Tuesday, March 3, 2015

Coral Bleaching and the Great Barrier Reef
http://ngm.nationalgeographic.com/2011/05/great-barrier-reef/holland-text


Introduction
Dating back about twenty million years, the Great Barrier Reef is an ancient and enormous coral reef ecosystem which hosts an abundance of living organisms. It is the largest living structure on the planet, and the largest reef system (5). Reefs are referred to as the “rainforests of the ocean” and have some of the richest biodiversity on the planet. This invaluable resource, with all its biodiversity, is essential to the aquatic ecosystem. The Great Barrier Reef is roughly half the size of texas. The Reef is home to thousands of different plant and animal species. Around 10 percent of the world’s total fish species can be found just within the Great Barrier Reef (5). There are numerous threats to coral reefs, including shipping accidents, pollution from oil spills and trash, overfishing, and tourism (4). Climate change is the greatest threat to the Great Barrier Reef, as warmer water temperatures put stress on coral populations, they undergo what is called coral bleaching. Two mass coral bleaching events took place in 1998 and 2002. The mass coral bleaching that occurred in 2002 resulted in over 50% of reefs experiencing some bleaching (5).

Geography of the Issue
Coral bleaching is a global issue. Coral reefs around the world have been greatly affected by unusually warm water temperatures as well as other factors including overfishing, pollution, and damage from tourism, most of which are caused by direct human pressures (4).
















http://i.telegraph.co.uk/multimedia/archive/00443/news-graphics-2007-_443175a.jpg

Specifically in the Great Barrier Reef, which is located off the Northeastern coast of Australia, there has been significant signs of damage due to these threats. Extending 2,300 km long and spanning an area of 344.4 square kilometers, the Great Barrier Reef, along with other coral reefs, is home to thousands of different species (1). The aquatic ecosystems that are found in coral reefs are in danger as a result of coral bleaching, specifically in the coast ecosystems in Australia and the Great Barrier Reef itself.



Addressing the Problem
History of Coral Reefs and the Great Barrier Reef
There has been a noticeable degradation of coral reefs over the past 30 years. In the Great Barrier Reef, coral cover has reduced by more than 50% in those years (1). High awareness of coral bleaching and efforts to mitigate it began around 10 years ago, with laws passing fishing regulations and monitoring and managing of coral reefs began to take place.






These pie graphs show the damage done to coral reefs as a result of the two major coral bleaching events of 1998 and 2002.


Conditions, however, have have shown little improvement, primarily due to global temperatures still rising. Increased carbon dioxide, and other greenhouse gases in our atmosphere, and its acidification of our oceans has had a huge impact on the oceanic environment as temperature increase. This gases contribute tremendously to the increase of global temperatures. Ocean water temperatures have increased by almost 1°C in the past 100 years, and are currently increasing at about 1 to 2°C per century (14). This clearly has far reaching effects as seen in its effect on coral reefs; it will take years to recover from the damage caused by global climate change on these reefs. The Great Barrier Reef Outlook Report for 2009 indicates that “if we want to keep the reef alive we need to halt carbon dioxide (CO2) in the atmosphere at current levels around 400 parts per million (ppm). We are approximately adding a further 2ppm every year. So in 50 years if we keep going with business as usual we will hit 500ppm by 2050” (3).




Science Behind the Issue
Corals are made up of layers of calcium carbonate secreted over time by soft bodied animals called coral polyps (12). Coral polyps and algae have a symbiotic relationship in which they rely on each other for survival. The zooxanthellae, a photosynthetic algae, are the main food source of the coral, and they also provide oxygen and other nutrients to the polyps. Healthy coral house these algae in their tissues. They are vibrant as a result of the many zooxanthellae living in them that give them their color. Without their algae, corals do not have enough food to survive (1). Coral bleaching is due to “stress” given off by external threats that include pollution, overfishing, damage, and especially global climate change. If the coral is exposed to warmer ocean temperatures, it expels their zooxanthellae. When they are expelled by the coral, it causes the coral to lose its color and turn completely white, causing the bleaching effect we see (10). Once a coral is bleached and deprived of its major food source and nutrients, it is placed in a vulnerable condition where it is susceptible to disease and in risk of death and starvation (9).



Consequences and Impacts of Coral Bleaching in the Great Barrier Reef
Coral reefs are often referred to as the “rainforests of the ocean” and have some of the richest biodiversity on the planet. The Great Barrier Reef itself houses 10% of the world’s fish species. “The reef is bountiful with a wide variety of fish (1500 species), hard corals (395 types), birds (175 species) and marine and land animals” (6).  Damage to coral reefs can have drastic risks to coastal and coral reef ecosystems. Without the corals to shelter them, many organisms that rely on coral would also be at risk of extinction, resulting to a decrease in biodiversity of marine species.


Coral reefs provide many benefits to humans. These benefits include protection in our shores from impacts of waves and from storms. They supply economic benefits to much of our industries, including the fishing and tourism, providing us with food and medicine and sights in vacation spots (8). Local communities rely on these industries as a major source of revenue. Without coral reefs, many of these communities would be in risk of economic breakdowns and would no longer be able to provide for their people.





It was estimated in 2003 that Australia's gross domestic product for mining, tourism and agricultural industries together in the Great Barrier Reef region was over $14 billion. 62 per cent of Queensland’s, the area located in the northeastern coast of Australia, ports exports were from the ports of Great Barrier Reef region (6).

Larger Consequences of Coral Bleaching
Coral bleaching is a problem for coral reefs all over the world. Higher global temperatures are a major cause for the bleaching, and subsequent death of many of our coral reefs worldwide. Due to coral bleaching, the Great Barrier Reef is already 50% reduced, while worldwide, coral reefs overall have faded by 19% (11). The Caribbean coral reefs are in danger of vanishing within the next 20 years and scientists have said that as much as 95% of Jamaica’s reefs are dying or dead as a result of coral bleaching (7).


