Bruce Bisset: See what we're doing to ocean

As we kill the ocean, we are killing ourselves, writes Bruce Bisset. Photo / File

Having lived on land for aeons now, we human animals have come to regard the sea not as a mother, but as merely a resource: a food-basket to be plundered, and a handy dumping ground for our waste.

Naively we believe the sea will sustain itself no matter what we do. But the hard fact is, we are killing the oceans.

Commercial over-fishing has rapidly depleted fish stocks so much so that three-quarters of all fisheries are unsustainable. There will not always be more fish in the sea.

Oil spills from drilling rigs despoil swathes of seabed; sonic "explosions" used by prospectors deafen dolphins and whales. And that's just the tip of the list. But it is the waste that comes from the land where we humans mass that is having the greatest impact.

Islands of debris have accumulated in all five major ocean gyres - subtropical regions where wind and current eddy - creating enormous dead zones where marine life cannot thrive. Silt from development and deforestation run-off creates similar coastal dead zones.

Many countries regard "sanitation" as merely dumping raw sewage and industrial waste into rivers, leading inevitably to the ocean.

From farms, too. Researchers puzzled at why cow DNA was found in the stomachs of shrimp 11km down in the Kermadec Trench might look no further than New Zealand's dairy industry for the answer.

Then there are the so-called microplastics: beads of degraded plastic less than 5mm in size, which are now ubiquitous in the world's seas.

But arguably worse is a pollutant you may never have heard of or considered: microfibres. Simply, the cast-off by-product of washing synthetic garments.

American ecologist Mark Browne has detailed results from 150 coastal sites around the globe which alarmingly showed some 85 per cent of all man-made water pollution consists of these microfibres. Typically they are microscopic - less than 1500 microns in length - and are strands of synthetics such as nylon and acrylic.

By analysing wastewater from washing machines, Browne estimates the average garment releases some 1900 such fibres when rinsed. Multiply that by the billions of pieces of clothing in use and you can begin to appreciate the size of the problem. Of course microfibres are not the only waste from clothing: apart from detergents and other cleansers in a wash cycle, toxic substances such as perfluorinated chemicals are used in textile processing, the source of some 20 per cent of China's industrial wastewater.

At base, the problem is we modern consumers are so disconnected from the natural world that we do not consider our purchase of a synthetic garment might harm the environment, let alone in what ways.

And being land animals, we are even more disconnected from the sea, and the harm we unthinkingly do it. It does not help that such micro-pollution is effectively invisible; we look at the "pristine" ocean never realising each drop of water holds a plethora of man-made contaminants.

Contaminants which are ingested by all the life living in those seas, and which pass back up the foodchain to be eaten by those causing the pollution: us.

Yep. As we kill the ocean, we are killing ourselves. It may be an artificial chain, but it's subsumed within a natural one. As all things are.

And that's the solution: getting back to nature. Only by accepting that everything that goes around comes around will we realise that using natural products that biodegrade is the only way to prevent ecosystem death.

Madly we have decided that synthetic life is preferable to natural life. The Earth is getting set to teach us how deluded that choice is.

Bruce Bisset is a freelance writer and poet.