What is the Great Barrier Reef?

          The Great Barrier Reef is the world’s largest coral reef and is a home to an extremely diverse ecosystem (UNESCO, 2012). The Great Barrier Reef is also one of the seven natural wonders of the world (7 Natural Wonders, 2008). The reef consists of “1,500 species of fish, 411 types of hard coral, one third of the world’s soft corals, 134 species of sharks and rays, six of the world’s seven species of threatened marine turtles, and more than thirty species of marine mammals” (WWF, 2012) The reef not only provides ecological benefits, but also offers economic benefits to the Australian economy by providing 63,000 people with employment and contributing $5.4 billion annually through reef industries (WWF, 2012).

Image is taken by Sloan Bragg
http://ngm.nationalgeographic.com/ngm/photo-contest/2011/entries/81876/view/

          Google Maps added to “Street View” their first underwater panoramas in September 2012 using the SVII to take 360-degree panoramic images. This allows the viewer to see underwater forests and marine life as if they were diving at The Great Barrier Reef (Watts, 2012). 

Image taken from Google Maps of Heron Island, Australia

Image of a diver with the SVII to capture 360-degree images of The Great Barrier Reef.
http://www.guardian.co.uk/environment/gallery/2012/feb/23/virtual-diving-panoramas-great-barrier-reef-in-pictures?intcmp=239#/?picture=386387541&index=3

Sources:

1. "Great Barrier Reef." The Seven Natural Wonders. Web. 30 Nov 2012. <http://sevennaturalwonders.org/the-original/great-barrier-reef/>.

2. "Great Barrier Reef." UNESCO. UNESCO World Heritage Centre, 2012. Web. 30 Nov 2012. <http://whc.unesco.org/en/list/154/>. 

3. "Great Barrier Reef." WWF Australia. WWF, 2012. Web. 30 Nov 2012. <http://www.wwf.org.au/our_work/saving_the_natural_world/oceans_and_marine/priority_ocean_places/great_barrier_reef/>.Watts

Great Barrier Reef Spatial Scale

         Coral reefs are typically found in tropical and sub-tropical waters due to their inability to thrive in temperatures below 18°C (NOA, 2008). Coral reefs also require very clear, saline water that is between the range of 32 to 42 part per thousand (NOA, 2008). 

This map taken from NOAA shows how coral reefs are typically found between 30° north and 30° south latitude, where tropical and subtropical waters typically occur. The red dots represent major coral reefs in the world.
http://oceanservice.noaa.gov/education/kits/corals/media/supp_coral05a.html

         The Great Barrier Reef is located in North Eastern Australia and is the only natural wonder that can be seen from space (7 Natural Wonders, 2008). The reef consists of 2,900 separate reefs and over 900 islands (7 Natural Wonders, 2008). The Great Barrier Reef Marine Park covers 345,000 square kilometers, which is "five times the size of Tasmania" or larger than the "United Kingdom and Ireland combined" (WWF, 2012). 

This image was taken by the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite.  

http://www.universetoday.com/67562/great-barrier-reef-from-space/

This image is from the European Space Agency
http://www.earthweek.com/2010/ew100507/ew100507x.html

Sources:

1. "Corals." NOAA National Ocean Service Education. NOAA, 25 2008. Web. 30 Nov 2012. <http://oceanservice.noaa.gov/education/kits/corals/coral05_distribution.html>.

2. "Great Barrier Reef." The Seven Natural Wonders. Web. 30 Nov 2012. <http://sevennaturalwonders.org/the-original/great-barrier-reef/>.

3. "Great Barrier Reef." WWF Australia. WWF, 2012. Web. 30 Nov 2012. <http://www.wwf.org.au/our_work/saving_the_natural_world/oceans_and_marine/priority_ocean_places/great_barrier_reef/>.

Historical State

             The Great Barrier Reef is the world’s largest collection of coral reefs and is off the northeast coast of Australia. It contains over 400 species of coral, 1,500 species of fish, and over 4,000 types of mollusks. (UNESCO, 2012). The entire area is a total of 348,000 square feet and extends 250 km offshore. The area also includes shallow areas, mid-shelf, outer reefs, and extends 2,000 meters deep. (UNESCO, 2012). This ecosystem has evolved for millions of years, having been exposed and flooded by four glacial and interglacial cycles. These changes in the ecosystem over the years have created the GBR as it is now. (UNESCO, 2012). The continental islands, coral cays, and reefs show the evolution through the growth of coral cays and new phases when rising sea levels created the continental islands. (UNESCO, 2012). This ecosystem is a historical gem that has been evolving to current conditions for millions of years and continues to do so.

Sources:

1. "Great Barrier Reef." UNESCO. UNESCO World Heritage Centre, 2012. Web. 30 Nov 2012. <http://whc.unesco.org/en/list/154/>.

Current Human Impacts

          Although the World Heritage listed The Great Barrier Reef as a “dynamic system” where the coral populations naturally increases and decreases, human activities have significantly accelerated the death of coral reefs, leaving little room for them to recover (Phillips, 2012). The rise in ocean temperature and acidification has led to the death of the organisms residing inside the coral skeleton, also known as coral bleaching, accounting for 10 percent of coral reef decline (Phillips, 2012). Global warming models show how higher water temperatures are also leading to more severe cyclones, which accounts for 48 percent of coral die off (Phillips, 2012). Coastal development and agricultural runoff has led to a significant increase in the amount of sediments, nutrients, and pesticides entering the ocean, causing algal blooms (Hoegh-Guldberg et al. 2004:32). This intensification of nutrients from runoff leads to the rise in crown of thorn starfish larvae survival due to the abundance of algae that the larvae consume (Phillips, 2012). Although the crown of thorn starfish is a natural predator of coral reefs, they are multiplying so quickly that the reef does not have enough time to recover from damage (Phillips, 2012). The crown of thorn starfish outbreak accounts for 42 percent of The Great Barrier Reef coral wipeout. In the past 27 years, over 50 percent of The Great Barrier Reef coral has been wiped out and if nothing is done in the next ten years only 25 perfect of the coral reef will remain (Phillips, 2012).

