The Dangers Of Coral Reef Bleaching

Elevated sea temperatures caused by climate change and extra-bright sunlight can result in coral bleaching. As the water gets warmer, corals will expel the algae known as zooxanthellae that lives in their tissues causing the coral to turn completely white. When temperatures drop, the corals can recover, but they might be vulnerable to disease and when

Coral reefs are found in shallow tropical waters along the shores of islands and continents. Coral bleaching is a topic that gets left in the dust. Not many people really pay attention or show much interest in it. Widespread bleaching, involving major coral reef regions and resulting in mass coral mortality has raised concerns about linkage of the events to global phenomenons including global warming or climate change and increased UV radiation from ozone depletion. Corals provide a lot not just for us humans but for marine life as well. Marine Biology provides information about how bleaching happens and how it affects the coral. Buchheims’ article is full of logos and a few pathos while the other source is full of ethos. In The Nature Conservancy’s director Stephanie Wear provides us with lots of professional opinions

Coral bleaching is normally characterized by the expulsion of the zooxanthellae algae, loss of algal pigmentation, or both. Coral bleaching events have had serious effects on corals and reefs worldwide. What is crucial to the understanding of zooxanthellae expulsion and bleaching is how the density of zooxanthellae within the coral is changing, if at all, under the prevailing range of environmental conditions (Gates and Edmunds, 1999). Over the last twenty years, there has been a dramatic increase in both the frequency and intensity of coral bleaching events. Sixty major bleaching events have been reported between 1960 and 1979, whereas only nine were reported prior to 1979 (Huppert and Stone, 1998). Given the dependence of the coral on this symbiotic algae, it is important to determine the cause of these bleaching events. According to Helvarg (2000, p.12):

Since early 1998, climate change has been demonstrating its effects in increasing the ocean 's temperature (West & Salm, 2003). Warm water stress corals causing the phenomenon known as coral bleaching, by which expulsion of colourful symbiotic algae the zooxanthellae, vital for

Bleached corals have reduced growth rates and have an elevated mortality rate. Coral bleaching also affects species such as fish and invertebrates that depend on living coral for food and shelter. Changes in the population and composition of reef fish occur when the corals they utilized are killed as a result of coral bleaching. Reefs affected by coral bleaching lose the aesthetic appeal that is fundamental to reef tourism. This aspect is highly relevant to the Great Barrier Reef because it is a popular tourist destination. It is estimated that the current bleached state of the Great Barrier Reef will cause Australia a loss of $1 billion in tourist income. Finally, coral reefs can be farmed for pharmaceutical compounds used to treat heart disease and cancer among other diseases. Bleached and dead corals are far less likely to provide these

The Barrier Reef is the largest reef in the world, and it is located in Australia. It is made up of different types of coral and fish, but sadly the reef is bleaching. Bleaching is the process of water temperatures getting too warm and as a result coral reefs can bleach. When water gets too warm, corals will get rid of the algae living inside their tissues causing the coral to turn completely white. Although, when coral reefs turn white this does not mean that they are dead, coral reefs can actually survive a bleaching event. It just means that the coral is under a lot of stress and

Located in tropical ocean waters, coral reefs provide priceless resources to both human and marine

In 1980, NOAA’s marine biologist started noticing the coral bleaching. There has been three important coral reef bleaching events in the history. The first global bleaching event “El Niño” was in 1998, it was a “huge underwater heatwave killed 16% of the corals on reefs around the world” . The second bleaching event was in 2010 and was called La Niña. This event affected especially areas near Palau and Micronesia in the Pacific. In October of 2015, NOAA announced the third global bleaching event in which has already become the longest event recorded, affecting coral reefs for consecutive years.

The bleaching of coral reefs is when warm water forces algae to leave the reef. Once the algae disappear, the coral goes from a vibrant color to a pale white. As one marine biologist said, “You go from a vibrant, three-dimensional structure teeming with life, teeming with color, to a flat pavement...” This bleaching makes the coral more vulnerable to diseases and a greater risk of death. The biggest bleaching events to have occurred in

A hypothesis created by a group of scientists determined that the cause for bleaching was due to stress (Brown and Ogden). This stress is closely linked to salinity changes, exposure to ultraviolet radiation in excessive amounts, huge climate changes and most importantly the increase in warm waters (Douglas ). Corals can survive in water that is between 25˚ and 29˚C. Any water temperature above that will result in the death of algae (Brown and Ogden). High ocean temperatures mixed with solar radiation are attributed to current large-scale bleaching events leading to global climate change, such as El Niño (Douglas ).

The Great Barrier Reef in Australia is experiencing bleaching. According to France-Presse, bleaching of a reef is “coral...that has been stressed by the heat” (France-Presse). When a coral has been “stressed by heat,” (France-Presse) the coral discards the algae that lives within itself which causes the coral to be more susceptible to disease. It can take up to several decades for a coral to recover from bleaching. Because of that fact that most coral does not have enough time to recover, it dies.

That's very bad for marine ecology and size of Great Barrier Reef, notes student Rachel Levin. On a genetical level, there have some reactions too. "We found they can switch on genes to produce proteins that neutralize the toxic chemicals," explains Levin, whose article on coral bleaching was published in the Molecular Biology and Evolution.

Australia’s scientists have released its comprehensive map of the Great Barrier Reef’s bleached corals revealing that less than 36% of the areas explored have not been severely bleached yet. The bleaching is caused by abnormally hot waters due to El Niño and climate change. These high temperatures cause corals’ symbiotic algae, which is their crucial food source, to become scarce and toxic, forcing the corals to expel it. Removing the algae turns the coral bone white and the coral begins to starve. Of the 911 individual reefs that researchers surveyed, a large 93%-843 reefs-experienced some kind of bleaching. Furthermore, the Great Barrier Reef is home to more than 1,500 different kinds of fish, 6 of the worlds remain seven marine turtle species

Coral reefs are threatened by global warming. They can only live in waters between 18 C and 30 C. Therefore, with the increase in temperature of the surrounding water, there has been an unprecedented increase in the number of coral bleaching events during the past 2 decades (which have had some of the warmest years in history). When ocean temperatures get too high, coral polyps lose the symbiotic algae inside them, causing them to turn white, or "bleach," and eventually die.

Coral reefs contain symbiotic algae called zooxanthellae which gives the coral its healthy brownish color. The algae "utilizes sunlight and the coral animal's respired CO2 to produce energy rich compounds that feed the coral host" (AIMS, 2003). When stress factors such as "heat, solar radiation, pollution, reduced salinity and changes in oxygenation" occur around the coral, bleaching can begin (Dennis). When bleaching occurs, the algae, which create nutrients for the coral to feed from, is released due to stresses to the reef. Thus the coral starves and its white calcium carbonate skeleton of the coral becomes visible (AIMS, 2003). But one of the main stresses that contributes to the lifeless white appearance of the coral is the warmer temperatures of the sea surface water.