Research Highlights in the Ocean Sciences by 2005 AGU Fellows (Continued)
Presiding: C R Sherwood, U.S. Geological Survey; E Druffel, University of California, Irvine
OS14A-01 INVITED 15:30h
Freshwater, Climate Variability and Physical Forcing of Arctic Foodwebs
The freshwater budget of the Arctic Ocean is widely believed to play a role in the global thermohaline circulation. This is not only due to the large delivery of fresh water to the system, but also due to its great storage capacity and variability in the various layers of its halocline complex. The resulting halocline complex is likewise known to be efficient in insulating the surface layers from the underlying warm inflows from the Atlantic and Pacific oceans, thus shielding the ice cover. But, at the same time, the halocline retards the vertical flux of nutrients. In fact, the late Max Dunbar once wrote a paper entitled "Hudson Bay has too much fresh water" noting that the surrounding river inflows to Hudson Bay blocked vertical exchange with the nutrient-rich Pacific waters below, and thus constrained production. Here I extend Dunbar's original concept and ask, `Does the Arctic Ocean have too much freshwater?', and then explore the question of light versus nutrient limitation for primary production. In addressing this question the roles of Atlantic and Pacific inflows are examined, and the panarctic shelf regions are distinguished among three basic types: inflow, interior and outflow shelves. Finally, remarks are made on projected climate changes that will likely have the greatest impact on arctic foodwebs.