The Evolution of Phytoplankton Communities in Gulf Stream Meanders and Eddies
Event: 2014 Ocean Surface Topography Science Team Meeting
Session: Science Results from Satellite Altimetry: Finer scale ocean processes (mesoscale and coastal)
Presentation type: Type Poster
Contribution: PDF file
During the formation of nonlinear Gulf Stream eddies, water with elevated CHL is trapped in cyclones and water with suppressed CHL is trapped in anticyclones. Following formation, CHL is observed to increase in the cores of anticyclones and decrease in cyclones. We suggest that the observed trends in CHL following eddy formation are a result of eddy-induced Ekman pumping generated by the influence of ocean surface currents on the surface stress.
To test this hypothesis we compare two separate eddy-resolving physical-biological simulations. The first simulation is forced with a realistic surface stress that includes the influence of ocean surface currents. The second simulation neglects this process and therefore does not include eddy-induced Ekman pumping. The time evolution of CHL within eddies is very different in these two simulations; the model including eddy-induced Ekman pumping reproduces observed trends in CHL within eddies, whereas the other simulation does not.