Coral reefs of the Andaman Sea - An integrated perspective

The Andaman Sea lies on the eastern edge of the Indian Ocean, bordered to the west by an arc of islands stretching from northern Sumatra to the Irrawaddy delta. Fringing reefs are abundant in the Andaman and Nicobar Islands (India), Mergui Archipelago (Myanmar), west coasts of Thailand and Malaysia and northwest Sumatra (Indonesia). Most have never been visited by scientists because of political constraints; consequently the region is one of the least studied coral reef areas in the world. Many inshore reefs are intertidal and occur in turbid settings, while offshore reefs exist in clearer waters. Regardless of physical rigours, reefs generally display high cover and high coral diversity. The Andaman Sea has a complex geological history, a varied seafloor topography, a highly dynamic oceanography and a large tidal range (2-5 m) coupled with periodic sea-level depressions. It is also a major sink for sediments from the Irrawaddy, the world's fifth largest river in terms of suspended sediment load. Human-made influences are limited; sedimentation from land reclamation and dredging are a principal negative factor though rising sea temperatures present a major threat. Natural damage results from aerial exposure on low tides, negative sea-level anomalies, earthquakes and tsunamis. The dynamic nature of the Andaman Sea and the in-built stress resistance of many shallow water corals could result in the region being an important 'refuge' during an era of global warming.