The Great Barrier Reef (GBR) has been damaged severely and large portions of coral have died. However, the GBR cannot be declared dead yet.
In a recent article by food and travel writer Rowan Jacobsen, Jacobsen declared the GBR dead by saying “Climate change and ocean acidification have killed off one of the most spectacular features on the planet”. This has been shared all over the internet causing a lot of confusion!
I actually do like the article even though it is really exaggerating the point. It definitely does bring attention to this serious issue . Luckily it is not yet true that the GBR is dead.
We definitely do have to worry about our oceans, but there is still hope for the Great Barrier Reef and all the other reefs around the world. Let’s try to change our behavior to help protect the reefs, instead of pointlessly grieving over something that is still there.
What are coral?
Even though they look like plants, they are animals. More exactly marine invertebrates. Coral are colonies of many identical small polyps. The polyps are basically a sac with a mouth opening and tentacles around it.
Hard coral build up a skeleton by secreting calcium carbonate (limestone) from calcium and bicarbonate ions from the seawater. Generations of polyps build up on the previous limestone skeleton. This is how a reef like the Great Barrier Reef is created over millions of years.
Many coral live in symbiosis with photosynthetic single-cell organisms (zooxanthellae) that produce most of the energy and nutrients for the coral. While the polyps are usually transparent and the skeleton is white, the zooxanthellae are responsible for the brilliant colors.
The bleaching at the Great Barrier Reef
Here the facts about the Great Barrier Reef and the recent bleaching event
- The Great Barrier Reef did undergo a massive bleaching event in 2016 (why do coral bleach)
- Especially the warmer north end of the reef was hit heavily by the event leaving a large portion of coral dead
- The main cause for the bleaching was unusually warm waters (El Niño)
- Distressed coral expel the small organisms causing the coral to bleach and starve
- At this point the coral might still recover if the stressor is removed
- If not, the coral will die and get covered in algae
This is what happened at the Great Barrier Reef, especially in the northern section. An estimated 25% of the coral have been reported dead with another 50% at risk or possibly already dead. No one can know exact numbers as the whole reef would have to be examined by researchers.
Bleaching events happen. It was not the first one and it won’t be the last but it possibly was the worst we have experienced so far. Probably due to the climate change the bleaching events get worse each time.
What happens now?
- The fish and other small creatures will either move away or die with the reef
- The fish and other small creatures will move away of die with the reef
- The skeleton of the hard coral remains under the algae cover while the soft coral disappear completely
- Slowly the skeleton will break into pieces
- When the conditions normalize again, the reef can slowly start to rebuild
- To re-colonize, the dead reef coral would now have to win the fight over the thick algae cover
- Hard coral reefs in particular need a long time to rebuild and it can take decades for them to recover completely
The next months and years will show how much of the reef is really gone and how much can recover. Previous bleaching events have shown that coral reefs are able to recover after such events. It is important that the stressor (too warm of water in this case) is removed and no other threat replaces it.
Let’s hope the Great Barrier Reef will find good conditions to recover from this devastating event and will be teeming with marine life again within a decade from now.
What are other threats to coral?
- Pollution: Besides the obvious direct pollution of the sea this also includes agricultural and urban runoff through increased coastal development
- Algae: Certain fish species like parrotfish keep the reef clean from algae. Overfishing of these species leads to reefs covered in algae. The coral then won’t get enough light and will die off
- Ocean acidification: Through absorption of the carbon dioxide from the air the pH of the ocean decreases. Only a few types of coral can tolerate high acidity
- Direct physical damage: By coral mining, blast fishing, digging canals, boats (dropping anchor) and swimmers/snorkelers/divers
What can we do?
Reefs At Risk Revisited issued the following list of how individuals can help to protect the reefs:
If you live near coral reefs:
- Follow local laws and regulations designed to protect reefs and reef species.
- If you fish, do it sustainably, avoiding rare species, juveniles, breeding animals, and spawning aggregations.
- Avoid causing physical damage to reefs with boat anchors, or by trampling or touching reefs.
- Minimize your indirect impacts on reefs by choosing sustainably caught seafood and reducing household waste and pollution that reaches the marine environment.
- Help improve reef protection by working with others in your area to establish stronger conservation measures, participating in consultation processes for planned coastal or watershed development projects, and supporting local organizations that take care of reefs.
- Tell your political representatives why protecting coral reefs is important.
If you visit coral reefs:
- Choose sustainably managed, eco-conscious tourism providers.
- Dive and snorkel carefully, to avoid physically damaging reefs.
- Tell people if you see them doing something harmful to reefs.
- Visit and make contributions to MPAs to support management efforts.
- Avoid buying souvenirs made from corals and other marine species.
Wherever you are:
- Choose sustainably caught seafood.
- Avoid buying marine species that are threatened or may have been caught or farmed unsustainably.
- Help to prioritize coral reefs, the environment, and climate change issues within your government
- Support NGOs that conserve coral reefs and encourage sustainable development in reef regions.
- Educate through example, showing your family, friends, and peers why reefs are important to you.
- Reduce your carbon footprint.
THE 3RD GLOBAL CORAL BLEACHING EVENT – 2014/2016 on Global Coral Bleaching. Retrieved 20/09/2016 from http://www.globalcoralbleaching.org/
Reefs at Risk Revisited on World Resources Institute. Retrieved 20/09/2016 from http://www.wri.org/publication/reefs-risk-revisited