Plastic Pollution's Deadly Impact On Seabirds

Seabirds are highly vulnerable to plastic pollution. They often mistake plastic for prey, and ingest it, which can lead to injury, poisoning from toxic chemicals, and starvation as plastic fills up their stomachs. Seabirds are also affected by microplastics, which are minuscule fragments of plastic that have broken down from larger pieces. Microplastics can cause inflammation in a bird's digestive system, a phenomenon called plasticosis.

Plastic pollution is particularly harmful to a group of seabirds called petrels, which cannot easily regurgitate the plastic they ingest. During the breeding season, they may even feed plastic to their chicks.

A recent study combined tracking data for over 7,000 petrels of 77 different species with existing maps of marine plastic pollution to calculate an exposure risk score for each species. The study found that many species spend a lot of time in areas of the ocean with high concentrations of plastic, with plastic exposure risk being highest in enclosed seas where plastic can become trapped, such as the Mediterranean and the Black Sea.

However, many other petrel species are at risk of encountering plastic in remote parts of the ocean, including the northwest and northeast Pacific, south Atlantic, and southwest Indian Ocean. This is due to large systems of circulating ocean currents, called mid-ocean gyres, which transport plastic debris thousands of miles from its source.

A quarter of petrels' plastic exposure risk occurred in the high seas, which are not within any country's jurisdiction, highlighting the need for international cooperation to tackle marine plastic pollution.

Plastic ingestion causes physical harm to seabirds

Additionally, plastic ingestion has been linked to a range of health issues in seabirds. Studies have found that plastic ingestion can lead to impaired kidney function, with higher concentrations of uric acid found in their bodies. It also negatively impacts cholesterol and enzyme levels, with the exact implications of this still being researched. Seabirds that have ingested plastic are often physically smaller, with shorter wings and bills, and have a lower body mass.

The physical harm caused by plastic ingestion can also lead to increased mortality rates among seabirds. Necropsies of dead seabirds have revealed that ingested plastic items can cause serious ulcerations in the gizzard or block the pylorus, making feeding impossible and leading to death. In some species, plastic ingestion is considered the major cause of injury and mortality.

Furthermore, the size of ingested plastic pieces varies greatly, ranging from small microplastics to larger pieces that can be up to 11.3 cm in length. Even longer plastic items, such as nylon lines, have been found inside birds, reaching lengths of 18.6 cm. The larger pieces of plastic can cause more immediate physical harm and obstruction, while smaller microplastics can build up over time and have more subtle but equally detrimental effects.

The physical damage caused by plastic ingestion is not limited to the immediate effects on the gastrointestinal tract. It also extends to the overall health and development of seabirds, making them more vulnerable to other threats in their environment.

Plastic pollution affects seabird reproduction and survival

Plastic pollution poses a serious threat to seabird reproduction and survival. The ingestion of plastic has been linked to a range of negative health effects in seabirds, including physical and chemical impacts.

One of the most common ways seabirds are affected by plastic pollution is by ingesting it, often mistaking plastic debris for prey. This can lead to gut obstruction, reduced gut volume, and in some cases, death. Plastic ingestion has also been found to affect seabird body condition, with birds becoming physically smaller and lighter, with shorter wings and bills and lower body mass. In addition, plastic ingestion can cause a range of health issues, including high cholesterol, kidney dysfunction, and increased levels of toxic chemicals in the body. These health issues can impair seabird reproduction and survival, as they may affect the birds' ability to find food, migrate, and reproduce.

Furthermore, plastic pollution can also affect seabird reproduction and survival indirectly. For example, plastic debris can entangle seabirds, restricting their movement and causing injury or death. Additionally, chemicals released from degrading plastics can attract seabirds, leading to further ingestion of toxic substances.

The impact of plastic pollution on seabird reproduction and survival is widespread and increasing. It is estimated that nearly 90% of seabirds have plastic in their stomachs, and this number is expected to rise to 99% by 2050 if no action is taken. The areas with the highest expected impact are those where plastic debris overlaps with a large number of seabird species, such as the Southern Ocean off Australia.

