Pollution's Impact: Animals Most Vulnerable To Human Activity

Pollution affects a wide variety of animals, from land to sea and air. Amphibians, such as frogs and salamanders, are incredibly susceptible to the negative effects of water pollution due to their sensitive skin and ability to absorb oxygen and dangerous chemicals through it. Plastic pollution, in particular, is a major threat to marine life, with at least 700 marine species affected, and an estimated 100 million marine mammals killed annually. Sea turtles, seals, whales, dolphins, seabirds, fish, crabs, and many other sea animals are dying and becoming sick due to ingesting or becoming entangled in plastic waste. Air pollution also has detrimental effects on wildlife and pets, with insects, birds, and bees being highly susceptible.

Plastic pollution in oceans

Impact on Marine Life

Microplastics

Plastic slowly degrades into microplastics and nanoplastics, which are tiny plastic particles that infiltrate the food chain, from marine life to humans. These microplastics have been found in the organs of over 114 aquatic species, even in the deepest ocean trenches. They are consumed by zooplankton and small marine animals, eventually making their way up the food chain.

Environmental Impact

The persistence of plastics in the ocean is a significant concern. Plastic can take hundreds, if not thousands, of years to degrade, exacerbating the long-term environmental impact. It accumulates in subtropical gyres, covering 40% of the world's oceans, with the Great Pacific Garbage Patch being a well-known example.

Global Efforts

Addressing plastic pollution requires urgent global action. The Global Partnership on Plastic Pollution and Marine Litter (GPML) was formed in 2012 to bring together various actors to tackle this issue. Additionally, international agreements, such as the United Nations Environment Assembly's agreement to develop a legally binding treaty to end plastic pollution, are crucial steps towards combating this crisis.

Individual Actions

Individuals can also play a role in reducing plastic pollution. Being mindful of plastic consumption, recycling, supporting sustainable brands, and participating in beach clean-ups are some ways to contribute to the effort.

Air pollution affecting birds

Air pollution is a pressing issue that affects not just humans but birds as well. Many of the emissions that drive climate change also present an immediate health concern for bird populations. In fact, a study by Cornell and the University of Oregon found that improved air quality under a federal program to reduce ozone pollution may have saved around 1.5 billion birds over 40 years—that's about 20% of bird life in the United States.

Ground-level ozone (O3) and nitrogen oxides (NOx), two common air pollutants, are powerful oxidants that can cause irreversible damage to birds' lungs. Birds are more susceptible to these pollutants than humans due to their higher breathing rate and the amount of time they spend in the open air. Long-term exposure can lead to severe health issues such as inflammation, ruptured blood vessels, and even lung failure. Additionally, studies have shown that exposure to polycyclic aromatic hydrocarbons (PAHs), commonly emitted by traffic, may lead to reduced egg production and hatching, increased abandonment of nests, and stunted growth in birds.

Air pollution also extends beyond direct impacts on birds, affecting their habitats and food sources. Ground-level ozone damages plant communities that birds rely on for food, shelter, and nesting. It also reduces the number of insects that birds consume. The accumulation of nitrogen oxides and sulfur oxides (SOx) leads to soil and water acidification, which can decrease the abundance and nutritional value of birds' food sources. This, in turn, affects the size of their clutches, as calcium availability in the environment is essential for eggshells.

Furthermore, air pollution contributes to eutrophication, an excess of nutrients in bodies of water, which can reduce fish and invertebrate populations that birds depend on for sustenance. The release of toxic chemicals and pollutants into the environment, such as pesticides and fertilizers, can also have indirect effects on birds. These chemicals can build up in the food chain, leading to bioaccumulation, which has detrimental consequences for birds of prey.

Overall, it is evident that air pollution poses a significant threat to birds and their ecosystems. Addressing air pollution is crucial not only for human health but also for the conservation of bird species and the preservation of their natural habitats.

Microplastics in marine animals' diets

Marine animals are increasingly ingesting microplastics, which are plastic fragments smaller than 5mm. These tiny plastics are often consumed by corals, planktons, marine invertebrates, fish, whales, and other marine biota, and are then transferred along the food chain.

