Wind-driven advection across temperature gradients enhances iron-induced phytoplankton blooms in the 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 specific species and, ultimately, for 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. Depending on the region along the circumpolar front, increased winds can enhance this process across temperature gradients, and further accelerate such temperature-controlled growth. These results indicate that favorable temperature may enhance the growth rate even further when iron is sufficiently available, and thus have far-reaching implications for increased productivity in a future warming climate.