The Ocean's Garbage Problem: An Ominous Threat

The ocean is filled with items that do not belong there, including plastics, metals, rubber, paper, textiles, and derelict fishing gear. Marine debris is defined as any persistent solid material that is manufactured or processed and intentionally or unintentionally disposed of or abandoned into the marine environment. While the exact amount of plastic waste in the ocean is uncertain, estimates range from 75 to 199 million tons, with a further 33 billion pounds of plastic entering the ocean every year. This plastic waste comes from a variety of sources, including single-use food packaging, plastic bags, bottles, and fishing gear, and it has been found in every corner of the ocean, from remote shorelines to the deepest parts of the seafloor. The impact of this waste is widespread harm to ocean life, with 100 million marine animals dying each year from plastic waste and 100,000 marine animals dying from entanglement in plastic.

The Great Pacific Garbage Patch

The GPGP is made up of the Western Garbage Patch, located near Japan, and the Eastern Garbage Patch, located between Hawaii and California. These areas of spinning debris are linked by the North Pacific Subtropical Convergence Zone, a few hundred kilometres north of Hawaii. The entire patch is bounded by the North Pacific Subtropical Gyre, a large system of swirling ocean currents formed by four currents: the California Current, the North Equatorial Current, the Kuroshio Current, and the North Pacific Current.

The gyre's rotational pattern draws in waste from across the North Pacific, trapping it in the stable centre. The amount of debris in the GPGP accumulates as much of it is not biodegradable. Plastics break down into smaller and smaller pieces, known as microplastics, rather than wearing down. These microplastics dominate the GPGP by count, but 92% of the patch's mass consists of larger objects. The patch is believed to have increased "10-fold each decade" since 1945, and a 2019 study estimated that 80% of the plastic in the GPGP comes from land-based sources, with the remaining 20% coming from boats and other marine sources.

The Ocean Cleanup project has been working to clean up the GPGP, removing more than one million pounds of trash by the end of 2024, or 0.5% of the total accumulated trash.

Mismanaged waste

The ocean is “ground zero” for the plastic pollution crisis. Mismanaged waste is a significant contributor to this crisis. Mismanaged waste refers to plastic waste that is not recycled, incinerated, or kept in sealed landfills. Instead, it ends up polluting the environment and, in many cases, the ocean.

Rich countries tend to produce the most plastic waste per person, but this waste is usually effectively managed and kept out of the natural environment. However, even in high-income countries, only a small portion of plastic waste is recycled, with the majority going to landfills.

The probability that mismanaged plastic waste enters the ocean varies depending on factors such as the location and length of river systems, proximity to coastlines, terrain, and precipitation patterns. Rivers are a major pathway for plastic waste to enter the ocean, with a recent study identifying 1000 rivers that contribute 80% of plastic emitted from rivers into the oceans.

The impact of mismanaged waste on the ocean is devastating. Marine debris, including microplastics, derelict fishing gear, and abandoned vessels, has been found in every corner of the ocean, from the deepest trench to the most remote Arctic ice sheets. It harms and kills marine animals, interferes with navigation safety, and poses a threat to human health.

Abandoned fishing gear

The ocean is inundated with plastic waste, and abandoned fishing gear, also known as "ghost gear", is a significant contributor to this pollution. Ghost gear is any fishing equipment that has been lost or abandoned in the sea, and it poses a grave threat to marine life and ecosystems. It is estimated that between 500,000 and 1 million tons of fishing gear are discarded or lost in the ocean annually, accounting for roughly 10% of marine debris. This abandoned gear includes nets, lines, ropes, traps, pots, and gillnets, and it can remain in the ocean for decades or even centuries, continuously entangling and killing marine animals.

Ghost gear is often made of plastic, which can take 500 to 1000 years to degrade. As it breaks down, it releases microplastics, which are ingested by marine life and can disrupt their natural hormone production and endocrine function, causing shell disease and affecting reproduction. Ghost gear is particularly harmful to marine mammals, seabirds, sea turtles, and sharks, with an estimated 100,000 marine animals dying from entanglement in plastic each year. It also damages critical marine habitats such as coral reefs, mangroves, and vegetation, threatening the food sources and livelihoods of coastal communities and fishers.

