Coral reefs not only provide the world with rich, productive ecosystems and photogenic undersea settings, they also contribute an economic boost valued at hundreds of billions of dollars. But their decline in recent years due to a variety of threatsfrom pollution to climate warminghas lent urgency to the search for new ways to evaluate their health.
A new study by Scripps Institution of Oceanography at UC San Diego scientists has revealed that fluorescence, the dazzling but poorly understood light produced by corals, can be an effective tool for gauging their health.
As described in the March 12 edition of Scientific Reports (a publication of the Nature Publishing Group), marine biologists Melissa Roth and Dimitri Deheyn describe groundbreaking research using fluorescence to test coral stress prompted from cold and heat exposures.
In experimental studies conducted at Scripps, Roth and Deheyn tested the common Indo-Pacific reef-building branching coral Acropora yongei under various temperatures. Branching corals are susceptible to temperature stress and often one of the first to show signs of distress on a reef. Roth and Deheyn found, at the induction of both cold and heat stress, corals rapidly display a decline in fluorescence levels. If the corals are able to adapt to the new conditions, such as to the cold settings in the experiment, then the fluorescence returns to normal levels upon acclimation.
While the corals recovered from cold stress, the heat-treated corals eventually bleached and remained so until the conclusion of the experiment. Coral bleaching, the loss of tiny symbiotic algae that are critical for coral survival, is a primary threat to coral reefs and has been increasing in severity and scale due to climate change. In this study, the very onset of bleaching caused fluorescence to spike to levels that remained high until the end of the experiment. The researchers noted that the initial spike was caused b
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University of California - San Diego