In the previous 2 post, we’ve been looking into what exactly is the Great Pacific Garbage Patch and the major presence of microplastics. But what are the consequences? Surely this problem is more than just an eyesore. The presence of trash has negative effects on the ecosystem as well as food webs of both marine and land organisms.
Out in the open water, the Atlantic waves and harsh sunlight would have worn down the many plastic items into ever tinier pieces called microplastics (Andrady, 2011) . These tiny pieces continue to float about in the ocean, sponging up chemicals and toxins. Fishes and other filter feeders end up eventually eating these microplastics where bioaccumulation of plastics occur within their bodies (Deng, Zhang, Lemos and Ren, 2017). Biomagnification then occurs up the food chain and eventually, these plastics end up in us humans when we eat seafood. Chemicals within the plastics like bisphenol A (BPA), that have been linked to environmental and health problems, as well as polychlorinated biphenyls (PCBs) that are adsorbed to plastics will also eventually end up in us when we consume seafood (Smith, Love, Rochman and Neff, 2018).
Besides the minute microplastics, there are many other larger pieces of trash that causes significant harm to animals living there. Animals have been found strangled by abandoned fishing nets and even six pack beverage rings that had been discarded. Do look into my previous post on “The Plight of Turtles” where more about the effects of macroscopic pollution on wildlife was discussed.
Another issue with marine debris is that the gyres in the ocean will cause all the debris to accumulate in common places. When microplastics and other pieces of garbage start to gather together near/on the surface of the ocean, a substantial amount of sunlight would be blocked (VishnuRadhan, Eldho and David, 2019). Plankton and algae, the 2 most common autotrophs in the ocean, below these marine debris will not be able to receive as much sunlight. This is a threat to their populations and when the producer population is threatened, the entire food web depended on those producers will be affected and change. Creatures like turtles and fishes that feed on these produces will have less food and hence die out. Subsequent animals up the food chain will then have less food and also die out. Seafood in general would then be less. If the rate at which we catch seafood remains the same, seafood populations will plummet faster, making it even more expensive for people (demand and supply). It may even result in more organisms going extinct!
Reference:
Andrady, A., 2011. Microplastics in the marine environment. Marine Pollution Bulletin, 62(8), pp.1596-1605.
Deng, Y., Zhang, Y., Lemos, B. and Ren, H., 2017. Tissue accumulation of microplastics in mice and biomarker responses suggest widespread health risks of exposure. Scientific Reports, 7(1).
Smith, M., Love, D., Rochman, C. and Neff, R., 2018. Microplastics in Seafood and the Implications for Human Health. Current Environmental Health Reports, 5(3), pp.375-386.
VishnuRadhan, R., Eldho, T. and David, T., 2019. Can plastics affect near surface layer ocean processes and climate?. Marine Pollution Bulletin, 140, pp.274-280.
