The authors are grateful to Dr. Zhengquan Yao and Chunshun Li of First Institute of Oceanography, Sate Oceanic Administration, China and the crew of the R/V Boonprakob for their assistance in sample collection. Special thanks to Dr. Penjai Sompongchaiyakul of Chulalongkorn University, Thailand for her assistance in collecting background information and organizing the cruise. This work was jointly supported by the cooperative research program between China and Thailand ‘‘Research on Vulnerability of
Coastal Zones’’ and Marine Public Welfare Research Project(Grant No. 201205001) and assisted by the Natural Science Foundation of China (NSFC) (Grant No. 41206055).