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PolskiSubtopic 2: How does plastic pollution affect marine life?
Why is the ocean so badly affected by plastic?
The ocean is a vast and deep body of water that serves as a giant repository for global pollution. A significant portion of the plastic waste in the ocean originates from lost cargo from ships and discarded fishing gear, which accounts for approximately 10% of the plastic debris located there. Marine aquaculture also contributes to the problem, particularly when polystyrene foam, which is used to make the frames of fish cages, finds its way into the ocean.
However, the primary source of ocean waste comes from land-based pollution. Extreme weather and high winds can bring litter and waste to the ocean water, while coastal pollution is carried out by tides. Additionally, thousands of rivers worldwide transport tons of loose litter and waste from landfills, ultimately depositing it into the ocean water too. Shockingly, just ten of the world’s rivers, eight of which are sourced in Asia, are responsible for the majority of plastic debris reaching the ocean. In particular, China’s biggest river, the Yangtze, is the largest contributor of plastic waste, as it generates 1.5 million metric tons per year. This is largely due to several countries’ waste management policy that includes outsourcing their plastic waste to China, which was the world’s leading importer of plastic waste until it was banned in January 2018.
Once in the ocean, plastic waste is subject to harsh conditions and constant motion, causing it to break down into microplastics. This process disperses plastic waste even further and deeper into the ocean, invading more habitats and making it nearly impossible to retrieve.
Source: European
What’s the impact on marine life?
Each year, hundreds of thousands of marine animals become entangled in plastic waste, particularly in ghost gear that restricts their movement and their feeding ability and causes injuries and infections to them. Ingesting plastic is also a major issue, since seabirds, turtles, fish, and whales usually mistake plastic waste for their prey due to its similar shape and color. Moreover, this kind of plastic can accumulate microbes and algae on its surface, which makes it attractive to some sea animals. Once ingested, plastic can cause internal organ damage or fatal intestinal blockages to them and lead to starvation, as their stomach is full of plastic and gives them the impression of being full. Plastic also infiltrates entire ecosystems, as microplastics resemble plankton, which is the main food source for hundreds of species at the base of the food chain in the ocean. Even coral polyps regularly consume microplastics. Additionally, plastics absorb pollutants in the ocean and contain harmful chemicals that could damage animals’ organs, making them more vulnerable to disease and affecting their reproductive ability, according to preliminary research.
The severe impact of plastic pollution on marine wildlife
According to a recent report by the RSPCA, plastic waste is responsible for harming wildlife, causing 579 cases in England and Wales in 2018, indicating an increasing trend, as 473 cases were reported in 2015. The primary cause of harm to animals is entrapment and physical wounds resulting from plastic waste. Marine creatures such as fish and birds can get entangled in plastic types of packaging, such as plastic bags and drink rings, leading to painful wounds, strangulation, or drowning. Sea-dwelling mammals, reptiles, and birds that need air to breathe can become so entangled that they cannot reach the surface for oxygen, leading to drowning.
The internet has seen many heart-wrenching viral videos and images showing the impact of pollution in our oceans, including sea turtles wrapped in plastic, whale sharks trapped in commercial fishing lines, and tiny seahorses holding cotton buds. Despite their heartbreaking nature, these images and videos play a crucial role in raising awareness of this worldwide .
A sea turtle wrapped in plastic. Source: WWF (n.d.)
https://www.wwf.org.uk/updates/learn-about-marine-turtles-and-plastics
An example of the deadly consequences of plastic consumption by marine life can be found on shearwater colonies off the coasts of Australia and New Zealand, which are particularly affected since these birds consume large amounts of plastic and feed it to their young. This leaves no space for actual food causing the fledglings to starve and, consequently, struggle to survive when they go out to sea. Biologists are attempting to save these birds by removing plastic from their stomachs with seawater. Surprisingly, some birds had up to 250 pieces of plastic removed. This is just one example of the impact of plastic on marine life. A recent BBC documentary, “Drowning in Plastic”, (see section Additional learning resources) told us the story of these shearwater colonies off the coast of Australia and New Zealand.
The Growing Concern of Microplastics in Our Food Chain
It is estimated that our oceans are being polluted by millions of tons of microplastics annually, which are introduced through small plastics such as microbeads and synthetic fibers from clothing, as well as from the breakdown of larger plastic items. As a result, microplastics have become ubiquitous in our oceans, and their presence is not limited to marine life, as they are now being discovered in our food chain.
A recent study conducted by Plymouth University showed that one-third of the 504 fish caught off the coast of South-West England contained microplastics. Additionally, the impact of microplastics on sea birds has been observed, with specific regard to the disrupted iron absorption in the small intestine and increased liver stress. This has raised concerns about the long-term effects of consuming microplastics on human health.
The Impact of Plastic Pollution on Coral Reefs
Coral reefs play a vital role in the ocean’s ecosystems and provide a home to numerous species; however, they are being destroyed by plastic pollution. Plastics contain harmful bacteria that can negatively affect coral, and they also prevent light and oxygen from reaching them. When coral encounters plastic, the chances of being affected by it increase by 89%. As a result, plastic pollution has become a major threat to the survival of coral reefs worldwide.
The Enduring Impact of Plastic on the Ocean
Plastic pollution poses a significant threat to our oceans as it does not biodegrade and can persist in the environment for hundreds of years, fragmenting into smaller pieces that can be even more harmful. This was highlighted by a viral social media post showing a Mars Bar wrapper from 1986 found on Constantine Bay in Cornwall. Consequently, people started to share similar stories of discovering old plastic waste on beaches and in other natural environments. The long-term effects of plastic on the ocean are severe and far-reaching since they pose a threat to both marine life and the entire ecosystem.
A Mars Bar wrapper from 1986 was found on the beach at Bay by Emily Stevenson. Source: Wilkinson (2019)
https://www.cornwalllive.com/news/cornwall-news/mars-bar-wrapper-found-beach-2852941