What Is Coral Bleaching?

Abstract Why Are Corals Important To Humans?

KJ BulawinBiology 115

References!Andersson, Andreas. "Acidifying the Ocean: Assessing Impacts on Coral Reefs." Jeffrey B. Graham Perspectives on Ocean Science Lecture Series. University of California, San Diego, San Diego. 11 Dec. 2013.Lecture. Buchheim, Jason. "Coral Reef Bleaching." Coral Reef Bleaching. Web. 8 Dec. 2015. <http:www.marinebiology.orgcoralbleaching.htm>."Hawaii to Experience Worst-ever Coral Bleaching Due to High Ocean Temperatures." The Guardian. Guardian News and Media Limited, 13 Sept. 2015. Web. 5 Dec. 2015. <http://www.theguardian.com/us-news/2015/sep/13/hawaii-coral-bleaching-

scientists-predict-worst-ever>."How Pollution Affects Coral Reefs." NOAA 200th:. National Oceanic and Atmospheric Administration, 19 July 2012. Web. 8 Dec. 2015. <http://

celebrating200years.noaa.gov/visions/coral/side.html>."Ocean Acidification -- Pristine Seas -- National Geographic." National Geographic. National Geographic. Web. 5 Dec. 2015. <http://ocean.nationalgeographic.com/ocean/explore/pristine-seas/critical-issues-ocean-acidification/>."What Is Coral Bleaching?" What Is Coral Bleaching? Web. 8 Dec. 2015. <http:// oceanservice.noaa.gov/facts/coral_bleach.html>.!!!!

What Can We Do To Help?Although many corals are able to survive bleaching events, it is still a good idea that we do our part in helping to save them. We should be careful what we let go into our drains that lead into our oceans. We should decrease water use because fertilizers and soap can easily be washed into drains, thus harming the marine ecosystem. We should decrease the amount of fossil fuels we put into the atmosphere, leading to less CO2

production. We should make sure we dispose of our trash properly because plastic bags and bottles could end up in the stomachs of our favorite creatures and near their homes. And lastly, we should practice safe and responsible snorkeling whenever we are near the reefs. By doing our part, we can help save the corals that we need for so much more than we think.

Current SituationsOne current situation with a bleaching event is happening in the island chain of Hawaii. They are still recovering from an event from last year, yet they are still having increases in water temperature from 3°F to 6°F. As Ruth Gates, the director of Hawaii Institute of Marine Biology, states “you can’t stress an individual, an organism, once and then hit it again very, very quickly and hope they will recover as quickly”, although these corals were able to recover there is a slim chance that they will again. As Hawaii relies on corals as one of their attractions, they need these corals. Although Hawaii is seen as paradise, without these corals they will lose out on revenue, appeal and possibly their title of paradise.

What Causes Coral Bleaching?• Temperature Changes The waters that corals usually inhabit range from 73°F-84°F (22.8°C-28.9°C)(NOAA). But temperature increases of as little as 1°C(33.8°F) for 4 weeks can cause bleaching. Although bleaching is usually associated with warmer temperatures, colder temperatures such as the 12.06°F drop in Florida of January 2010, caused corals to bleach as well (NOAA). During an El Niño event, the waters in the Eastern Equatorial Pacific, get warmer as the winter season approaches-causing bleaching events to occur and be able to predict based on the cycle.• Ocean Acidification 20% of the world’s Carbon Dioxide gets absorbed into the ocean(Andersson, 2013). The ocean is currently at 8.1 on the pH scale, while over the past 300 years it has been averaging about 8.2(National Geographic), that means it is becoming more acidic. When CO2, either from fossil fuels- also leading to global warming-or other, reacts with water it forms Carbonic Acid. It releases Hydrogen ions which increase the acidity of the water. Since corals, as well as shells of other animals, are made from Calcium Carbonate, they have less building material due to the acid ruining formation. Therefore, the corals have decreased growth rate and an increased break down rate.• Pollution Pollution from land runoff can cause diseases and death of coral. According to NOAA, approximately 80% of ocean pollution originates from activities on land. Although humans may think that they cannot be blamed for harming marine life, they play a huge role. As the landscape changes due to coastal development, an increase in runoff of sediments, agricultural nutrients, pesticides as well as sewage flow into the ocean. Those items may be good for the land but definitely not for the ocean. Eutrophication occurs when an excess of land nutrients invade the water causing an excessive increase in plant development and death of animal life from a lack of oxygen. Other items such as plastic bags, metal, and fishing nets known as marine debris, can damage reefs too.

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Coral Bleaching

Coral reefs are located in shallow, tropical waters all around the world. They are made when individual scleractinians, stony corals, secrete calcium carbonate to start forming the reef. Although corals belong to the Cnidarian Phylum, they are able to have symbiotic relationships with plenty of fish as well as algae. Zooxanthellae, a type of algae, live in the coral’s tissue providing them with food and their bright colors. They are the main source of food for the coral during the day, while at night it relies on predation(marinebiology.org).In return, the coral provides the algae with a home and the necessities, such as carbon, to perform photosynthesis. When the water, already warm due to being tropical, has even the slightest temperature increase, the Zooxanthellae will become stressed out and flee from the coral. Since the coral’s is transparent, its pale skeleton shows through-giving the effect of it being bleached. According to (marinebiology.org,) they lose 60-90% of its Zooxanthellae during a bleaching. For most events, corals are able to bounce back but for those that cannot, they become more prone to disease and death.

Corals have a symbiotic relationship with algae called Zooxanthellae. When the water conditions are not right, for example if it is warmer than usual, the algae will become stressed and leave the coral. Upon doing so, the coral loses its food supply along with its color, thus becoming bleached. Bleached corals have a higher risk of becoming ill and dying. Corals are important not only to marine life but to humans as well. If corals keep dying out, all inhabitants of Earth will be affected. But we can help do our part to prevent this from happening by decreasing our output of Carbon Dioxide

Although corals are under the sea, they are important to us on land. Often called “Rainforest of the Sea”, corals are the most diverse habitats of the world being home to about 25% of all marine species (NOAA). Being so diverse gives them the capability for some species to survive major events. Scientists estimate that there may be another 1 to 8 million undiscovered species located in and around these reefs.

To humans this is important because it gives us new medicines. Cures for cancer, arthritis, human bacterial infections and viruses have been developed from coral reef animals and plants. For those that live near tropical regions, corals can help their economy. They bring in tourists that will enjoy snorkeling as well as a relaxing vacation and people can fish for food or to sell. Lastly, they help the land is that they help shape the shoreline. They lessen the impact of wave energy from storms and tsunamis, which reduces the damage to land. According to NOAA, up to 90% of wave energy is absorbed by corals. Without corals, some parts of the world, like Florida, would be submerged if it weren’t for these reefs.

This diagram shows how CO2 enters into the atmosphere then the ocean causing Calcium Carbonate to have a faster breakdown rate than it can be created. http://www.eschooltoday.com/ocean-acidification/what-causes-ocean-acidification.html

A diver researchers the corals of Kaneohe Bay, Hawaii.(The Guardian, 2015)

A bleached Acropora coral among healthy corals located in the Keppel Island, Great Barrier Reef. https://upload.wikimedia.org/wikipedia/en/9/90/Keppelbleaching.jpg