Coral reefs are fragile ecosystems, and even a slight change in their marine habitat could drastically impact the corals, and other marine life too. One of the main threats to the reefs is climate change. As global warming occurs through out the world, the ocean waters will also start to get warmer, which is what is known as ocean warming. Even 2 degrees Celsius change in the water can have a massive impact on the corals. This is because the corals can feel this slight change and will start to feel stressed, and their first natural reaction is to expel their symbiotic zooxanthellae since this algae is not a part of them. The corals at this stage are now hopeless without their symbiotic partner, and will not be able to survive without oxygen and food. The now starving corals will turn into a ghostly white and perish.
Since humans need healthy coral reefs to be able to get fish, it makes sense that they would want to protect the reefs. But instead, overfishing and destructive fishing has become another threat to the marine ecosystem. Not only do corals protect the fish, the fish also protect the reefs by keeping them clean and giving them nutrients and food to thrive. If there weren’t enough fish in the reefs to do so, the corals would not be able to survive. Destructive fishing also does massive damage to the reefs because in some reefs, people have large nets to catch fish in. This technique is not only pointless, but also harmful because the nets will only get caught in the corals, smashing them and the fish too. Some fishermen pour a chemical into the water to stun the fish so they can catch them, but the chemical is very harmful to the corals, and will eventually kill them. Natural disasters occur only once in a while, and so...
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...conditions eventually led to the bleaching of a tremendous amount of corals, and caused a total of 70% to 80% of all shallow-water corals deaths.
Although, weather isn’t the only threat nature brings to the coral reefs. Invasive species and predators of the corals are also threats to the corals. The crown-of-thorns Starfish (Acanthaster planci) is one of the corals predators. They slowly crawl over corals and literally “eat the life out of them” as they consume all of the corals living tissues, then move on to the next coral. Other predators of corals include fish, barnacle, marine worms, snails and crabs. During 1978, a massive amount of Crown-of-Thorns Starfishes invaded the reefs in the Fagatele Bay National Marine Sanctuary in American Samoa. This was an extreme case of predation and had devastating results as 90% of all corals at the sanctuary were destroyed.
Coral reefs around the world are in danger. One of the causes is global warming, which has been increasing the temperature of the ocean water resulting in coral bleaching. This essay will focus on damage occurring to the Great Barrier Reef.
This article discusses how important the organisms symbiotic with coral reefs are, as well as how important coral reefs are to our environment. Also explained is how natural and non natural things things like hurricanes and overfishing affects them. A study is quoted about how water acidity also plays a role in the bleaching of corals. Lastly, restoration and conservation efforts are discussed and how we could possibly help our oceans.
Coral Reefs are said to be the “tropical rainforest” of the sea. They are home to over 25% of all marine life (http://coralreefalliance.org.stories/storyReader$77). Over the past few decades they have been subjected to destructive anthropogenic practices. Some of the major threats to coral reefs include sedimentation, water pollution, harmful recreational activities, and global warming. All of these things cause stress on corals and can potentially cause mortality. Corals are made up of two parts, a polyp and zooxanthellae. A polyp is a calcerous body that grows from a hard part of the ocean floor. Zooxanthellae is a photosynthetic algae which lives in the polyp and provide energy for themselves and the coral. In many cases, corals undergo “bleaching,” which is a process where corals lose the zooxantheallae or chlorophyll pigment, and turn white (Wilkinson et all). After bleaching corals can survive for several months. It is possible for corals to recover by hosting more zooxantheallae, but it can take between 5 and 50 years for them to recover completely (Wilkinson et all, 1999).