Microplastics are often mistaken for food by marine animals. For example, sea turtles mistake plastic waste for jellyfish or algae, their primary prey. Studies suggest that over half of the world's sea turtles have consumed plastic, and that as many as 50% of sea turtles are ingesting plastic at an unprecedented rate, causing blockages in their digestive system and leading to death.

Similarly, whales often mistake marine debris for a potential food source. In some species, such as baleen whales, the whale's mouth is so large that it unknowingly picks up plastic debris while feeding. A study found that hundreds of species of cetaceans have been negatively impacted by plastic pollution in the past two decades, with obstructions puncturing and tearing the stomach lining, leading to starvation and death. According to the Marine Pollution Bulletin, cetaceans are ingesting plastic debris at a rate as high as 31%, and 22% of those cetaceans are at an increased risk of death.

Fish are also at risk of ingesting microscopic plastic debris. A study at the University of Exeter UK suggested that it could take up to six times longer for fish to rid themselves of microscopic marine debris compared to larger pieces of plastic ingested orally. Studies suggest that commonly consumed fish species, such as brown trout, cisco, and perch, have ingested plastic microfibers.

The impact of microplastics on marine animals is not limited to ingestion. Marine life can also become entangled in plastic debris, such as fishing nets, lines, and plastic packing bands, leading to injury and death. An eight-year study in Southeast Alaska and British Columbia documented 388 sea lions entangled in plastic debris, mainly plastic packing bands and rubber bands, which can cause severe infection and death.

Microplastics are a significant threat to marine animals and their ecosystems. They can cause entanglement, ingestion, and habitat loss, and can have detrimental effects on the health and survival of a wide range of marine species.

Abandoned fishing gear

A single abandoned net is estimated to kill an average of 500,000 marine invertebrates (crabs and shrimp), 1,700 fish, and four seabirds. In addition, lost fishing gear, which is mostly made of plastic, breaks down into microplastics over time. These microplastics then enter the ocean food chain and leach toxic chemicals, posing a danger to marine life and humans who consume seafood.

Ghost gear has been identified as the most deadly form of marine plastic debris, damaging vital ocean habitats and aquatic life. It is estimated to comprise up to 10% of plastic waste in our oceans by volume and impacts 45% of all marine mammals on the Red List of Threatened Species. The problem is exacerbated by the fact that abandoned fishing gear was previously treated as private property, making it challenging for authorities to remove this environmentally harmful debris.

However, there are efforts being made to address the issue of ghost gear. For example, the World Wide Fund for Nature (WWF) is advocating for a legally binding global treaty on plastic pollution, which includes targeting lost or discarded fishing gear. Additionally, the Global Ghost Gear Initiative unites governments, NGOs, and key players in the fishing industry to adopt best practices to prevent, mitigate, and remove ghost gear.

Overall, abandoned fishing gear is a significant threat to marine life and ecosystems, and concerted efforts are needed to reduce its impact on the environment.

Effects of water pollution on amphibians

Amphibians such as frogs and salamanders are incredibly susceptible to the negative effects of water pollution due to their sensitive skin. Their unique ability to absorb oxygen through their skin also leaves them vulnerable to absorbing dangerous chemicals.

Pesticides, nitrogen-based fertilisers, and heavy metal contaminants pose a direct threat to amphibians and often find their way into water systems via runoff after heavy rain. These pollutants can directly kill amphibians, weaken their immune systems, and cause physical deformities or abnormalities. For instance, exposure to water pollution, particularly chemical contamination, can cause amphibians to experience a shift in their skin microbiome, increasing their vulnerability to disease, and morphological deformities, reducing their chances of survival.

A meta-analysis of various experimental studies found that the overall effect of pollutant exposure resulted in a medium decrease in amphibian survival and mass and a large increase in abnormality frequency. This translated to a 14.3% decrease in survival, a 7.5% decrease in mass, and a 535% increase in abnormality frequency across all studies.

Additionally, the presence of multiple stressors, such as UV-B radiation, other chemicals, or pathogens, can act synergistically with pollutants, further exacerbating their harmful effects on amphibians.

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