Top 6 Threats To Coral Reefs

Even though all of the coral reefs in the world add up to only about the size of France, they still protect our coastlines, provide billions of dollars worth of food and jobs, and they are a home to many of the critters of the sea! Sadly, these reefs are meeting premature deaths due to some serious threats that need to be addressed.

1. Ocean Acidification

KOMPAS LASTI KURNIA- Marine Photobank / Via wwf.panda.org

Ocean acidification is usually due to the uptake of CO2 from the atmosphere, which lowers the pH of the ocean. These conditions stress the corals out and they reject the algae that live in them. Without the algae, the corals not only lose their beautiful colors, but they lose their food source, and begin to die. From 1876-1979 only three bleaching events were recorded, whereas in 2002 more than 400 events were recorded.

2. Destructive Fishing Practices

Malik Naumann- Marine Photobank / Via oceanservice.noaa.gov

Destructive fishing practices include utilizing poisons, explosives, as well as large-scale pelagic drift nets, and bottom trawling. Bottom trawling is a widely used fishing method, which drags a weighted net along the ocean floor, obliterating anything it comes into contact with. Not good for the coral reefs. It can take up to 10,000 years for a coral reef to form, so once they are destroyed, it can take a long time for the reefs to recover if they are not permanently damaged.

3. Overfishing

permaculturenews.org / Via icriforum.org

Key reef species as well as deep-water commercial fish are being taken out of the ocean at an alarming rate. Overfishing certain species that live near coral reefs can throw off the ecological balance of the reef and affect its biodiversity. As an example, if you take out the majority of the herbivorous fish, then the reef is going to be consumed by algae, which, in large amounts, can compete with the coral for resources and kill it. The fish need the reef for habitat and protection but the reef needs the fish just as much to keep everything balanced.

4. Tourism

Nancy Boucha- Marine Photobank / Via unep.org

Sand, surf, and sea. Who doesn’t want to take a vacation involving all of those things? Unfortunately, it turns out our desire to be on the beach or in the water is leading to a lot of destruction for the reefs. Some reefs are getting too much attention from divers and snorkelers, causing unintentional damage by kicking the reef or boats dropping their anchors on it. There should only be 5,000-6,000 dives on sites per year to keep them healthy. The development of new resorts is also causing an influx of sewage pollution and increased sedimentation, which can reduce the amount of light that reaches corals, stressing them out.

5. Pollution

Ziggy Livnat- Marine Photobank / Via celebrating200years.noaa.gov

Land-based pollution is a huge cause of coral reef degradation all around the world. If we take the Caribbean as an example, 80% of the ocean pollution originates from land activities. There is runoff that carries nutrients from agricultural areas, sediment, and pesticides. These additions to the ecosystem can lead to decreased oxygen in the water, an abundance of toxins, and the smothering of coral, leaving it unable to efficiently feed or reproduce. Our plastic bags, bottles and abandoned fishing gear can also kill key reef species.

6. Climate Change

Craig Quirolo- Reef Relief/Marine Photobank / Via nwf.org and floridakeys.noaa.gov

Since the late 19th century, global ocean temperature has risen by about 1.3°F. Just like acidifying oceans, coral does not appreciate rising ocean temperatures. Rising (as well as falling) temperatures stress the coral out, and their vital algae jumps ship. Warmer waters can also lead to an increase in coral diseases (they have plagues too!), which can cause mass mortality of both the coral and the ecosystem. Climate change also causes sea level rise, which alters ocean circulation as well as the frequency, intensity, and the distribution of tropical storms. These changes can have grave effects on the diversity and health of our coral reefs.