Leading scientists advise climate change will cause increases to the frequency and intensity of extreme weather events. Rising sea levels pose a significant risk to coastal communities, while the world’s oceans could become too acidic to support coral reefs and other calcifying marine organisms. Coral reefs contain only six per cent of the area of the Great Barrier Reef, yet they provide critical habitat and food for numerous species in the ecosystem. However, climate change has already impacted coral reefs in the Great Barrier Reef as corals are very helpless against its potential impacts. Eight mass coral bleaching events has occurred since 1979, triggered by unusually high water temperatures. And because of this, zooxanthellae (photosynthetic algae) leave their tissues and corals will have no more colours hence ‘bleaching’. Without the zooxanthellae, the corals that remain gradually starve to death. Once the coral dies, fish and a multitude of other marine species are soon affected. Rising sea levels and more frequent and intense storm surges will see more erosion of Australia’s coastline, causing community and residential
Imagine a lush underwater place. Beautiful structures colorful animals and places that would never have been thought of before. In reality that's not what it really looks like, really the ocean is a desolate place that is barren like a desert. Many marine species have been lost by as much as 49%.(seeker) A big part of that reason is because of coral bleaching which causes as stated above a decline in species that depend on the coral as there home. Coral bleaching is a serious problem that could cause problems for everyone if we don’t fix it.
Bleaching is when the ocean water become too warm, “corals will expel the algae (zooxanthellae) living in their tissues causing the coral to turn completely white. This is called coral bleaching. When a coral bleaches, it is not dead. Corals can survive a bleaching event, but they are under more stress and are subject to mortality.” (Cave and Gillis). When a coral bleaches, it is more of like a self defense mode, which makes it turn white. The coral loses its food source as well. The downfall of this is that without the cooler waters, the corals could die of starvation or disease. Cooler waters from below can help a bleached coral bounce back to its natural state. However, if the water stays too warm for an extended period of time, “the corals don't just bleach, they cook and they die very quickly,.” (Westcott). Throughout time, much of the corals near Cairns and northward have lost the most corals. Hughes states that, “near Cairns, the Great Barrier Reef has lost 47 percent to 83 percent of their coral and as you go northward, the Great Barrier Reef has lost 11percent to 35 percent of its corals.” (Cave and Gillis). In another report, “a study last year found the largest die off of corals ever recorded with about 67 per cent of shallow water coral found dead in a survey of a 700km stretch.” (Johnston). In 2016 and 2017, there were back to back bleaching events. According to CNN reports, “back to back bleaching events in 2016 and 2017 have devastated a 1,500 km (900 miles) stretch of the UNESCO World Heritage Site.” (Westcott). Before the 2016 bleaching event of the Great Barrier Reef, there have only been two bleaching events, 1998 and 2002. According the Hughes, “only 9 percent of the reef has avoided bleaching since 1998.” (Cave and Gillis). That means that over 90 percent of the Great Barrier Reef has been affected by coral bleaching at least once in the past 19 years.
The world’s coral reefs are quintessential to global biodiversity, so much so that they are often referred to as the "rainforests of the sea". Although their actual space occupied by reefs is relatively small, constituting less than 0.1% of the world's ocean surface, they support over 25% of all marine species on earth. They provide complex and varied marine habitats that support a wide range of other organisms including, but not limited to, fish, mollusks, worms, crustaceans, echinoderms, sponges, tunicates and other cnidarians. Some of these animals feed directly on the corals, while others graze on algae on the reef. The reef also provides a protective habitat for many of these animals.
All over the world coral reefs play an important part in our environment. Not only are the reefs colorful and beautiful to look at but the coral reefs house several different types of fish and other sea creatures. Coral reefs have started to decline over the years due to “climate change, El Nino events, overfishing, pollution and other pressures” (Newnham 1). A healthy coral reef can also collapse due to a natural disaster (Newnham 2). There can be several different reasons why a coral reef has started to decline or has been destroyed.
Coral reefs can be found in shallow and deep waters and are one of the most diverse ecosystems. They are home to many and most of the marine organisms in the ocean. Most of these ecosystems are at risk however due to the rising temperatures of the oceans. Sea temperatures in many tropical regions have increased by almost 1°C over the past 100 years, and are currently increasing at ~1–2°C per century (Ove Hoegh. 1999). Because of this increase in temperatures, the future of our worlds coral reefs are in danger and at risk to things like coral bleaching, effects of rising ocean acidification levels and the effects from sea levels rising.
