We will conduct sensitivity studies of the impact of physical and biological process variations on primary production, nutrient cycling, phytoplankton species composition, and carbon export to benthos. We will provide recommendations on how, when and which observations should be made to ensure effective improvement in understanding of the Bering Sea ecosystem.

Using historical observations from National Oceanic and Atmospheric Administration (NOAA) biophysical mooring site 2, a multi-year (1958-2005) model run is planned to produce a long time series of biogeochemical model results. Seasonal variations and interannual changes in the results will be used to elucidate the lower trophic level productivity response to climate changes.

Figure by Meibing Jin, in June 2006. Preliminary results in multi-year run at M2 site of Southeastern Bering Sea. Modeled surface phytoplankton is compared with daily SeaWiFS Chl a data and imposed with daily SSMI sea ice concentration. Note that there appears to be discrepancies at the peak of bloom in certain year (e.g. 1998 and 1999), however that could be due to gaps of missing SeaWiFS Chl a data in cloudy days which are common in the Bering Sea.