Coral Reef Basics and Its Impact on Ocean Life

2012 Coral Reef Basics and Its Impact on Ocean Life Biology 1010 Professor LynneGilbert-Norton 4/25/2012

Contents Introduction... 2 Coral Explained... 2 Evolution... 3 Eating Habits... 4 Location... 4 Reproduction... 5 Coral Reefs are Home to Many... 6 The Benefits and Importance of the Coral Reef... 6 Future of Coral Reef... 7 The Effects of Climate Change... 7 Conclusion... 8 Works Cited... 9 1 P a g e

Coral Reef Basics and Its Impact on Ocean Life Reflection Deciding what interested me to write about wasn t the challenge about this report; the challenge with the scientific paper is writing in a different style. I found though, once I started my research on the topic of coral and the coral reef, it was easier to write about it. Even more, learning about coral was very interesting. I had no idea that coral was an animal, and I was totally clueless about what they provide for the ocean and the other sea creatures. This paper is brief overview about coral, where it is, how it procreates, their benefits to the sea, and the future for it. Introduction The coral reefs of this world are scattered across the rim of the global equator, creating a community environment for their species and so many others. Often coral is categorized into just a beauty of the sea without regard to what it provides for oceanic life. It seems that most don t realize that coral and coral reefs are alive and provide a haven of security for so many other types of living beings. This report will explain what coral is, where it came from, how it reproduces, why it s important to ocean life, as well as the bleak future outlook for coral around the world. Coral Explained Coral is composed of tiny, fragile animals that are often mistaken as a rock or plant (Coral Reef Alliance). They belong to the cnidaria group, which also includes hydras, jellyfish, and sea 2 P a g e

anemones (Coral Reef Protection: What Are Coral Reefs?). They are sessile animals meaning they are fixed and do not move. Coral is able to reach out with tentacles to catch prey such as small fish and planktonic animals in order to feed. They also live in colonies, much like a huge city, that consists of many individual animals. Each individual animal is called a polyp. Only a fraction of the many species that inhabit coral reef produce limestone that helps build the coral reef (Coral Reef Alliance). The most important of these is the coral, a reef-building organism. Coral secretes a hard calcium carbonate (also known as limestone) skeleton which serves as the uniform base or substrate for the colony. Not only does the skeleton serve as the base, it provides protection because the polyps are able to contract into the structure if predators approach them. The limestone builds up the coral reefs over time completely blanketing it while the living coral colony occurs at the surface of the skeletal structure. The limestone is continuously accumulated by the living colony which adds to the size of the coral reef structure. Size of the coral reef varies greatly and is dependent on the species of the coral and environmental conditions. The different species provide quite an array of diversity in the sizes, shapes, and complexity for the coral reef ecosystem. Environmental conditions and competition with other species tend to segregate coral species into characteristic zones (Coral Reef Protection: What Are Coral Reefs?). Evolution Geological records indicate that the ancestors of modern coral reef ecosystems were formed at least 240 million years ago. They evolved about the same time the first mammals appeared, in the Triassic period. The majority of established coral reefs range between 5,000 and 10,000 years old and are often determined by size, but that isn t always true. Different types of coral grow at 3 P a g e

different rates dependent upon the water temperature, oxygen level, amount of turbulence, and the availability of food (Coral Reef Alliance). Eating Habits Each polyp is able to eat in two different ways according to the type of species it is. Most coral polyps are inhabited by tiny algae called zooxanthellae (pronounced zo-can-thel-ee), which provides nourishment to the coral. These algae use sunlight to make sugar for energy, just like plants are able to do, through the process of photosynthesis. The algae are able to process the waste of the coral to conserve nutrients and in turn provide the coral with oxygen. The coral provides the algae with carbon dioxide as well as a safe, protected home. The second way that corals feed is by catching zooplankton, tiny floating animals. During the night, coral polyps come out of the skeleton to feed and make the reef look like a wall of starving mouths. The polyps stretch out their long, stinging tentacles capturing any zooplankton that are swimming by. The zooplankton is then put on the polyps mouth and then digested in their stomachs (Coral Reef Alliance). Location Coral reefs are found in shallow, clear water where light can easily penetrate the coral polyps for the purpose of photosynthesis for the zooxanthellae. Zooxanthellae are dependent on light for photosynthesis because it helps create food for the coral. The coral communities also require certain temperatures, mainly tropical or sub-tropical and exist around the world in a band of 30 degrees north to 30 degrees south of the equator. There are three classifications for coral reefs. The fringing reefs are the most common type of coral reefs. These animals project seaward directly from the shores of islands or continents. Then there are the barrier reefs that are 4 P a g e

platforms separated from the adjacent land by a bay or lagoon. And last are the atolls which rest on the tops of submerged volcanoes. These types of coral reef are usually oval or circular with a central lagoon (Coral Reef Protection: What Are Coral Reefs?). Reproduction Some coral are hermaphrodites that are able to produce both sperm and egg at the same time. Other corals are gonochoric, which means they produce single-sex colonies. In these single-sex colonies, all of the species in the colony may only produce sperm while all the species in another colony may only produce eggs. Coral larvae forms in two different ways; either fertilized within the polyp body or outside of the body in the water. If fertilization of an egg occurs in the body of the polyp, it was achieved from the sperm that was released through the mouth of another polyp. Once the mature larva is ready, the mother spits it out through its mouth into the water (Coral Reef Alliance). Another way that coral reproduce is by ejecting large quantities of eggs and sperm into the surrounding water so the eggs and sperm fertilize the water. This is called coral spawning. Once fertilized, the coral larva is attracted to the light, so it will swim to the surface of the water to remain for days or weeks. As long as it is not eaten by predators, it will fall back to the sea floor and attach itself to a hard surface. It then meta-morphs into a coral polyp and begins to grow. It will divide itself in half and make an exact genetic copy of itself. Eventually, more polyps will be added and the colony of the coral reef develops and as it matures, the reproduction and life cycle continues (Coral Reef Alliance). 5 P a g e