Here’s a before and after picture showing a coral reef in the Caribbean.

Coral bleaching of coral reefs has major global consequences. As previously stated, much of our economy would fail without coral reefs. “If the reefs vanished, experts say, hunger, poverty and political instability could ensue” (11). Coral reefs house nearly half of the fish populations we humans consume and depend on for our livelihood. Coral reefs also provide attraction for much of the aquatic tourist industries. Many countries depend on these industries as major driver in their economy, and without coral reefs, these countries would be at risk of poverty. Coral reefs also supply an amplitude of biodiversity in our ocean waters, and their degradation would result to the extinction of many marine species.



Solutions to Coral Bleaching

Scientists have already began implementing conservation strategies including reducing ocean acidity, placing giant canopies on shallow coral reef ecosystems and shading them, thus reducing water temperature, and replanting coral on devastated reefs. Efforts to reduce ocean acidity includes adding biocarbonates or lime into the water. However, to offset the effects of our carbon emissions, we need to add around 9,000 million tonnes of lime to the ocean every year, while we only produce around 300 million tonnes per year (2). Also, the price of giant canopies to shade coral reefs and reduce their water temperatures is too large to make it a viable option. The best method of conservation would be through replanting corals. Currently, scientists are breeding more adaptable corals so that they can withstand higher temperatures and high levels of acidity. One way of doing this is by exchanging the coral's algae species for more robust types (2).

Efforts to Replant Coral:

Another solution to the prevent the bleaching of coral is to mitigate global climate change. Land and sea temperatures are certainly projected to continually warm and sea levels are expected to rise during the 21st century (15). These estimations are based on our current dependence on fossil fuels (mainly coal and petroleum), which contribute greatly to the greenhouse gas emission into the atmosphere and acidity levels in the ocean (11). In order to slow down the process of global climate change and the increase of Earth’s temperatures, we need to find alternative and cleaner sources of energy that emit as little carbon and greenhouse gas as possible, as well as reduce our reliance on fossil fuels. Methods can include adopting energy sources through solar, wind, and hydropower, burning biofuels, or contribute in decreasing fossil fuel consumption by carpooling, biking, and walking as means as transportation (8).


As discussed earlier, with the high cost of maintenance of coral conservation and great measure of human reliance on fossil fuels as a main source of energy, the solutions to coral degradation are seemingly unrealistic. However, if countries place more efforts and finances into coral conservation, coral populations would be able to rise again. The determining factor to the survival of coral species is human behavior and our willingness to change our ways. In order to restore coral reefs, we would have to comply to adopt new sources of energy and contribute greatly to mitigate global climate change, as well as contributing to less pollution, overfishing, and exploitation from tourism. However, it could take many years or decades to change our behavior.

Organizations Acting to Address Coral Bleaching
There are some organizations helping to restore coral reefs, notably the National Oceanic and Atmospheric Association (NOAA).  NOAA has made major leaps into organizing ways to in coral conservation and restoration, especially through their Coral Health and Monitoring Program (CHAMP). CHAMP is dedicated to providing “services to help improve and sustain coral reef health throughout the world” (10). NOAA is leading efforts to enhance global capacity to predict and manage bleaching events, mainly through the use of satellite sensors that monitor ocean conditions. This allows them to notified the likelihood of bleaching events and respond to minimize the stress on coral. NOAA is also working to reduce overfishing by collaborating with fishing organizations and fishing communities. They were able to ban damaging fishing practices in federal waters, worked with enforcement agencies to enforce fishing restrictions, and assisted in developing approaches to meet both society's needs while still protecting coral reef and fish (9).




Although increased efforts have been made by NOAA to restore coral reefs, these solutions have not been applied with significant levels of success. To our understanding, there has not been any attempts to implement some of the more costly and difficult solutions. As long as temperature continues to accrue, the conditions of coral reefs will unlikely show signs of great improvement. According to NOAA, reducing the effects of coral bleaching and ocean acidification will require global cooperation and innovation. Collectively, we all have to contribute to efforts to mitigate climate change and reduce pollution to restore coral reefs to how they once were.

Conclusion
The likelihood of resolving the damage conducted by coral bleaching is skeptical. The survival of coral reefs, specifically the Great Barrier Reef, is completely dependent on human behavior. In order to see noticeable improvement in the livelihood of coral reef ecosystems, we would immediately have to change our current lifestyle. All we know is that if an enormous effort is not made to counteract and slow down the process of coral bleaching in our coral reefs, the Great Barrier Reef will be completely wiped out by 2050 (2).
Whether directly or indirectly, humans have an immense impact on the environment. From the trash our streets and local neighborhoods, to pollution in our air, and far reaching into the depths of the ocean, the environment around us is impacted by what we do. While human innovation proposes an amazing lifestyle, we must not hold innovation so dearly so as to put our world’s ecosystems in jeopardy.

















Reference List
  1. Australian Government: Great Barrier Reef Marine Park Authority. http://www.gbrmpa.gov.au/about-the-reef/facts-about-the-great-barrier-reef
  6. Great Barrier Reef: Booking and City Guide. http://www.greatbarrierreef.com/v/economy/
  9. National Oceanic and Atmospheric Administration (NOAA). http://celebrating200years.noaa.gov/visions/coral/welcome.html#solutions
  14. Hoegh-Guldberg, O. (1999). Climate change, coral bleaching and the future of the world's coral reefs.Marine and Freshwater Research. (Peer-reviewed article)

Disclaimer: We do not own any of the images displayed.
Posted by at

3 comments:

Subscribe to: Post Comments (Atom)