Coral Bleaching

Coral reefs are home to countless sea beings that contribute to the health of the ocean and affect our economy. But corals are becoming bleached to a bone-white color across the world, and it's happening quickly.


what it is

Coral bleaching is the appearance of our coral reefs turning a white color as though it were bleached. The reason corals are so colorful to begin with is actually not from the coral itself, but the tiny little algae called zooxanthellae that lives in the tissue of the coral that radiates its beauty. This algae and the coral are a real romantic symbiotic relationship. The coral offers themselves as a home to the zooxanthellae and in turn, the algae cooks the coral dinner of carbohydrates as food derived from photosynthesis. Now, certain conditions can stress the coral out and when this happens, the algae takes its leave. No algae means no color and thus, they appear white, or bleached, due to their transparency that reveals their skeletons. This does not yet mean that the coral are dead, but it does mean that they are extremely susceptible to disease and will die very, very soon.

The conditions of which that stress the coral out are caused by: changes in temperature, long sun exposure, chemical pollutants, and extremely low tides that expose the coral. Coral reefs are found throughout the world in both tropical and subtropical regions, but the Great Barrier Reef off the northeastern coast of Australia is the largest and most spectacular; stretching 2,300 kilometers long. One of the great things that the ocean does for Earth is it absorbs heat from the atmosphere. However, this mean that the water's temperature also rises, which stresses the corals worldwide. Global warming, combined with El Niño and pollutants from runoff of agricultural and industrial industries, are the main contributing factors for coral bleaching. In the Great Barrier Reef, for example, 93% of the coral are experiencing bleaching- half of the world's coral reefs have died in just the last 30-50 years and 32% more are on the verge. In 30 years, more than 90% of the world's coral reefs will be gone, if not completely. 

The value of coral reefs

Ironically enough, coral reefs only cover less than one percent of the Earth's surface (less than 2% of the ocean bottom), and yet they are home to 25% of all marine beings! Because of this statistic, they are known as the "rainforests of the sea". Economically, they generate a value of $172 billion to the world per year due to their contributions to our food and raw materials, regulation of extreme ocean events, water purification, recreation, tourism,  and the maintenance of oceanic biodiversity. Coral reefs also act as a buffer for shorelines against waves, storms, and floods that could otherwise devastate communities. And they provide us some of the oxygen we breath.

Corals are related to jellyfish and can structurally look very similar; a polyp-like shape with an opening on one end and stinging tentacles. Their tentacles use stinging cells called nematocysts that allow the coral to capture small beings that swim too close, and then they utilize their digestive tissue. The difference between corals and jellyfish are a mineral skeleton that the corals posses. There are over 2,500 kinds of corals with varying shapes and structures. And corals not only rely on their algae, but other beings for survival. For example, some of them are home to crab and shrimp that defend the corals by using their pincers. Coral reefs are the cities of the ocean, containing the hustle and bustle of a multitude of life.


What can be done

Unfortunately, the only way to conserve our coral reefs is to stop using as much of our fossil fuels that contribute to global warming and thus, oceanic warming. Many coastal industries and factories are monitoring their effluent to ensure it does not find its way to the sea or does not contain any pollutants that could harm the coral reefs. Hawai'i went a step further and banned certain sunscreens that contain oxybenzone and octinoxate that hurts the corals. The type of sunscreen that is still safe to use is the kind that doesn't go invisible once rubbed in. Many scientists, however, say this doesn't really save coral reefs as much as mitigating global warming, overfishing, and pollution would and legal emphasis should be concentrated on those issues. But regardless of how little it helps, it's at least going in the right direction! And many areas have shut down tourism access to their coral reefs to prevent any more stress or pollution.

Another effective way to help save coral reefs is simply by spreading awareness. And that's exactly what two mermaids are doing at the Aquarium of Western Australia. They swim around wearing 33-pound silicone tails and biodegradable glitter; educating children about ocean health and how to save coral reefs from disappearing. They believe that adults sometimes care and sometimes don't- but children usually always do, and they'll remember it. Especially if it comes from a mermaid!