Under the Surface
Are we wasting our waters? Time to clean up our yard. An examination of human impact on the environment.
You’re hosting a house party. Aircon is pumping, pool is perfect, and everyone’s there. Then the local garbage collectors show up and they really don’t like you. They park their truck, dump their waste and throw it into your house. They pump car oil into your pool. Then, they set your house on fire. They’ve killed the party, and you’re furious – how can someone trash your home like that?
This story isn’t just imagination – it’s reality for today’s marine ecosystems. The Great Barrier Reef (GBR) is experiencing its greatest die-off event in modern history (1). That’s a fact. It doesn’t look good on our conscience, much less our economy. Financial services giant Deloitte Australia claims the GBR is responsible for 64, 000 jobs and earns us $6.4 billion every year (2). But the reef is also a home to marine wildlife. It’s crumbling around us, so it’s time we learned why and what we can do.
A ruined reef – but whose fault is it anyway?
So how do we rate on reef protection? Pretty poorly. Terry Hughes and others from James Cook University say our GBR experienced unprecedented destruction most recently in 2016. About 91% of the GBR has now been damaged (1). Marine experts argue we’re at fault. Oil pollution and climate change are anthropogenic (human-caused or accelerated) activities - they’re all driving reef damage (3). Two main issues affect the GBR: coral bleaching and biodiversity losses.
Coral bleaching occurs when marine climates are disturbed. In response to hostile environmental changes, coral release their photosynthetic algae (zooxanthellae) into the water (4). These algae ordinarily live in harmony, or “symbiosis” with coral, providing them with food and useful items (5). It’s like having a roommate who buys you groceries but doesn’t ask for the money back. But when coral become stressed, they “kick out” their algae friends. This response eventually kills the coral cells, turning them a “bleached” white colour (4).
This reduced coral cover leads to less biodiversity in our reef ecosystem (6). Marine biodiversity refers to the variety of living things in our oceans – the higher the biodiversity, the more variety (7). A reef with five starfish species has a higher biodiversity than another area with two starfish species. Marine biologists report coral bleaching is accelerating the loss of biodiversity (6). This compounds existing consequences of human intervention, which has already driven a 0.5% yearly loss in coral habitat from 1985-2012 (3). The GBR is currently home to over 12 000 marine species, which is declining (8). However, this estimate uses older and hard-to-obtain data, so we don’t know exactly how badly we’re killing off the reef’s biodiversity (6).
Climate crisis closing in
The reef’s marine life is also struggling to adapt to climate change caused by our increased output of greenhouse gases, like carbon dioxide (11). In the 20th century alone, global average sea surface temperatures increased by above 0.7°C (11). Over the coming decades, we’re predicted to witness a 2-3°C increase with current warming trends (12). These temperatures don’t seem that bad, but they take a sledgehammer to coral-algae symbiosis (11). It’s like if your aircon was permanently disabled and replaced with a heater – suddenly, the roommate situation gets tense. (11). Flinders Marine Biology PhD Student and Saving Nemo Outreach Officer, Cassie Hoepner, researches the relationship between clownfish and anemones. She says ‘rising sea temperatures would be the number one threat to clownfish in the wild’.
Although GBR sea temperatures have only increased marginally (0.05-0.09°C per decade) (13, 14), Nature journal findings demonstrate that extreme warming events are occurring ever more frequently and lasting longer (13). Although milder warming may build the reef’s tolerance (15), the rate of change is the issue: with greatly accelerated warming, reefs can’t adapt in time (11). It’s like an exam – you might pass if you prepare, but if the lecturer springs it suddenly? Good luck.
That’s not all – our warmer oceans are also getting more acidic. The ocean already has an acid-base balancing system, but our excessive production of carbon dioxide pushes this balance into producing more acid (16). Who cares? Well, more acidic oceans hurt marine life, particularly producers like plankton that support the GBR ecosystem (17). Damaging the producers is like if the garbage collectors set your kitchen cupboard on fire in the middle of your house party – everyone relies on this stockpile.
A sticky situation
What’s more confronting is the sheer amount of pollution being tipped into our marine home. The ABC reports that in 2017, Globex Shipping allegedly spilt 10-15 tonnes of oil off the coast of Townsville, near the GBR. The punishment? A $17 million fine which is very hard to collect from overseas companies (18). These fines are a slap on the wrist for oil giants – BP, for instance, is worth at least $38 billion.
This spill is a drop in the ocean – every year, about 8.4 million tonnes of petroleum contaminates our waters (19). In the short term, oil is highly toxic and covers marine life in a thick, sticky coating – fish and others find it hard to breathe (20). Long term effects? We still aren’t entirely sure. Current chemicals used to make oil less sticky and break it down can also hurt marine life (20). Scientists are trialling new ways of breaking down existing oil pollution, including bacteria that “eat” up spills (19). Or we could just not throw cans of oil into someone else’s home.
Coming back to Bight us
This theme of marine destruction hits hard and locally. South Australia is home to part of the Great Australian Bight (21). The ABC reports that this reef – teeming with healthy marine life – could also hold massive, unexplored oil reserves. Although BP has since changed its mind over extracting this oil (22), Norwegian company Equinor is very interested. Given their way, an oil well would be set up just 372 km out from our local shores (23). Since the recent launch of the draft plans, 15 local SA councils have already voiced their concerns. In their proposals, Equinor even admitted there is a risk of oil spills (23) – and we all know the outcomes of these “accidents.”
Cleaning our backyard
But it doesn’t have to be like this – we can still preserve our reefs and take back control. Scientists argue there is still some time to set up conservation areas (14). These protected areas of the reef – parts where we don’t boat in and screw things up – are vital to curbing pollution efforts (24). What else can we do? Tell our governments that we take climate action seriously. Force them to listen by holding them accountable to their jobs each election. Battery-powered vehicles and renewable energy infrastructure isn’t just a pipedream – it makes a difference (25), and we should demand these changes.
Hoepner, our emerging marine scientist at Flinders, works with school students to show them how important it is to protect our reef. What’s her number one tip? She urges us to take action and be vocal: ‘Write to your local MPs - make sure they know climate change is a priority for the future of our environment. Talk to family and friends. Make sure as many people as possible know why this is such an important issue.’
The Great Barrier Reef is one of seven natural wonders of the world. Over recent decades, though, the real wonder is that it’s still standing – but our reef is on life support. It’s time to wake up to reality, start cleaning up and protect our backyard. If we don’t, there won’t be one left.
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