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= South Atlantic Garbage Patch = The South Atlantic Garbage Patch is the accumulation of marine debris, largely composed of microplastics. This patch is located within the South Atlantic Gyre. Ocean gyres revolve around expansive areas of stationary, calm water. Within these areas, debris drift and aggregate slowly into a garbage patch.

History
In 1988, the NOAA (National Oceanic and Atmospheric Administration), described the Great Pacific patch in a paper. Researchers found that there were relatively high concentrations of debris accumulating by the ocean currents. After the confirmation of the within the North Pacific Gyre by Charles J. Moore in 1997, explorations to the other gyres began.

In November 2010, The 5 Gyre Institute, partnered with Pangaea Exploration and Algalita Marine Research Foundation, set out to conduct the first transatlantic research study of the South Atlantic Gyre from Walvis Bay, Namibia.

The 5 Gyres spent over 75 days sampling sea surfaces traveling ling between South America and Southern Africa, from Rio de Janerio to Ascension Island. Back to Rio de Janerio, to Cape Town, to Namibia, to Uruguay. More than 150 samples were taken, and all contained plastic particles. During the exploration, 5 Gyre didn’t just study plastic density, type and spatial distribution, but also analyzed the plastic particles for chemical uptake, since plastic has been shown to absorb persistent organic pollutants such as DDT, flame retardants, (PBDEs) PCBs, and PAHs at high concentrations.

Location/Size
Studies have been conducted to predict where surface pollution will end up in the ocean and each model suggests an accumulation in mid-ocean subtropical gyres, so the general flow of these gyres may help predict where the accumulation occurs, though it does not help in predicting the exact size. Litter accumulation may differ in studies, but the South Atlantic Garbage Patch is at its highest concentration at around 25-35°S and 0-20°W. Although the smallest of the garbage patches, covering approximately 715,520 square km (276,263 square mi), it still qualifies as one of the main garbage patches. Located within the South Atlantic Gyre, this garbage patch follows the same behavior as other patches do to accumulate debris. While, even in the 1970s, there was an identified concentration of debris in the southeast Atlantic Ocean through sampling west of 12°E, recent studies suggest different areas to identify the garbage patch. However, the South Atlantic garbage patch is recorded to have a high macro debris load of 5 tons, posing a distinct danger to the surrounding marine life.

Amount of pollutants, composition, potential sources
There is various speculation on the sources of the pollution that makes up the South Atlantic garbage patch. It is sourced from individuals, but the issue lies in tracking where a majority of macro debris comes from, in terms of land or ships. While many assume that over 80% of the debris in the sea is from land-based sources, there is little evidence to agree with this assumption, but there are various analyses that link pollutants to specific areas/activities. Much of the macro debris found in garbage patches is fishery related, such as nets and fishery gear, so there is the assumption that these are likely not land-based. However, determining the sources of other items, such as food or domestic goods, from land or ships proves difficult due to the possibility of it coming from either source. Due to this complication, it is difficult to determine the main source of pollution, rejecting the traditional assumption of a majority of ocean pollution belonging to land-based sources, and recognizing the possibility of other causes.

Analysis of debris, plastic bottles in particular because of how identifiable they are and their accumulation in other sites, show how varied the pollutant sources are, with 75% of analyzed bottles in the South Atlantic Garbage Patch identified as being from Asia. However, some models also suggest that a majority of sea debris comes from South America, but there is no conclusive source for pollutants in the South Atlantic.

Effects on Ecosystem
The circular motion within ocean gyres pulls in debris, particles of plastic smaller than 5mm. This debris eventually finds itself ensnared within the central area of the gyre and proceeds to break down into a “plastic soup”. The global production of plastic has seen an increase of over 300 million tons per year in the last 70 years with a continued annual growth of around 8%. Most plastic wastes are dumped in landfills or pollute surrounding environments. The comparatively light composition and the density of plastic allow it to disperse far from source areas.

Because the plastic within the South Atlantic Garbage Patch does not disintegrate into organic substances, the microplastics it breaks down into oftentimes kill the sea species that attempt to consume them. These microplastics are as small as the algae and plankton that form the basis of the ocean food web. The chemicals present in microplastics may be absorbed by the predators to these species. Sea creatures often become entangled in plastic waste. One such instance is that of the sea turtle, which has been noted to mistake plastic bags for jellyfish, a common food for them. Plastics are now prevalent in the world’s oceans. “Plastic waste… is now so common it reaches the seabed. We found it in plankton, throughout the food chain, and up to top predators such as seabirds,” David Barnes of the British Antarctic Survey (BAS), stated in a press release reported in 2018 on the increasing levels of plastic in the South Atlantic. A study spanning the five subtropical gyres, coastal Australia, Bay of  Bengal and the Mediterranean Sea recorded an estimate of the total number of plastic particles and their weight floating in the world’s oceans. There, we see the South Atlantic Gyre estimated to have 25.6 million pounds of plastic debris on its surface.

Researches at the University of Hawaii reported findings from a 212 day experiment that revealed an increase in the emission rate of low-density polyethylene (LDPE) - components used in the making of textiles, construction materials and various plastic goods. This LDPE present in the ocean, when exposed to sunlight, would produce greenhouse gases.

Garbage Patches Effect on Human Health
The National Oceanic and Atmospheric Administration has yet to answer whether the garbage patches pose any [immediate] harm to human health although, generally speaking, the effects of microplastics may be harmful to humans if exposed to multiple sources like “seafood, sea salt, tap water, beer, and even honey.” Though their research community is “actively exploring the issues”. Plastic debris with loops and “ghost nets” also threaten marine life with entanglement, and marine debris can transport species from place to place, possibly disrupting the ecosystems that they travel to.

A byproduct of the garbage patch does include the issue with debris within causing damage to marine vessels, since debris is difficult to see if it is floating below the water surface and “Nets can become entangled in propellers and clog intakes”.

Cleanup Efforts
The NOAA Marine Debris Program focuses on marine debris prevention and removal from shorelines and coastal areas where debris is easier to pick up. Although larger debris within the garbage patches can be removed by people, the patches contain microplastics and “finding a cost effective technological solution which can take on these challenges is an extremely daunting task.” Because plastic degrades into smaller and smaller pieces, but doesn’t disintegrate into organic substances, these microplastics have been consumed by other organisms. This not only may kill them, but the concentration of chemicals may increase trophic levels of the food chain.

Finding the source of the marine debris could very well help prevention, however there are several different possible sources such as “ineffective or improper waste management, dumping or littering, and stormwater runoff”.

Another issue when discussing cleanup efforts comes from the gyres being located outside national territories, holding no singular party responsible, therefore intergovernmental bodies and private initiatives are left responsible for cleanup efforts.