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Why is environmental DNA (shortened to eDNA) so helpful for ecologists, conservationists, and biologists? It is incredibly useful for monitoring species in an environment without ever having to see or capture them.
Imagine you want to find out if there are any river otters living in a nearby waterway. River otters are typically wary of humans and do much of their hunting at night, so it may be difficult for you to observe them going about their business. In the past biologists would capture animals to study and then release them, but what if you never caught one or didn’t want to disrupt their lives? How could you be sure there are no otters in the area, or if the otters had just avoided capture?
Now imagine that you have an enormous library of DNA samples of all the mammals that might be found in Canada. You could take a sample of water from your nearby waterway and see if any of the eDNA in the sample matches any DNA present in the library. You might find DNA matches in your library that shows there is DNA from beavers, geese, fish, and river otters in your water sample. This would prove there are river otter there, even if you never saw them!
This eDNA can also be used to monitor the health of organisms in their natural environment in non-invasive ways. Think about how difficult it would be to perform a physical exam on a wild whale, and how stressful it would be for the animal. Whale researchers have developed new ways to assess the health of whales without having to capture or harm them.
By flying specialized drones over the top of whales while they are breeching, researchers can collect a sample of the visible spray blown out of the blowhole when the whale takes a breath. This spray includes water, air, and whale ‘snot’ which includes DNA. This collected eDNA is a good indicator of whale health, as scientists can determine if the whale is suffering from a viral or bacterial illness, whether is it male or female, if it is pregnant, as well as gathering important genetic information about the species.
Previous methods of studying whales involved taking DNA samples from deceased whales or driving boats up to whales and taking a sample of their skin and blubber. Using drones provides an excellent hands-off alternative that allows researchers to gather a great deal of information about their study animals without having to touch living whales or endanger those collecting the samples.
To learn more about how researchers are using eDNA you may like to read some of our past Quick Snips on our Blog. You can find Quick Snips about eDNA and the Loch Ness monster, eDNA discovering species that were thought to have vanished, using eDNA in rivers to measure biodiversity, and sampling eDNA in air to detect elusive birds.