Just as the pandemic struck, Christina Islas Lynggaard, a postdoctoral researcher at the Globe Institute at the University of Copenhagen, sat in her apartment surrounded by vacuum cleaners and filters. She put them to the test and eventually landed on a wet vacuum, which was, for her purposes, pretty good. The others did not quite fit the bill – they had a good draw, but the minute you put there a filter, it disturbed their feeds. “He died, then the engine overheated, and it was very difficult,” Lynggaard said.
All of this testing was done for an interesting case, which seems obvious in hindsight but could have valuable ecological applications. In short, Lynggaard and other researchers on his team were looking for a way to collect environmental DNA (eDNA) from the air to measure biodiversity or look for the presence of rare or invasive species.
“We had no idea of the best way to collect DNA from the air,” said Kristine Bohmann Ars. Bohmann is an associate professor at the Globe Institute and one of the researchers involved in the effort.
Ultimately, it looks like you can get DNA from the air by sucking it through a vacuum cleaner (or something similar), grabbing it into an attached filter, and analyzing it. Bohmann, Lynggaard, and others recently published the results of their work in Current Biology. The release of the study coincides with other research showing largely the same conclusions using a slightly different method developed by a team in the UK and Canada.
In the past, trying to measure biodiversity or verify the presence of a species was a tedious job that often involved setting up cameras or going out and waiting to spot the species. More recently, however, researchers have used eDNA for this purpose, as it may be easier. According to an article from last February, the most common form of eDNA testing involves filtering water from the environment through a membrane and studying the accumulated material, often pieces of skin, feces, mucus, etc. .
“The air is the equivalent of the water that surrounds everything on earth, like water surrounds everything in a lake or in the ocean,” said Bohmann. However, these two articles describe something that, on the whole, has never been done before: measuring Ådne from the air. The concept is not entirely new; a search last year used the air, water and soil to detect big brown bats. Still, the Danish researchers think they are in the game with this work.
“I had a very good feeling about this. I knew I had to do this study “. Bohmann said, recalling the first grant application she wrote for this project, which was refused.
Proof of concept
In 2019, however, Bohmann and Lynggaard’s second attempt to secure a grant was successful. To test their ideas, the team traveled to Copenhagen Zoo Force wet vacuum and, at the suggestion of one of their co-authors, two fans. The fans were like those found in laptops, but with a printed box in 3D for the filters can be attached. Lynggaard tested many filters before landing on class F8 filters, which are good to collect and retain particles.
From there, the team took a stroll through the zoo and collected samples in three different areas: a stable, which contained the okapi and a tiger; the outer holding area; and inside the “house of the rainforest” which featured birds, reptiles, sloths, etc. . Back in the lab, the water could also pass through a filter.
The lab itself was thoroughly cleaned and had strict entry rules to avoid contaminating the samples. The team also collected air samples from the lab to get a feel for the ambient DNA present.
At first they were not sure of the type of DNA that they would find, if necessary. Of the 40 samples they collected, the team members have identified 49 different species of rhinoceros guppies to the Rainforest Room. Each sample contained DNA from six to 21 creatures. Some of the detected species such as water vole and red squirrel, were not even zoo animals; they were next door. “We circled the chair absolutely stunned, surprised, shocked,” said Bohmann.