The air, although invisible, is full of information about the beings that inhabit the planet. Now, two recent experiments managed to capture those traces that animals leave in the atmosphere.

This achievement, say its authors, offers a novel approach to monitoring biodiversity and helping to protect species that are in danger of extinction.

The finding was achieved thanks to what experts call “environmental DNA” , better known as eDNA, by its English name.

Living beings leave traces of their DNA as they interact with the environment.

Therefore, environmental DNA is a useful tool to detect a wide variety of species in different habitats.

Many biologists, for example, use the eDNA that animals leave behind in the water to map species in aquatic environments.

But capturing eDNA from the air is much more complex That is why the two new investigations are an advance in this field.

What did these experiments achieve and how can they help protect biodiversity ?

On the trail of animals

There are several methods to track or monitor the presence of animals.

Investigators usually use cameras or observe them directly. Or they also chase clues such as footprints or feces.

These methods, however, require the animals to be present or have recently been present, and can be invasive techniques.

Instead, capturing DNA from the air offers the advantage of detecting animals that are even out of sight.

The downside is that eDNA is easily diluted in air, making it more difficult to detect.

So two separate teams, one in Denmark and one in the UK and Canada, devised a way to capture that elusive eDNA.

To do this, they used a series of air-capturing devices and tested them in two European zoos, one in the UK and one in Denmark.

catch the air

The team from Denmark used a water-based vacuum cleaner and two wind-blowing fans, which they placed in three different areas of the zoo.

One of these fans was the size of a golf ball.

For its part, the team from the United Kingdom and Canada installed several vacuum pumps with filters , with which they collected 70 samples in various areas of the zoo.

With this technique of capturing filtered air, the researchers obtained DNA samples from the animals.

Those samples could be traces of saliva, skin, feces or breath floating in the air, although the researchers did not determine the exact source of that DNA.

Both experiments were successful, detecting eDNA even from outside the zoos.

The Danish team obtained 40 air samples, in which they detected 49 species, including mammals, birds, amphibians, fish and reptiles.

“We were amazed when we saw the results,” Kristine Bohmann, professor of evolutionary genomics at the University of Copenhagen and leader of the study, said in a statement.

For their part, the UK-Canada team identified DNA from 25 species, including tigers, lemurs and dingoes.

They even detected the DNA of animals that were inside closed buildings.

“The animals were inside, but their DNA was leaking out ,” Elizabeth Clare, a professor in the School of Biological and Chemical Sciences at Queen Mary University of London, said in a statement.

Species Protection

The finding from both studies demonstrates that eDNA from the air could be used to monitor species in their natural habitat.

“The non-invasive nature of this approach makes it particularly valuable for observing endangered or vulnerable species, as well as those in hard-to-reach environments such as caves and burrows,” says Clare.

“Air sampling could revolutionize terrestrial biomonitoring and provide new opportunities to track the composition of animal communities, as well as to detect the invasion of non-native species.”

For Bohmann, as he tells BBC Mundo, the challenge now is to test his technique in less controlled environments , such as a reserve or a natural park, and face questions about how long eDNA lasts floating in the air.

Mehrdad Hajibabaei, a professor in the department of Integrative Biology at the University of Guelph, who was not involved in the investigations, calls both studies “a great way to prove the concept that eDNA can be detected from filtered air samples. ” “.

In the future, this approach should be validated by expanding the sampling to natural ecological environments, such as national parks or conservation areas,” Hajibabaei tells BBC Mundo.

A similar opinion is held by Michael Russello, a professor in the Department of Biology at the University of British Columbia, who was not involved in the studies.

“These two studies really expand the potential of eDNA to provide information in various applications, from biodiversity and invasive species, to public health , just to mention a few,” Russello tells BBC Mundo.

Russello also argues that applying these techniques in less controlled settings will bring more complexities, but that both experiments “represent exciting developments” in this area of ​​research.

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