The great pacific garbage patch
By: Lara zakaria, hannah shewan, sarah ohio-ohezmo, anisha vasireddy, celine markintonis
introduction |
Great Pacific Garbage patch is a gyre (system of circulating ocean currents) which consists of marine debris particles. Located in the North of the Pacific Ocean, and consisting of plastic manly coming from Asia and from the Yangtze river, it is estimated that the Great Pacific Garbage Patch is between the Size of Texas (700,000 sq km) and the size of Russia (15,000,000 sq km)
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impacts of the great pacific GARBAGE PATCH |
ENVIRONMENTAL IMPACTS: Overall ecosystem health is gravely affected by the accumulation of trash. Marine debris ingestion and entanglement directly impacts marine life. Additionally, the mere presence of marine debris can disrupt an entire food web through its indirect impacts. Imagine that the entire biosphere is one large food web comprised of interrelated food chains. The disruption of tropic levels within a food chain can have effects on the entire food web. The ratio of plastic to zooplankton in the major ocean gyres, which tend to concentrate floating material, is estimated to be up to 6:1 by weight. Whales, fish and other marine species depend on zooplankton for food, as they are the fundamental link to the phytoplankton who the capture sun’s energy. Researchers currently believe plastics are taken up by zooplankton, thus entering the food chain. Plastics also bring toxins into the food chain. When plastics break down, they produce toxic products. They also aggregate pollutants in the environment. Both are released when animals digest the plastic. While many of these species are threatened, still others form part of our diet. This means that plastic ingested by wildlife not only affect them - their guts may be perforated and they may starve - but toxins from the plastics may also be absorbed by humans. Globally more than 200 species are known to be affected by marine rubbish including whales, seals, dugong, seabirds, turtles, crabs, sea snakes, sharks, rays and other fish. Studies show that “ingested marine debris is quite common in samples of dead and captured seabirds and turtles”, indicating that many marine organisms mistake small bits of plastic and trash for food. Ingestion of marine debris causes various effects in marine life, including “reducing the absorption of nutrients in the gut, reducing the amount of space for food in the gizzard and stomach, uptake of toxic substances that comprise the debris or have been absorbed into the debris, ulceration of tissues, and mechanical blockages of digestive processes.” Entanglement is also a significant threat to marine species. For example, up to 40,000 fur seals are killed each year when they get tangled in debris. This contributes to a population decline of 4-6% per year. Entanglement affects nearly all groups of marine vertebrates. We know that in Australian waters turtles, cetaceans, seals, sea lions, seabirds, sharks and rays, crabs and other animals are affected. Derelict fishing gear is particularly harmful as it often results in “ghost fishing”. This occurs when lost or abandoned fishing gear continues to catch fish that then goes to waste. Debris entanglement can also have damaging effects on marine habitats, such as coral reefs and sea grass destruction resulting from contact with derelict fishing gear. By 2050 there could be as much plastic as fish in the ocean, plastic can prevent ocean absorbing CO2 from the atmosphere which in turn exacerbates climate change. HUMAN HEALTH IMPACTS Plastic does not decompose. After coming into contact with the sun, plastic products continue to break into smaller and smaller pieces called “micro-plastics.” Pre-production plastics, or “nurdles,” are small plastic pellets that are later melted and moulded to produce everyday plastic products. Massive quantities of nurdles often spill off ships and into the sea. Scientists are concerned that plastics, particularly micro-plastics and nurdles, “are able to adsorb, concentrate, and deliver toxic compounds to organisms that ingest them or to benthic communities. In fact, studies have demonstrated that plastics readily absorb contaminants with greater ease than natural sediments like rocks and sand. The contaminants that plastics absorb include polychlorinated biphenyls (PCBs) and dichlorodiphenyltrichloroethane (DDT). DDT and PCBs are persistent organic pollutants (POPs) that “can accumulate and pass from one species to the next through the food chain.” POPs have been linked with “reproductive, developmental, behavioural, neurologic, endocrine, and immunologic adverse health effects” in humans. Because micro-plastics and nurdles are easily ingested by species at the bottom of the food chain, humans are in danger of ingesting large quantities of POPs when consuming larger species, like tuna and wahoo. As fisheries contribute greater than 20 percent of the average per capita animal protein intake for more than 1.5 billion people, these bioaccumulation effects are significant. Particularly at risk are the populations of small island states and developing nations who derive 90% of their animal protein from fish. POPs can also affect the next generation because they are transferred to developing offspring through the placenta and breast milk. While the consumption of marine species may result in serious indirect impacts on human health, marine debris that washes ashore may also immediately and directly injure beachgoers. Debris such as glass