Located off Australia’s northeastern shore, the Great Barrier Reef is the largest reef system in the world. It was used by aboriginal Australians for hunting and fishing thousands of years ago and continues to play a major role in the economy, with tourism to the reef employing over 64,000 people and contributing $5.2 billion annually to Australia’s economy with people travelling to the Sunshine Coast, Bundaberg. Townsville and beyond just to get a glimpse of the natural wonder. However, increased oceanic temperatures are posing a threat to the reef. Coral bleaching occurs whenever oceanic waters become too warm, causing corals to expel the algae living within their tissues.
1) The Great Barrier Reef is the largest reef system in the world.
Located off the coast of Queensland, Australia, the GBR is composed of 2,900 individual reefs, 900 islands, and extends 2,300 kilometers (1,429 miles). It is considered one of the Seven Natural Wonders of the World and is the only living organism that can be seen from space.
2) Marine algae provide up to 90 percent of the energy corals require to grow and reproduce.
Corals have a symbiotic relationship with marine algae (or zooxanthellae). When sea temperatures rise, the algae creates reactive oxygen molecules that are toxic to the coral. In order to survive, the corals are forced to expel the algae. However, without the algae, the coral slowly starves.
3) Various factors contribute to coral bleaching.
While bleaching on a global scale is due to a rise in ocean temperature, local bleaching can be caused by a variety of stressors including disease, sedimentation, pollutants, extreme low tides, and changes in the water’s salinity.
4) Coral bleaching impacts more than just corals.
Animals such as fish, sea turtles, and seabirds rely on reefs for food and shelter. Loss of reefs would decrease the number of these animals, which would impact island ecosystems. Additionally, a lowered fish population would impact the livelihood of individuals connected to the fishing industry. Furthermore, coral reefs serve as deterrents from tidal surges, and dead reefs would mean that shorelines would become vulnerable to effects from oceanic forces.
5) The Great Barrier Reef is teeming with thousands of species of plants and animals.
Besides being a living organism itself—corals are animals, and there are over 400 types in the GBR—the reef is home to countless species of plants and animals. It supports sponges, anemones, worms, tropical fish, humpback whales, six of the seven varieties of sea turtles on earth, hammerhead sharks, and squids, to name a few.
6) The majority of corals in the Great Barrier Reef system have been affected by bleaching.
The Great Barrier Reef is made up of 2,900 smaller reefs and of the 911 reefs that were recently studied, 93 percent were marred by some sort of bleaching. The majority of damage has occurred in the northern portion of the reef; the southern half has avoided severe damage.
7) Bleached corals are not necessarily dead.
Bleaching is not a death sentence. When algae is expelled, the bright white skeleton of the coral is exposed. However, if conditions return to normal, more complex corals in deeper water tend to recover from bleaching better than their simple, shallow-water counterparts.
8) Bleaching has affected the GBR in the past.
In 1998, there was a global bleaching event, and 50 percent of the corals in the GBR were affected. Mass bleaching occurred again in 2002, affecting 60 percent of reefs. As water temperatures regulated, the corals were able to recover, but unfortunately, they were not so lucky during this last bout of bleaching.
9) Climate change is responsible for increased water temperature.
The Greenhouse Effect occurs whenever high levels of carbon dioxide in the earth’s atmosphere render it incapable of properly processing it all. The carbon dioxide becomes trapped within the atmosphere, causing a rise in global temperatures.
10) We can help.
Reducing your carbon footprint is the most effective way to slow down rates of bleaching. This can be done by carpooling, driving low carbon vehicles, or walking and cycling whenever possible.
