资源环境科技发展态势分析平台

Satellite observations show higher near‐surface phytoplankton chlorophyll (Chl) in anticyclonic eddies (AEs) than in cyclonic eddies (CEs) in the subtropical gyres, which is opposite to the prevailing features in mid‐latitude oceans. Recent studies have attributed this anomalous effect solely to changes in phytoplankton biomass, therefore reached a conclusion that AEs are more productive than CEs, contrary to the conventional eddy pumping paradigm. Here we show that the Chl variations are due mainly to physiological adjustments instead. The high Chl in AEs are mostly explained by photoacclimation to low light environment caused by deepened mixing and more rapid light attenuation, and vice versa for CEs. Such a scenario indicates that phytoplankton are likely more cellular pigmented, rather than more abundant, in the AEs than in the CEs. These findings invite us to rethink the effects of eddies on oceanic productivity and carbon cycling in the subtropical gyres.