Plastic Pollution In Oceans: An Ominous Marine Crisis

Marine debris is a pressing issue, with plastic being the most common type found in our oceans, waterways, and Great Lakes. It is challenging to determine the exact amount of plastic in the ocean, but studies provide estimates. In 2016, a study by Borrelle et al. suggested that approximately 23 million metric tons of plastic waste entered the ocean and waterways globally. Another study from 2014 estimated 244,000 metric tons of floating plastic in the ocean, while a 2017 study found 79,000 metric tons in the Great Pacific Garbage Patch alone. The impact of plastic pollution on marine ecosystems and biodiversity is devastating, and it continues to increase, threatening marine life and human health.

Plastic debris in marine life: ingestion, suffocation, and entanglement

Plastic is the most common type of marine debris in our oceans, waterways, and Great Lakes. It is used to create everyday items such as toys, food storage, and medical supplies, but also includes larger items such as lost or discarded fishing gear or large sheets of plastic used in agriculture. Plastic marine debris can enter water bodies in several ways, including limited trash disposal resources, improper trash collection, littering, or stormwater runoff. Once in the environment, plastic does not break down like natural materials and may remain in the ecosystem indefinitely.

The presence of plastic in marine ecosystems has led to several issues, including ingestion, entanglement, and suffocation of marine life. Over 100 species of seabirds, for example, are known to ingest plastic artifacts or become entangled in abandoned or lost netting. Ingestion of plastic items can cause internal and external wounds, suppurating skin lesions, and ulcerating sores in marine life. It can also lead to the blockage of the digestive tract, resulting in satiation, starvation, and debilitation, which can be fatal.

Entanglement in plastic debris can cause similar issues, leading to death from starvation and debilitation, with a reduced quality of life and lowered reproductive performance. Published images of seabirds, marine mammals, and fish entangled in plastic netting have attracted considerable media and public attention, highlighting the emotive issues surrounding this problem.

In addition to ingestion and entanglement, plastic debris can also cause suffocation in marine life. The fragments of plastic debris can blanket the biota of soft sediment, reef, and rocky substrata, inhibiting gas exchange between pore waters and overlying seawater, leading to anoxia and hypoxia. These issues have been observed in various locations, including the Southern Ocean, the North Pacific gyre, and the South Pacific Islands.

Plastic waste in the ocean: microplastics and nanoplastics

Plastic is one of the most commonly found items in marine debris. It is used to create everyday items such as toys, food storage, and even medical supplies. Plastic marine debris can also include larger items such as lost or discarded fishing gear or large sheets of plastic used in agriculture. A study by Borrelle et al. estimated that in 2016, about 23 million metric tons of plastic waste entered the ocean and waterways globally. Another study estimates that there are 5.25 trillion particles (or 244,000 metric tons) of plastic floating in the ocean.

Plastic waste in the ocean is a significant issue as plastic does not decompose like natural materials. It can persist in the environment for hundreds of years, breaking down into smaller and smaller pieces called microplastics. These microplastics, measuring less than 5mm in size, can be the result of large plastics breaking down or can be produced as small plastics such as microbeads found in personal care products. They can also come from microfibers shed from synthetic clothing or fishing nets. Microplastics can absorb harmful pollutants and release them into the ocean, affecting marine life and ecosystems.

Microplastics have now become part of the food chain, found in drinking water, salt, beer, and even the soil where we grow our food. They can be ingested by marine animals, entering their bodies and tissues, and leading to harmful consequences for their health and the planet's ecosystems. Over time, microplastics can further fragment into even smaller pieces called nanoplastics, which can be ingested by living organisms, impacting their feeding, digestion, excretion, and reproduction.

To address the issue of plastic waste in the ocean, it is crucial to prevent plastic from entering waterways and oceans in the first place. This can be achieved through improved waste management systems, recycling, and reducing the use of single-use plastics. Additionally, the design and usage of disposable packaging should be reconsidered, and the manufacturing of unnecessary single-use plastics should be minimized.

Plastic pollution in marine ecosystems: biodiversity loss and climate change

Plastic pollution is a pressing issue in marine ecosystems, causing biodiversity loss and contributing to climate change. Marine plastics are estimated to contribute to the death of over 100,000 marine mammals annually, through entanglement, ingestion, and toxic contamination. The impact of plastic pollution on marine life varies depending on the size of the plastic fragments. Large plastic items can entangle marine mammals and fish, leading to starvation, injury, and increased vulnerability to predators. Discarded fishing nets can also smother and damage coral reefs, hindering their healthy growth.

Smaller plastic fragments, including microplastics and nanoplastics, can be mistaken for food by seabirds and other marine species, resulting in suffocation, starvation, and toxic contamination over time. A study of mussels from UK waters found that 100% of the samples contained microplastic pieces. Microplastics can adsorb up to one million times more toxic chemicals than the surrounding water, posing a significant threat to marine apex predators such as orcas and great white sharks through bioaccumulation. Biomagnification occurs when chemicals accumulate in the fatty tissues of animals that have consumed contaminated prey, resulting in higher toxin concentrations in top predators.

