International Journal of Marine Science, 2024, Vol.14, No.1, 21-28 http://www.aquapublisher.com/index.php/ijms 25 Figure 4 Distribution pattern of plastic waste in the ocean (Image source: http://society.yunnan.cn/system/2021/04/11/031386729.shtml) 2.3 Mechanisms of plastic waste dispersion Ocean currents and wind play crucial roles in the dissemination of plastic waste in the ocean. Ocean currents transport plastic waste from one region to another, while wind can propel floating plastic debris to drift in specific directions. These natural forces result in the accumulation of plastic waste in the ocean, forming garbage patches, such as the "Great Blue Ocean Belt" in the North Pacific Ocean. Rivers constitute one of the primary pathways for plastic waste entering the ocean. Plastic debris can be washed into the ocean from rivers, especially during floods and heavy rainfall. River discharges from coastal cities and industrial areas are significant sources of plastic waste entering the ocean, and human activities in coastal areas are also a source of plastic waste. Waste discharge from fisheries, tourism, coastal cities, and ports can lead to the accumulation of plastic waste in coastal waters. These areas are often hotspots for plastic waste, and the global issue of improper waste disposal and garbage accumulation exacerbates the problem of plastic waste on a global scale. When waste is not properly handled, it may eventually find its way into rivers or the ocean. Shipping and maritime activities can lead to the accidental loss of plastic waste. At sea, plastic debris may fall off ships or cargo vessels, becoming part of marine litter. Some plastic waste may settle to the ocean floor, especially tiny plastic particles. These particles deposit into the habitats of benthic organisms and may potentially impact benthic ecosystems. Plastic waste can enter the food chain through bioaccumulation. Marine organisms such as fish, shellfish, and plankton may ingest plastic particles, transferring them to higher levels of the food chain. 3 Impact of Climate Change on Plastic Waste in the Ocean 3.1 Effect of temperature rise on plastic waste The increase in temperature generally accelerates the decomposition rate of plastic waste, as higher temperatures expedite chemical reactions and physical processes, making plastic molecules more prone to breakdown. However, decomposition does not imply complete disappearance; instead, plastic is transformed into microplastic particles, potentially posing new challenges for ecosystems and organisms. With rising temperatures, chemicals present in plastic waste (such as phthalates and polybrominated diphenyl ethers) may be released into the surrounding environment, elevating the concentration of harmful substances in water bodies. Elevated temperatures can influence ocean currents, wind patterns, and marine circulation, thereby altering the distribution of plastic waste. Some studies suggest that climate change may make it easier for plastic waste to enter certain regions, such as the Arctic, posing new threats to local ecosystems (Figure 5). Certain organisms may find it easier to ingest plastic waste as their food sources are affected or mimicked by plastic debris. This could lead to more instances of bioaccumulation of plastic waste, affecting the food chain. The rise in temperature may cause an increase in sea
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