Coral Reefs are Home to Many Up to 9 million species call the coral reef their home. They house a quarter of all marine species even though they only cover a tenth of the ocean s surface. Of these 9 million species, approximately 35,000 and 60,000 are distinguished (Species on Coral Reefs). The Benefits and Importance of the Coral Reef Due to the vast amount of species they shelter and the high productivity they yield, coral reefs are quite often referred to as the rainforests of the sea. They provide spawning, nursery, refuge, and feeding areas for a dynamic array of organism, including sponges, cnidarians, worms, crustaceans (like shrimp, crabs, spiny lobsters), mollusks, echinoderms (like starfish, sea urchins, sea cucumbers), sea squirts, sea turtles, and sea snakes. Coral reef structures act as natural breakwater which is an important role to minimize wave impacts from storms such as cyclones, hurricanes, or typhoons (Benefits of Coral Reef). Because coral reefs and their associated communities (sea grasses, mangroves, and mudflats) have sensitive indicators, they are able to tell the water quality as well as the ecological integrity of the ecosystem. They can tolerate relatively narrow ranges of water clarity, salinity, temperatures, and other chemical and water quality characteristics. Thus, coral reefs are excellent ambassadors for the quality of the environment. Scientists are able to monitor coral reefs and with proper equipment they are able to identify any changes in water quality including impacts from land-based activities. It s important to monitor changes in water quality so that local resource managers understand the implications of actions occurring in watersheds that are associated with particular coral communities (Coral Reef Protection: What Are Coral Reefs?). Being able to make the connection allows aid in the 6 P a g e

development of good management plans for coral reefs and other marine and coastal resources. Not only do coral reefs provide a safe home for many marine species, but they also protect coastlines from erosion and provide sand for beaches (Coral Reef Protection: What Are Coral Reefs?). Future of Coral Reef Primarily because of human activities, coral reefs may cease to continue living. Additionally, the threat of climate change and acidification in the ocean are harming coral reefs, which both are linked to rising carbon dioxide levels in the atmosphere. Corals lose zooxanthellae due to high water temperatures, a condition known as coral bleaching. Coral bleaching that is severe or prolonged can leave the coral vulnerable to threats from predators as well killing a coral colony. Other actions disrupt the coral reefs ecosystem, such as overfishing and overharvesting of corals. The implications of these actions and environmental factors can lead to complete extinction of the coral colonies (Coral Reefs: Threats & Solutions). The Effects of Climate Change In depth, coral bleaching occurs when the intimate association between coral and zooxanthellae breaks down and causes a rapid whitening of the coral. This is clearly a stress response from the coral that can be caused by many factors, but mostly because of the rise in the ocean s temperature. If the temperature decreases, there is potential for the coral to recover, but if the temperature continually rises, the colony that is affected will die. Another effect of climate change is ocean acidification. This is an ongoing decrease in the ph of the Earth s oceans that is caused by their uptake of anthropogenic carbon dioxide from the 7 P a g e

atmosphere. The decrease in ph makes the water more acidic which has a negative impact on the ocean s calcifying organisms such as the coral reef (Status Of and Threat to Coral Reefs). Conclusion The extinction of the coral reef species will be devastating to not only the ocean animals, but even for tourism. Humans are captivated by their elegance. The only thing that is missing from that equation is their importance. They provide an immense amount of safety, homes, and food for so many different species, that without the coral reefs, those species continued life could potentially be threatened. Knowing that they are alive, they are animals, how they eat, reproduce, where they are and so many other facts about them can create awareness. Through awareness, it is possible for humans to change their behaviors in hopes to save the coral reef from disappearing. 8 P a g e

Works Cited "Benefits of Coral Reef." n.d. International Coral Reef Initiative. Web. 24 April 2012. <http://www.icriforum.org/about-coral-reefs/benefits-coral-reefs>. Coral Reef Alliance. 2010. Web. 24 April 2012. <http://www.coral.org/resources/about_coral_reefs/coral_overview>. "Coral Reef Protection: What Are Coral Reefs?" 6 March 2012. EPA United States Environmental Protection Agency. Web. 24 April 2012. <http://water.epa.gov/type/oceb/habitat/coral_index.cfm>. "Coral Reefs: Threats & Solutions." 2010. Smithsonian National Museam of Natural History: Ocean Portals. Web. 24 April 2012. <http://ocean.si.edu/ocean-life-ecosystems/coral-reefs/threatssolutions>. "Species on Coral Reefs." 11 April 2012. Microdocs. Web. 24 April 2012. <http://www.stanford.edu/group/microdocs/species.html>. "Status Of and Threat to Coral Reefs." n.d. International Coral Reef Initiative. Web. 24 April 2012. <http://www.icriforum.org/about-coral-reefs/status-and-threat-coral-reefs>. 9 P a g e