Monsoon gates made this sea Old World trade’s hinge
The Arabian Sea occupies the northern Indian Ocean between Arabia, Iran, Pakistan, India, and the Horn approaches. Hormuz and Bab-el-Mandeb have linked east–west trade since third-millennium networks, while monsoon winds long rationed when fleets could move. Its deepest point lies 5,395 metres down.
Mid-summer winds haul moisture northeast from African and oceanic sources, soaking Arabian-basin shores. The wider Arabian Sea large marine ecosystem—from Laccadives toward the Red Sea and Persian Gulf—ranks among Earth’s most biologically productive. Modern hubs include India’s Jawaharlal Nehru and Mormugao ports, Pakistan’s Karachi–Qasim–Gwadar cluster, Iran’s Chabahar, and Oman’s Salalah; islands include Socotra, Masirah, and Astola.
Carlsberg Ridge structure bounds parts of this productive basin.
The sea covers about 3,862,000 square kilometres, spans roughly 2,400 kilometres at its widest, and bottoms out at 5,395 metres, its deepest water lying in the Alula-Fartak Trough near the Gulf of Aden. Its two arms are the Gulf of Aden, reaching the Red Sea through Bab-el-Mandeb, and the Gulf of Oman, leading to the Persian Gulf. The Indus is the largest river flowing in, and its sediment built the Indus Fan across a shelf that runs more than 300 kilometres off parts of India, drowned when the last glacial maximum ended.
Systematic mapping of the floor began with the International Indian Ocean Expedition of 1959 and Soviet surveys in the 1960s. French surveyors found the Falaj Valley off Oman in 2009, an undersea valley 81 kilometres wide named for the country's old irrigation channels, while the De Covilhăo Trough, discovered in 1930, sinks past 4,400 metres. Seven largely seasonal ocean fronts divide the water, with temperature contrasts topping 5 °C in places. Yemen has the longest shoreline, about 1,640 kilometres including the Gulf of Aden.
Source: Arabian Sea
