Sea level anomalies control phytoplankton biomass in the Costa Rica Dome area



[1] Satellite data show that chlorophyll-a concentration (Chl-a) in the northeastern tropical Pacific is well correlated with sea level anomaly (SLA). This correlation spans a wide spectrum of scales from large-scale phenomena like ENSO to mesoscale cyclonic and anticyclonic eddies. Negative SLA (e.g. during La Niña events and in cyclonic eddies) is associated with the lifting of isopycnals in the nutricline and increased Chl-a due to enhanced phytoplankton growth, while positive SLA (e.g. during El Niño events and in anticyclonic eddies) is associated with a deeper nutricline and reduced Chl-a due to decreased phytoplankton growth. The coupling between SLA and Chl-a anomaly in the Costa Rica Dome (CRD) area is tighter than has previously been recorded anywhere in the world ocean. 70% of the interannual variations in Chl-a anomaly in the CRD area is explained by a combination of the positive and negative effects of SLA.