​​ Coral reefs are kind of a canary in the coal mine for climate change -- Brian Tissot, Ph.D., professor, Humboldt State University

It's not hard to spot the signs of climate change: rising sea levels, shrinking polar ice caps and warmer winters, to name just a few. One that's lesser known, but gaining more attention: the widespread bleaching of coral reefs.

Several CSU campuses are currently studying this phenomenon and the potentially permanent damage climate change is wreaking on these fragile environments.

"Coral reefs are kind of a canary in the coal mine for climate change," says Brian Tissot, Ph.D., professor of conservation biology at Humboldt State University and director of the Humboldt Marine and Coastal Science Institute.

Dr. Tissot, an alum of California Polytechnic State University, San Luis Obispo, has focused much of the past 20 years on studying the population of yellow tang, a type of fish highly sought after in aquariums, off the west coast of the island of Hawaii. He has also conducted research in Micronesia, Indonesia and the Philippines, and says that over the years he's seen noticeable changes in the coral reefs as a result of climate change.

"Hawaii in particular this last year was really bad," says Tissot. "It was super warm and the coral was starting to bleach. This year was probably the biggest year they've ever seen in terms of bleaching."

What is Bleaching?

Bleaching occurs when coral reefs lose their algae—their food source—often as a result of water temperatures rising beyond sustainable levels. The result: Coral reef structures change from vibrant colors to a stark, ghostly white.

If the problem persists, the coral ecosystem—often several thousands of years old—dies.

"Over the next century, coral bleaching could kill large areas of coral reef throughout the world and, and [at] the very least, probably will be a key process resulting in changes in coral species," warned a 2007 study from California State University, Northridge.

To illustrate the effects of bleaching, watch this time-lapse video from Queensland University of Technology of mushroom coral violently expelling its algae :


The process, called pulsed inflation, happens when the coral expels the algae, turns white, and then faces starvation. Scientists worry that entire coral reef ecosystems, including massive portions of the Great Barrier Reef, may never recover once this process occurs.

How the CSU Works to Save Coral Reefs

Over the years, Dr. Tissot has taken a number of Humboldt State graduate students to Hawaii to join his yellow tang studies. Both graduate and undergraduate students at Northridge have studied the coral reefs of French Polynesia and also partner with research facilities in Oahu, Japan and France.

San Diego State University is home to the Coastal and Marine Institute (CMI), which brings students together with researchers and visiting scientists to examine important environmental issues. Earlier this year, SDSU researchers published findings that highlight the ways in which coral reefs are affected by an overabundance of algae, another common problem caused by pollution and climate change.

California State University, Monterey Bay has conducted research on the topic as well. Recent expeditions took students to Pulley Ridge, a series of islands off Florida believed to be the deepest coral reef in U.S. waters, as well as to the nearby Carmel Canyon and the Ulithi Atoll in Micronesia.

What's Next?

The hope, of course, is that research efforts like these will help save fragile reefs around the world before it's too late.

And, happily, the news is not all dire. One Northridge project looked at why some types of coral suffer while others thrive.

Monterey Bay researchers have found evidence that coral reefs are extremely adaptable, and in fact may be able to adjust to higher temperatures. An updated analysis "suggests that corals may have already responded adaptively to some warming over the industrial period," wrote Cheryl Logan, Ph.D., assistant professor in the School of Natural Sciences and lead author of a Monterey Bay study.

Tissot continues to collect a wide range of data about the effects of people on marine ecosystems. In particular, he examines the aquarium trade and how establishing Marine Protected Areas (MPAs) in Hawaii are helping fish populations recover.

"It's all relevant to California because there are similar areas here," he says. In fact, there are 124 MPAs spanning 851 square miles up and down the entire coast of California, much of it home to coral reefs.

With luck, ongoing research at the CSU and beyond into the effects of climate change will help reefs in California and across the globe find new life.​