Coral Reefs
More information on Branching Corals.
Introduction
Bu Tinah’s coral reefs are not only beautiful, but are surviving the highest temperature fluctuations known to any corals in the world!
Acropora downingi Wallace, 1999
Acropora downingi is one of the more common branching corals encountered in Abu Dhabi waters. A. downingi colonies are like tables of horizontal radiating branches which become fused at the centre of large colonies. The color is usually brown, grey or green, often with pale margins. They occur in the shallow margins of fringing reefs.
A. downingi has a relatively restricted distribution and is common. This species occurs in the Red Sea and the Gulf of Aden, the north-west Indian Ocean and the Arabian Gulf.
Coral reefs are known as the rainforests of the sea because they are home to more than 25 percent of all marine life. They are among the oldest, most fragile and most diverse ecosystems in the world. They provide food and shelter to a variety of marine organisms. Despite what some may think, corals are neither plants nor rocks, but are in fact small live animals that are embedded in calcium carbonate.
Corals consist of several individual animals called polyps that form colonies. Coral reef survival largely depends on their symbiotic relationship with microscopic algae known as zooxanthellae. The zooxanthellae undergo photosynthesis and provide nutrients to the corals.
Under stressful conditions, the corals tend to lose their zooxanthellae and this results in what is known as coral bleaching, due to the loss of color of the coral. Coral bleaching may eventually lead to death of the coral if the stressful conditions are prolonged.
Globally, coral reefs have suffered as a result of mass bleaching events due to temperature anomalies. Examples of these temperature anomalies include the increase in sea surface temperatures in 1996, 1998 and again in 2006 where coral reefs around the world suffered from mass bleaching and mortality. However, many reefs have begun to show signs of recovery. Temperature anomaly events are expected to occur with increasing frequency as a result of global warming and climate change.
The coral reefs of Bu Tinah, also suffered from mass mortalities that occurred when sea temperatures remained above average for a prolonged period, however, these reefs have shown high resilience and capacity to cope under extreme conditions. It is possible that the coral reefs on Bu Tinah and the UAE are going through adaptive processes by which they are increasing their thermal tolerance levels. The corals here are unique in that they are surviving the highest temperature fluctuations known to any corals with greater than 20oC variation annually.
Classified as Least Concern (LC) on the IUCN Red List and listed on Appendix II of CITES.
