Study of material flux from East Asian rivers into the ocean

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The purpose of this study is to evaluate the influence of East Asian rivers in the biogeochemical cycling in the ocean. Originally, we intended to study the Yantze river estuary using a Chinese research vessel "Venus II" in colaboration with professor Y.Qin and other scientists of the Quindao Oceanographic Institution (Academica Sinica). Planning of this project had been made through correspondence and it was agreed that the survey would start in November, 1995. However, Chinese counter part informed us that the survey needed to be postponed. Then, Principal Investigater, Y.Nozaki also visited Quindao to discuss further the detail plan and to make preliminary survey on the Yanzte river. But unfortunately, due to abrupt change of policy in marine sciences in China, we could not get the permission of Chinese Government (SOA : the State of Ocean Administration).Therefore, we shifted to the second target and could successfully work on the Chao Praya (Manum) river in Thailand. Field sampling was made 3 times a year, February, July and November, 1996 through colaboration with Professors Manuwadi Hungspreugs, and Anond Snidvongs, and students of Chulalongkorn University. It is important to note that our party could be based on the laboratory of SEAFDEC (Southeast Asian Fisheries Development Center) at the Chao Praya river mouth. Water and sediment sampling was made by using a fishing boat in the Chao Praya estuary and the Gulf of Thailand. Heavy metals like rare earth elements and indium in the water samples were measured by ICP mass spectrometric method. Organic matters in sediments were also measured at Nagoya University by K.Ohta. Some of the results have been accepted for publication on the journal of "Earth Planetary Science Letters".