Wind-driven Advection Across Temperature Gradients Supports Phytoplankton Blooms in the Iron-limited Antarctic Polar Front
Abstract We demonstrate how the wind-driven Ekman transport enhances the advection and mixing of cells from the colder waters of the Surface Antarctic Waters from the south to the warmer waters of the northern Polar Front (PF) belt. This mechanism provides cells a mean ambient temperature near optimum levels for species-specific and, ultimately, community growth rates high enough to develop blooms under non-light limiting, macronutrients and iron conditions. A Lagrangian trajectory model was constructed for tracking plankton cells as tracers forced by winds and surface currents. We argue that wind-driven Ekman drift of surface currents can carry phytoplankton cells into warmer waters and thus increase their growth rates to potentially generate blooms, even under iron-limiting conditions. Depending on the region along the circumpolar front, increased winds can enhance this process, and further accelerate such temperature-controlled growth.
