The air, although invisible, is full of information about the beings that inhabit the planet. Now, two recent experiments have managed to capture these traces that animals leave in the atmosphere.
This achievement, say the authors of the experiments, offers a new approach to monitoring biodiversity and helping to protect species that are in danger of extinction.
The discovery was made thanks to what experts call “environmental DNA”, better known as eDNA, by its name in English.
Living things leave traces of their DNA as they interact with the environment. And this environmental DNA is a useful tool for detecting a wide variety of species in different habitats.
Many biologists, for example, use the eDNA that animals leave in the water to map species in aquatic environments.
However, capturing DNA from the air is much more complex. That’s why the two new experiments are a breakthrough in this field.
What have these experiments achieved and how can they help protect biodiversity?
On the trail of animals
There are several methods to track or monitor the presence of animals. Scientists often use cameras or observe them directly. Or they also follow clues like footprints or feces.
These methods, however, require animals to be present or have been present recently, and can be invasive techniques.
Instead, capturing DNA from the air offers the advantage of detecting animals that are not around. The downside is that eDNA is easily diluted in air, making it more difficult to detect.
Two separate teams — one in Denmark and one in the UK and Canada — came up with a way to capture 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.
hold the air
The team from Denmark used a water-based vacuum and two fans, which were placed in three different areas of the zoo.
One of the fans is the size of a golf ball.
The team from the United Kingdom and Canada installed several vacuum pumps with filters, with which they collected 70 samples in various parts of the zoo.
Using these techniques to capture filtered air, the researchers obtained DNA samples from the animals.
These samples could be traces of saliva, skin, feces or breath floating in the air, although the researchers have not determined the exact source of the DNA.
Both experiments were successful, detecting eDNA even outside zoos.
The Danish team obtained 40 air samples, in which they detected 49 species, including mammals, birds, amphibians, fish and reptiles.
“We were surprised when we saw the results,” said Kristine Bohmann, a professor of evolutionary genomics at the University of Copenhagen and leader of the study.
In turn, the team from the UK and Canada identified DNA from 25 species, including tigers, lemurs and dingoes (a wild canid from Australia).
They even detected the DNA of animals that were inside closed buildings.
“The animals were inside, but their DNA was leaking out,” said Elizabeth Clare, a professor at the school of biological and chemical sciences at Queen Mary University of London.
species protection
The findings of both studies demonstrate that eDNA from the air can 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 detect the invasion of non-native species.”
Bohmann told BBC News Mundo (the BBC’s Spanish service) that the challenge now is to test his technique in less controlled environments, such as a reserve or a nature park, and find out 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 experiments, calls the two studies “a great way to prove the concept that eDNA can be detected from filtered air samples.”
“In the future, this approach could be validated by expanding the sampling to natural ecological environments such as national parks or conservation areas,” Hajibabaei told BBC News Mundo.
A similar view is held by Michael Russello, a professor in the biology department at the University of British Columbia, who was also not involved in the studies.
“These two studies really expand the potential of eDNA to provide information in a variety of areas, from biodiversity and invasive species, to public health, just to name a few,” Russello told BBC Mundo.
Russello also argues that the application of these techniques in less controlled environments will bring more complexities, but that both experiments “represent exciting developments” in this area of ​​research.
