Temperature Rise Over 50 Years More Dangerous Than It Sounds, Increase in Coral Bleaching Triggered by Heat

Sophia Ottoni-Wilhelm, Contributing Writer

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Climate data for 2014 reveal it was the warmest year in recorded history, with 1998 coming in at a close second. While it may not seem particularly consequential in the midst of a never-ending Oberlin winter, changes in global temperature are incredibly impactful to our planet. Geologists predict a 2 degrees Celsius increase in the Earth’s climate over the next 50 to 100 years, while environmentalists contend that this jump may occur in as few as 10. Regardless, the change puts our planet at risk.

Entire ecosystems, in particular coral reefs, face the possibility of extinction should the ocean become even slightly warmer. Reefs house anywhere from hundreds to thousands of diverse species, providing them with all the nutrition, shelter and safe nesting areas they need to thrive. Coral structures are living animals with plants growing within. These plants house zooxanthellae — little photosynthetic algae that live on shallow, warm parts of the ocean floor, where there’s close access to the sunlight they use to generate 90 percent of the reef ’s metabolic needs.

When reefs experience stress, either in the form of temperature changes or nutrient loss caused by pollution, they expel their zooxanthellae, leaving the remaining plant tissue without a source of nourishment. Without the usual intake of amino acids, glucose and glycerol, reefs can develop white patches and eventually die — a phenomenon known as coral bleaching. In 1998, the second hottest year in recorded history, coral bleaching occurred in reefs in 60 countries and island nations around the world. Corals in the Indian Ocean were especially hard-hit, with researchers on the Maldives and Andaman islands reporting that 70 percent of their reefs died in the year following the temperature spike. Nearly two decades later, many of the reefs affected have yet to show any sign of regrowth.

Yes, coral reefs can recover from bleaching and disease. Unfortunately, recovery is dependent on environmental stressors that probably will not be relieved as the global economy continues to tax the atmosphere and planet with ever-increasing ferocity.

College senior and Geology major Rachel Zuckerman is studying coral reefs for her honors thesis. She explained, “Globally, corals are producing half as much as they were in the ’70s. This can be attributed to increased sediment and nutrient input from land, ocean circulation and acidification, predominantly manmade processes. Reef systems have a dynamic geochemical process sensitive to temperature and chemical gradients. As our climate changes, we see these corals respond with bleaching, other forms of disease and death or decreased growth rates.”

Many geologists believe that last year’s temperature hike could prove more catastrophic to reef health than that of 1998. Already this year warm water has been hitting reefs in the southern Pacific and Indian Oceans. In a Dec. 19, 2014 interview with The Guardian titled “Major Coral Bleaching in Pacific May Become Worst Die-Off in 20 Years, Say Experts,” Professor Ove Hoegh-Guldberg, a coral reef specialist from the University of Queensland, said, “Many coral reef scientists are expecting something similar to 1997–98 to unfold in the next six to twelve months.” Coordinator of the Coral Reef Watch Dr. Mark Eakin added, “[Due to the circulatory wind pattern] El Niño, bleaching could continue until 2016 — lasting twice as long as the 1998 event.”

As coral reefs die out, humans lose a great deal of the natural shoreline protection provided by their structures and are left vulnerable to wave erosion and storm damage. Additionally, reefs provide livelihood and food for communities living nearby and have even played a role in the evolution of modern medicine. The National Oceanic and Atmospheric Administration reported, “Coral reef plants and animals are important sources of new medicines being developed to treat cancer, arthritis, human bacterial infections, Alzheimer’s disease, heart disease, viruses and other diseases.” Perhaps most importantly, coral reefs sequester CO2.

According to the U.S. Geological Survey, “Before human-caused CO2 emissions began, the natural processes that make up the global ‘carbon cycle’ maintained a near balance between the uptake of CO2 and its release back to the atmosphere.” Coral reefs naturally sequester CO2 and, as they die out, the carbon cycle becomes unbalanced.

Educate yourself and others in your life about the dangerous effects climate change has on coral reefs and other vital ecosystems. Write to your politicians at a local and state level to ask them to consider investing in research, prevention and treatment plans for reefs before we lose them all for good.

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