I have known about climate change since I was very young. My parents and teachers would discuss the harmful effects of increased carbon emissions across the world: animals becoming endangered, the average temperature of the earth increasing and strange weather patterns. The heartbreaking part, though, was that these effects were caused by humans. Today, I feel lucky that I was able to, as a child, enjoy the environment before it got too warm.
This aspect of the world remained an integral part of my formal (through school) and informal (through my family members and friends) education. I learned that the coral reefs, vital underwater ecosystems, were at risk of dying out soon.
Many people dream of visiting the Great Barrier Reef in Australia. It’s the largest coral reef system in the world, renowned for the stunning marine life, but it has been recently facing threats causing coral bleaching.
Corals are ancient animals that, about 25 million years ago, evolved to become reef-building forms. Different coral reefs form different structures, some forming structures where the primary “branches” have secondary structures forming off of them. Others are table-like, and there are some that look like the tops of mushrooms.
They are made up of polyps, soft-bodied organisms that secrete calcium carbonate (CaCO3). This secretion helps create an exoskeleton that then helps with protection and provides a structure for the groups of corals, called coral reefs. Each polyp is connected to another through a shared tissue that then allows the polyps to act as a single organism. Because of the collective nature of the polyps (they share the same resources and communicate together), a structure containing them is called a coral and is actually considered a single organism.
A polyp has three tissue layers: an outer epidermis, a middle layer called mesoglea and an inner layer of cells. The inner layer is located in the polyp’s gastrovascular cavity and is the space for digestion. All polyps have two features: they have a mouth where they consume food and get rid of waste and they have a set of tentacles which help with capturing plankton, clearing away debris and defense.
Most corals engage in a symbiotic relationship with algae. The algae are able to reside within the corals, protecting them and giving them necessary nutrients. In return, the algae produces oxygen, helps the coral with the waste removal process and supplies the corals with the organic products that come out of photosynthesis. In fact, about 90% of what the algae produces is transferred to the coral. Thus, if the coral ends up expelling the algae out, which could happen if the coral ends up becoming stressed, the coral could end up dying. The algae is also the reason for the coral’s color: without it, the coral takes on its strikingly white color, which is called coral bleaching.
Recently, coral reefs have had to face an average global temperature increase. Even the slightest temperature increase can disrupt the relationship between the corals and the algae. Most reefs grow where temperatures are between 23 and 29 degrees Celsius (73-84.2 degrees Fahrenheit) and can deal with as high as 40 degrees (104 degrees Farenheit) for a short period of time. Most also need for the water to be very salty and clear (to allow for more light to penetrate). However, the recent temperature increase has caused the corals to experience stress, which has resulted in the coral bleaching process.
Coral reefs provide a habitat for many sea species, leading to increased biodiversity across the world’s oceans and paving the way for scientific and medicinal discoveries. They also provide coastal protection. They are a natural barrier against erosion, storms and floods. The islands and coasts around where coral reefs are found also have a significant connection to them, historically, culturally and spiritually.
Coral reefs are very important in many aspects, not just environmentally. Ensuring the implementation of proper strategies to protect them is essential. Hopefully one day, when I get the chance to visit the Great Barrier Reef, I will see the plethora of colors and beautiful species that are supposed to be there.
VAAGEESHA DAS is a second year college student and columnist for The Dominion Post. Information comes from: National Oceanic and Atmospheric Administration. (2024, June 13). NOAA’s Coral Reef Information System (Coris) – what are coral reefs. NOAA Coral Reef Information System (CoRIS) Home Page. https://tinyurl.com/aboutcorals; Status of coral reefs. Reef Resilience. (n.d.). https://tinyurl.com/coralstatus