To mitigate the impact of plastic pollution on seabird reproduction and survival, it is crucial to reduce the amount of plastic entering our oceans. This can be achieved through improved waste management, reducing consumption of single-use plastics, and promoting reusable and recyclable alternatives.

Plastic pollution is a global issue

The effects of plastic pollution on seabirds are wide-ranging and detrimental. Plastic ingestion has been linked to physical changes in seabirds, including reduced body mass and shorter wings and bills. It also leads to health issues such as high cholesterol and impaired kidney function. The presence of plastic in the digestive system can cause gut obstruction and blockages, affecting the bird's ability to absorb nutrients and maintain a healthy body condition.

The threat of plastic pollution to seabirds is not limited to direct ingestion. Plastic debris in the ocean can release toxic chemicals, which are then absorbed by seabirds, leading to increased organic pollutant loads in their bodies. These chemicals can have harmful effects on seabird health, although the full extent of these impacts is still being studied.

The sources of plastic pollution in the oceans are varied. It includes pre-production plastic pellets, user plastics, and industrial waste. The garbage patches in the oceans, often called "ocean garbage patches," are areas of accumulated floating debris, resulting from years of wasteful consumption and improper disposal of trash. Some countries lack effective waste management systems, contributing to the plastic pollution issue.

The impact of plastic pollution on seabirds is not limited to a specific region but is widespread. It affects seabird species in remote places like the North Pacific, South Pacific, and South Atlantic Oceans. The Southern Ocean boundary in the Tasman Sea between Australia and New Zealand is identified as an area of high expected impact due to the overlap of plastic debris and a large number of seabird species.

Addressing plastic pollution is crucial for the conservation of seabirds and the marine ecosystem as a whole. Effective waste management practices and a reduction in plastic consumption are essential to mitigate the impacts of plastic pollution on seabirds. Local communities and individuals can play a significant role in reducing plastic waste through beach clean-ups, reducing single-use plastic consumption, and advocating for better waste management policies.

Plastic debris in the ocean is often mistaken for prey

Seabirds are particularly vulnerable to plastic pollution in the ocean. Nearly 60% of all seabird species studied so far have had plastic in their gut, and this number is expected to reach 99% by 2050.

Seabirds often mistake plastic floating in the water for prey. Albatross, for example, mistake plastic items for squid, one of their primary food sources. Albatross also eat flying fish eggs, which are laid on floating debris, and thus end up consuming plastic along with the eggs.

Other seabirds that are prone to eating plastic include shearwaters and petrels. Even diving birds, such as the Tufted Puffin, have been found with plastic in their stomachs.

The plastic ingested by seabirds can cause physical gut blockage and organ damage, including reduced kidney function. It can also lead to high cholesterol, which may cause circulatory problems.

The impact of plastic ingestion on seabird health is not yet fully understood, and further studies are needed to determine the full scope of the problem. However, it is clear that plastic pollution poses a significant threat to seabirds worldwide.

Plastic pollution affects seabird behaviour

Plastic pollution also affects seabird behaviour by changing the availability of prey. Plastic debris can accumulate in the oceans, mimicking tiny marine organisms that seabirds feed on. This can lead to the ingestion of plastic by seabirds and their prey, resulting in reduced nutrition and growth.

The impact of plastic pollution on seabird behaviour is not limited to direct ingestion. Seabirds can also become entangled in plastic debris, leading to injuries, drowning, and increased vulnerability to predation.

The effects of plastic pollution on seabird behaviour are widespread and pervasive, with plastic ingestion reported in over half of the studied seabird species. The threat of plastic pollution to seabirds is expected to increase as plastic production continues to rise.

Overall, plastic pollution has significant and detrimental effects on seabird behaviour, including feeding, nesting, and survival.

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