Bio-optical Provinces of the Biển Đông

The biogeochemistry of the southwestern South China Sea or the Biển Đông (East Sea) is strongly influenced by the summer southwest monsoon. There is an upwelling system that sets up along the central coast and discharge from the Mekong River is transported into the central South China Sea. During a cruise in June 2016, 22 stations were sampled and measurements of physical parameters such as temperature, salinity, beam transmittance etc were made using a CTD rosette system. Spectral diffuse attenuation coefficients were measured using a free-falling spectroradiometer and water samples were taken for measurements of absorption of dissolved and particulate material as well as chlorophyll specific phytoplankton absorption. The bio-optical measurements were used to delineate bio-optical provinces of these waters during the pre-monsoon season. Results of these analyses will be presented.