The problem of ghost gear is widespread, with recent studies indicating that it makes up 46-70% of all floating macroplastics (>5mm in size) in the ocean gyres by weight. In the upper Gulf of California, Mexico, illegal and abandoned gillnets have driven the vaquita porpoise to the brink of extinction, with only around 10 individuals remaining. Additionally, 5.7% of all fishing nets, 8.6% of traps and pots, and 29% of fishing lines used globally are lost each year.

Efforts are being made to address the issue of ghost gear. Fisheries and Oceans Canada (DFO) has implemented reporting requirements for lost and retrieved gear in groundfish and shrimp fisheries, and they have supported programs valued at $8.3 million to reduce abandoned fishing gear. The WWF is collaborating with fishers, government agencies, and other organizations to remove abandoned nets, establish gear collection and recycling programs, and develop tools for better gear tracking and management. They are also advocating for a legally binding global plastic pollution treaty to address the threat of ghost gear to marine wildlife.

While progress is being made, the impact of ghost gear on the ocean ecosystem is severe and widespread. It is essential to continue raising awareness about the issue, implementing effective policies, and supporting initiatives that aim to remove and prevent further accumulation of abandoned fishing gear in our oceans.

Microplastics

Marine microplastics are small plastic fragments of debris that are less than five millimeters long. They can be formed from larger plastic debris that degrades into smaller pieces or can be microplastics by design, known as microbeads. These microbeads are tiny pieces of manufactured polyethylene plastic that are added as exfoliants to health and beauty products. They easily pass through water filtration systems and end up in the ocean, posing a potential threat to aquatic life.

The prevalence of microplastics in the ocean is a growing concern. A recent study estimated that there are approximately 358 trillion microplastic particles floating on the surface of the world's oceans, with trillions more in deeper waters. This figure is expected to increase as more plastic waste is produced and mismanaged, with an estimated 11 million metric tons of plastic ending up in the ocean each year instead of landfills or waste management centers.

Scientists are still working to understand the full scope and impact of microplastics in the ocean. The development of standardized field methods for collecting sediment, sand, and surface-water microplastic samples will enable global comparisons of the amount of microplastics released into the environment. This research will help determine the distribution, impacts, and fate of these microplastics, which are now found in every corner of the ocean, from the deepest trenches to remote Arctic ice sheets.

Marine life consumption

Marine life is bearing the consequences of human-created ocean debris. Mismanaged waste, such as single-use plastic products, is a significant contributor to ocean pollution. Marine animals ingest plastic waste or become entangled in it, causing injury and death. It is estimated that 100 million marine animals die each year from plastic waste, with 100,000 of these deaths caused by entanglement.

The Great Pacific Garbage Patch, located between Hawaii and California, is the largest trash site in the world. It has 180 times more plastic than biomass, indicating that marine organisms in this region may be consuming plastic as a primary food source. This is supported by research that states that by 2050, plastic will likely outweigh all fish in the sea.

Plastic pollution in the ocean has a detrimental impact on marine life and ecosystems. It disrupts the delicate balance of marine ecosystems, allowing some species to spread beyond their usual environments and outcompete native species. Floating plastic debris can act as a magnet for toxins, becoming increasingly harmful to any animal that ingests it. Microplastics, in particular, can be consumed by marine animals, entering the food chain and leading to disastrous consequences for the health of the planet and all its inhabitants.

In addition to microplastics, ghost gear, or abandoned fishing gear, is another significant source of ocean trash. Ghost gear continues to entangle and harm wildlife as it drifts through the ocean, pushing some marine mammal species to the brink of extinction. The northern right whale and the vaquita are two examples of species threatened by entanglement in ghost gear.

The presence of plastic in the ocean is a pressing issue that requires global cooperation. While it is challenging to retrieve plastic from the ocean, reducing plastic consumption and improving waste management practices can help mitigate the impact of plastic pollution on marine life and ecosystems.

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