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WWF-Australia collects white waxy residue surrounded by algae found in the waters affected by Montara oil rig leak in the Timor Sea. © WWF-Aus / Kara Burns

WWF-Australia collects white waxy residue surrounded by algae found in the waters affected by Montara oil rig leak in the Timor Sea. © WWF-Aus / Kara Burns

Marine pollution

Our oceans are often depicted as picture-postcard azure waters teeming with plants and animals. In reality, many marine environments have become a dumping ground.

 

It was once thought that our oceans were so vast that any pollutants would soon be diluted and dispersed. But we now know that some litter, like plastics, can take years to decompose or will never. Toxic chemicals, either leaching from rubbish or flushed into our oceans, accumulate within the water and food chains, even on the seafloor, posing serious risks to marine animals.

 

Entire ecosystems can be disrupted when our river systems transport unwanted nutrients and sediments into our oceans. They can fuel an over-abundance of phytoplankton and algae, which smother food sources and contribute to coral eating crown of thorns starfish outbreaks, with devastating consequences.

Whether it's run-off from the land, the deliberate dumping of sewage, dredging, accidental oil spills, nets or discarded rubbish, marine pollution is threatening some of our most fragile habitats and endangered species.

Impacts

 

Marine pollution, 80% of which is generated by land-based activities, is having a devastating effect on our oceans. As well as degrading habitat, pollution directly threatens marine animals and plants, some of them rare and endangered.

Oil spills can be catastrophic, but not all the oil that enters the sea leaks from ships. A large amount of oil can be traced back to factories within our cities - and poor containment or disposal methods.

Garbage discarded in our oceans poses a number of dangers. Marine species often mistake plastics, for instance, as food, only to experience excruciating deaths when it blocks their breathing passages and stomachs. Discarded ‘ghost nets' and fishing gear can also seem like a tasty morsel or entrap unwitting marine animals.

When detergents, fertilisers or sewage containing a variety of chemicals are discharged into our oceans, especially in large doses, it can begin the lethal process known as eutrophication. The excess nutrients cause plants and algae to bloom, reducing water quality and depleting the supply of dissolved oxygen. At its worst, this suffocates marine life.

What we're doing

WWF is active on a number of fronts to protect our marine environments and their unique creatures. We're tackling pollution at its source and inspiring our members to make more sustainable choices.

 

Causes

 

During flooding, massive amounts of sediment and farm chemicals are washed from farms and transported to the ocean via river systems. Adding undesirable nutrients and pesticides to the marine system disturbs the balances within these ecosystems, while sediment smothers and blocks sunlight to coral and seagrasses.

Dredging for port development and other construction is another man-made source of marine pollution. It removes important components from the seafloor that support biodiversity, and exposes acid sulphates and other contaminants that can either inhibit plant growth or accumulate in food chains.

Pollution released from industrial and urban areas commonly flow down drains directly into our oceans. Chemicals are also dumped at sea, or released from urban areas and boats.

Rubbish, including that most persistent rubbish of all - plastics - comprises a large proportion of marine pollution. If not disposed of carefully, almost all our land-based rubbish has the potential to reach the sea. There, it threatens marine creatures or is swept back to shore, where it pollutes beaches and coastal habitats.

Derelict fishing gear, often referred to as ‘ghost nets’, is a global issue. Whether lost or discarded, these trawl and gill nets continue catching fish and other marine wildlife long after they are abandoned. Those that fall to the seafloor can also attract other rubbish to form larger sea hazards.

Spinner dolphins surfacing in extensive light oil sheen with high density of small wax particles. © WWF-Aus / Kara Burns

© WWF-Aus / Kara Burns

 

How you can help

• We can all help to reduce the extent of marine pollution, simply by making more conscious choices. Many of the chemicals we apply to our lawns, flush down our toilets, spray on our crops or use in our factories, pose a risk to our oceans. Finding biodegradable, natural and/or safer alternatives is a great start, then we must minimise and contain any chemicals that we do choose.


• Improving our recycling efforts is another progressive step. Say 'no' to plastic shopping bags and reduce your reliance on single-use plastic packaging and non-recyclable products. Remember that anything capable of finding its way into drains or becoming airborne has the potential to enter our oceans, so dispose of all rubbish safely.

• When it comes to shopping, consider more sustainable sources of products, especially sugar and beef, which can contribute to marine pollution in Great Barrier Reef catchments.

• If you live by the sea, perhaps contact your local Coastcare group and join in beach clean-up activities.

 

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