Pollution-Resistant Species: Nature's Resilience Against Adversity

While most species cannot adapt to polluted environments, a few have found ways to live with and even thrive in pollution. Some microbes, for example, have evolved to eat plastic. Genetic variation can also make certain species resistant to the effects of toxic chemicals. This is the case for the killifish, a small, silvery fish found in the Gulf of Mexico and along North America's Atlantic coast. While this genetic change has made the killifish more resistant to toxins, it has also reduced the species' tolerance to low oxygen levels.

Killifish have evolved to withstand high levels of pollution in the Gulf of Mexico and North America's Atlantic coast

The killifish's ability to survive in these conditions is due to a genetic variation that makes them resistant to the effects of toxic chemicals. Their genome allows them to withstand chemical pollutant concentrations that are thousands of times higher than the normally deadly dose. This genetic change has come at a cost, however, as it has reduced the species' tolerance to low oxygen levels. As global temperatures rise and ocean oxygen levels decline, this could become a significant problem for the killifish.

The evolution of the killifish is a clear example of how species can adapt to highly polluted habitats, demonstrating an evolutionary advantage. However, it is important to note that most species will not be able to adapt genetically to their polluted surroundings. The ability to withstand specific pollutants can also make a species more vulnerable to other environmental stressors.

The killifish's adaptation to pollution may even become a disadvantage once the water is cleaned of pollutants. The adapted fish may have greater difficulty surviving than those without the genetic variation. This highlights the complex trade-offs that can occur when species evolve in response to human-made environmental changes.

Microbes can adapt to eat plastic, especially in ecosystems with high levels of plastic pollution

Genetically adapting to highly polluted habitats can be an evolutionary advantage for certain species. However, evolving the ability to exist in a polluted environment often comes at a cost. For example, the killifish, a small, silvery fish found in the northern Gulf of Mexico and North America's Atlantic coast, has evolved to withstand high concentrations of heavy metals and dangerous chemicals. But this genetic change has also reduced the species' tolerance to low oxygen levels.

Microbes are another species that can adapt to polluted environments. Microbes living in oceans and soils worldwide can evolve to eat plastic, especially in ecosystems with high levels of plastic pollution. This is because microbes have congenital or acquired abilities to survive in harsh environments. They can attach to new environments and release certain enzymes that allow them to utilise persistent plastic pollution as their only carbon source. Bacterial species from Pseudomonas, Escherichia, and Bacillus genera have enormous potential for degrading plastics, especially for recalcitrant polymers such as PE, PET, and PS. Fungi are also able to degrade plastics, with filamentous fungi playing an important role in the degradation and mineralisation of plastic pollutants.

While some species may be able to withstand pollution, most animal and plant populations will not be able to adapt genetically to their polluted surroundings.

Some species can adapt to polluted environments, but this often makes them more vulnerable to other environmental stressors

While some species can adapt to polluted environments, this often makes them more vulnerable to other environmental stressors. For example, the killifish, a small silvery fish found in the Gulf of Mexico and North America's Atlantic coast, has evolved to withstand high concentrations of heavy metals and dangerous chemicals. However, this genetic change has reduced the species' tolerance to low oxygen levels, which is a problem as ocean oxygen levels are expected to decline drastically as global temperatures rise.

Similarly, microbes living in oceans and soils worldwide have been found to evolve to eat plastic, especially in ecosystems with high levels of plastic pollution. While this may be seen as a positive adaptation to human-made pollution, most species will not be able to adapt genetically to their polluted surroundings at all. This is because they lack the high levels of genetic variation required to evolve quickly.

In some cases, once the water has been cleaned of pollutants, the adapted fish may have greater difficulty surviving than those without the variation. This highlights the complex trade-offs that species face when adapting to polluted environments, and the potential long-term consequences for their survival.

Populations of fish in polluted areas along the Atlantic and Gulf coasts carry a genetic variation that makes them resistant to toxic chemicals

The genetic change that has made the killifish more resistant to toxins has also reduced the species' tolerance to low oxygen levels. This is a problem as oxygen levels in the sea vary, and as global temperatures rise, ocean oxygen is expected to decline drastically. Once the water has been cleaned of pollutants, the adapted fish may have greater difficulty surviving than those without the variation.

Scientists have sequenced the complete genomes of nearly 400 Atlantic killifish from polluted and non-polluted sites at New Bedford Harbour in Massachusetts, Newark Bay in New Jersey, Connecticut's Bridgeport area, and Virginia's Elizabeth River. These sites have been polluted since the 1950s and 1960s by a complex mixture of industrial pollutants, including dioxin, heavy metals, hydrocarbons, and other chemicals.

While it is clear that some species can genetically adapt to highly polluted habitats, this often comes at a cost. Certain changes in the genome may help a species withstand a specific pollutant, but they can make the species more vulnerable to other environmental stressors. Most animal and plant populations will not be able to adapt genetically to their polluted surroundings at all.

Most animal and plant populations will not be able to adapt genetically to their polluted surroundings

Furthermore, the ability of a species to adapt to pollution often depends on the presence of high levels of genetic variation that allow them to evolve quickly. Most species do not possess this level of genetic variation and, therefore, cannot adapt to rapid environmental changes. This is especially true for species that we care about preserving. As a result, the vast majority of animal and plant populations will not be able to keep up with the pace of human-induced environmental changes and will struggle to survive in their polluted surroundings.

Frequently asked questions