Coral Bleaching on the Great Barrier Reef
What You Should Know
EVER HEARD OF THE GREAT BARRIER REEF?
It is the largest living structure on earth and the greatest coral reef system in the world stretching along Australia’s Queensland Coast from Bundaberg in the South, right past the tip of Cape York in the North.
It is 2300 km in length and comprises of 3000 individual reefs, 1600 species of fish, 130 types of sharks and more than 30 types of whales and dolphins.
WHAT IS CORAL EXACTLY
Coral consists of tiny organisms that are similar to sea anemones or jellyfish, but have a limestone skeleton which forms the structure of reefs.
Coral polyps attach to rocks and divide into thousands of clones to form reefs.
Coral thrives in warm water but is extremely sensitive to temperature change.
WHY IS CORAL SO IMPORTANT
Coral reefs are essential to healthy ocean ecosystems which mean healthy oceans.
They create habitat and protection for a quarter of all animal species found in the ocean, including not only fish but turtles, dugongs and even sharks.
They are a food source for fish, birds, coastal plants and people.
They are a source of major pharmaceuticals such as new cancer and HIV drugs.
They offer protection from storms and act as a buffer for low-lying coastal regions
WHAT CAUSES CORAL BLEACHING
Climate change is the number one cause of coral bleaching due to increased sea temperatures.
2016 saw the highest sea temperatures ever recorded on the GBR with temperatures 0.77°C higher than normal.
High sea temperatures force corals to expel tiny photosynthetic algae, called ‘zooxanthellae’.
These algae are important food sources for coral, and the expulsion of these algae lead to the starvation of coral.
When coral starve, they have reduced fats needed in sperm and egg cells, the result being smaller or immature eggs which result in less fertile species of coral.
Acidification of oceans caused by the absorption of excess CO2, due to carbon emissions, also contributes to coral bleaching.
IS RECOVERY POSSIBLE?
In some cases, coral may recover if ocean temperatures drop within eight weeks and algae can repopulate coral.
It can take 10–15 years for coral to recover, sometimes longer for older coral.
Recovery is more likely if water pollution and overfishing are limited.
Unfortunately, leading scientists are predicting further serious coral bleaching events within the next five years.
HOW MUCH OF THE GREAT BARRIER REEF IS BLEACHED?
55% of the total Great Barrier Reef is considered severely bleached
Only 21% of the Great Barrier Reef shows no signs of bleaching — the rest has been impacted to some degree
Seven hundred kilometres of the Northern Great Barrier Reef has been affected by coral bleaching with 87% now severely bleached.
There has been a 67% loss of shallow water corals.
2016 saw the third major bleaching event in history. Earlier records of extensive coral bleaching occurred in 1998 and 2002.
Water temperatures stayed cooler over the Southern Great Barrier in 2016 thanks to cloud cover from Tropical Cyclone Winston, which resulted in less damage to the Southern Great Barrier Reef.
Greenhouse emissions caused by the burning of fossil fuels warms the oceans.
Coal mining is one of the biggest threats to the Great Barrier Reef, and Australia is the largest exporter of coal in the world!
The proposal for Adani Mega Coal Mine in the Galilee Basin in north Queensland will make it impossible for Australia to meet the COP21 treaty and the 1.5-degree target.
Time is running out.
The greatest threats to coral bleaching recovery are water pollution, dredging, increased shipping, mismanagement of commercial fishing and outbreaks of the crown of thorns starfish.
Poor water quality does not cause coral bleaching but does impact on coral’s ability to recover.
Scientists also believe that coral bleaching is not caused by El Nino weather patterns. Professor Terry Hughes, Director of the ARC Centre of Excellence for Coral Reef Studies at James Cook University (JCU) says two out of the three bleaching episodes occurring in 2002 and 2017 were both El Nino years. La Nina years are warmer now than El Nino years 20 ago. We cannot attribute this to coral bleaching.
There are no solutions to the problem without tackling climate change.
Rapidly curbing our carbon emissions and rallying leaders of other countrires to do the same is the only solution.
The Australian Government’s Reef 2050 Sustainability Plan only deals with building the reefs resilience to climate change and requires significantly more investment and effort in curbing factors contributing to climate change rather than other threats.
UNESCO needs to put increased pressure on the Australian Goverment to take the neccessary steps to maintain its World Heritage listing by adding the GBR as one of the World Heritage sites in danger and linking climate change with the policies of countries who manage World Heritage sites.
Australia needs to put an end to coal mining and excessive coal shipping.
WHO IS RESPONSIBLE
The Australian Federal Government needs to commit to reducing carbon emissions and putting policies in place to limit warming to no more than 1.2C.
Current policies aren’t even close to getting us to a 2C commitment.
VALUE OF THE GBR TO AUSTRALIA
70 000 jobs and an estimated $2 billion in tourism dollars each year
WHAT CAN YOU DO TO HELP
1. Support the Great Barrier Marine Park to stand up to governments and industry.
2. Reduce electricity use. If you can opt for solar energy and put pressure on the government to invest in the future of renewable energy.
3. Drive less, ride your bike, walk or use public transport.
4. Lobby for climate change with local government.
5. Educate yourself and join an environmental group you care about. Play your part and be part of a sustainable future.
6. Use eco-friendly detergents and recycled products to reduce grey water and landfill
7. Reduce chemical garden fertilizers and other such products
8. Buy organic produce
9. Buy fish caught sustainably
10. Use organic skin products when swimming in the ocean, particularly over the reef.