Bay of Bengal

Bay of Bengal
Name	Bay of Bengal
Caption	Map of the Bay of Bengal
Location	South Asia and Southeast Asia
Type	Bay
Inflow	Ganges, Brahmaputra River, Meghna River, Irrawaddy River, Godavari River, Mahanadi River, Krishna River, Kaveri River
Basin countries	Bangladesh, India, Indonesia, Myanmar, Sri Lanka
Area	2,172,000 km²
Max-depth	4,694 m
Salinity	Variable, lower in north

Bay of Bengal. It is the northeastern part of the Indian Ocean, bounded on the west and northwest by India, on the north by Bangladesh, and on the east by Myanmar and the Andaman and Nicobar Islands of India. This expansive bay serves as a critical maritime basin, profoundly influencing the climate, ecology, and human civilizations of the surrounding regions through its vast river systems and monsoon dynamics.

Geography

The bay forms a roughly triangular embayment of the Indian Ocean, with its apex pointing south toward Sri Lanka. Its western boundary is defined by the eastern coasts of India, including the Coromandel Coast and regions such as Odisha and Andhra Pradesh. To the east, it is bordered by Myanmar and the long Andaman and Nicobar Islands archipelago, which separates it from the Andaman Sea. Major peninsulas, including the Indian subcontinent itself, shape its contours, while significant offshore features include Sagar Island at the mouth of the Ganges. The Sunderbans, the world's largest mangrove forest, straddles the delta at its northern head.

Hydrology

The bay receives immense freshwater discharge from some of Asia's largest rivers, primarily the Ganges, Brahmaputra River, and Meghna River, which combine to form a massive delta. Other major contributors include the Irrawaddy River from Myanmar, and the Godavari River, Mahanadi River, Krishna River, and Kaveri River from India. This influx creates a pronounced salinity gradient, with lower salinity in the north. Oceanographically, it is influenced by the seasonal reversal of the Indian Ocean monsoon currents, and its deep central basin reaches depths exceeding 4,000 meters, with the floor featuring abyssal plains and the Ninety East Ridge.

Climate

The climate is dominated by the seasonal Indian Ocean monsoon, which brings heavy rainfall to the surrounding coasts from June to September. This system is responsible for the formation of severe weather events, including devastating tropical cyclones such as the 1991 Bangladesh cyclone, Cyclone Nargis, and Cyclone Amphan. These storms often make landfall in vulnerable regions like Bangladesh and Odisha. The bay also plays a crucial role in the broader Asian monsoon system, with its warm sea surface temperatures fueling convective activity that affects weather patterns across the Indian subcontinent and Southeast Asia.

Marine life and ecosystems

The bay supports diverse marine ecosystems, ranging from the vast Sunderbans mangrove forests, a UNESCO World Heritage Site and habitat for the Bengal tiger, to extensive coral reefs around the Andaman and Nicobar Islands. Its waters are rich in phytoplankton due to nutrient-rich river discharge, forming the base of a food web that sustains significant fisheries. Important species include the Irrawaddy dolphin, various species of sea turtle like the Olive ridley sea turtle which nests on the coasts of Odisha, and commercially vital fish such as Hilsa. The Swatch of No Ground is a major submarine canyon that creates a unique marine habitat.

Human history and economy

Historically, the bay has been a cradle of ancient civilizations and a hub for maritime trade since the era of the Chola dynasty, Gupta Empire, and Sriviijaya. It was a central corridor for the Maritime Silk Road, connecting ports like Mamallapuram, Satgaon, and later Colombo. European colonial powers, including the Portuguese Empire, Dutch East India Company, French East India Company, and British East India Company, fiercely contested its waters. Today, it remains vital for international shipping lanes, offshore hydrocarbon exploration, and the economies of coastal nations, with major ports such as Chennai Port, Chittagong, Yangon, and Port of Colombo facilitating global commerce.

Environmental issues

The region faces severe environmental challenges, including widespread plastic pollution and marine debris. Nutrient runoff from agriculture, coupled with industrial effluents from cities like Kolkata and Dhaka, contributes to large seasonal hypoxic zones, often called "dead zones," which threaten marine life. Sea level rise linked to climate change poses an existential threat to low-lying areas like the Ganges Delta and the Sunderbans. Other pressing concerns include overfishing, the degradation of coral reef and mangrove habitats, and the impacts of frequent cyclones exacerbated by warming seas.

Category:Bays of the Indian Ocean Category:Geography of Asia