This is a chart taken from an article in The Age, an Australian daily broadcast newspaper.
http://www.theage.com.au/environment/conservation/great-reef-catastrophe-20121002-26vzq.html

An image of a thorn starfish outbreak eating coral. Credit: Katharina Fabricius, Australian Institute of Marine Science
http://www.livescience.com/23611-image-gallery-great-barrier-reef-through-time.html

          In addition to the destruction of coral, wildlife populations have also been significantly damaged due to unsustainable fishing methods and marine based pollution (Hoegh-Guldberg et al. 2004:32). Destructive fishing methods such as trawling for prawns is allowed in over one third of the Great Barrier Reef and leads to bycatch and seafloor destruction (WWF, 2012) Other destructive fishing methods such as cyanide and dynamite fishing also destroy the coral and reef wildlife (Hoegh-Guldberg et al. 2004:32). Overexploitation of fish has led to an imbalance in the ecosystem. The fish are key predators and prey in the coral reef food chain and when their population is significantly reduced, the population of the organisms they fed on drastically increase while the organisms that fed on the fish dramatically decrease (Hoegh-Guldberg et al. 2004:32). Coastal developments have led to an increase in pollution and chemicals that are dumped into the ocean, which then accumulate and poison corals and organisms (Hoegh-Guldberg et al. 2004:32). The disposal of plastic bags in the ocean not only suffocates marine wildlife but also prohibits photosynthesis by blocking the sun (Hoegh-Guldberg et al. 2004:32). The dangerous fishing and disposal practices from human exploitation of these coral reefs have serious affects on not only the coral but also the marine life. 

This is an illustration of the destructive effects of ecosystem overfishing. Credit: John Michael Yanson
Source: Adapted from Pauley et al., 1998; Goni, 2000
http://see-the-sea.org/topics/commerce/overfishing.htm

This image of the horseshoe reef shows the destruction of the reef by crown of thorn starfish. The left side of the image is the before the outbreak and the right side is an image after the destruction.
Credit: AIMS Long-Term Monitoring Team
http://www.pbs.org/newshour/multimedia/before-after-aims/2.html

This image of the MacDonald reef shows the before (left) and after (right) a tropical cycle damaged the coral reef.
Credit: AIMS Long-Term Monitoring Team
http://www.pbs.org/newshour/multimedia/before-after-aims/index.html

Sources:

1. "Great Barrier Reef." WWF Australia. WWF, 2012. Web. 30 Nov 2012. <http://www.wwf.org.au/our_work/saving_the_natural_world/oceans_and_marine/priority_ocean_places/great_barrier_reef/>.

2. Hoegh-Guldberg, Hans, and Ove Hoegh-Guldberg. " Implications of Climate Change for the Australia’s Great Barrier Reef.” WWF Australia. (2004): 32. Web. 30 Nov. 2012. <http://awsassets.wwf.org.au/downloads/cl029_great_barrier_reef_2050_the_implications_of_climate_change_1fev04.pdf>.

3. Phillips, Nicky. "Great reef catastrophe." Age [Melbourne, Australia] 2 10 2012, Web. 30 Nov. 2012. <http://www.theage.com.au/environment/conservation/great-reef-catastrophe-20121002-26vzq.html>.

Future Prospect of The Great Barrier Reef

The Great Barrier Reef has been impacted significantly by human endeavors. The climate change that has occurred over the past decades has reduced the number of coral in the GBR due to coral bleaching. (University of Michigan) Coral bleaching is caused by combination of some or of all of the following: increased temperature, higher UV radiation, sedimentation reduced lighting levels, and changes in salinity. Such coral bleaching kills zooxanthellae that are needed for corals to photosynthesize; if there are less or no zooxanthellae, the coral is unable to produce energy for itself (University of Michigan). Such effects create lasting damage on the Great Barrier Reef, leaving us to question whether the GBR will still exist for future generations to enjoy. If the human effects continue, there is a great chance that the GBR will continue to lose significant amount of tourism, have an increased amount of coral bleaching, and have a change in resources as well. If the Great Barrier were to decrease, the deep-sea creatures that were prevented from reaching shallow waters could potentially change the current status quo of the shallow water ecosystems due to the GBR being absent as a barrier. (University of Michigan). The Great Barrier Reef Marine Park Authority has created a 25 Year Plan to help save and protect the Australia’s precious ecosystem. The plan strives to protect and maintain this ecosystem through conservation, resource management, education, communication, research and monitoring, integrated planning, and legislation (GBRMPA, 2011).  As well, the entire Great Barrier Reef is protected under Australian legislation, such as the Environment Protection and Biodiversity Conservation Act 1999. (GBRMPA, 2011).

Sources:

1. Australian Government Great Barrier Reef Marine Park Authority. GBRMPA, 2011. Web. 30 Nov 2012. <http://www.gbrmpa.gov.au/about-the-reef>.

2. "Human Impact on the Great Barrier Reef." University of Michigan. Web. 30 Nov 2012. <http://sitemaker.umich.edu/gc2sec7labgroup3/introduction>.