What is Coral Bleaching?

Understanding coral bleaching is the key to preventing it, stopping it when it occurs, and knowing why it is bad for our oceans. Certain conditions can cause the living beings in the ocean to become damaged or die. The best thing we can do is to educate ourselves on how it is happening and why it is so bad for our undersea creatures. When coral becomes unhealthy so can many other things that are underwater. Learn more about coral bleaching why it can be so distressing and harmful to underwater life.

What is a Coral?

A coral is an animal that creates a calcium carbonate skeleton that looks much like a rock and has a symbiotic relationship with single cell algae known as zooxanthellae. This lives inside the soft tissue of the coral and uses sunlight to help produce the food through photosynthesis. It also provides the corals with food to eat and gives back zooxanthellae with nutrients as well as shelter. Corals get their color from tiny algae that live in their tissues.

Corals also have the ability to capture food. When it is dark, they stretch out their tentacles to catch small organisms that float around in the water and digest them. Corals have two different ways in which to capture food, through small organisms and zooxanthellae. When you have really hot summers, you can expect the corals to get stressed, and it is more likely that bleaching will occur.

Corals live in warm shallow water where they receive plenty of sunlight. While corals can be found in many places across Pacific Ocean, there are plenty of other places around the world like Indian Ocean, Caribbean Sea, Red Sea, and Arabian Gulf where corals can be found.

Coral is a very beautiful and unusual animal. Each coral head consists of thousand of individual polyps. These polyps are continually budding and branching into genetically identical neighbors.
– Antony Garrett Lisi

What is Coral Bleaching?

  • Coral and algae depend on each other to survive. Corals have symbiotic relationship with microscopic algae called zooxanthellae that live in their tissues. These algae are coral’s primary source of food and give them their color.
  • When temperatures in the ocean become too warm due to temperature, nutrients, and light, it causes the corals to get stressed. When this happens, the algae leaves the coral’s tissue.
  • When the algae leaves the coral’s tissue, it causes the coral in the ocean to turn completely white by expelling symbiotic algae that lives inside them. This happens when the temperature is at approximately 104 degrees.
  • When conditions change, the corals become stressed which causes them to turn white, leaving them extremely vulnerable. Without the algae the coral loses its major source of food, turns white and is more susceptible to disease.
  • Coral reef bleaching is the whitening of the invertebrate taxa which causes it to change it pigment which can cause issues for other coral and other underwater creatures in the ocean.
  • When coral bleaching happens, this does not mean that they are dead. Corals can survive a bleaching event but they are under more stress than ever before.
  • According to NOAA, In 2005, the U.S. lost half of its coral reefs in the Caribbean in one year due to a massive bleaching event.
  • There are currently more than 400 species of coral reef in Great Barrier Reef alone.

Causes of Coral Bleaching

  • Elevated temperatures due to climate change are typically what causes coral bleaching to happen. When El Nino occurs, this is when the temperatures in the water rise the most, causing problems for corals and underwater life.
  • Extra bright sunlight can cause water to become overly warm and cause coral to whiten.
  • Disease in the coral or in the water can cause coral to turn white.
  • Water pollution that comes from agricultural and urban run-off.
  • When the levels of saltiness and salinity in the sea water change, this can also cause the coral to turn white.
  • Sedimentation that occurs when activities that occur under the sea such as dredging occur.

Other Trigger Factors

  • The starvation of oxygen due to the rise in zooplankton that is often causes by fishing in ocean waters.
  • Too much solar radiance getting into the water which causes too much ultraviolet light.
  • Acidification in the water or significant changes in the chemistry of the water. Some of the chemicals that can get into the water are industrial waste, farm run off, and chemicals that come into the water through water and sewage treatment facilities. There is not proper enforcement when it comes to industrial waste which causes extreme concern for environmentally-conscious experts.
  • Too much sedimentation
  • Infections caused by bacteria.
  • The levels of salinity in the water.
  • Herbicides
  • Low tide exposure
  • Cyanide fishing
  • Global warming which is what causes the elevated sea levels.
  • African dust storms that are caused by drought and create mineral dust.
  • Ingredients that belong in sunscreens that do not biodegrade and come off of tourists when they are diving, swimming, or snorkeling.

Global Warming

  • Global warming is one of the major causes of coral reef bleaching in the ocean. The changes in the weather directly impact the temperature of the water which ultimately causes more issues for the creatures living below the water.
  • It has also caused farms, cities, and forests to see a significant increase in diseases that come primarily from mosquitos.
  • Disruption of certain habitats such as alpine meadows and coral reefs could leave many animal and plant species extinct.
  • When the sea surface becomes warmer then this will causes more hurricanes in the Gulf and Atlantic coasts.
  • When the sea levels begin to rise then there very well could be coastal floods along the Eastern seaboard and in the Gulf of Mexico.
  • Global warming can also cause glaciers to melt and cause severe droughts in areas that need the rain water the most.

Why Coral Bleaching is so Bad?

  • Corals receive their bright colors from the algae inside of their tissues. These organisms live in sync with the coral underwater animals and share resources with them. Algae provides food for the corals and if the algae becomes sour then the corals cannot survive. This is what causes them to become bleached on the outside.
  • If the algae does not reabsorb in a reasonable amount of time then the coral will die. They cannot survive without one another. As climate change continues, corals will be placed under more stress.
  • Reefs make up about 1 percent of the Earth’s undersea ecosystems but most people are unaware of just how important they are for undersea life.
  • Coral reefs currently shelter more than 25 percent of the marine species under water.
  • Corals also help to protect shorelines as well as support fishing industries.
  • The beautiful colors of the coral reef bring travelers from all over the world to come and see them. If people aren’t coming to see them then this takes away quite a bit of tourist money coming into these areas.
  • People also underestimate the possibilities that come with coral reefs. They could be a medical breakthrough waiting to happen.
  • Overall, damaged coral reef is a huge blow to not only the creatures under the sea, but the people on dry land as well.
  • Dead coral then becomes covered with various different types of algae and has the ability to cause a change in species of fish and a number of other animals living in the reef.
  • This will soon be what causes the underwater animals and creatures to then become extinct.

How Can We Stop Coral Bleaching?

  • Take a walk, bike, or public transportation instead of driving. This eliminates many of the pollutants that get into the air and cause oceans to overheat.
  • Support tree conservation and plant a tree at a local park or outside of your home. Trees create more oxygen which in turn reduces agricultural run-off that usually ends up down in the ocean.
  • Talk to your local legislators and government officials. Make sure that they are aware that you are supportive of climate legislation.

Coral bleaching is a serious issue that often goes ignored by local and national governments and legislatures. The potential of consistent global warming that causes the water to become overheated, has severe negative impacts on the underwater creatures trying to thrive in the ocean. It is not something that can be ignored.

Causing less air pollution will help the situation in the long run but something needs to be done about it now. Every single step you take to prevent this from happening now and in the future is a step to bettering our environment and our sea creatures. Let’s keep our sea creatures alive and keep our air healthy on dry land.

Image credit: US Geological Survey , SarahDepper
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About Rinkesh

A true environmentalist by heart ❤️. Founded Conserve Energy Future with the sole motto of providing helpful information related to our rapidly depleting environment. Unless you strongly believe in Elon Musk‘s idea of making Mars as another habitable planet, do remember that there really is no 'Planet B' in this whole universe.