Scientists discover how corals fight diseases and bleaching

Australian researchers have achieved a breakthrough in understanding the immune system of coral reefs.

Caroline Palmer, Bette Willis and John Bythell, scientists from the Australian Research Council Centre of Excellence for Coral Reef Studies, James Cook University (Queensland) and Newcastle University (UK) conducted the experiment.

"Potentially, this will enable us to more accurately predict the vulnerability of coral reefs to disease and bleaching, before there are obvious signs of stress," said Palmer.

"Variation in levels of immune function among different species is likely dependent on the energy they assign to it. As energy is vital for an effective immune response, corals that utilise energy to grow and reproduce rapidly have less to spare for their immune response," she added.

Corals like the staghorns and Acropora are most vulnerable to temperature stress or disease.

The coral immune system is mainly protected by melanin, which may also be used to stop harmful UV light from reaching the symbiotic algae and causing bleaching.

"Our increased understanding of coral immune systems may therefore be used to address the causes rather than the symptoms of coral declines", said Palmer.

Two of the main factors that cause corals to bleach are attacks by disease-causing microbes and temperature stress.

The preventive measures envisioned involve minimising human impacts which might further injure the coral, such as dredging, building construction, pollution, land runoff or damaging corals by boat activity or fishing.

The paper was published in the June issue of The FASEB Journal.