Andaman Sea

Andaman Sea
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Name	Andaman Sea
Location	Bay of Bengal, Indian Ocean
Type	Sea
Basin countries	Myanmar, Thailand, India
Islands	Andaman Islands, Nicobar Islands, Mergui Archipelago

Andaman Sea The Andaman Sea lies in the northeastern Indian Ocean between the Bay of Bengal, Malay Peninsula, and Nicobar Islands, bordering Myanmar, Thailand, and India. The sea interfaces with maritime routes connecting the Strait of Malacca, Gulf of Martaban, and the wider Indian Ocean, and is proximate to the Andaman and Nicobar Islands, Mergui Archipelago, and Phuket. Major ports and coastal cities on its shores include Yangon, Mawlamyine, Ranong, Phuket (city), and Port Blair.

Geography

The basin occupies waters adjacent to the Bay of Bengal and the eastern margin of the Indian Ocean and is bounded by peninsulas and island chains such as the Malay Peninsula, Andaman Islands, and Nicobar Islands, with shelf regions near Tenasserim Hills and the Rakhine Coast. Important coastal physiographic features include the Irrawaddy Delta, the Sittang Delta, and the Krabi coastline, while notable islands and archipelagos comprise Havelock Island, Little Andaman, Great Nicobar, Carbyns Cove, and the Similan Islands. Navigation corridors link the sea to the Gulf of Thailand, the Malacca Strait, and the Indian Ocean tsunami of 2004-affected littoral zones. The sea’s littoral jurisdictions intersect the Exclusive Economic Zones of Myanmar, Thailand, and India and are relevant to maritime boundaries adjudicated under instruments similar to the United Nations Convention on the Law of the Sea.

Geology and Bathymetry

The basin overlies complex tectonics between the Indian Plate and the Burma Plate with subduction-related structures along the Cocos Plate junction and the Sunda subduction systems, and displays features formed by the Sunda Trench dynamics and the Andaman-Nicobar Ridge. Seafloor morphology includes continental shelf segments, slope escarpments, submarine canyons, and abyssal plains with bathymetric highs near the Andaman Islands and Nicobar Islands, and deeper troughs approaching the Java Trench influence. Seismic activity and historic megathrust events, including rupture areas linked to the 2004 Indian Ocean earthquake and tsunami, shape sedimentation, turbidity currents, and slope stability, while active faulting around the Sagaing Fault and fracture zones influence regional uplift and subsidence. Stratigraphic records from cores reveal Quaternary sedimentation patterns associated with sea-level changes tracked in studies from institutions like the Geological Survey of India and the Bangkok Research Center.

Oceanography and Climate

Surface circulation is modulated by the seasonal monsoon systems, with the Southwest Monsoon driving stronger currents and upwelling in boreal summer and the Northeast Monsoon reversing winds and stratification in boreal winter; these interact with the Indian Ocean Dipole and remote forcing from the El Niño–Southern Oscillation. Thermohaline structure exhibits temperature and salinity gradients influenced by freshwater input from the Irrawaddy River, Sittang River, and seasonal runoff from Peninsular Thailand, while vertical mixing is influenced by tidal regimes of the Malacca Strait and internal waves generated by sill passages near Great Nicobar. Meteorological impacts from systems such as Cyclone Nargis, tropical cyclones forming in the Bay of Bengal, and seasonal monsoon depressions modulate storm surge risk, coastal erosion, and sea surface temperature anomalies monitored by agencies like the Bangkok Meteorological Department and the India Meteorological Department.

Biodiversity and Ecosystems

The sea hosts diverse marine ecosystems including mangrove forests along the Irrawaddy Delta and Mergui Archipelago, coral reef assemblages around Similan Islands and Havelock Island, seagrass beds in sheltered bays near Phuket, and pelagic habitats frequented by migratory species recorded by organizations such as the World Wide Fund for Nature and the International Union for Conservation of Nature. Fauna include reef-building corals, fishes documented in monographs by the Smithsonian Institution, megafauna such as green sea turtles, olive ridley sea turtles, whale sharks, and cetaceans observed in surveys by the International Whaling Commission and regional research programs. Coastal wetlands support avifauna linked to the Ramsar Convention sites on Andaman Islands and Myanmar shorelines, while mangrove and coral conservation is undertaken by bodies including the Department of Fisheries (Thailand), Bombay Natural History Society, and regional universities. Threats stem from coral bleaching events tied to warming recorded by the Intergovernmental Panel on Climate Change, overfishing affecting stocks managed under frameworks like Regional Fisheries Management Organizations, and habitat loss from coastal development.

Human Use and Economy

Maritime commerce traverses major shipping lanes connecting the Strait of Malacca to the Arabian Sea and Pacific trade, serving ports such as Port Klang, Singapore, Phuket Port and influencing activities by shipping companies including Mearsk-class carriers and regional terminals. Fisheries provide livelihoods for coastal communities in Myanmar, Thailand, and India with species targeted by industrial fleets and artisanal fisheries recorded by the Food and Agriculture Organization; aquaculture operations and shrimp farms around Andhra Pradesh and Phuket contribute to regional exports. Tourism hubs like Phuket, Havelock Island, and Similan Islands National Park drive economic activity linked to dive operators, hotels, and conservation tourism managed by agencies such as the Tourism Authority of Thailand. Energy exploration has attracted investments for offshore hydrocarbon prospects evaluated by companies like PetroVietnam-style operators and national oil companies, while ports and naval presence of actors like the Indian Navy and Royal Thai Navy support maritime security, search and rescue, and fisheries enforcement.

History and Maritime Significance

Historic maritime routes across the basin connected ancient trading centers such as Arakan, Tambralinga, Srivijaya, and Pegu (Bago) with spice and silk trade lanes to Aden, Calicut, and Guangzhou under sailing regimes recorded by travelers like Marco Polo and chronicled in maritime histories by the British East India Company era. Colonial strategic use involved British India, French Indochina-era interests, and conflicts during the Second World War including naval operations proximate to the Burma Campaign; later Cold War-era activities included surveillance and patrols by navies such as the Royal Navy and United States Navy. The 2004 seismic event produced profound humanitarian and geopolitical responses involving multinational relief coordinated by agencies including the United Nations and regional cooperation through initiatives inspired by lessons from the Indian Ocean tsunami of 2004. Contemporary maritime law, fisheries disputes, and transboundary conservation reflect diplomatic engagement among states and institutions like the Association of Southeast Asian Nations and bilateral commissions.

Category:Seas of the Indian Ocean