Now that corals have been briefly described we can see why the effects of climate change damage coral reef systems. Ocean acidification is one result of climate change. Acidification is caused by an increase of carbon dioxide in our oceans and leads to a decrease in the pH levels of seawaters. This pH decrease reduces the ability of corals to make their hard skeletons. Rates of coral calcification on the Great Barrier Reef and many other reef systems around the world have declined by 15-20% since 1990 due to increasing thermal stress (De’ath 2012). It has already been mentioned that the oceans are absorbing almost all of the excess heat from climate change. This effects coral reef systems in what is known as coral bleaching. The term bleaching refers to the loss of corals’ colors. A coral’s color is the result of the zooxanthellae present. When water becomes too warm the
The leading natural cause of destruction among the coral reefs is global warming. Global warming causes the bleaching of coral reefs to occur. Bleaching is a response to stress by the coral reef that happens when the water becomes to warm. The coral then put out a brownish zooxanthelle which causes them to lose their color. Without the zooxanthelle, the corals cannot provide nourishment for itself and th...
Climate change has been affecting coral reefs in a negative way. If the climate continues to get warmer more of our coral reef become bleached, the structure of the reefs will become weak, and algae that keeps coral healthy will die. In the essay, “A framework for understanding Climate change impacts on Coral Reefs” by Joshua Clinner (2016), he emphasizes our climate change has become one of the long-term threats to coral reef. The article “Climate change and human impacts are damaging the world’s coral reefs”, which didn’t include an author (2001), states that the sea temperatures throughout the tropics has increased dramatically leaving much of the coral unhealthy. Spencer Hall (2008), discussed in his article “Coral Reefs and Climate Change”, how the increase in climate change puts a lot of stress on coral reefs because they are very sensitive to the change of temperature. Rigel B (2003) states in his essay, “Climate Change and Coral Reefs”, that coral reef has already been negatively impacted by
Coral reefs are well known for their colorful array of marvelous sights including a parade of exotic flora and fauna. They are said to be the foundation for a quarter of marine species, and are a crucial support for human life as well. The coral reef ecosystem is a diverse collection of species (ranging from microscopic to larger-than-life in size) that interact with each other and their physical environment. If any piece of a coral reef is harmed or removed the entire community can be seriously affected, even to the point of collapse. Unfortunately, human impact has resulted in long-term stresses that, unlike the short-term stress of natural disasters, coral reefs are not as capable to recover from. “Approximately half of the world’s coral reef ecosystem resources are considered by scientists to be in 'poor' or 'fair' condition and have declined over time due to several anthropogenic threats” (“Status of Corals” par. 2). Through poorly administered commercial practices, carelessness and ignorance among the common people, and human aggravated natural processes coral reef destruction has become a serious issue afflicting the world’s biodiversity and it’s intricate biosphere mechanics (“Human Impact on the Great Barrier Reef” 1) (“What Are Coral Reefs?” 1).
Corals provide shelter for nearly one quarter of all known marine species. The reefs are home to over 4000 species of fish, 700 species of coral, and thousands of other forms of plant and animal life. Living coral reefs are the foundation of marine life, and this also means that they are essential for human life, but all over the world they are dead or dying because people are destroying them at a very fast rate. Already 10% have been lost, and there are predictions that 705 of all corals on the planet will be destroyed in 20 to 40 years unless people stop doing what they are doing now – i.e., pollution, sewage, erosion, cyanide fishing, bad tourism.
If the coral reefs were to become extinct, then future generations would not have the benefits that these animals have to offer, such as possible medicines, pest control, and carbon dioxide control. Fisheries are also contributed by corals and if they were eliminated would reduce the food source greatly. By not preserving corals, we are taking food directly out of our grandchildren's mouths. With the technology that is rapidly being discovered, we learn more and more about what we can do with bone structure and hard corals. Right now we are doing restructuring procedures and learning that bone tissue and blood vessels spread into the coral graft and eventually bone replaces most of the coral implant.