Australia's Great Barrier Reef
At Risk from Climate Change and Coral Bleaching
The Great Barrier Reef, Queensland, Australia is the only natural phenomenon in the world that can be seen from space. Comprising some 2800 reefs composed of archipelagos of mainland islands, coral cays, fringing reefs and barrier reefs that drop off into the depths of the continental shelf, it is home to an unrivalled abundance of marine life. The Reef covers an area of more than 300,000 km² — greater than that of the entire United Kingdom — and is the largest protected marine area in the world.
Spectacular World-Heritage-listed Marine Diversity
More than 400 wonderfully varied types of coral adorn the Reef and attract approximately 1500 fish species, 4000 molluscs and countless invertebrates. Because of its global importance for species diversity, the Great Barrier Reef was one of Australia’s first World Heritage Areas and was inscribed in 1981. It is also largest structure ever built entirely by living creatures. Over millions of years, it has been constructed from the limestone deposits of billions of tiny coral polyps, animals that work in symbiosis with zooxanthellae bacteria that can convert sunlight to energy via photosynthesis. This incredible team of engineers created the elaborate reef and continue to do so. Today’s reef is formed on the foundations of an older reef, which began growing more than 10,000 years ago. However, despite its great age, this natural wonder of the world may be facing its toughest battle — climate change.
Global Warming Leads to Coral Bleaching
Rising temperatures could lead to catastrophic coral bleaching, which occurs when the bacteria abandon the coral polyps, causing the coral to starve. The bacteria provide as much as 90% of the coral’s energy requirements, making reefs highly dependent on this mutually beneficial relationship. The Great Barrier Reef has been at risk before, when the Crown-of-Thorns Sea Star caused severe damage to about 17% of the Reef from the 1970s to 1990. Two major coral-bleaching events also occurred in 1998 and 2002, with smaller scale bleaching in 2006. Even slight temperature increases could have a devastating impact on this fragile ecosystem because coral bleached reefs take a long time to return to health, if they ever do. Temperature increases of just 1.5–2°C lasting for more than six weeks can cause bleaching, and if high temperatures continue for more than eight weeks, corals will usually die.
Reducing Ecological Footprints May Help Save the Reef
To try to alleviate the problem of coral bleaching, Queensland’s Great Barrier Reef Marine Park Authority has developed a Coral Bleaching Response Plan for quick detection and response to this environmental issue. However, it remains to be seen whether human beings can curtail global warming enough to save this incredible submarine “metropolis”. To help save this ecosystem, environmentally conscious people worldwide can attempt to limit their carbon emissions and reduce their ecological footprint by offsetting flights (or taking fewer long-haul flights), using energy efficient appliances and motor vehicles, eating locally and buying local products to reduce “food miles”, as well as reducing overall fossil fuel consumption. Only with a collective effort can this miraculous marine ecosystem remain to fascinate future generations.
Turtles and many fish rely on reefs
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Coral gardens bloom with colour
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