MEPS 333:61-74 (2007)  -  doi:10.3354/meps333061

Offshore and nearshore chlorophyll increases induced by typhoon winds and subsequent terrestrial rainwater runoff

Guang Ming Zheng1,2, DanLing Tang1,2,*

1Laboratory for Tropical Marine Environment Dynamics (LED), Remote Sensing and Marine Ecology Group, South China Sea Institute of Oceanology, Chinese Academy of Sciences, 164 West Xingang Road, Guangzhou 510301, China
2Graduate School of the Chinese Academy of Sciences, 19A Yuquan Road, Beijing 100049, China
*Corresponding author. Email:

ABSTRACT: The response of phytoplankton chlorophyll to Typhoon Damrey in the South China Sea (SCS) in September 2005 was studied by remote sensing. Chl a concentration increased in 2 areas after the typhoon: (1) An offshore bloom along Damrey’s track exhibited a chl a peak (4 mg m–3) 5 d after the typhoon’s passage. It was preceded by sea-surface cooling (–5°C), mainly on the right side of the typhoon track, and sea-level decrease (–25 cm) along the typhoon track 1 d post-typhoon. The offshore bloom was due to nutrient increase from mixing and upwelling. (2) A nearshore chl a increase succeeded typhoon rain (>300 mm on 26 September) on Hainan Island in the northwest SCS. In the bloom region, the water was rich in suspended sediments, phytoplankton, and colored dissolved organic matter, and was entrained by an eddy. This nearshore feature may have resulted from rainwater discharge and seaward advection by a typhoon-induced current. By these 2 mechanisms, both typhoon winds and rain can enhance production of marine phytoplankton.

KEY WORDS: South China Sea · Typhoon Damrey · Ocean color · Remote sensing · Phytoplankton bloom

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