We’ve all seen the sickening images of turtles with straws stuck in their nostrils, seagulls stuck in soda can plastic rings, and the Great Pacific Garbage Patch – a seemingly endless amount of plastic polluting our oceans and waterways. But what about the plastics that we cannot see?
Microplastics are tiny plastics that are not biodegradable and their small size makes them nearly impossible to clean up once they have entered our environment. Microplastics are created one of two ways: as the byproduct of larger plastics or made up synthetically for commercial use (such as microbeads in body scrubs and glitter in makeup products). Microplastics, unfortunately, are often found in our environment, harming not only ecosystems but also marine life. Microplastics typically end up in our water; not just in drinking water but also in lakes, rivers, and even oceans.
To fully understand the harm microplastics cause to the environment, you must first understand how the massive amount of microplastics that wind up in our bodies of water (mainly focused on ocean exposure), how they spread through the food chain through contamination and digestion, what happens to marine life through their presence, and how we can avoid these issues.
How Do Microplastics Enter the Ocean?
Plastic does not suddenly appear out of nowhere in the ocean, so how does so much waste end up washing up on beach shores and swirling through the currents of its deep depths? There are many ways that plastics can enter the ocean:
Littering
Inadequate waste management
Microbeads in personal care products that wash down the drain (now banned in USA, Canada, and the UK)
Illegal dumping
Landfills
Trash transportation
Wind and rain
On land, plastics can break down through the sunlight, degrading them into microplastics. This process can also occur underwater; however, the degradation process is slower due to lower temperatures, limited direct sunlight, and reduced oxygen in deeper areas [1]. This continuous cycle of plastic breakdown poses a threat to lakes, rivers, and oceans, as wildlife can ingest these microplastics, leading to their integration into the food web [2].
With the amount of plastic pollution on earth, more than 90% of the marine plastics found in surface water are composed of microplastics [3]. Even more concerning, microplastics account for approximately 85% of plastic pollution observed on shorelines worldwide [1]. That's a lot of microplastics to account for, especially considering the minimal size of microplastics.
How do Microplastics Impact Our Oceans?
Problem 1: Plastics Disrupt Ecosystems
What happens to the harmful substances that may be attached to microplastics as they are ingested and transferred from one organism to another? Microplastics like microbeads, synthetic fibers, and plastic fragments, can absorb other chemicals that are harmful to the environment and marine life [4]. Understanding the potential impact of these toxins and chemicals is crucial for assessing the broader consequences of microplastic pollution on both ecosystems and human health [5].
Our beaches are only a small portion of the issue as microplastics are far more abundant in the ocean. On the surface of the ocean alone, there are approximately 5.25 trillion particles of plastic, which equals the weight of over 2,100 blue whales—269,000 tonnes [6].
Plastics break down due to erosion from the waves and sunlight where heavier microplastics sink to the bottom and lighter ones continue to flow with the current [6]. Colonizing organisms such as algae and bacteria often cling onto these plastic pieces and sink along with heavier plastics that make their way to the ocean floor where they stay without biodegrading or decomposing [6].
Plastic entanglement or consumption by aquatic life is mainly what we think when we consider how plastic impacts animals; but those are not the only concerns, much like algae and bacteria, organisms can get moved from their habitats by floating plastic. According to the Smithsonian Environmental Research Center, “Scientists have found that some coastal species, carried from land to sea on plastic litter, can survive for not only weeks or months, but even years on these plastic rafts” [7]. Due to these roaming organisms moving and settling in various locations, different species and habitats can become unbalanced by taking up resources that other local species need to thrive [8].
Problem 2: Organisms Ingesting Plastics Harm the Food Web
Organisms live based on their surroundings, so with microplastics floating around and on the ocean floor there is no surprise that these particles often end up in marine life through their gills or by consumption, even by smaller species such as plankton or oysters while filtering water [6]. These organisms are low on the food web, so when larger creatures eat them, the microplastics they ate go up the food chain, passing their toxins along with them until they eventually get ingested by the fish that we eat and then by us [3]. This process of microplastics being passed up the food web by organisms eating one another is known as the “trophic transfer” of microplastics.
As microplastics move through the food chain, a big concern is the happenings of the toxins and chemicals that are associated with these plastics and the bioaccumulation of their pollutants. Hundreds of species of animals have been found to have microplastics inside of them. Larger animals such as whales, sharks, and manta rays are highly impacted since they ingest large amounts of microplastics due to their size and diet of smaller aquatic organisms [6].
This sort of research is very important since marine life and their ecosystems are so vital to the world. Fish play a key role in aquatic ecosystems as they regulate the process of circulating material and energy, and the ecosystem can be monitored for stability and function through their presence [9].
