The Top 4 Threats Facing Coral Reefs

Although many people don’t realize it, our coral reefs are in serious danger. In fact, more than half of the world’s coral reefs have died off in the last three decades. Worse yet, if we don’t act fast, up to 90% of the world’s reefs could die off in the next hundred years.

That makes identifying and combatting threats to coral reefs critical, not only to the health of the reefs themselves but to the health of the ecosystems that they support. Additionally, it’s critical to protecting the ocean areas that people call home.

This guide goes over a few of the top threats to coral reefs, why they matter, and what causes them.

Overfishing

Overfishing is a major threat to coral reefs, even though it doesn’t directly harm the corals themselves. Instead, overfishing involves taking too many fish out of the ocean.

When too many fish are taken out of the ocean, the whole reef ecosystem is affected. For one thing, without enough fish, algae that grow on the reef can start to get out of control. This can lead to algae suffocating corals or causing them to become sick.

On top of that, some algae can produce harmful toxins when it grows prolifically. This can lead to not only the corals getting sick, but also can cause the fish and shellfish that survive off algae to consume harmful toxins, too.

This leads to killing off the fish and shellfish, as well as spreading toxins to humans who fish these creatures and consume the contaminated fish.

Finally, overfishing can cause an increase in pollution. This is because overfishing usually involves gear such as nets, trawl lines, and traps. These pieces of equipment can get caught on the reef and can build up in the oceans, causing fish to choke or suffocate on the plastics.

Land-Based Pollution

Overfishing isn’t the only threat to coral reefs. Another major problem that reefs are facing is land-based pollution.

Unlike pollution caused by overfishing, land-based pollution refers to pollution that happens on land but eventually spreads out to the reefs.

One example of this is the use of fertilizers on farms. Fertilizers wash off plants when it rains, and make their way back into streams, creeks, and rivers. These streams and rivers then flow out into oceans, taking the fertilizers with them.

Because fertilizers are full of chemicals and toxins, when they arrive at coral reefs, they cause corals to become sick. This leads to corals dying off, which then affects the animals that call the reef home.

Another type of land-based pollution that can affect reefs involves plastics and other materials being left on beaches. When the tides wash in, they carry these plastics and debris off the shore and out to the oceans. Animals can then become trapped in these materials or choke on them and die.

When animals die due to this kind of pollution, they upset the food chain, leading to a lack of predators which can allow micronutrients to grow out of control. Once again, this leads to algae overgrowth which can kill off corals.

Climate Change

Climate change is another serious problem facing coral reefs. Climate change affects coral reefs by causing rising ocean temperatures. Rising ocean temperatures can cause a number of harmful effects.

For one thing, rising ocean temperatures can cause certain types of algae to grow out of control. This causes harmful blooms, which can make corals sick and release toxins into the ocean.

At the same time, rising ocean temperatures can kill off other kinds of algae. Without enough algae growing on corals, they can become bare and bleached. This kind of bleaching causes general stress and sickness to the reef and can cause the corals to die off.

Another way that climate change affects coral reefs is by increasing the acidity of oceans. Oceans absorb CO2, which is one of the main greenhouse gases that leads to rising planetary temperatures.

With more CO2 in the atmosphere, more CO2 makes its way back into our oceans, leading to an unbalanced pH. With the pH of the oceans out of whack, fish can start to die off, as can other microorganisms that call the reef home. This, in turn, affects corals, causing them to die and leading to the elimination of the reef altogether.

Tourism

Although there’s nothing wrong with eco-tourism, it has to be done sustainably. Unfortunately, tourism is also causing coral reefs to die off.

The main reason for this is that sometimes when people are swimming on the reefs, they accidentally break corals. Breaking the corals can cause the rest of the plant to become sick. That disease can then spread to corals on the rest of the reef.

Additionally, tourism can introduce sunscreen into the water. Many sunscreens contain harmful toxins which can cause corals to become sick and die, as well.

The Bottom Line

There are a number of serious issues affecting our coral reefs today. If we’re not careful to combat these threats, our coral reefs could disappear within the next century.

The good news is that we can prevent these threats from further harming our coral reefs. Taking actions like reducing your carbon footprint, cleaning up trash and disposing of harmful products appropriately, and fishing and participating in eco-tourism responsibly can all help our corals start to regain their health.