A case study to set the scene
The Mekong River is one of the world’s great river systems. It flows along 4,909 km and through six countries including China, Myanmar, Thailand, Laos, Cambodia, and Vietnam. It is the twelfth longest river in the world and the seventh longest in Asia. It is also is one of the most biologically diverse rivers in the world—second only to the Amazon. The Mekong River’s biodiversity is fundamental to the natural resource-based rural livelihoods of a large population. At the end of the Mekong, the river flows through an extensive delta and meets the South China Sea.
The South China Sea is adjacent to a region in Vietnam of rapid land use change, strongly influenced by riverine inputs, including a seasonal offshore jet that transports the Mekong River plume well offshore. The drainage basin into which the river flows is rather small when compared to its discharge volume. The riverine fluxes of water, sediments, and nutrients likely are affecting the natural balance of the South China Sea. This area provides an excellent site for exploring and characterizing the role of riverine inputs with human-induced modifications, as well as the role of ocean circulation in controlling productivity in a tropical coastal marine ecosystem. A variety of biological processes are affected by the circulation of the South China Sea, especially during upwelling, which has a strong effect on the spatial distribution of phytoplankton biomass and activity.