Ocean Pollution's Impact On Birds: Understanding The Devastating Effects

Birds are affected by a wide range of pollutants, from visible forms of pollution such as plastic and oil spills, to invisible pollutants like air pollution, light, and sound. Over 56% of seabird species globally are estimated to have been affected by anthropogenic debris, predominantly plastic. Birds are particularly vulnerable to oil pollution, especially species of auk, seaduck, and diver that spend a lot of time on the surface of the water. Oil can suffocate birds, destroy the waterproofing on their feathers, or, if ingested, damage their internal organs and affect their metabolism.

Birds are also affected by air pollution, which can cause respiratory problems and DNA mutations, and reduce egg production and hatching. Birds have a highly efficient respiratory system, which makes them sensitive to air pollution. They are exposed to more airborne particles than humans because they have a higher breathing rate and spend more time outdoors.

Birds can be used as indicator species to monitor the health of the natural environment and levels of pollutants. Monitoring birds and their eggs can provide useful information on the levels of pollution in their environment.

Ocean pollution affects birds' reproductive health

Marine pollution has been shown to have a negative impact on the reproductive health of birds. Plastic waste and debris have caused substantial environmental pollution globally in the past decades, and they have been accumulated in hundreds of terrestrial and aquatic avian species. Birds are susceptible and vulnerable to external environments; therefore, they could be used to estimate the negative effects of environmental pollution.

The accumulation of plastic waste and debris in the environment has continuously increased, resulting in substantial environmental pollution. Plastic debris is ubiquitous in oceans, and its potential impacts on a wide range of marine organisms have raised serious concerns. Seabirds are particularly vulnerable to oil pollution, especially species of auk, seaduck, and diver that spend a lot of time on the surface where the oil forms a film.

Plastic can also be a very visible form of pollution, especially when covering our beaches. It is estimated that 4.8–12.7 million metric tons of plastic enter our oceans each year. It is therefore not surprising that marine species encounter it. Over 56% of seabird species globally are estimated to have been affected by anthropogenic debris, predominantly plastic, through ingestion, entanglement, or incorporating it into their nests (which can, in turn, create an entanglement risk).

Birds have the largest number of species (more than 10,000 living species) among the tetrapod classes. They are believed to be highly sensitive and vulnerable to external conditions and, therefore, could be used to monitor environmental changes and assess the negative effects of environmental pollution.

Some studies have found that ingestion of microplastics has reproductive toxicity to birds. For example, chicks of Japanese quail with observed plastic ingestion exhibited a minor delay in sexual maturity and a higher incidence of epididymal intra-epithelial cysts in males, although there were no effects on reproductive success. Similarly, the ingestion of microplastics can also reduce the reproductive output of Flesh-footed Shearwater.

The ingestion of microplastics by birds can activate inflammatory responses, leading to reduced food intake, delayed ovulation, and increased mortality. In this context, it is important to determine the potential microplastics concentration that is detrimental or sublethal to body condition, development, growth, reproduction, and other physiological functions in birds.

Oil spills can cause hypothermia and reduced buoyancy in birds

Oil spills can have devastating effects on birds, particularly those that spend a lot of time on the water's surface where the oil accumulates. When oil sticks to a bird's feathers, it causes them to mat and separate, impairing their waterproofing abilities. This exposure of the skin to extreme temperatures can result in hypothermia or hyperthermia.

As the bird instinctively tries to get the oil off its feathers by preening, it ends up ingesting the oil, causing severe damage to its internal organs. The urge to preen overrides all other natural behaviours, including evading predators and feeding, making the bird vulnerable to secondary health problems such as severe weight loss, anemia and dehydration.

The loss of waterproofing also affects the bird's buoyancy, causing many oil-soaked birds to beach themselves in an attempt to escape the cold water. Oil spills can thus have both direct and indirect effects on birds, highlighting the urgent need to address this environmental threat.

