.Ecosystems in Action: Lessons from Marine Ecology about Recovery, Resistance, and Reversibility. By: Palumbi, Stephen R.; McLeod, Karen L.; Grnbaum, Daniel. Bioscience, Jan2008, Vol. 58 Issue 1, p33-42, 10p, 1 diagram, 5 graphs, 1c; DOI: 10.1641/B580108
Coral Reefs: Indicators, Threats, and Conservation Resources. By: Bischof, Barbie. Environment, Dec2007, Vol. 49 Issue 10, p3-4, 2p;
Integration of Multi-Source Data to Monitor Coral Biodiversity. By: Jitkue, K.; Srisang, W.; Yaiprasert, C.; Jaroensutasinee, K.; Jaroensutasinee, M.. Proceedings of World Academy of Science: Engineering & Technology, Dec2007, Vol. 26, p202-206, 5p;
Robert Traul
Course Research Paper
GLG 413/513
June 6, 2008
The Importance of Corals and Coral Reefs (Above and Below the Ocean)
Coral reefs are one of the most beautiful ecosystems in the marine environment. Their habitat is both rich and diverse. Coral Reefs cover about 0.2 percent of the oceanŐs bottom (an area roughly the size of Texas), but they are the home to more than 25 percent of all marine species. They are known as the rainforests of the ocean. These reefs require certain conditions to survive. Unfortunately, human activity that takes place within these reefs is leading to their disappearance. It is important that human beings fully understand the importance of these underwater ecosystems to be able to enjoy them for millions of years to come.
Reef-building corals are generally found at depths less the 150 ft, where the sun is able to penetrate. Most coral species require temperatures between 18 and 30 degrees Celsius (Palumbi, Pg. 2). Thus, most of them are in tropical waters, but some can be found in temperate seas and a few even exist in cold waters. Most major corals are distributed in the Caribbean and Southeast Asia/Australia. The coral species is divided into two types, soft and hard. Soft corals, or Gorgonians, are solitary or small colonies and can be found in deeper water. They are made up of a protein/calcium carbonate material and lack an exoskeleton. This is why they are able to sway with the ocean currents. Soft corals generally do not contribute to the actual reef building, although their calcium carbonate skeleton can contribute to a major part of its foundation. Hard corals, or Scleractinians, are the ones that will form the major groundwork for coral reefs and they are composed of stony calcium carbonate. They have rigid exoskeletons, or corallites, that protect their soft delicate bodies.
There are three major types of coral reefs: fringing reefs, barrier reefs, and atolls. Fringing reefs form in shallow waters along the coastlines of continents and islands. Growth is upward until the reef reaches near the surface and then out into deeper waters. There is a wave breaking area towards shore that is referred to as the lagoon/reef that is often strewn with broken coral pieces and free sand. Barrier reefs also form along coastlines, but further away from land and in somewhat deeper water. As long as the underlying sea bed is shallow enough to allow corals to develop, a barrier reef can develop in any type of open ocean water. Finally, atoll reefs form rings around islands with a lagoon in the middle. They begin as fringing reefs surrounding a volcanic island; then, as the volcano sinks, the reef continues to grow, and eventually only the reef remains.
Coral reefs are formed by calcium carbonate produced by tiny coral polyps. A coral colony may consist of thousands of polyps. Polyps are typically carnivorous, feeding on small particles floating in the water. While corals are the chief architects of reef structure, they are not the only one that contributes to the final product. Coralline algae cement various corals together with compounds of calcium, and other organisms such as tube worms and molluscs donate their hard skeletons (Jitkue, Pg. 2). Together these organisms are able to construct the different types of reefs that are present on our ocean floors today.
These coral reefs are very diverse and special ecosystems that support a collective amount of marine life. Amongst the reefs are complex food webs and prey relationships. This ecosystem is made up of a species that interact with each other and the physical environment. Corals can obtain food in a variety of ways. The main source of energy for coral ecosystems is the sun. Corals are animals, not plants; sunlight is a key component to their survival. They require the sun to power millions of microscopic algae, called zooxanthellae which live in their tissues. Through photosynthesis, phytoplankton, algae, and other plants convert light energy into chemical energy, thus feeding many herbivores of the ocean. The algae provide the corals with food and oxygen in return for raw materials and a secure place to live. This joint effort is what allows the reef to survive in nutrient-poor tropical seas.
Reef-building corals rely on the photosynthetic products of zooxanthellae for the majority of their nutrients (Bischof, Pg. 3). However, corals are also suspension feeders and capture zooplankton for food. They utilize two main methods of prey capture: nematocyst adhesion and mucus entrapment. Nematocysts on the tentacles and mesentarial filaments can be used to sting prey and move it into the mouth. Some corals will trap prey in sticky mucus on their tentacles and move the prey into the mouth using the mucus and cilia.
Not only does this under water organism have an ecosystem that revolves around it, but it also plays a role with its contributions to the earthŐs atmosphere. Coral reefs are important in determining the amount and balance of carbon dioxide in the atmosphere. This process starts with the zooxanthellae algae that remove carbon dioxide from the air through photosynthesis. The aglea makes carbohydrates that are then available to the coral polyps to feed on. It is important to understand that when photosynthesis is occurring during the day, more oxygen is produced by photosynthesis than carbon dioxide by respiration.
