Coral reefs are one of the ocean’s most astonishing sites. They are like modern day cities providing homes, food and protection to many different species of sea life. The reefs also provide erosion protection to the coastlines from battering waves. In addition, they contribute to local economies through fishing and tourism. The most beautiful coral reefs in the world have existed for thousands of years, such as, the Great Barrier Reef on the Australian Coast. Sadly, they are now being destroyed. “Researchers estimate that nearly 60 percent of the world's reefs are seriously threatened,” (Anonymous, 2001, 4) and “it is estimated that 30% of coral reefs have now lost >90% of reef-building corals and there is little to no prospect of recovery” (Trappon et. al., 2011, 2). There are many detrimental factors that affect the fragile corals. One of these is global warming. Climate change has caused increased water temperatures, sea level changes, ocean acidity, increased carbon dioxide levels and more. There are also many human related factors. Some of these factors are: water pollution, coastal development, destructive fishing practices, coral mining and careless tourism. All of these things are contributing to coral bleaching and other issues that kill the coral reefs.
Coral reefs are called the rainforests of the sea because of their diverse ecosystem (Anonymous B, 1). “The ancient Greeks mistakenly believed that corals were plants. Corals are actually animals, related to anemones and jellyfish” (Woods 2003, 0). They consist of many colonies with each individual coral being called a polyp. The corals have hard skeletal structures that are made from calcium carbonate that is secreted by the polyps. The calcium carbonate builds up over time, continually adding to the size and shape of the structure (Anonymous B, 3). The corals have a symbiotic relationship with a single-cell allege called zooxanthellae. These algae live inside the coral. The coral provides a safe home for the zooxanthellae and zooxanthellae provide food for the coral from the sugar it produces through photosynthesis. In turn, the corals excrete nitrogen waste, which the alga consumes as food (Woods 2003, 1). The zooxanthella also gives the coral its vibrant color.
Corals are sessile animals, which means they do not move, but are fixed in one place. (Anonymous B, 4) In order to survive, they live close to the surface so light can penetrate down to reach the corals for the purpose of photosynthesis. The water, in which the corals thrive, needs to be 68 -82 degrees Fahrenheit (Kalman 2008, 1). For these reasons, they live in shallow, tropical waters. The reefs are home to more than 25% of all marine life. They provide food, homes and breeding grounds for sea life that inhabit the area, which makes them a big part of the oceans' ecosystem (Kalman 2008, 1).
In addition, coral reefs provide many benefits to humans. The reefs contribute billions of dollars to local economies through the fishing and tourism industries. They also provide the main protein food source for many impoverished coastal lying countries (Glick 1999, 7). “More than 30 million people depend on coral reefs for their livelihoods” (Anonymous, 2001, 11).
For all of the beauty and benefits that the coral reefs provide, in return they are being destroyed. Corals are “often thought of as the ocean’s “canaries in a coal mine.”” This is because they are particularly sensitive to changes in their watery environment (Kalman 2008, 1). “Nearly one-third of the 704 species studied are listed as “Critically Endangered,” “Endangered,” or “Vulnerable.” (Kalman 2008, 5) So, what is it that is destroying these beautiful fragile reefs?
Coral bleaching is one of the main complications for corals. This process happens when there is an increase in environmental stress (Kalman, 2008, 3). Causes of bleaching can include: increased water temperatures, increased water acidity, increased water levels, increased UV radiation, storms, chemical exposure, sediment covering the coral, chemical household products, and overload of nutrients and fertilizer (Woods 2003, 6).
Global warming has had many affects on the oceans. One of these affects is the rising water temperatures. This increase of temperature causes the fragile corals to be threatened. Due to the increased water temperature, the photosynthetic process of the zooxanthellae is being disturbed. This causes a buildup of substances that are poisonous to the algae. In order for the coral to protect itself, it releases the zooxanthellae along with some of its own tissue. This process causes the coral to lose their color and become bleached (Woods 2003, 5). Bleached corals are weaker and more prone to disease. However, they can survive if conditions return to normal quickly (Anonymous C, 4).
Increased ocean acidity is also contributing to the killing of the coral reefs. The ocean’s acidity has been changing as the result of the astonishing increase of human produced carbon dioxide that has been released into the atmosphere over the past 250 years. This is because the waters absorb the carbon dioxide from the air, which benefits humankind by reducing greenhouse gasses in the atmosphere, but dramatically affects the waters (Anonymous C, 2). The dissolved carbon dioxide in the water lowers the oceans pH level. The decreased pH level causes a disruption of the corals calcification process and weakens the existing coral skeleton making it more vulnerable to disease, erosion, and damage from fishing and tourism. The reduced pH also affects other ocean life by reducing food levels and the calcification of shellfish (Springer-Verlag 2009, 5).