Problem 3: Plastics Physically Harm Organisms
When animals mistakenly consume plastic, it can bring them significant harm and often leads to death. The ingested plastic fills their stomach, causing a decrease in their hunger. This typically makes the animal eat less, which gives them less energy causing them to weaken over time. Larger plastic items can obstruct their digestive system, preventing the plastic from leaving their bodies. Alternatively, the plastic may be fragmented into smaller pieces within the stomach and disperse throughout the animal's body [10].
There are also harmful substances present in microplastics, such as plasticizers, which have hormone-like effects and can disrupt fertility. In some cases, these additives can even induce the development of ovaries in male animals. Flame retardants, another common addition to plastics, are known to be carcinogenic. These chemicals are released from microplastics and can also lead to tumor formation in fish [6].
Due to their tiny size, microplastics are extensively present throughout marine ecosystems. This characteristic makes them highly susceptible to ingestion by all sorts of organisms, leading to a range of detrimental consequences. These include hindering the growth and development of animals, influencing their feeding patterns and behavior, causing reproductive toxicity, impairing immune functions, and even resulting in genetic damage [9].
The sharp edges of microplastics can also harm these creatures through physical injuries, such as damaging the sensitive mucous membranes in the stomach of smaller organisms like crabs and mussels—which can cause inflammation. Plastics have become ubiquitous in our environment and with their widespread use, it is crucial to know more about their impact on the world around us [6].
What We Can Do
By making an effort to reduce plastic waste, adopting sustainable practices, participate in community clean-ups, and supporting initiatives that promote more regulation for waste management, and supporting organizations dedicated to protecting our oceans, we can stop this from continuing. Eliminating our use of single-use plastics, avoiding plastic packaging whenever possible, participating in waste clean-ups, and showing your support through your social media channels. By taking any of these small actions we can collectively improve the microplastic crisis. Let's strive for a future where oceans are free from the harms of plastic and where our marine life can thrive for generations to come.
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References:
[1] Jambeck, J., & Ocean Portal Team. (2018, April). Marine Plastics. Smithsonian Ocean. https://ocean.si.edu/conservation/pollution/marine-plastics
[2] Nicosia, A. (Feb. 2022). A Beginner's Guide to Microplastics: What are They and Why are They a Problem? Plastic Detox. Retrieved from: https://www.plasticdetox.com/post/a-beginner-s-guide-to-microplastics-what-are-they-and-why-are-they-a-problem
[3] International Fund for Animal Welfare (IFAW). (2021, July 12). How does plastic get into the ocean? IFAW. Retrieved May 14, 2023, from https://www.ifaw.org/journal/plastic-pollution-ocean?ms=UONDC230037102&gclid=CjwKCAiA_6yfBhBNEiwAkmXy54dRJw8eGSzYeb_1WVmhXvRVfgRHrlm35CyAMK0STppNCeY_uFVD9xoCeqIQAvD_BwE
[4] National Oceanic and Atmospheric Administration. (2022, January 27). A Guide to Plastic in the Ocean. NOAA’s National Ocean Service. https://oceanservice.noaa.gov/hazards/marinedebris/plastics-in-the-ocean.html
[5] Plastics in the Food Chain. Plastic Soup Foundation. (n.d.-b). https://www.plasticsoupfoundation.org/en/plastic-problem/plastic-affect-animals/plastic-food-chain/
[6] Ocean Care. (n.d.). Microplastics: Barely visible, but anything but harmless. OceanCare. https://www.oceancare.org/en/stories_and_news/microplastics/?utm_campaign=plastik&utm_source=gad-g&utm_medium=sea&utm_content=plastik-en
[7] Smithsonian Environmental Research Center. (n.d.-a). Citizen Science Project: Floating Ocean Ecosystem Tracker. The What. https://serc.si.edu/floating-ocean-ecosystem-tracker/what
[8] Smithsonian Environmental Research Center. (n.d.-b). Citizen Science Project: Floating Ocean Ecosystem Tracker. The Why. https://serc.si.edu/floating-ocean-ecosystem-tracker/why
[9] Li, Y., Sun, Y., Li, J., Tang, R., Miu, Y., & Ma, X. (n.d.). Research on the Influence of Microplastics on Marine Life. iop science. https://iopscience.iop.org/article/10.1088/1755-1315/631/1/012006
[10] Animals Eat Plastic. Plastic Soup Foundation. (n.d.-a). https://www.plasticsoupfoundation.org/en/plastic-problem/plastic-affect-animals/animals-eat-plastic/
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