Also, recent studies have connected the release of Dimethylsulfoniopropionate (DMSP), which is given off from both algae on the reef and phytoplankton, the overall climate change on your planet. The release of DMPS usually indicates that either of those tiny animals in the plankton is feeding on the algae, or that a massive growth of algae has occurred (Palumbi, Pg. 4). Once released from the ocean and into the atmosphere, outputs of DMSP produce cloud formations, in which these clouds then reflect more sunlight back into space and cool the earth and its atmosphere.
The coral itself is also a form of food to many species under water. One of the most important predators of corals is the Pacific OceanŐs Crown of Thorns Sea Star. It is estimated that a single Crown of Thorns Sea Star can eat from two to six square meters of corals per year. Many fish species such as parrotfish, butterfly fish and tangs also include corals as part of their diet. Because many fish use the coral reefs as a source of food. This also attracts the numerous predators like sharks and sting rays, which use the area as a place to catch a meal from the multiple fish that flood the reef.
Coral reefs over the past decade have been studied for medical purposes. As a matter of fact, eastern cultures have been using coral reefs as a medical resource since the 14th century. The field of science and medicine expects the coral reef species to contribute to future medical advances. If coral reefs are properly managed, they are potential storehouses of medical genetic resources (Bruckner 2007).
Specifically, the antiviral drugs Ara-A and AZT and the anticancer agent Ara-C were developed from extracts of sponges found on a Caribbean reef. They were among the earliest modern medicines obtained from coral reefs (Bruckner 2007). In addition, Dolostatin 10 was isolated from a sea hare found in the Indian Ocean. It is under clinical trials for use in the treatment of breast and liver cancers, tumors, and leukemia (Bruckner 2007).Coral reefs represent an important and untapped source of natural products with medical potential as pharmaceuticals, nutritional supplements, pesticides, and even cosmetics (Bruckner 2007).
One of the first steps to locating a promising cure in the medical field is locating the right compound (Bruckner 2007). Before a new drug can be synthesized, there must be an adequate amount of the compound available for research and testing. Many fit species occur at a low biomass or have a limited distribution (Bruckner 2007). Unfortunately in some cases a compound may occur only in species exposed to a rare environment triggered by a specific type of stressor. Due to the small quantity of this organism, collecting a sufficient amount for continued production of a new medicine is extremely difficult (Bruckner 2007).
Certain types of sea coral, collected specifically from reefs in the Pacific Ocean, are being used to create a new bone substitute that may be of use in some operations that require bone grafts. Surprisingly, coral reefs are very similar to bone, both in chemical composition and structure. Trauma, periodontal disease and congenital birth defects result in millions of people with scarce bone in the facial area, predominantly the upper and lower jaw area(The New York Times 1988). The most common and successful method of treating this problem is a bone graft. To perform this procedure, the surgeon makes a cut over the bone defect. The bone graft is shaped and inserted into and around the area. The new bone is held in place with pins, plates, or screws. Stitches are used to close the wound. A splint or cast is usually used to prevent injury or movement while healing.
According to most surgeons, grafts are effective for the majority of patients. One of the main problems is that they require two surgical procedures, increasing the chances of scarring and other complications. Doctors and researchers have hunted for an effective substitute to reduce the reconstructive process (The New York Times 1988). In coral, there is a hard deposit built up by minute animals called coral polyps, which consist of calcium carbonate. This type of calcium is inappropriate for grafting because the body would quickly absorb it. Nevertheless it can be converted with heat, water and phosphates to hydroxylapatite, a calcium phosphate that is the major mineral component of human bone (The New York Times 1988).
When converting the coral, it is essential to retain its maze of pores and channels. Doctors believe this structure allows bone to grow into and through it. According to an expert physician in this field, Dr. Rosen, explains that the substitute serves as a matrix for bone growth and is not susceptible to shrinkage (The New York Times 1988). As a matter of fact, Dr. Rosen has used the substitute in 65 patients. Of the operations, he said a third were for ''purely cosmetic reasons.'' Moreover, he has followed 45 patients for more than a year, and has found that the new substitute is ''holding up very well'' (The New York Times 1988).
Coral reefs also have an important role in coastal protection by slowing down potentially damaging tidal waves. Although there are exceptions when dealing with devastating tsunamis, coral reefs are a major defense mechanism with the protection of their neighboring mangroves. Much of the South Pacific islands rely on the reefs for protection of their homes and fisheries.
Although itŐs one of the biggest threats to coral reefs, tourism is also an important factor in relevance to certain countries economy. Last year alone over 1.2 million tourists visited the Great Barrier Reef. Every year the numbers of visitors increase by 10%. It has brought many resorts to the area who want to make some money in this $1 billion business. Tourism is the worldŐs fastest growing industry, worth over $7 billion annually in the Caribbean. The coral reefs also provide approximately one-tenth of all fish caught for human consumption, or around 4 to 8 billion tons annually (Jitkue, Pg. 4). Marine Scientists worry how much longer the reef can survive with the increasing popularity and tourists. A healthy reef is not only a better protector for coastlines, but are also thought to be some of the most active fisheries in the ocean when compared on a per unit base with the deep ocean.
Coral reefs are rich organisms that offer numerous benefits in the science field and for tourism purposes. They accent the environment with their irreplaceable beauty and rich structure. Coral reefs are a growing field of interest in the science field. It is crucial that the ecosystems are managed in a regular basis and kept clean. Tourism is one of the main causes of destruction of the reefs. Nevertheless, human beings are one of the most reliable sources of preserving the ecosystems protecting coral reefs.
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