Round 1 – Why coral reefs are disappearing and why they are so important

Hello! My big research question is: Why and how we should help restore coral reefs? Today, I will be focusing on: why coral reefs are disappearing, because in order to find a solution, you need to understand the problem. I started of my research by reading an article written by the US Environmental Protection Agency (EPA). This article was a great resource because it clearly explained the threats facing coral reefs by splitting them into 2 categories, local threats and global threats. Local Threats include…

1. Physical damage
2. Land based pollution
3. Overfishing
4. Coral harvesting

Global Threats include…

1. Climate change
2. Ocean acidification

Physical damage:

This one is the most straight forward threat to coral reefs. It’s essentially any damage or destruction of coral reefs caused by humans, such as certain fishing techniques, recreational misuse, boat anchors, quarrying (extraction of minerals), dredging (cleaning the ocean bed) and change of costal landscape (costal development).

Photo: Destruction being caused by a ship’s anchor.

 

Land based pollution:

This includes…

• Sedimentation – Loose soil particles that settle at the bottom of the water. (2)

This is problematic because if this sedimentation settles onto coral reefs, it can suffocate them, leaving them unable to feed, grow, and reproduce.

 

• Nutrients – coming from fertilizer, animal waste, and sewage can also be harmful

Coral reefs are used to living in an environment with low nutrient levels, so they do not benefit from this. However, algae and certain microorganisms do. The growth of algae blocks the sunlight, consuming the oxygen that coral reefs need. Microorganisms like bacteria and fungi can cause            disease in coral, eliminating them one by one.

 

• Disease – Bacteria and parasites from sewage, storm water, and livestock pens

This one is more rare, but once these one parasites cause disease in coral even once, it can devastate an entire coral reef.

 

• Toxic Waste – metals, chemicals, pesticides, sunscreens, urban + agricultural runoff, and landfill runoff

Many of these substances affect coral growth, feeding and reproduction.

 

• Marine Debris – Trash and microplastics (such as bags, bottles, and fishing gear)

This garbage can break or damage corals when carried around by the current, block the sunlight needed by coral for photosynthesis, and hurt essential marine life.

Overfishing:

This one is fairly self explanatory, but it throws off the entire marine food web. An example of this is when one certain fish used to keep coral reefs clean of algae, but since many of them have been hunted, coral reefs are left without that protection.

Coral harvesting:

People do this for a variety of reasons, from wanting to make jewelry, all the way to just being curious. This is essentially the same as physical damage, except it is done on purpose, and not as a result of another action.

Photo: Boat carrying harvested coral

 

Climate change: Climate change has negatively impacted our whole planet, so it’s no surprise that it’s one of the biggest risks our coral reefs are facing. Both rising temperatures and levels of carbon dioxide in our atmosphere play a big role in the danger of coral reefs.

All corals have this microscopic algae that lives on it, which uses photosynthesis to provide the corals with the nutrients it needs. When seawater temperatures get to high, the coral loses it’s algae, leaving it without a food source. Scientists call this “coral bleaching” because a coral without it’s algae loses colour and turns white. (3)

The ocean absorbs some of the carbon dioxide that is found in our atmosphere, causing damage to coral reefs. This process is called “ocean acidification”. The carbon dioxide increases the ocean’s acidity, which decreases the coral’s ability to dissolve certain salts and ions it needs. This results in slow growing corals and sometimes death of coral plants.(1)

 

Now that I’ve looked at what problems coral reefs are facing, I am going to explain why coral reefs are so important!

Coral reefs are at the start of an incredible ecosystem. It begins with the coral reefs providing a home for small organisms, which are then eaten by fish. Those fish are eaten by bigger fish, then by bigger fish, who may be eaten by a shark or a dolphin. The barrier reefs contains over 400 species of coral, 1,500 species of fish, 4,000 species of mollusk, and 6 species of turtle. And that’s just one reef! Without coral reefs, a big part of the ocean’s ecosystem will collapse, leaving many marine animals endangered or extinct. The disappearance of the marine animals could cause further problems for our planet, because each animal contributes in a different way.

Coral reefs also help protect shorelines from waves and tsunamis, reducing wave energy by up to 95%.

Something quite interesting that I learnt is that humans actually have a lot to learn from corals. Coral has an amazing way of repairing it’s own DNA, and scientists are looking into exactly how it does that. Some scientists think that if we can figure this out, it could potentially cure cancer.

It is estimated that the oldest corals lived 450 million years ago. Which is almost double the amount of years ago than the oldest dinosaur. Because of this, it is hard to imagine a world without coral. If we looks at these numbers, it makes sense that most of our marine world is based upon the existence of the coral reefs.(4) (5)

 

 

That’s all for this round! Next round, I will be looking at different ways we can help save coral reefs. As a side note, I just wanted to give everyone my best wishes during this difficult time. I know it’s been hard for many people, and I hope that life will return to normal soon.     Sources:

1. https://www.epa.gov/coral-reefs/threats-coral-reefs
2. https://cfpub.epa.gov/npstbx/files/KSMO_Sediment.pdf
3. https://www.netflix.com/watch/80094032?trackId=14170289&tctx=0%2C3%2C85ae2029-d749-45ad-92ea-d814fd1bd23b-787342522%2C25f93712-ad22-4f42-bca5-22bb0aeafdad_46668738X3XX1586882783650%2C25f93712-ad22-4f42-bca5-22bb0aeafdad_ROOT
4. https://www.youtube.com/watch?v=3kb0bz-3lWc
5. https://www.youtube.com/watch?v=eNqbSi_6KdA

Photos (in order): https://earthtouchnews.com/oceans/coral-reefs/watch-this-is-what-cruise-ship-anchors-can-do-to-a-coral-reef

https://www.northcountrypublicradio.org/news/story/17601/20110505/flooding-pushes-sediment-pollution-into-lake-champlain

https://www.hakaimagazine.com/news/what-happens-when-coral-reef-dies/

http://www2.clarku.edu/departments/biology/biol201/2008/ermiller/coraldisease.html

https://www.cleveland.com/opinion/2015/11/lake_erie_dumping_of_cuyahoga_river_dredge_no_no_no_editorial.html

https://medium.com/usfws/the-trash-at-the-edge-of-the-world-47049d25e464

https://www.worldwildlife.org/threats/overfishing

https://oceanservice.noaa.gov/education/kits/corals/media/supp_coral07b.html

https://www.vox.com/science-and-health/2017/4/18/15272634/catastrophic-coral-bleaching-great-barrier-reef-map