Pollution's Impact: Animals Endangered By Human Activity

Animals are vulnerable to harm from pollution, which can affect their habitats, food supply, and health. While some animals are more affected by pollution than others, it is difficult to determine the exact percentage of animals impacted. Pollution comes in many forms, including air, water, and land pollution, and can have devastating effects on wildlife, contributing to the decline of many threatened or endangered species.

Air pollution, for example, can harm wildlife by degrading their habitats and reducing the availability and quality of their food supply. Water pollution, such as excess nutrients, can cause harmful algal blooms, which can create dead zones that deprive aquatic life of oxygen. Land pollution, including plastic waste, can directly harm animals through ingestion or entanglement.

The effects of pollution on animals can vary depending on the species and their specific environments. Additionally, some animals may be more susceptible to certain types of pollution than others. While it is challenging to quantify the exact percentage of animals affected by pollution, it is clear that pollution has significant impacts on the natural world.

How does air pollution affect animals?

Animals are vulnerable to harm from air pollution. Pollutants of concern include acid rain, heavy metals, persistent organic pollutants (POPs), and other toxic substances. Air pollution can harm wildlife in two main ways: by affecting their habitats and by reducing the availability and quality of their food supply.

Impact on habitats

Habitat refers to the place where animals live, including in and on the soil, as well as in water. Acid rain, a product of air pollution, can change the chemistry and quality of soils and water. This can make water bodies too acidic for some animals to survive or carry out their normal physiological functions. Acid rain can also increase the release of heavy metals like aluminum into water habitats, which is toxic to many aquatic organisms, including fish.

Some heavy metals, such as mercury, can be transported through the air over long distances from their emission sources. These metals can then accumulate in the tissues of wildlife and people, passing from one species to another through the food chain. As these chemicals move up the food chain, they become more concentrated in a process known as biomagnification. This has led to the decline of raptor populations, such as the bald eagle, due to thinning egg shells.

Other forms of air pollution, such as smog, particulate matter, and ground-level ozone, likely affect wildlife health in similar ways to humans, including harming their lungs and cardiovascular systems. An animal's vulnerability to air pollution depends on its method of respiration, whether it uses lungs, gills, or another form of gas exchange.

Impact on food supply and quality

Air pollutants, including heavy metals, toxics, and POPs, enter the food chain and damage the supply and quality of food for wildlife. Once consumed, these pollutants are stored within the animal's tissues. As larger animals eat smaller ones, these pollutants bioaccumulate and increase in concentration. Top-level predators, such as bears and eagles, are particularly susceptible to the harmful effects of these air pollutants.

For example, due to high levels of mercury in certain types of fish, it is recommended that human consumption of these fish be limited. Air pollutants can cause various issues in wildlife, including endocrine disruption, organ injury, increased susceptibility to diseases and stresses, reduced reproductive success, and even death.

Changes in the abundance of species due to air pollution can have cascading effects on other species within the ecosystem. For instance, the loss of certain fish species due to high levels of aluminum could benefit certain duck species that feed on insects but be detrimental to eagles and ospreys that rely on fish as a food source.

While it is challenging to fully understand the extent and specific ways in which air pollution impacts different species, it is clear that it poses a significant threat to wildlife and ecosystems.

How does water pollution affect animals?

Water pollution is a serious threat to animals, with over 40% of US rivers and 46% of US lakes affected, according to the Environmental Protection Agency. Water pollution can affect animals in several ways, including direct and indirect exposure to toxins, habitat degradation, and the disruption of food chains.

One of the primary ways water pollution harms animals is through the release of hazardous substances into their habitats. For example, pesticides are used extensively, with over 300 million tons used annually, and often end up in waterways. These chemicals are often carcinogenic and can cause fish kills, as well as lower pH and oxygen levels, which are unsustainable for aquatic life. Similarly, mercury, a highly toxic heavy metal, is the primary cause of contamination in US estuaries and lakes. Mercury accumulates in the tissues of animals, which then become prey for higher predators in the food chain, resulting in a process called bioaccumulation. As a result, large predator fish like walleye and trout can have mercury levels over a million times higher than the surrounding water, posing a significant risk to humans and wildlife that consume them.

Water pollution also affects the habitats of animals. For instance, nutrient pollution from fertilizers can cause eutrophication, leading to the growth of algae blooms that block sunlight, depriving underwater plants of the light they need to survive. These blooms can create "dead zones" by depleting the oxygen in the water, which is essential for the survival of fish and invertebrates. Additionally, acid rain, caused by air pollution, can alter the pH levels of waterways, causing immediate distress or death to aquatic plants and animals.

Water pollution also impacts the food sources of animals. For example, pollutants can enter the food chain, accumulating in the tissues of animals and increasing in concentration as they move up the food chain. Top-level predators like eagles and bears are particularly susceptible to the bioaccumulation of these toxins, which can lead to endocrine disruption, organ injury, increased vulnerability to diseases, and reduced reproductive success.

Furthermore, water pollution can cause the degradation of entire ecosystems. For instance, the Mississippi River carries pollution into the Gulf of Mexico, creating an 8,000-square-mile dead zone where aquatic life cannot survive. This pollution affects not only marine life but also birds and land animals, impacting over 130 federally protected species.

Overall, water pollution poses a significant threat to animals, affecting their habitats, food sources, and health, and requiring urgent action to mitigate its harmful effects on the environment and human health.

How does plastic pollution affect animals?

Plastic pollution has a direct and deadly effect on wildlife. From small finches to blue whales, thousands of animals die every year from eating and getting caught in plastic.

