Essential Principle 1

The Bay of Bengal is the shallow embayment in the northeastern Indian Ocean basin and connected to the global Ocean 



A. The Bay of Bengal’s Large Marine Ecosystem is the major physical feature connecting the littoral countries Bangladesh, India, Indonesia, Malaysia, Maldives, Myanmar, Sri Lanka, and Thailand in South and South-East Asia.

B. The Large Marine Ecosystem (LME) of the Bay of Bengal covers an area of about 3,585,440 km2 and includes Bay of Bengal, Andaman Sea, Laccadive Sea, Gulf of Mannar, Palk Strait, Gulf of Martaban, Straits of Malacca along with connected river estuaries, and smaller bays and gulfs.

C. Freshwater from river-systems like the Ganges-Brahmaputra-Meghna (GBM) river system, Irrawaddy, Salween (Thanlwin/Salawin), Godavari, Krishna, Kaveri, Mahanadi, Mahaweli, Aceh, and Malacca influence the characteristics of the Bay or parts of it on various scales. The GBM river basin is the second-largest hydrologic region in the world.

D. The Bay of Bengal Large Marine Ecosystem, its river basins, and river systems, and the global Ocean are all connected. Rivers transport sediments, dissolved gases, nutrients, minerals, and pollutants from basin areas into the Bay. River-basin areas of the Bay drain single largest sediment load to any sea in the world. Sediment and freshwater have reduced the salinity of surface waters along the shore. The Bay of Bengal is an integral part of the water cycle and are connected to the region’s river basins and water systems. Changes in water systems affect the quality, quantity, and movement of water, including retention time.

E. Water currents circulate within the Bay of Bengal’s Large Marine Ecosystem are powered by wind, waves, energy from the sun, and water density differences. The concave coastline shapes continental slope and seabed. Its geographic orientation close to the equator and the direction of the prevailing winds such as monsoon, and the shores, and structures on the shores influence the path of circulation.

F. Sea level is the average height of the Bay of Bengal relative to the land, taking into account the differences caused by tides. Variations in precipitation, evaporation, runoff, as well as wind and waves result in changed sea level. Due to the influence of water density and wind, the seasonal changes of the sea level in the Bay are remarkable and one of the highest in the world.

G. An important vertical circulation process in the Bay of Bengal is upwelling and downwelling. In this process, sub-surface water is brought toward the surface, and conversely, a downward displacement happens. Upwelling and downwelling are seasonal, being created by monsoon winds. This circulation process is key to mix the oxygen and nutrient-poor water in the deeper areas of the bay with the oxygen and nutrient-rich surface water.

H. The Bay of Bengal is susceptible to negative influences and its resources are limited.


Version: August 2019

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