Iraqi coastal waters boast a living coral reef, covering an area of 28 km2 in the Persian Gulf, at the mouth of the Shatt al-Arab river (29°37′00″N 048°48′00″W﻿ / ﻿29.61667°N 48.80000°W﻿ / 29.61667; -48.80000).[9] The coral reef was discovered by joint Iraqi–German expeditions of scientific scuba divers carried out in September 2012 and in May 2013.[9] Prior to its discovery, it was believed that Iraq lacks coral reefs as the local turbid waters prevented the detection of the potential presence of local coral reefs. Iraqi corals were found to be adapted to one of the most extreme coral-bearing environments in the world, as the seawater temperature in this area ranges between 14 and 34 °C.[9] The reef harbours several living stone corals, octocorals, ophiuroids and bivalves.[9] There are also silica-containing demosponges.[9]