5 Main Causes of Coral Reef Destruction

5 Main Causes of Coral Reef Destruction

Coral reefs aren’t just beautiful underwater fixtures that make the ocean more colorful and vibrant—they’re integral to the survival of many species of marine life. Widely known as the “rainforests of the sea,” coral reefs are home to around 25 percent of the ocean’s fish and other organisms, which is why their health is key to a robust and self-sufficient marine ecosystem.

As coastal construction increases and global temperatures rise, an estimated 33 percent of corals are now in danger of extinction. Marine studies have also shown an 80 percent decline in some forms of coral over the last decade, and thanks to climate change and certain destructive human practices, it’s showing no signs of stopping any time soon.

What is Coral Reef Destruction?

Coral reef destruction is defined as the degradation (and potential mass death) of the ocean’s corals. It is normally caused by illegal fishing techniques, pollution, careless tourism, other natural phenomena such as earthquakes and hurricanes, and of course, climate change—the culprit responsible for our warmer oceans and the main reason (according to experts) behind the death of nearly half of the Great Barrier Reef’s corals.

Corals are living organisms—they can get sick and die, just like any other plant or animal. Due to a variety of local and global factors, which can be either independent or interacting, more and more of the world’s reefs are dying.

What are the Main Causes of Coral Reef Destruction?

empty soda can polluting colorful coral reef

The extinction of coral reefs can be particularly devastating for certain areas of the world that depend on them for their livelihood (through tourism or fisheries) or as their primary food source. But even if you don’t live in any of these areas, coral reef destruction affects you, too. While it may not seem like it, we humans rely heavily on coral reefs (whether we know it or not) for food and other crucial resources.

The blatant and rapid destruction of coral reefs is no longer something we can continue to downplay or ignore, and the first step to knowing how to solve this global problem is by knowing what the main causes are. Coral reef destruction can be preventable, but awareness on a massive scale is necessary to implement changes that will be long lasting.

Reef Bleaching

bleached coral reef

Reef bleaching occurs when extreme water conditions cause corals to expel the internal microorganisms that give them their vibrant colors. Bleaching events are attributed to a number of factors, including pollution and extreme low tide, but the most common (and widespread) is the change in water temperature thanks to global warming. As the planet heats up, water temperatures tend to rise as well.

Thankfully, bleached corals are technically not dead yet. Coral reefs have been known to recover from a bleaching event, particularly when water temperatures cool during winter. However, when corals are in this state, they do become more vulnerable to disease and possible death, especially if they are continuously subjected to stress.

Poison or Dynamite Fishing

coral reef destruction caused by bomb fishing in Indonesia

It is unfortunately common practice to use cyanide and other poisons to fish for coral reef dwelling creatures. The poison is not specific enough to necessarily kill a specific fish, but is used to stun fish that are then used in domestic saltwater aquariums. Although many fish can metabolize the cyanide and will only feel the effects temporarily, the same is not true for coral polyps. When cyanide gets in the nooks and crannies of the reef, the coral often dies in the cloud of poison.

In Southeast Asian countries, including the Philippines and Indonesia, dynamite or blast fishing is still commonly practiced. As the name suggests, this is when fishermen use explosives—usually crude and homemade ones—to make it easier for them to catch more fish.

Water Pollution

Water pollution caused by oil

Water pollution is perhaps the most obvious cause of coral reef destruction. Reefs are harmed when oil, fertilizer, and human or animal waste are dumped in the area. These elements can end up changing the chemical makeup of the water, but the waste can also block life-giving sunlight to the reef.

Floating trash can also cut young coral polyps off from the nutrients they need to grow into a thriving reef.


A coral reef with branches, sponges, fish and underwater sedimen

Marine sediment is comprised of insoluble particles that are transported from land areas to the ocean. Human settlement and agricultural activities can contribute to the amount of particles that are washed off into the sea, but construction and mining along sea coasts can also create a great deal of silt and soil run-off.

When sediment enters the ocean, it can smother coral reefs, depriving them of sunlight and nutrients. Also, fish are unable to feed and coral polyps are unable to grow, leaving the area inhospitable to reef life.

Careless Tourism

tourist standing on a coral

Increased tourism is one of the major causes of the destruction of coral reefs. The following factors all contribute to coral reef damage:

  • Uncontrolled building and irresponsible business operations
  • Increased discharge of wastewater
  • Careless tourist behavior

Boats and other vessels used for recreational activities can damage coral reefs with carelessly dropped anchors or accidental grounding. Meanwhile, divers, snorkelers, and other sea lovers often inadvertently damage the reef by playing on them, stepping or sitting on them to rest, or simply by touching them and exposing them to their skins’ oils.

Tourist activities have a direct impact on the marine ecosystem, and much of the coral reef destruction caused by tourism could be prevented with just a bit of education for those who want to explore these interesting natural creations.

What Happens if Coral Reefs Become Extinct?

Scientists around the world are scrambling to ensure the survival of the world’s remaining coral reefs, as they’re extremely vital to the continued well-being of the planet.

The forecasts, nevertheless, are dire: Even if global warming came to a complete halt today, scientists still expect more than 90% of corals to die by 2050. Without drastic intervention, we risk losing them all, and since we rely on them for so many things, the complete destruction of coral reefs could mean a different kind of world for future generations.

But what can we do about it? While it may seem like whatever one person does is nothing but a drop in the bucket, that drop will certainly not go unnoticed.

You can help save the coral reefs by volunteering your time to local conservation programs, supporting reef-friendly businesses, conserving water to reduce your wastewater production, using less plastic, being a more responsible tourist, and most importantly, by spreading awareness and educating others.


  1. Who wrote this article? What evidence do you have (as you provide none) that temperature increases are responsible for bleaching?

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