Enhanced primary production in the oligotrophic South China Sea by eddy injection in spring

(Chl‐a) concentration of 0.3–0.4 mgm−3 was observed at the centre of northern South China Sea (SCS) by NASA’s Sea‐ viewing Wide Field‐of‐View sensor. As this region is remote and known to be oligotrophic in spring (Chl‐a concentration typically at ∼0.05–0.08 mgm−3), it is intrigu-ing to explore this unusual happening. Based on six different remote sensing data and numerical modelling, the results suggest that the injection of an ocean eddy is the most likely cause of the bloom. Due to long‐range transport of a large (700 × 500 km) anti‐cyclonic ocean eddy, coastal nutrients and plankton could be brought across hundreds of kilo-metres to the centre of northern SCS and impact the biogeo-chemistry. The open ocean part of the northern SCS basin has long been considered generally free from coastal in-fluences. This work provides new evidence that proves otherwise. Moreover, from the perspective of physical oceanography, it is interesting to observe that, outside the monsoon seasons, there can be well‐defined anti‐ cyclonic ocean circulation existing in the SCS without the prevailing monsoonal wind. Citation: Lin, I‐I, C.‐C. Lien