SOUTHAMPTON scientists have discovered the key reason coral reefs can be devastated by bleaching, in findings that could have major implications for marine conservation.

An imbalance of nutrients in reef waters can stop vital algae from surviving on coral, leaving them appearing white and at risk of dying, with major effects on ecosystems.

Researchers from the University of Southampton and the National Oceanography Centre, Southampton, have discovered high water temperatures block the algae from being able to complete photosynthesis.

The algae and coral depend on each other for survival and Dr Jörg Wiedenmann, senior lecturer of Biological Oceanography at the university and head of the Coral Reef Laboratory, said the results could be important for the future design of marine reserves.