Over the last century, the sea level has risen 20 cm. This is “due to thermal expansion and melting of land-based ice, and is projected to be another 60 cm higher by 2100” (Springer-Verlag 2009, 9). With the rising sea levels, the coral reefs can drown. This event occurs because it is difficult for corals to obtain the proper amount of sunlight at these deeper depths necessary for photosynthesis. Without photosynthesis, the algae will not be able to produce the food needed for the corals to survive (Knowlton 2001, 12). This will especially affect the slow growing corals and will cause a drastic reduction of this species (Anonymous A, 4).
Beyond the environmental factors affecting the reefs, there are other human related factors. One of these is over-fishing. Coral reefs have an extensive amount and variety of seafood, which fishermen have long taken advantage of. Many fisheries, dependent on coral reefs, have harvested unsustainably and depleted the numbers of sea life faster than it can reproduce. As the fishermen continue to take from the reefs, the ecosystem becomes unbalanced. With this imbalance, the corals can be affected greatly by the consequences, such as, the overgrowth of algae, which can smother the reef. Also, the reefs are damaged by harmful fishing practices such as the use of cyanide. Cyanide is used to stun the fish prior to capture, but this harmful chemical is absorbed by the coral (Glick 1999, 11, 12). Other causes related to fishing practices are stick banging and the use of explosives, which damage the corals structure (Anonymous C, 9).
Another human related factor is coastal development. More and more of the world’s coastlines are being developed without any regard to the habitat of the coastal waters. Channels are being dug for safe ship passage, piers are being built on top of the reefs, and land is being paved allowing polluted water and silt to runoff into the oceans. “Rapid development over the past 50 years has contributed to excessive sewage runoff, which harms coral reefs by causing accelerated algae growth.” Other practices such as mining, farming, destruction of forests and the use of fossil fuels create air pollution and water run off pollution. These pollutants poison marine life. All of this is destroying the coral reefs and, in turn, endangering the coastline from the erosion that was being prevented by the coral reefs (Glick, 1999, 10).
There are also numerous threats to the coral reefs from tourism and coral mining. Although tourism generates millions of dollars to local economies, it can have a devastating affect to the coral reefs in two ways. First, sewage that is not properly contained or resorts that dump waste directly into the ocean hurt the coral reefs. Secondly, is the physical contact tourism brings to the reefs. Tourists swimming, diving, boating and fishing cause direct damage the corals by touching, kicking, grabbing, walking on or stirring up sediments. Boaters also drop anchors directly on top of the corals causing damage to their structure (Anonymous C, 11). Removal of coral through mining has also contributed to coral depletion. The corals have been mined for souvenirs to be sold in the tourist trade and for use in various types of construction (Anonymous C, 10).
In order to save the magnificent coral reefs, action must be taken. The reduction of greenhouse gasses must be reduced worldwide. This will require researchers to come up with better environmentally friendly technologies. In addition, water pollution, habitat destruction and harmful fishing practices must be controlled internationally. Funding for research on how the coral reefs are affected by different issues and how to protect the reefs from these issues is essential, as well as increased funding for reef restoration (Eakin, Kleypas, Hoegh-Guldberg, 2008, 4). Enlarging protected marine areas around reefs worldwide, to protect them from dangerous fishing practices and tourism related damage, would also aid in their survival. The reefs are minimally protected in this way now (Glick 1999, 13). “Some scientists have predicted that by 2030 massive and devastating coral bleaching events will occur every year” (Woods, 2003, 10). So, it is vital to take actions now to protect the fragile coral reefs.
Coral reefs provide not only beauty, but contribute to the vast ocean ecosystem. They provide food, protection and breeding grounds to thousands of species of sea life. Human beings also benefit from these amazing reefs by their ability to contribute billions of dollars into the local economies through fishing and tourism. Coral reefs also provide a source of a food protein to impoverished coastal countries. Yet, these slow-growing magnificent structures of the ocean are being destroyed at an alarming rate. These fragile animals and their symbiotic partners, zooxanthellae, are greatly affected by global warming and its consequences, such as, increased water temperature, increased acidity levels, and increased water levels. These threats can cause devastating, mass coral bleaching events. In addition, human activities like destructive fishing practices, careless tourism, coral mining and coastal development are adding to the threats. In order to save these important and invaluable beautiful reefs, the world population must change their habits, improve technologies in order to reduce pollution and use environmentally friendly construction and development practices. If we do not take action, these beautiful life and economy sustaining structures will forever be lost for future generations. This would be a tragic event for the earth’s oceans and to the worldwide society.