The Great Pacific Garbage Patch, also described as the Pacific Trash Vortex, is a gyre of marine litter 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.
The patch is characterized by exceptionally high concentrations of pelagic plastics, chemical sludge and other debristhat have been trapped by the currents of the North Pacific Gyre.
Despite its size and density (4 particles per cubic meter), the patch is not visible from satellite photography, nor even necessarily to a casual boater or diver in the area, since it consists primarily of a small increase in suspended, often-microscopic particles in the upper water column.
Since plastics break down to even smaller polymers, concentrations of submerged particles are not visible from space, nor do they appear as a continuous debris field to human eyes. Instead, the patch is defined as an area in which the mass of plastic debris in the upper water column is significantly higher than average.
The Great Pacific Garbage Patch
In April 2008, Richard Sundance Owen, a building contractor and scuba dive instructor, formed the Environmental Cleanup Coalition (ECC) to address the issue of North Pacific pollution. ECC collaborates with other groups to identify methods to safely remove plastic and persistent organic pollutants from the oceans.
The JUNK raft project was a trans-Pacific sailing voyage from June to August 2008 made to highlight the plastic in the patch, organized by the Algalita Marine Research Foundation.
Project Kaisei is a project to study and clean up the garbage patch launched in March 2009.
In August 2009, two project vessels, the New Horizon and the Kaisei, embarked on a voyage to research the patch and determine the feasibility of commercial scale collection and recycling.
The SEAPLEX expedition, a group of researchers from Scripps Institution of Oceanography, spent 19 days on the ocean in August, 2009 researching the patch. Their primary goal was to describe the abundance and distribution of plastic in the gyre in the most rigorous study to date.
You can see more info about the Great Pacific garbage patch on Wikipedia.