“What can the canary in the coal mine tell us? Historically, canaries accompanied coal miners deep underground. Their small lung capacity and unidirectional lung ventilation system made them more vulnerable to small concentrations of carbon monoxide and methane gas than their human companions. As late as 1986, the acute sensitivity of these birds served as a biological indicator of unsafe conditions in underground coal mines” Scitable by Nature Education
Just as coal miners used canaries as indicators of the breathability of the air inside a mine, scientists today use animals, plants, fungi and bacteria as indicators of environmental health. Species used to evaluate the health of an ecosystem are known as bioindicators.
One example of a bioindicator is algae. High concentrations of algae, also known as algae blooms indicate that an aquatic system has high levels of nitrogen and phosphorus. High levels of nitrogen and phosphorus are often caused by fertilizer run-off and can kill aquatic species, so it is important to know when levels are too high in order to maintain the natural aquatic ecosystem.
Another example of a bioindicator is frogs. Mutated frogs can be an indicator of toxins in their environment. These toxins, such as, discarded pharmaceuticals, can cause developmental mutations ranging from additional limbs to hermaphroditism.
Bioindicators have two advantages over traditional measures of environmental quality. First, bioindicator species allow scientists to look at changes in an ecosystem over time. Traditional sampling methods are more likely to miss sporadic changes in pollutant concentrations, which can be seen with bioindicators. Second, bioindicators can help to predict indirect environmental changes by allowing scientists to see the bigger picture of the system. Traditional methods can only tell us that something is wrong, not how that is potentially going to affect all of the species in that system. Bioindicators are nature’s way of communicating that something is wrong and greater study is needed to better understand what they are trying to tell us.
Resources
http://sciencelearn.org.nz/Contexts/Enviro-imprints/Science-Ideas-and-Concepts/Bioindicators
http://sciencelearn.org.nz/Contexts/Enviro-imprints/Science-Ideas-and-Concepts/Bioindicators