Australian Institute of Marine Science
2 October 2012
http://www.sciencedaily.com/releases/2012/10/121002094147.htm
In the last 27 years, the Great Barrier Reef has lost half of its coral cover. The loss of coral is due to storm damage (48%), crown-of-thorns starfish (42%), and coral bleaching (10%). These findings are based on the studies of researchers from the Australian Institute of Marine Science in Townsville, Australia, and the University of Wollongong (in Australia). Since 1985, an international monitoring program has more than 100 reefs under its surveillance; in 1993, the program started to include more detailed annual surveys of 47 reefs. Researchers predict that if the current trend continues, coral cover will halve again by 2022. The pattern of decline varies in the Great Barrier Reef- the northern parts seem to be less affected by the southern parts. Tropical cyclones ravage the southern parts of the GBR, while 2 severe coral bleaching events damaged the northern & central parts of the GBR. Crown-of-thorns starfish are having population explosions all along the GBR, causing harm as they can quickly eat and kill an entire colony of coral. Coral covers take about 10-20 years to recover, but the intervals of "attacks" are too short for the coral to fully recover. Efforts are being made to reduce crowns-of-thorn starfish, since coral cover could increase 0.89% per year if these starfish were removed.
This article connects to the ecology unit because coral on the Great Barrier Reef is a keystone species, since it makes up the environment many other species live in (coral changes will cause habitat changes for many species). Crown-of-thorns starfish and coral represent predation; the starfish are the predators and the coral are the prey.
Is there anything that the ecologists are doing to protect Great Barrier Reef?
ReplyDeleteScientists are encouraging people to reduce the global warming effect, since global warming causes water temperatures to rise and lead to events such as coral bleaching. Data is also being collected by ocean sonar systems to better understand the impact of climate change on the GBR. There are also zoning systems- zones of areas where removal of resources by activities such as fishing is prohibited. Mostly, the GBR is being monitored closely, monitoring things like the chemicals and pesticides released into the water by farmers along the coast.
DeleteWhat exactly is coral bleaching and what causes it?
ReplyDeleteCoral bleaching happens when coral polyps, the animals that make up coral, shed the algae (zooxanthellae) that give the coral its color, which is necessary for coral's survival. After coral sheds its algae, it turns white in color and dies.
DeleteScientists don't know what exactly causes it, but it's probably caused by warming waters- corals in the Caribbean and Florida have bleached when sea surface temperatures rose higher than the average temperature for as little as a month.