THERE are five major gyres in the oceans worldwide, three of which come in close proximity to the African continent.
A gyre is a large system of slow rotating ocean currents - almost like a whirlpool - which circles large areas of stationary water, this is where the extent of the massive pollution problem becomes apparent. Debris picked up by the currents drifts into these stationary areas and, due to the lack of movement in the water, can accumulate for years.
These areas are called garbage patches. The Indian Ocean, North Atlantic Ocean, and North Pacific Ocean all have significant garbage patches. Unfortunately, according to the 5 Gyres Research Institute, about 90% of the debris in all the garbage patches is plastic.
The word “patch” in reference to these gigantic areas of devastating pollution doesn’t do justice to the sheer size of the problem.
To put their mass into perspective one of Africa’s closest garbage patches is the Indian Ocean garbage patch, discovered in 2010 by Marcus Eriksen - a marine scientist and founder of the 5 Gyres Institute - and his crew. It comprises an area of at least five million square kilometres in size, but with no clear boundaries. That’s larger than South Africa and Ethiopia combined.
Eventually, the debris which has become trapped at the centre of the gyre, breaks down into a kind of plastic soup because in the ocean, sunlight and waves cause floating plastics to break into increasingly smaller particles, but they never completely disappear or biodegrade.
These tiny plastic particles are as small as the algae and plankton that form the basis of the entire ocean food web. Species such as shrimp, birds, and fish consume these micro-plastics, which will often kill them. The plastic chemicals can also be absorbed by predators of these species and work their way into human diets since the concentration of these chemicals increases through each trophic level of the food chain. The effects are toxic with health effects ranging from cancer to malformation and impaired reproductive ability.
These garbage patches have already had devastating impacts on the fishing and tourism industries in many parts of the world which are affected economically by plastic entering nets, damaging propellers and other equipment, and washing up on beaches.
In this image, scuba divers are removing an agglomeration of nets from a reef, a debris pile that was swept together in the North Pacific Gyre. (Photo/NOAA/NMFS/OPR/Flickr).
Fixing the problem
Garbage patches generally accumulate far from any country’s coastline meaning, it is nearly impossible to track where it came from, and therefore few nations have accepted the responsibility of cleaning them up.
The tiny plastic particles that make up most of the “soup” patches are also very difficult and expensive to detect and remove.
Fortunately there is hope.
21-year-old Boyan Slat is a Dutch entrepreneur and inventor who has created the world’s first ocean cleaning system whose pilot programme will be deployed in 2016 in Japan - specifically, at Tsushima Island.
Instead of going after the plastic, Boyan devised a system through which, driven by the ocean currents, the plastic would concentrate itself, reducing the theoretical cleanup time from millennia to years.
The system, which involves a static platform that passively collects plastics when wind and ocean currents push debris to the 2000-meter booms, will be the longest floating structure ever deployed in the ocean. The plastic is then picked up by ships using a conveyor belt and there are plans underway to recycle it into biofuel.