HR: 13:55h
AN: OS53B-02 INVITED     [Abstracts]
TI: Convection and the Seeding of the North Atlantic Bloom
AU: * D'Asaro, E A
EM: dasaro@apl.washington.edu
AF: University of Washington, Applied Physics Laboratory 1013 NE 40th Str, Seattle, WA 98105 United States
AB: The springtime North Atlantic bloom occurs when the reduction in vertical mixing and increased daylight allows overwintering diatoms to grow rapidly. However, these diatoms sink sufficiently fast during the winter to end up far below the springtime euphotic zone. How, then, is the spring bloom is seeded? This question is explored using vertical velocity data from neutrally buoyant floats. The large vertical velocities which occur in the deep wintertime convective layers can act to retain some of the diatoms near the surface as a seed population. This model is found to apply in the Labrador Sea, but not near the southern edge of the bloom near Bermuda. The depth of wintertime convection relative to cell sinking rate may thus limit the southern extent of the spring diatom bloom.
DE: 4855 Plankton
SC: Ocean Sciences [OS]
MN: 2004 AGU Fall Meeting