Plastic Entanglement

Plastic floating at sea and balloons released in the air can entangle animals, causing injury and death. Large amounts of plastic debris have been found in the habitat of critically endangered Hawaiian monk seals, including in areas that serve as pup nurseries. Entanglement in plastic debris has also led to injury and mortality in the endangered Steller sea lion, with packing bands being the most common entangling material.

Plastic Ingestion

Plastic bags are often mistaken for food by turtles, and whales are found with plastic in their stomachs. A recent study found that a quarter of fish at markets in California contained plastic in their guts, mostly in the form of plastic microfibers.

Plastic consumption can lead to starvation once an animal’s stomach is full of plastic, as well as other negative health effects that we are just now starting to understand.

Plastic in the Food Chain

Plastic has entered the food chain through fish and other marine animals. It is estimated that 60% of all seabird species have eaten pieces of plastic, with that number predicted to increase to 99% by 2050. Adult birds also feed this plastic to their chicks, threatening their chances of survival.

Plastic in the Environment

Plastic is found in the single-use packaging we discard, the consumer goods that fill our stores, and in our clothing, which sheds microplastic fibres in the wash.

The problem is growing, with the fossil fuel industry planning to increase plastic production by 40% over the next decade. This means more toxic air pollution and plastic in our oceans.

Urgent action is needed to address the global plastic pollution epidemic.

How does climate change pollution affect animals?

Climate change pollution affects animals in a variety of ways, from altering their migration patterns to causing physical harm.

Migration Patterns

Animals' migration patterns are being disrupted by climate change. Warmer weather causes plants to bloom earlier or expand into cooler locations, which changes ecosystems and, in turn, animals' migration patterns. For example, warmer temperatures have delayed the start of the caribou migration as they use colder temperatures and snowfall as indicators for when to migrate. Similarly, warmer weather has caused an increase in insect populations, which stress caribou.

Food Supply and Quality

Climate change pollution can also affect the availability and quality of animals' food supply. For example, warmer ocean temperatures in the Gulf of Maine have pushed major food sources for Atlantic puffins farther north, resulting in delayed breeding seasons and low chick survival rates. In addition, warmer April temperatures in Alaska have made it harder for bald eagles to see salmon in rivers while hunting, despite higher temperatures being associated with higher numbers of nestlings.

Habitat Loss

Rising temperatures can affect vegetation, food sources, access to water, and more, causing habitat loss for certain animals. For example, melting Arctic ice reduces polar bears' access to habitats and seal hunting ranges. Similarly, the snowshoe hare is increasingly exposed to predators due to the loss of snow cover, which it relies on for camouflage.

Natural Disasters

Climate change has led to an increase in natural disasters such as droughts, wildfires, and hurricanes, causing catastrophic loss of life and habitat for wildlife. For example, Australia's Black Summer bushfires (2019-2020) burned 186,000 square kilometers and are estimated to have killed or displaced three billion koalas, kangaroos, and other animals.

Human-Wildlife Conflict

Climate change intensifies human-wildlife conflict by forcing people and animals to share increasingly crowded spaces due to habitat loss and extreme climate events. For example, jaguars sometimes prey on domestic animals and disrupt human livelihoods, leading to retaliatory killings that further decline their populations.

Extinction

The combination of challenges caused by climate change pollution could lead to the extinction of many animals, particularly those already vulnerable or near extinction. For example, the North Atlantic right whale is on the brink of extinction, with an estimated 336 individuals remaining, partly due to a warming ocean and continued conflicts with humans.

How does pollution affect endangered animals?

Pollution affects all animals, and while an exact percentage is unclear, it is known that it has a devastating impact on wildlife and ecosystems. Endangered species are particularly vulnerable to the effects of pollution, and it is a factor in their decline.

Endangered animals are at risk from the various forms of pollution, including air, water, and land pollution. Water pollution, for example, can directly kill amphibians such as frogs and salamanders, which have incredibly sensitive skin that absorbs dangerous chemicals like pesticides, nitrogen-based fertilizers, and heavy metal contaminants. These chemicals can also weaken their immune systems and cause deformities. Similarly, air pollution can affect the quality of the environment or habitat in which animals live, as well as the availability and quality of their food supply. Acid rain, a product of air pollution, can change the chemistry and quality of soils and water, making it uninhabitable for some species. It can also increase the release of heavy metals such as aluminum, which is toxic to many animals, including fish.

Endangered marine species are also at risk of ingesting plastic or getting entangled in it. Plastic debris in the ocean is often mistaken for food by sea turtles, who may choke or starve as a result of eating it. It is estimated that over half of the world's sea turtles have consumed plastic. Plastic pollution also affects the reproduction of some species of turtles and birds. Additionally, abandoned fishing gear, also known as ghost gear, is a major threat to marine biodiversity and comprises up to 10% of plastic waste in oceans by volume. It continues to capture and kill wildlife, pollute habitats, and enter the food web as it degrades. Ghost gear impacts 45% of all marine mammals on the Red List of Threatened Species.

Pollution can also affect animals through bioaccumulation, where chemicals or toxins are passed along and increase in concentration as one animal is eaten by another. For example, the use of the pesticide DDT caused the population of Peregrine Falcons to plummet as the birds fed on fish and small mammals affected by DDT in their environment. The chemicals built up inside the falcons, causing sickness and reproductive issues. Similarly, fertilizer runoff can result in harmful algal blooms that release a neurotoxin known as domoic acid. Fish that eat this harmful algae accumulate it in their bodies, and when sea lions eat the fish, they ingest high levels of toxic domoic acid, which causes neurological issues, seizures, aborted pregnancy, and death.

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