Coral Fluorescence a Strong Indicator of Coral Health

The most diverse and beautiful feature of all marine habitats are the coral reefs, which are the foundation of many marine ecosystems. But these underwater structures are in danger due to coral bleaching. A great decline was noticed in the coral reefs due to threats from pollution and climate warming. These coral reefs are getting help from scientists who are looking for new ways to evaluate their health.

Marine biologists Melissa Roth and Dimitri Deheyn at the Scripps Institution of Oceanography at UC San Diego, claim that fluorescence is a poorly understood light phenomenon that is displayed by the corals as an effective tool in monitoring the coral's health. With the help of fluorescence, they will test the coral stress that is triggered due its exposure to different temperatures.

For this study, the scientists tested the levels of fluorescence and fluorescent proteins in the common branching coral from the Indo Pacific region known as Acropora Yongei. They subjected this coral to both heat and cold stress.

They noticed a decline in the fluorescence level the moment the corals were inducted with both cold and heat stress. They also noticed that the onset of bleaching was the main reason for the fluorescence to spike to a high level and this high level was maintained till the end of the experiment.

"This is the first study to quantify fluorescence before, during, and after stress," Deheyn said in a press statement. "Through these results we have demonstrated that changes in coral fluorescence can be a good proxy for coral health."

Corals produce fluorescence through green fluorescent proteins, but not much is known about the function of this emitted light. The scientists predict that fluorescence protects against the damaging sunlight or is used as a biochemical defense that is produced at the time of stress.

The study is described in the March 12 edition of Scientific Reports.