Pollution's Impact: Biodiversity Loss And Its Causes

Pollution is one of the biggest threats to the environment and biodiversity. It affects all ecosystems, from marine to forest, and has devastating effects on the wildlife and plants that reside in them. The sources of pollution are varied, from transport to agriculture, and the pollutants themselves are diverse, including nitrogen, sulphur, and plastic waste. The impact of these pollutants on the environment is far-reaching, from the air we breathe to the water we drink, and the consequences for biodiversity are dire, with species becoming endangered or even extinct.

Eutrophication: the accumulation of nutrients in water, causing algae blooms and oxygen loss, leading to biodiversity loss

Eutrophication, the accumulation of nutrients in water, is a major cause of biodiversity loss. Eutrophication is caused by an increase in nitrogen and phosphorus compounds, which act as limiting growth factors for photosynthesis. While eutrophication can occur naturally over centuries, human activities have significantly accelerated the process.

The increase in nutrients causes excessive plant and algal growth, leading to dense blooms of phytoplankton and algae. These blooms reduce water clarity and harm water quality, impacting the growth and survival of other organisms. The algal blooms limit light penetration, causing die-offs of plants in littoral zones and reducing the success of predators that rely on sight to catch prey.

As the blooms eventually die off, microbial decomposition severely depletes dissolved oxygen, creating hypoxic or anoxic "dead zones" that lack sufficient oxygen to support most organisms. This loss of oxygen in the water can lead to the suffocation and death of fish and other aquatic life, directly causing a loss of biodiversity.

The impacts of eutrophication on biodiversity can vary depending on the scale, organism groups, and trophic states. For example, studies of zooplankton and zoobenthos across 261 lakes in the Lake Taihu watershed, an area undergoing severe eutrophication, found significant cross-taxon congruence, indicating a simplified community structure and a loss of biodiversity. Eutrophication also affects commercial and recreational fisheries, posing significant public health and economic risks.

Air pollution: toxic gases, particularly in industrial areas, harm birds and high-altitude creatures, leading to respiratory issues and potential extinction

Air pollution is a significant threat to biodiversity, and toxic gases, particularly in industrial areas, are harmful to birds and high-altitude creatures. Birds have a sensitive respiratory system, which puts them at a higher risk of inhaling toxic pollutants. Birds inhale and exhale in a single breath, leading to the inhalation of large amounts of toxic gases, such as sulfur dioxide, nitrous oxide, methane, carbon monoxide, and hydrogen sulfide. These gases cause respiratory issues and can lead to potential extinction.

Birds are not the only creatures affected by these toxic gases. High-altitude creatures, such as certain bird species and other animals, are also at risk. The constant exposure to toxic fumes in the atmosphere can cause breathing problems and increase the likelihood of extinction. The accumulation of toxic gases in the atmosphere is due to physical, chemical, and biological factors, which have detrimental effects on biodiversity.

Industrial activities, such as burning coal, oil, and gas, release fossil fuels and greenhouse gas emissions that trap the sun's heat and contribute to climate change. Climate change is a long-term effect of air pollution and poses a significant threat to biodiversity. Many species cannot adapt to the rapid changes caused by climate change, leading to displacement, stress, and depletion in numbers.

Additionally, air pollution contributes to eutrophication, the process of nutrient accumulation, particularly nitrogen, in water bodies. This leads to algae blooms and a subsequent loss of oxygen and life. As a result, aquatic ecosystems are impacted, and biodiversity is lost. Furthermore, air pollution affects vegetation, reducing its ability to naturally filter water systems and capture carbon, which further exacerbates the impacts of climate change.

The effects of toxic gases and air pollution on birds and high-altitude creatures highlight the need for mitigation measures and conservation efforts to protect biodiversity and ensure the health and survival of various species.

Acid rain: a combination of sulphur dioxide, nitrogen oxide, and moisture, causing mucus buildup in fish gills, making breathing difficult

Air pollution is one of the biggest threats to the environment and biodiversity. It affects ecosystems, particularly sulphur and nitrogen emissions, ground-level ozone, and water bodies. One of the most significant impacts of air pollution is the formation of acid rain, which occurs when sulphur dioxide and nitrogen oxide combine with moisture in the atmosphere. Acid rain has detrimental effects on both the environment and humans, and one of its consequences is mucus buildup in fish gills, making breathing difficult.

Acid rain increases the acidity of water bodies, soils, and vegetation, causing adverse effects on flora and fauna. The increased acidity in aquatic environments, such as streams, lakes, and marshes, can be harmful to fish and other wildlife. Fish gills are particularly affected by acid rain, as studies have shown that the continuous intake of acidic water leads to mucus buildup, making breathing challenging and potentially leading to suffocation.

The sensitivity of fish to acid rain varies among species, with some adult fish dying at lower pH levels. At a pH of 5, most fish eggs cannot hatch, and some acidic lakes have no fish populations. Additionally, the release of aluminium caused by acidification can be toxic to both plant and animal life, further exacerbating the problem.

