The Great Pacific garbage patch
The Great Pacific Garbage Patch is a gyre of marine debris in the central North Pacific Ocean. The patch extends over an indeterminate area, with estimates ranging very widely depending on the degree of plastic concentration used to define the affected area.
Based on researches between 1985 and 88, the patch was predicted for the first time in 1988. In 1997, Charles J. Moore, a race sailor came upon an enormous stretch of floating debris. Moore alerted the oceanographer Curtis Ebbesmeyer, who subsequently dubbed the region the "Eastern Garbage Patch" (EGP).
Tha patch is mainly made of plastic, chemical sludge and other debris, and it is not visible on satellite images, because it consists primarily of suspended, very small particulates in the upper water column. The patch is defined as an area in which the mass of plastic debris in the upper water column is significantly higher than average. There is more than one patch as another one was discovered in the Atlantic Ocean as well!
Llike other areas of concentrated marine debris in the world's oceans, the Great Pacific garbage patch formed gradually as a result of marine pollution gathered by oceanic currents. The patch is stationary and located near the North Pacific Gyre. The gyre's rotational pattern draws in waste material from across the North Pacific Ocean. As material is captured in the currents, wind-driven surface currents gradually move floating debris toward the center, trapping it in the region.
The origins of the debris in the patch is questionable. There are researches showing about 80% of the waste is land-based, coming through the greater rivers (like Ganges) all around the world and the other 20% comes from ships, but there are still ongoing projects focusing on the problem.
Because it is hardly visible, as it was mentioned above, the exact size of the patch is still unkown. Estimates of size range from 700,000 square kilometres (270,000 sq mi) to more than 15,000,000 square kilometres (5,800,000 sq mi) (0.41% to 8.1% of the size of the Pacific Ocean). However the media likes to mention it as the size of the continental U.S., survey missions show this is not true, the patch is much smaller and it seems there are two distinct zones of concentrated debris in the area.