and aluminium may cut people walking on the beach. More threatening, however, is the possibility of hazardous medical waste, like needles, washing ashore and injuring the public. ECONOMIC IMPACTS Marine debris has serious negative consequences on beach tourism and real estate property values. A study of New Jersey estimated the state lost billions of dollars in tourism revenue as a result of marine debris washing ashore. A similar study demonstrated that New York forwent anywhere from $950 million to $2 billion. This decline in economic revenue stems from tourists foregoing ventures to the beach because of its distasteful appearance. For instance, a South African study concluded that 10 pieces of marine debris per meter of beach would deter 40 percent of foreign tourists. Like tourism, housing values also suffer from the distasteful appearance and stench of trash floating nearby waterfront homes and cluttering the streets and alleys of neighbourhoods. As a prime beach tourism destination and real estate hub, south Florida must take measures to limit the amount of marine debris washing upon our beaches and reefs by investing in both public education to reduce single-use plastic consumption and in cleanups. CHEMICAL EFFECTS ON BIODIVERSITY Plastics both leach and absorb dangerous pollutants and toxic chemicals, including additives used in manufacturing. When plastics are broken down through photodegradation, which is the process by which light breaks down complex molecules into simpler products through oxidation, they leach out these colorants and chemicals which cause environmental and health problems. For example, bisphenol A, also known as BPA, affects the growth, reproduction, and development of aquatic organisms and is an endocrine (hormone) disruptor in humans. This means that it which interferes with the production, secretion, transport, action, function and elimination of natural hormones. Plastics also absorb pollutants such as PCBs. These can be consumed by marine animals and concentrate and persist in the fatty tissue of living organisms when they are ingested, and therefore bioaccumulate up food webs, which has a wide-ranging impact on many different species. The impact of toxic chemicals leaching into water can also affect the behaviour of aquatic animals who rely on chemicals to understand the world around them, from smaller animals such as periwinkles to larger animals such as crabs and fish. For example, periwinkles usually protect themselves from predators by withdrawing into their shells when they sense crab chemicals in the water. However, a study by the French National Centre for Scientific Research have shown that after periwinkles were placed in water containing plastic pellets, they no longer responded to those chemical cues. Being robbed of the ability to sense danger could leave animals more vulnerable to predation in the wild, which can affect entire food webs by increasing populations of predators etc. In evaluation of the negating impacts of the Pacific Ocean Garbage Patch, we have come to the conclusion that the effects on the environment are of the greatest concern. This is due to the fact that the issues of pollution on the environment transcend into the food chain causing harm to humans as well. Furthermore, the economic impacts of the pollution are only a result of the harm that is being inflicted on the environment. Therefore more effort should be exerted to deal with the environmental impacts, which coincides with the ecocentric viewpoint. |
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1. Wind blowing over the ocean surface exerts forces on the water creating a system of surface currents. The wind drags ocean surface in the direction of the wind. However there is deflection because of the Coriolis Effect. The Coriolis Effect takes into consideration the rotation of the earth to the path of the water. The Coriolis force is used to explain the apparent deflection of the path of water or an object on the water. In fact the object will not actually change path but it appears to as the earth is rotating from west to east. This deflection will be about 45 to the right in the Northern hemisphere and to the left in the Southern hemisphere at the surface of the water from the equator. At the equator the Coriolis Effect is 0. The Coriolis Effect is determined by the motion of an object, the motion of the earth and the latitude. The magnitude is given by 2vw (sin) where v is the velocity of the object, w in the angular velocityM of the earth and is the latitude.
2. Beneath the surface the Coriolis Effect effects every layer of water. Each layer is deflected slightly less from each other layer forming a spiral called an Ekman spiral. The spiral is around 100m deep.
3. If one adds up all the vectors in an Ekman spiral the resulting flow of water is at 90 to the wind direction. The net transport of water in this direction is called Ekman transport.
Plastics are made by a process called polymerization where molecules called monomers are confined by chemical bonds into a polymer. A polymer is a chain of monomers chemically bonded.
There are two types of plastics: 1. Thermoplastics 2. Thermosets Thermoplastics: These are plastics which have a lined up chain of monomers forming the polymer. During the curing process the thermoplastic pellets become softer and therefore, when the plastic is heated it will melt and when cooled it will solidify. This type of plastic can be tough but can be easily recycled. Examples of these include polystyrene and polypropylene.
