The rotation of the earth causes the oceans to continuously move and the winds to blow. There are five large rotating ocean currents that are called ‘gyres’. These are huge vortexes in which all floating objects are slowly sucked into the middle. It is comparable to the kitchen sink drain.
There are five major gyres on earth: the North Pacific, South Pacific, Indian Ocean, North Atlantic and the South Atlantic Gyre. They are in sub-tropical areas, above and below the equator. All five gyres have higher concentrations of plastic rubbish compared to other parts of the oceans. In the North Atlantic Gyre, 20,328 pieces of plastic were found per square kilometre, while in the North Pacific Gyre, this can be as high as 334,271 pieces per square kilometre. These pieces are largely made up of tiny fragments of less than 5 mm that we can barely see with the naked eye. These are the microplastics.
In the centre of the gyres there is no wind. These areas have traditionally been avoided by shipping. But in 1997 captain Charles Moore sailed from Hawaii to Southern California through the North Pacific Gyre. There, in the middle of the ocean, he saw pieces of plastic floating by every day. Later he returned to the area to do closer research. There appeared to be a significantly higher concentration of plastic then elsewhere in the ocean. The plastic appeared to not only float, but also to hang suspended below the surface. Moore called the phenomena plastic soup, the term now used worldwide.