Simulated decadal variations of surface and subsurface phytoplankton in the upstream Kuroshio Extension region

Abstract Using outputs from an ecosystem model embedded in eddy-resolving ocean general circulation that can realistically simulate decadal modulations of the Kuroshio Extension (KE) between stable and unstable states, variations phytoplankton concentration upstream KE region are investigated. During states KE, surface concentrations anomalously suppressed to south front, while those north enhanced. Although anomalies prominent only during winter spring, significant subsurface centered around 60 m depth persist even summer autumn. Anomalies throughout year biomass integrated over upper 100 despite strong spring bloom season. An analysis nitrogen suggests vertical movement isopycnal surfaces, mixing nutrients, meridional shifts jet contribute anomalous biomass.