The decline in fish populations due to acid rain can have broader ecological implications. Fish play a crucial role in the food chain, and their absence can disrupt the balance of the ecosystem. Furthermore, nitrogen compounds in acid rain can contribute to eutrophication, the process of nutrient overload in aquatic ecosystems, leading to algae blooms and a loss of oxygen and life. This, in turn, affects biodiversity as ecosystems are impacted.

Nitrogen deposition, a significant component of acid rain, poses a severe threat to European biodiversity and the conservation of natural habitats and species. It leads to species replacement and ecosystem dysfunction, altering the functionality of ecosystems such as peatlands. Thus, acid rain, through its impact on fish gills and its broader ecological consequences, is a significant contributor to biodiversity loss.

Climate change: caused by greenhouse gas emissions, it affects biodiversity as species cannot adapt as quickly as the changing climate

Climate change, caused by greenhouse gas emissions, is a pervasive and growing global threat to biodiversity and ecosystems. The enormous increase in the emission of greenhouse gases (CO2, methane, and nitrous oxide) in recent decades is largely due to the burning of coal, oil, gas, and fossil fuels, as well as deforestation. These gases surround the ozone layer and trap the sun's heat, causing the climate to change at a rate that outpaces species' ability to adapt.

The impact of climate change on biodiversity is evident in the increasing frequency and intensity of natural disasters, rising sea levels, decreasing crop productivity, and loss of biodiversity. For example, coral reefs, which provide habitats for thousands of species, are at risk of dying due to rising ocean temperatures and acidification, threatening the survival of marine organisms such as shellfish, corals, sharks, turtles, and whales.

The melting of ice in the Arctic region due to global warming is endangering native animals such as polar bears, Arctic foxes, and wolves. The rise in sea levels caused by melting ice also leads to the extinction of many endangered and endemic plant and animal species in coastal areas and islands. Over 180,000 islands worldwide contain 20% of the world's biodiversity, and these are at risk of being submerged.

Climate change is also causing an increase in the intensity and frequency of fires, storms, and droughts. In Australia, for example, intense fires at the end of 2019 and the start of 2020 destroyed 97,000 square kilometers of forest and surrounding habitats, adding to the stress on biodiversity already placed by other human activities. It is estimated that the number of threatened species in the area may have increased by 14% as a result of these fires.

To mitigate the effects of climate change on biodiversity, global efforts are needed to significantly reduce greenhouse gas emissions and increase forest cover. The goal set by the Conference of Parties (COP 21) in Paris in 2015 is to limit global warming to well below 2°C, preferably to 1.5°C, compared to pre-industrial levels. This goal has been adapted as a legally binding treaty by 196 participating countries.

Chemical pollutants: these can damage the immune and reproductive systems of animals, increasing their vulnerability to diseases and reducing their chances of successful reproduction

Chemical pollutants can have detrimental effects on the immune and reproductive systems of animals, making them more susceptible to diseases and less likely to reproduce successfully.

Firstly, chemical pollutants can suppress immune processes, making animals more vulnerable to diseases. For instance, halogenated aromatic hydrocarbons (HAHs), including dibenzo-p-dioxins, dibenzofurans, polychlorinated biphenyls (PCBs), and polybrominated biphenyls (PBBs), have been found to cause immunosuppression in almost all species tested, including primates. Dioxins and PCBs can also lead to myelosuppression, thymic atrophy, and inhibition of immune complement system components. In addition, inhaled pollutants can enhance susceptibility to or exacerbate viral, bacterial, and neoplastic diseases. Furthermore, early-life exposure to environmental chemicals has been linked to an increased risk of developing infectious, metabolic, and neurodegenerative diseases later in life.

Chemical pollutants can also disrupt the reproductive processes of animals, reducing their chances of successful reproduction. These pollutants can interact with steroid hormone receptors, altering levels of blood sex steroids and disrupting sexual development. This can lead to issues such as decreased sperm quality, ovulatory dysfunction, and increased risk of miscarriage. For example, ethinyloestradiol, an oestrogen found in contraceptive pills, has been shown to induce physiological feminisation in wild fish. Other chemical pollutants, such as bisphenol A, have been associated with reproductive conditions like ovarian cysts, uterine polyps, and impaired implantation in IVF patients. Overall, environmental toxins can have profound effects on reproductive health, including hormonal imbalances, reduced gamete quality, and adverse reproductive outcomes.

The impact of chemical pollutants on the immune and reproductive systems of animals is a growing concern. While some data is available from animal studies, more research is needed to fully understand the mechanisms by which these pollutants exert their effects. Nonetheless, the evidence suggests that chemical pollutants contribute to increased vulnerability to diseases and reduced reproductive success in animals, highlighting the importance of addressing these issues to protect biodiversity.

Frequently asked questions