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Effects of Water Pollution on Aquatic Ecosystems

written by: Sean Fears•edited by: Niki Fears•updated: 1/12/2009

Whether the compounds being added to our watersheds are natural or foreign, they have an effect if the flora and fauna are not adapted to them. Find out some of the ways in which water pollution effects and causes changes in aquatic ecosystems!

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    Most affected

    Water pollution can come as a result of natural or unnatural compounds being added to a watersource. These can sway the balance of an ecosystem resulting in danger to natural wildlife of aquatic environments.

    Some animals and plants are highly susceptible to the effects of water pollution:

    • Amphibians tend to be very pollution sensitive due to the fact that they absorb chemicals in the water through their skins; this is one reason why many amphibian populations are in distress today.
    • With addition of detergents to the eco-system, insects that normally have the ability to walk on water will be unable to.
    • Younger animals also have a greater sensitivity to chemical compounds, especially those that mimic organic compounds, since they are still undergoing the physiological changes associated with maturation. These effects can range from physiological effects such as suffocation and thinning of eggshells to the alteration of neurochemistry.

    That is why one water-quality monitoring technique involves a survey of macroinvertebrates in the stream; if animals with narrow requirements are present, then the stream health has to be above their minimum threshold. By definition, pollution reduces aquatic biodiversity! Since no species (or very few) live in total isolation, the difficulties of these species often get passed on to others.

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    Pollution-tolerant organisms

    Other organisms are highly tolerant to pollution of their environments, among these are aquatic worms, leeches, and snails. As a rule, as complexity increases, tolerance to pollution decreases. Keep in mind that, even though these species may be able to survive in less than ideal environments, the species that rely on them for food may not be able to. Further, any pollutants or toxins in the prey animals or plants will be concentrated in the predators unless their systems are capable of removing the compound from their system.

    Even if an organism can survive in such conditions, the presence of pollutants may stress them sufficiently to make them more susceptible to a threat normally fought off -- such interactions are suspect in both colony collapse disorder in bees and "white nose syndrome" in bats. Such interactions are a critical consideration when considering real-world situations, especially when you add climate change (which can be considered as adding heat, and potentially sediment, pollution to watersheds, as well as altering food webs) and extinctions of other organisms to the equation.