Joint expeditions performed by scientific scuba divers from MSC Basrah (Iraq) and SDC Freiberg (Germany) carried out in September 2012 and in May 2013, revealed the existence of a true live coral reef in Iraqi coastal waters for the first time ever.

The Iraqi coast at the northern end of the Persian Gulf is dominated by the large swampy river delta of the rivers Euphrates, Tigris and Karun, merging into the Shatt al-Arab that represents the main outflow in the Arabian/Persian Gulf.

The Shatt al-Arab, the only continuous freshwater source in the region, causes salinities to decrease in the extreme north to about 36‰ in summer. Underwater visibility is often limited to 1 m or less.

Sediment particles are distributed throughout the Gulf by strong winds and currents generated during winter. The seasonally varying turbidity near the delta and along part of the Iranian coast is the reason for the hypothesized absence of coral reefs in this region.

Furthermore, it is accepted that the Coriolis effect deflects the Shatt al-Arab river plume towards Kuwait and suppresses reef growth there.

Different type of reef

This newly discovered coral reef differs from counterparts established in adjacent Kuwait. In fact, the reefs in Kuwait are fringing reefs distributed around islands9, or close to the coast at water depths between 0–10 m.

These reefs are settled on sandy ground in relatively transparent water. The newly discovered reef at the mouth of the Shatt al-Arab is located at greater depths in a zone of low visibility, and rapidly changing conditions (temperature and salinity) due to strong currents.

These currents are triggered by tides and the significant freshwater sediment-loaded discharge by the Shatt el-Arab