FY 2003

Characteristics and variability of the inner front of the southeastern Bering Sea

Kachel, N.B., G.L. Hunt, Jr., S.A. Salo, J.D. Schumacher, P.J. Stabeno, and T.E. Whitledge

Deep-Sea Res. Pt. II, 49(26), 5889–5909, doi: 10.1016/S0967-0645(02)00324-7 (2002)

The inner front of the southeastern Bering Sea shows marked spatial variability in frontal characteristics created by regional differences in forcing mechanisms. Differences in forcing mechanisms (sea ice advance/retreat and storm strength and timing) and early spring water properties result in strong interannual variability in biological, chemical, and physical features near the front. We have developed a simple model based on surface heat flux and water-column mixing to explain the existence of cold belts (Cont. Shelf Res. 19(14) (1999) 1833) associated with such fronts. Hydrography, fluorescence and nutrient observations show that pumping of nutrients into the euphotic zone occurs, and this can prolong primary production at the inner front. The effectiveness of this process depends on two factors: the existence of a reservoir of nutrients in the lower layer on the middle shelf and the occurrence of sufficient wind and tidal energy to mix the water column.