Future Science · Need to Know Science · New Science

We’re Killing the Great Barrier Reef

Because of us, the Great Barrier Reef is dying. What’s worse, there’s not a lot we can do to help.

The 1,600 mile-long landmark is currently undergoing its worst bleaching event ever, with over 93% of the reef affected. This is a huge problem. As well as being an astonishing spectacle, the colours of the Great Barrier Reef (or indeed any coral reef) represent one of the biggest, most complex and most necessary ecosystems on the planet.

Zooxanthellae algae is the substance which gives many corals their brilliant colourful appearances. There is a very effective symbiotic relationship between the two organisms.

The algae gains nutrients through sunlight, the surrounding ocean, and the corals themselves. Corals provide the algae with shelter, nutrients and a constant supply of carbon dioxide which aids in photosynthesis. In turn, the algae provides nutrients to the coral. The cyclical relationship allows both coral and algae to thrive. Many algae contain a luminescent pigment which protects the algae from UV damage; a kind of marine suncream, if you will. When conditions become such that corals are ‘stressed’, they either expel the algae or digest it. As a result the corals lose the fluorescent pigments giving them their colour and they appear bleached.

This bleaching indicates that the coral’s main food source is in very short supply. As with any life-form, a lack of food can very quickly lead to death. Though we are all aware of the beauty of the Great Barrier Reef, many are unaware of how vital the reef is for both marine and human life.

The GBR supports a huge array of creatures, from microscopic plankton to whales. Over 1SOFT CORAL,800 species of fish, 4,000 species of mollusc, 10,000 species of sponge and 125 species of shark all rely on the reef for food, shelter, protection and as a mating location. A full list of the animals which call the reef home can be found here.

As bleaching continues to affect the reef, the coral is at a much greater risk of death. In fact, Professor Terry Hughes, head of the National Coral Bleaching taskforce, has suggested that as many as 50% of all bleached corals are dead or dying.

“We’ve never seen anything like this scale of bleaching before. In the northern Great Barrier Reef, it’s like 10 cyclones have come ashore all at once.”

Thousands upon thousands of creatures rely on the reef – just imagine the devastation to the marine ecosystem that has already occurred.

Not only to marine creatures rely on the reef, but humans do too. The National Oceanic and Atmospheric Administration (NOAA) claim that millions of people have some dependence upon coral reefs. The GBR has social, economic and spiritual meaning for the Aboriginal tribes of Australia and Torres Strait islanders. The reef contains fish traps for sustenance, burial grounds for the dead and represents a way of life which is thousands of years old.

If the reef dies, the culture and livelihood of these people could be lost.

Alongside the indigenous populations of Australia and the surrounding islands, modern living is also reliant upon the reef.

According to the GBR Marine Park Authority, 2014 saw 2.19 million visitor days to the reef. The data used to make up a ‘visitor day’ include:

  • full day EMC passengers who undertake a trip of three hours or more
  • part day EMC passengers who undertake a trip of less than three hours
  • passengers who are exempt from the EMC.*

*EMC (environmental management charge) refers to a fund tour-operators charge which goes towards conservation and management of the reef.

dive-on-the-great-barrier-reef-19024_700x525
Dives such as this may soon be a thing of the past.

According to the Australian Government, in 2012 the economic contribution from these visitors was over $5.5 billion dollars .Were we to lose the reef, the blow to Australia’s tourism levels would be phenomenal.

So why is this coral bleaching happening, and what can we do to stop it?

The blame, unfortunately, lands solely on our shoulders.

We’ve know that coral reefs have been in danger for a long time (this article is from 2008) yet we’ve done very little to preserve them. There was a mass coral bleaching event in 1998 where over 90% of the reefs surrounding India died. Before this, coral bleaching was extremely rare and certainly not fatal. Since 1998, however, there have been six major bleaching events. That is too many in too short a time to be natural. A combination of phenomenon such as El Nino, over-fishing, ocean pollution and global warming has resulted in oceanic conditions which can no longer support the delicate conditions required for coral to thrive.

Mildly bleached corals can recover if temperatures can cool quickly enough, but much of the reef is already to badly affected.

“The coastal area that I study north of Broome has huge tides, and we thought the corals there are tough “super corals” because they can normally cope with big swings in temperature, so, we’re shocked to see up to 80% of them now turning snow-white. Even the tougher species are badly affected.” – Dr. Verena Schoepf from the University of Western Australia.

Some scientists have suggested that reducing ocean acidity through adding lime or bicarbonates to the water could counteract some of the damage caused by high levels of atmospheric carbon dioxide. Others have proposed that finding a way to cool down shallow waters may help to improve conditions for algae and corals to survive.

There are actually a number of possible solutions, but sadly none of them are very practical, particularly for a reef as large as the GBR.

Our desperate attempts to find a solution may well be in vain. With 93% of GBR corals bleached, it may already be too late.

 

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