A shallow inland sea hinges on the Strait of Hormuz
The Persian Gulf—also called the Arabian Gulf—is a West Asian mediterranean sea between the Arabian Peninsula and Iran, tied to the Indian Ocean through the Strait of Hormuz. About 251,000 square kilometres in area and 989 kilometres long, it averages only some 50 metres deep and maxes out near 90 metres.
Iran holds most of the northern shore and Saudi Arabia most of the southern; at Hormuz the gap narrows to about 56 kilometres. The Shatt al-Arab, called Arvand Rud in Iran, delivers Tigris and Euphrates water at the north-western end. Going clockwise, the coasts belong to Iran, Oman’s Musandam exclave, the UAE, Saudi Arabia, Qatar, Bahrain, Kuwait and Iraq. The International Hydrographic Organization draws the southern limit on a line from Ràs Limah in Arabia to Ràs al Kuh in Iran.
The basin is Cenozoic in age, linked to the Arabian plate sliding beneath the Zagros, and the sea began refilling about 15,000 years ago as Holocene waters rose. Fishing grounds, rocky and coral reefs and pearl oysters define its ecology, though industry and oil spills have harmed it.
Qeshm, an Iranian island inside the Strait of Hormuz, is the largest in the gulf; others include Greater and Lesser Tunb and Kish under Iran, Bubiyan under Kuwait, Tarout under Saudi Arabia and Dalma under the UAE, while Bahrain is itself an island state. Portuguese and British powers once used such islands for trade and empire, and developers have lately added artificial ones like Dubai’s World Islands and Doha’s Pearl.
Rivers from Iran and Iraq contribute an estimated 2,000 cubic metres per second, and Qeshm sees only about 180 millimetres of rain a year, so fierce evaporation leaves a shortfall near 416 cubic kilometres annually. The Indian Ocean makes it up: saltier, denser gulf water drains out along the bottom of the strait while fresher ocean water pours in over the top. One study put yearly evaporation at 1.84 metres of water depth against just 0.08 metres of rain.
Source: Persian Gulf
