As the pandemic struck, Christina Islas Lingard – a postdoctoral researcher at the University of Copenhagen’s Globe Institute – sat in her apartment surrounded by voids and filters. She tested them, and eventually landed on a water vacuum, which, for her purposes, was very good. The rest didn’t quite make the cut – they had good suction, but the second you put a filter on, it messes up their power supply. “It just dies, and then the engine overheats, and it was really hard,” Lingard said.
All of this testing was done for an intriguing case, one that appears obvious in hindsight but could have valuable environmental applications. In short, Lingard and other researchers on her 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.
Out of thin air
“We had no idea how best to collect DNA from the air,” Kristen Bowman told Ars. Bowman is an associate professor at the Globe Institute and one of the researchers involved in this effort.
As it turns out, it appears that you can collect eDNA from the air by suctioning it through a vacuum (or something similar), capturing it in an attached filter, and analyzing it. Bohmann, Lynggaard, and other researchers recently published the results of their work in Current Biology. The study’s publication coincides with different research that shows pretty much 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 existence of a species was hard work that often involved setting up cameras or going out and waiting for a species to be discovered. However, recently, researchers have used eDNA for this purpose, Because it could be easier. according to paper As of last February, the most common form of eDNA testing involves filtering environmental water through a membrane and studying accumulated material — often DNA-carrying bits of skin, feces, mucus, etc.
“Air is equivalent to water in that it surrounds everything on Earth, just as water surrounds everything in a lake or ocean,” Bowman said. However, these two papers describe something that has largely not been done before: measuring eDNA from air. The concept isn’t entirely new; One piece of research from last year used air, water, and soil to discover large brown bats. Despite this, the Danish researchers believe they are working on something in this work.
“I had a very good feeling about this. I just knew I had to do this study.” Bowman said, remembering the first grant application she wrote for this project, which was turned down.
But in 2019, Bowman and Lingard’s second attempt at a scholarship came. To test their ideas, the team went to the Copenhagen Zoo armed with a water vacuum and—suggested by one of their authors—two blowing fans. The fans were like those in laptops but with a 3D-printed casing so that the filters could be attached to them. Lynggaard tested a lot of filters before landing on F8 series filters, which are good at collecting and retaining particulates.
From there, the team walked around the zoo and collected samples from three different areas: a stable containing an okapi and a tiger; outdoor holding area; And inside the “Rainforest House”, in which birds, reptiles, sloths, etc. appeared. Vacuums suck the air in these areas, and parts of animal waste fall into the filters, or in the case of water vacuum, . Back in the lab, the water can also be run through a filter.
The lab itself was thoroughly cleaned and had strict rules on entry to avoid contaminating samples. The team also collected air samples from the lab to identify the surrounding DNA present.
At first, they weren’t sure what types of DNA, if any, they would find. Of the 40 samples they took, team members identified 49 different species, from rhinos to guppies, in the Rainforest Room. Each sample contains DNA from between six and 21 creatures. Some of the discovered species—such as the waterhorse and the red squirrel—were not even zoo animals; They were nearby. “We were falling off the chair, surprised, surprised, shocked,” Bowman said.
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