Birds are affected by both visible and invisible ocean pollution

Plastic pollution can affect birds in several ways. Birds can ingest plastic, get entangled in it, or use it to build their nests, which can then create an entanglement risk for their chicks. Plastic can also carry toxic chemicals that can be harmful to birds. For example, di (2-ethyl hexyl) phthalate (DEHP), a plastic additive, has been found to cause kidney damage in quails and potentially toxic effects on the liver and cerebellum in Japanese quails.

In addition to plastic, oil spills are another form of visible ocean pollution that can affect birds. Oil spills can suffocate birds, destroy the water-proofing properties of their feathers, leading to hypothermia and reduced buoyancy, and cause internal organ damage and metabolic issues if ingested. Even relatively small amounts of oil can have sublethal effects on birds, impacting their long-term breeding success and survival.

Invisible ocean pollution, such as air pollution, can also have significant impacts on birds. Birds have a highly efficient respiratory system, making them sensitive to air pollution. Air pollutants like ground-level ozone and nitrogen oxides can cause direct and irreversible damage to birds' lungs, leading to inflammation, ruptured blood vessels, and lung failure. Birds are exposed to more airborne particles than humans due to their higher breathing rate and time spent outdoors. Air pollution has been linked to reduced egg production and hatching, increased clutch or brood abandonment, and decreased growth rates in birds.

In conclusion, birds are affected by both visible and invisible ocean pollution. Plastic and oil spills are visible forms of pollution that can cause direct harm to birds, while invisible pollutants like air pollution can have subtle but important effects on their health and habitats. Addressing these issues is crucial for the preservation of avian species.

Ocean pollution can cause DNA mutations in birds

Birds are highly susceptible to environmental changes and are vulnerable to external conditions. They are affected by a range of pollutants, from visible forms of pollution such as plastic and oil spills, to invisible pollutants like light and sound.

Plastic waste and debris have caused substantial environmental pollution globally, and they have been found in hundreds of terrestrial and aquatic avian species. Birds often mistake plastic for prey, and plastic particles have been found in the gastrointestinal tracts, faeces, and even feathers and other tissues of several hundred avian species.

While the physical effects of plastic pollution on birds are well-documented, the potential genetic effects are less understood. However, there is evidence to suggest that ocean pollution can cause DNA mutations in birds.

A study on mice found that air pollution can cause DNA mutations in sperm. Similarly, research on gulls living close to steel mills in the Great Lakes region showed that they had increased rates of DNA mutations. While the exact role of air pollutants was unclear, a subsequent study on mice exposed to ambient air in close proximity to a steel mill showed that the mice exhibited twice as many genetic mutations as their rural counterparts.

Although there has been limited research on the genetic effects of plastic pollution on birds specifically, the evidence from studies on mice and gulls suggests that ocean pollution has the potential to cause DNA mutations in birds. Further research is needed to confirm this and to understand the full extent of the problem.

Ocean pollution affects bird habitats

Plastic pollution in oceans also affects bird habitats indirectly. Plastics can absorb and release toxic chemicals, such as polycyclic aromatic hydrocarbons (PAHs), which are emitted by marine traffic. These toxins can cause DNA mutations in birds, disrupt essential cell processes, and potentially lead to cancer. Additionally, the accumulation of nitrogen oxides (NOx) and sulfur oxides (SOx) due to pollution can cause soil and water acidification, reducing the availability of calcium, a crucial component for eggshells. This, in turn, leads to smaller clutch sizes.

Furthermore, ocean warming caused by the absorption of excess heat and carbon dioxide contributes to the decline of forage fish populations, the primary food source for seabirds. As a result, seabirds must travel farther and dive deeper for food, expending more energy than they can afford, impacting their breeding success.

The impacts of ocean pollution on bird habitats are complex and interconnected. It is crucial to address these issues and implement effective conservation measures to protect avian species and the ecosystems they depend on.

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