IndoTROPICS studies on the plume of the Mamberamo river into the Bismarck Sea, West Papua, Indonesia

The tropical river ocean processes in coastal settings (TROPICS) program in Indonesia (Indotropics) was carried out in the Mamberamo estuary on May–June 1999 and August 2000. The Mamberamo River flows northward from the high mountains of West Papua to the narrow and steep continental slope of the Pacific Ocean. The data for the 1999 Mamberamo estuary cruises show the dispersal of fresh water coming out of the Mamberamo River into the Bismarck Sea, and the plume is clearly defined by the pattern of salinity, turbidity, and nutrient distribution. The Mamberamo River and other nearby rivers supply high concentrations of phosphate and nitrate to the New Guinea Coastal Current, so that nutrient concentrations are higher in the surface estuarine plume, compared to offshore areas. The distribution of fishes and benthic animals were also sampled over this area.