A model of near‐sea ice phytoplankton blooms

Arctic phytoplankton spring blooms have increased in magnitude and extent over the past two decades, particularly in waters near the sea ice edge. We develop an idealized model of phytoplankton dynamics that takes into account the role of sea ice meltwater flux and its impact on surface mixed layer depth. Satellite observations feature a characteristic peak in phytoplankton concentration at around 100 km from the ice edge. Model dynamics capture this peak and overall structure of the phytoplankton distribution. In the model, the characteristic spatial scale emerges from a balance of exponential growth near the ice edge, horizontal advection, and increased decay with distance from the ice as the mixed layer deepens. Observations and data further agree in that meltwater impacts phytoplankton concentrations up to 1000 km from the ice edge. Results suggest that reduced meltwater input under future sea ice retreat may suppress spring phytoplankton blooms in the region.