Japan Geoscience Union Meeting 2019

Presentation information

[J] Oral

A (Atmospheric and Hydrospheric Sciences ) » A-OS Ocean Sciences & Ocean Environment

[A-OS13] Ocean circulation and material cycle in coastal seas

Mon. May 27, 2019 1:45 PM - 3:15 PM 102 (1F)

convener:Kiyoshi Tanaka(University of Tokyo), Akihiko Morimoto(Ehime University), Yuichi Hayami(Saga University), Kazuhiko Ichimi(Seto Inland Sea Regional Research Center, Kagawa University), Chairperson:Akihiko Morimoto, Yuichi Hayami

2:15 PM - 2:30 PM

[AOS13-09] Enhanced West Philippine Sea intrusion diminishes hypoxia conditions in the Pearl River estuary

*Hon-Kit Lui1,2, Chen-Tung Arthur Chen1, Wei-Ping Hou2, Jian-Ming Liau2 (1.Department of Oceanography, National Sun Yat-sen University, 2.Taiwan Ocean Research Institute, National Applied Research Laboratories)

Keywords:hypoxia, Kuroshio, Pearl River estuary, West Philippine Sea, intrusion, South China Sea

The hypoxia condition (dissolved oxygen <2 mg/L) in the Pearl River estuary is worsening in the past decade, partly due to the rising anthropogenic activities. For instance, excess nutrients cause enhanced biological productivity in the surface ocean. Yet, dead phytoplankton sink to the bottom of the coastal zone, where they decompose and consume oxygen. If the oxygen consumption rate exceeds the supply rate, then hypoxia or even anoxia may develop, leading to so-called dead zones. Here we show that a strong invasion of high dissolved oxygen but low nutrients West Philippine Sea seawater into the South China Sea in the form of Kuroshio occurred around 2003-2004. Apparently due to the oxygen supply carried by the remnants of the intruded Kuroshio, little hypoxia developed off the Pearl River estuary, where the anoxic condition develops in some years with weak Kuroshio intrusion.