“…Previous studies have demonstrated that abundant diazotrophic cyanobacteria including Trichodesmium is transported by the Kuroshio (Cheung et al., 2019; Jiang et al., 2019; Shiozaki et al., 2018), which is widely distributed and even blooms (>1,000 trichomes L −1 ) in the ECSYS, particularly in warm seasons (Jiang, Li, et al., 2018; Marumo & Asaoka, 1974; Shiozaki et al., 2010). In addition, severe N deficiency (N:P ratio usually <6) according to Redfield N:P ratio (16; Redfield, 1958) and relatively abundant dissolved Fe (dFe; 0.47–10.01 nmol L −1 ) on the surface are observed in the offshore ECS (Zhang et al., 2022), because of riverine/atmospheric inputs as well as intrusion of nearshore Kuroshio Branch Current (Guo et al., 2014; Zhang et al., 2022). This intrusion across the shelf break transports a substantial amount of dFe to the broad shelf, representing natural Fe fertilization in the ECS (Zhang et al., 2022).…”