What Is The Great Pacific Garbage Patch?
The Great Pacific Garbage Patch (GPGP) is the largest of the five offshore plastic accumulation zones in the world’s oceans. It is located halfway between Hawaii and California.
Due to seasonal and interannual variabilities of winds and currents, the GPGP’s location and shape are constantly changing. Only floating objects that are predominantly influenced by currents and less by winds were likely to remain within the patch.
By simulating concentration levels in the North Pacific, the researchers were able to follow the location of the patch, demonstrating significant seasonal and interannual variations. On average the patch orbits around 32°N and 145°W. However, the team observed seasonal shift from west to east and substantial variations in latitude (North to South) depending on the year.
How Big Is It?
The GPGP covers an estimated surface area of 1.6 million square kilometers, an area twice the size of Texas or three times the size of France or 12.5 times the size of Java island.
The mass of the plastic in the Great Pacific Garbage Patch (GPGP) was estimated to be approximately 80,000 tonnes , which is 4-16 times more than previous calculations. This weight is also equivalent to that of 500 Jumbo Jets.
The center of the GPGP has the highest density and the further boundaries are the least dense. When quantifying the mass of the GPGP, the team chose to account only for the denser center area. If the less-dense outer region was also considered in the total estimate, the total mass would then be closer to 100,000 tonnes.
A total of 1.8 trillion plastic pieces were estimated to be floating in the patch – a plastic count that is equivalent to 250 pieces of debris for every human in the world.
Using a similar approach as they did when figuring the mass, the team chose to employ conservative estimations of the plastic count. While 1.8 trillion is a mid-range value for the total count, their calculations estimated that it may be range from 1.1 to up to 3.6 trillion pieces.
Impacts on Humand and Wildlife?
Plastic has increasingly become a ubiquitous substance in the ocean. Due to its size and color, animals confuse the plastic for food, causing malnutrition; it poses entanglement risks and threatens their overall behavior, health and existence.
Studies have shown that about 700 species have encountered marine debris, and 92% of these interactions are with plastic. 17% of the species affected by plastic are on the IUCN (International Union for Conservation of Nature) Red List of Threatened Species.
Floating at the surface of the Great Pacific Garbage Patch (GPGP) is 180x more plastic than marine life. Animals migrating through or inhabiting this area are then likely consuming plastic in the patch. For example, sea turtles by-caught in fisheries operating within and around the patch can have up to 74% (by dry weight) of their diets composed of ocean plastics. Laysan albatross chicks from Kure Atoll and Oahu Island have around 45% of their wet mass composed of plastics from surface waters of the GPGP.
Since 84% of this plastic was found to have at least one Persistent Bio-accumulative Toxic Persistent Bio-accumulative Toxic (PBT) chemical, animals consuming this debris are therefore ingesting the chemicals attached to the plastic.
Fishing nets account for 46% of the mass in the GPGP and they can be dangerous for animals who swim or collide into them and cannot extract themselves from the net. Interaction with these discarded nets, also known as ghost nets ghost nets , often results in the death of the marine life involved.
Once plastic enters the marine food web, there is a possibility that it will contaminate the human food chain as well. Efforts to clean and eradicate ocean plastic have also caused significant financial burdens.
Through a process called bioaccumulation, chemicals in plastics will enter the body of the animal feeding on the plastic, and as the feeder becomes prey, the chemicals will pass to the predator – making their way up the food web that includes humans. These chemicals that affected the plastic feeders could then be present within the human as well.
The United Nations reported that the approximate environmental damage caused by plastic to marine ecosystems represents 13 billion USD. This figure included the cost of beach cleanups and the financial loss incurred by fisheries.
Source : The Ocean Cleanup
Pic by : phys.org