Close to 30 years ago, the Voyager 1 space probe took a photograph of planet Earth from about 6 billion kilometers away. Earth, and every living being on it, was reduced to nothing more than a Pale Blue Dot.
The Dot, however, is made up of 71% water, 96.5% of which is made up of the oceans. And, among all the things the space probe reduced to a single, pale blue dot, is the largest living thing in the world—the Great Barrier Reef. A major bucket list contender, the Great Barrier Reef has more recently been listed as dying, its terminal stages now documented from outer space (see image below). The Reef, approximated as 500,000 years old, is feeling the impacts of spikes in water temperature as a result of human activity, particularly greenhouse gas emissions, warm the Earth and its waters. When we burn oil, coal, and gas, the Earth and its oceans are heated, which in turn disturb the climate underwater, depriving coral of their vital food source, algae. Notably, bleached coral can last for up to six weeks, allowing some coral to recover, should there be a drop-in temperature. However, severely bleached coral will die off. Greenpeace reports, “coral bleaching is reaching epidemic levels”.
The Dot also houses several great blue holes that extend hundreds of feet below sea level. Many of these holes are marine caverns that provide access to underwater cave passages, form sinkholes, and house mysterious creatures. More recently, a “mysterious blue hole” was discovered within the Great Barrier Reef. The largest hole, however, is the Great Blue Hole, a large underwater sinkhole off the coast of Belize. Lying near the center of Lighthouse Reef, the Great Blue Hole is part of the Barrier Reef Reserve System, one of 62 of the United Nations Educational, Scientific and Cultural Organization’s (UNESCO) World Heritage Sites under threat due to climate change.
So, what exactly lives in the depths of blue holes like that of the Great Barrier Reef and Belize? Among a variety of sharks, sea turtles, and rays, the blue hole is home to “a world of swimming colour”—parrotfish, butterfly fish, and angelfish live and feed harmoniously among the coral reefs. But what makes the Great Blue Hole, a part of the Barrier Reef Reserve System, any different from the Great Barrier Reef? Unlike coral bleaching occurring elsewhere, coral colonies in blue holes are still healthy! A closer look at the Great Barrier Reef and Belize’s blue holes, provide various explanations for why coral in the holes are thriving.
The Great Barrier Reefs hole is positioned in the middle of the dying coral reef, which has otherwise become the poster child for coral bleaching. So how does the coral within the hole still thrive, while all surrounding coral are responding to the rising water temperatures? The hole’s position within the walls of the lagoon have protected the coral for decades. The coral, which showed no signs of damage from 2017’s category 4 Cyclone Debbie, could thus help other parts of the Great Barrier Reef regenerate.
In Belize, a restoration project was launched, where 90,000 corals grown in nurseries were planted in shallow reefs, increasing coral by 35%. This success is directly linked to a grassroots movement by united fisherman, tour guides, and environmentalists who are working to conserve the 700-mile Barrier Reef Reserve System.
In an effort to block the sun’s rays and protect coral from bleaching, scientists are developing a cling film that is 50,000 times thinner than the average human hair. This film, which is meant to sit on the surface of the water directly above coral, is a biodegradable shield that contains the same ingredients corals use in making their skeletons—calcium carbonate. In trials, the film has reduced light reaching multiple different coral types by upwards of 30%. Although the project still requires further testing, the development is an exciting step towards protecting the coral in our waters.
You can help in your own way, too! The Great Barrier Reef and the waters of our world are under major threat from plastic pollution and run-off waste. Check out the tip-sheet below from the National Oceanic and Atmospheric Administration to discover ten ways to protect coral reefs and let us know what underwater sites you are most excited to explore!
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