- The problem is that although some of these plastics can be recycled, they are still thrown into the sea plastic does not decompose in water. This is because the large amount of electrostatic forces which would be needed to overcome the many bonds in all polymer structures. For example, plastic bottles take up to 450 years to decompose. ----------------------------------------------------------------------------------------------------------------- Ecocentric viewpoint a philosophy or perspective that places intrinsic value on all living organisms and their natural environment, regardless of their perceived usefulness or importance to human beings. It believes that we as humans need to change our attitudes and value species more. A person following this viewpoint would likely: - shop at plastic free and waste free shops such as Hetu in South London a zero -waste store that sells food in a form very close to its original using mostly unprocessed and unrefined plant based ingredients. Other products have some form of social responsibility and the store reckons it can help you get to zero waste in two weeks -Use sustainable fashion such as thrifting, or buying from stores such as thought Clothing -Organic, which sells eco-friendly and sustainable items sustainable-made from cotton, bamboo, and hemp Overall by reducing usage of ‘single-use’ products there will be less waste in the world and ultimately, less pollution Anthropogenic viewpoint A viewpoint which views things in terms of human needs and values Government intervention to solve problems For example, in the Yangtze river which is deposits 55% of plastic and is a large contributor to the great pacific garbage patch, many policies are being implemented. The Yangtze region (the area surrounding the river’s banks) covers almost 450 million acres of land and is home to more than 400 million people, approximately a third of China’s population. The combination a high population, rapid development and a consumerist lifestyle has mean that the waste management infrastructure has not been able to keep up, leading to the Yangtze river becoming a dumping ground and being partially responsible for the great pacific garbage patch. Previously China took in 45 percent of the world’s plastic waste imports, yet in 2026 banned accepting these imports. In addition, tax emptions to firms who complete the recycling of products will be granted. In February of 2019, new guidelines regarding the consequences of people dumping sewage into the Yangtze were implemented and new policies regarding the waste from ships are also being implemented in order for China to overall take a firmer stance against the pollution. Technocentric viewpoint This viewpoint believes humans are the most important and thinks of nature in relation to what it gives humans. It outlines that we should continue our everyday activities as we are, and soon technology will adapt to fix the problem. Solutions involving technology that aim to resolve the issue are:
The aim is to ‘create a coastline where there are none’ so that the plastic can be contained and consequently removed. This essentially streamlines the traditional vessel and nets method. How it works: The device moves faster than the plastic, which is moving with the current. This is because the float and the plastic both experience the same force from the current, but the float also experiences a force from the wind and waves (because it is partially above the surface). This then leads to the plastic being contained on one edge. As the current applies pressure on the skirt, since the depth in the middle of the device is greater, it is pushed less so it consequently forms a u-shape. To understand why the plastic trails slower than the float, one must first consider the current. As winds blow across the ocean, they pull on the water’s surface. This buildup of energy forms waves. When the waves reach the shore, they become unstable and topple over. This energy release cause longshore currents (here, the wave energy is directed parallel to the shore). As explained before, the surface currents are typically 20-40 degrees to wind direction and this is the direction in which the plastic flows. (Not so greatly affected by Ekman transport since it forms at 300 feet below the surface whereas plastics, such as polypropylene—used in bottle caps— has a density of 0.92g/cm3 while the sweater’s average density is 1.027 g/cm3.) As a result, the plastic and float are moving at the speed of the current. However, one must next consider the wind direction. Remember, the wind speed is much greater than the current (since it only transfers the parallel energy to the current) so the float receives a large force from the wind to increase its speed. The net effect of the two is that the float moves faster than the plastic, collecting it up. The drag reorientates the device so that it can change direction and catch all the plastic. Both the plastic and the float are orientated by the wind so they automatically go towards the highest plastic concentration because it is affected by the gyres in the same way that plastics are in order to “take advantage of natural oceanic forces”. The plastic is then collected, transported to land and recycled. The problem with this method is that it is reliant on the wind direction to clear all the plastic. As a result, it is only expected to clean 50% of the garbage island every 5 years. This highlights the need to have a ‘multi-pronged approach’.
Pyrolysis is a process of thermal decomposition which takes place in an inert atmosphere. It aims to convert waste plastics into usable crude oil and uses pressure and high heat in the presence of water to decompose the long chain plastic polymers into short-chain petroleum hydrocarbon monomers (fuels). The length of these polymers is usually around 18. Below is a flow chart of how the process takes place: 
Essentially, the plastic waste is ground into tiny chunks which can then be mixed with the water. The chemical reaction is the image below takes place, converting the polymer into smaller hydrocarbons. Although solid minerals are also created, these can be separated via fractional distillation.
The chemical reaction: 
In conclusion, a technoscentric viewpoint is likely to be the most effective at tackling and reducing the size of the great pacific garbage patch. Despite this, due to the flaws to achieve the best outcome a combination of different approaches will help reduce the negative impacts of the garbage patch most effectively.
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