The ocean is particularly vulnerable to plastic waste. Once plastic enters the marine environment, it can spread widely, carried by waves and storms to remote regions and embedding itself in shorelines and delicate coastal ecosystems. Over time, plastic breaks down into smaller and smaller fragments, making it increasingly challenging to retrieve and remove from the ocean. The persistence of plastic in the marine environment poses a continuous threat to marine life and ecosystems.

Plastic pollution in the ocean has far-reaching consequences, contributing to climate change. The production of plastic from oil and gas extraction and refining contributes to greenhouse gas emissions. Additionally, the incineration of plastic waste releases carbon dioxide, dioxins, and methane into the atmosphere. Plastic pollution also affects ecosystems' ability to support climate change control strategies. For example, coral reefs play a crucial role in carbon sequestration, but plastic pollution, particularly discarded fishing nets, damages these ecosystems, reducing their capacity to mitigate climate change.

Addressing plastic pollution in marine ecosystems requires a multifaceted approach. Preventing plastic from entering the ocean is of utmost importance, including improving waste management practices and reducing the use of single-use plastics. Additionally, there is a growing focus on developing biodegradable materials and innovative solutions, such as edible food packaging and mesh bags to capture microfibers from clothing, to minimize the environmental impact of plastic waste. Global cooperation and the implementation of treaties, such as the London Convention and the London Protocol, are essential to curb plastic production and promote sustainable alternatives.

Sources of plastic marine debris: land and ocean-based sources

Marine debris is a global issue that affects all people and environments, and plastic is the most common type of this debris. It is challenging to determine the precise amount of plastic in the ocean, but studies have estimated that about 23 million metric tons of plastic waste entered the ocean and waterways globally in 2016. Another study estimated that eight million metric tons of plastic entered the ocean in 2010.

Plastic marine debris comes from both land-based and ocean-based sources. Land-based sources include human activities on land, such as littering, dumping in rivers and streams, and industrial losses. Intentional or unintentional disposal of waste on land or in waterways can contribute to marine debris if it is subsequently carried out to sea. Stormwater runoff, which occurs when stormwater flows along streets or the ground and carries street litter into storm drains, is another significant land-based source of marine plastic pollution.

Ocean-based sources of marine plastic debris include items lost from vessels or platforms at sea, such as fishing gear from commercial vessels, recreational boats, or shore-fishing activities. Offshore oil and gas platforms are also sources, as all items lost from these structures become marine debris. Cargo lost from freighters, cruise ships, and other vessels is another contributor, with an estimated 10,000 containers lost at sea each year.

Natural disasters, such as hurricanes, tornadoes, tsunamis, floods, and mudslides, can also contribute to marine plastic pollution. High winds, heavy rains, and tidal surges associated with these events can carry trash, including plastic items, out to sea. For example, the 2011 earthquake and tsunami in Japan resulted in five million tons of debris, much of which ended up in the ocean.

Microplastics, small plastic particles less than 5mm in size, are another significant source of plastic marine pollution. They can form when larger plastics break down or be produced as small plastics, such as microbeads found in personal care products. These microplastics can enter waterways and the ocean through drains and contribute to the overall plastic content in marine environments.

Monitoring and reducing plastic in marine environments

Plastic is the most common type of marine debris in our oceans, waterways, and Great Lakes. It is used to create everyday items, from toys and food storage to medical supplies and clothing. Plastic marine debris can also include larger items, such as lost or discarded fishing gear or large sheets of plastic used in agriculture.

The issue of plastic in marine environments is a pressing one, as plastic does not decompose like natural materials. Instead, it breaks down into smaller and smaller pieces, known as microplastics, which can be even more challenging to locate and clean up. These microplastics can absorb harmful pollutants, such as pesticides and dyes, and release them into the ocean, creating several negative consequences for marine ecosystems.

To address this issue, monitoring and reducing plastic in marine environments is crucial. Monitoring is essential to assess the effectiveness of measures implemented to reduce plastic debris. However, it is challenging due to the large spatial and temporal heterogeneity in plastic debris amounts and our limited understanding of its pathways and long-term fate. Most monitoring efforts have focused on beach surveys of stranded plastics, but these provide crude estimates and are biased by clean-up efforts. At-sea sampling is another method, but it requires large sample sizes due to the high spatial and temporal variability in plastic distribution.

To reduce plastic in marine environments, a combination of policies, legislation, regulations, and initiatives at the global, regional, and national levels is necessary. For example, the London Convention, or MARPOL, prohibits the discharge of plastic into the sea. Additionally, companies are developing alternatives to plastic for common items, such as biodegradable materials that can be composted at home. Public participation is also key, with initiatives like beach clean-ups and the Marine Debris Tracker app encouraging people to get involved in their local areas.

Overall, addressing the issue of plastic in marine environments requires a multi-faceted approach involving scientific research, policy interventions, and public engagement to reduce the amount of plastic entering our oceans and waterways and mitigate its environmental and economic impacts.

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