NEW YORK – A team led by investigators in Canada and the UK has demonstrated the feasibility of identifying species in a certain region based on the environmental DNA (eDNA) collected at air quality stations.
The approach, described in a correspondence article in Current Biology on Monday, points to the possibility of tapping into air quality monitoring networks at a given location to get a glimpse at the biodiversity found there.
Because air quality monitoring stations are used around the world and collect samples frequently — often daily or weekly — such networks may provide a resource for measuring large-scale biodiversity within and across continents, senior author Elizabeth Clare, a biologist at York University in Toronto, said in an email.
"That is something we really have no other way of doing using existing methods," she explained. "In biodiversity science, we do not have large-scale infrastructure to use in monitoring."
The study expands on previous proof-of-concept studies, including a Current Biology paper that Clare and her colleagues published early last year that suggested that the DNA swirling around in air samples collected at a zoological park could accurately identify 17 animal species known to reside there, along with eight additional bird or mammal species.
"Our study provides compelling evidence that air can be used as a source of DNA for biomonitoring," the authors of that study suggested, arguing that the potential development of airborne DNA sampling "will have major implications for global terrestrial biomonitoring."
For their latest study, the researchers used targeted 16S ribosomal RNA, cytochrome c oxidase I, and internal transcribed spacer amplicon sequencing to profile vertebrate, invertebrate, and plant/fungal barcodes in filter samples from air quality monitoring sites. These included nine "total suspended particulate matter" samples collected in an hour, week, or month from filters at an air quality network site near a deer park in a southwest suburb of London.
The investigators also tested eight samples from PM10 particulate matter filters at an air quality site in Scotland that were stored at room temperature for eight months before attempting DNA extraction, amplification, and sequencing.
"Almost every country has some kind of air pollution monitoring system or network, either government owned or private, and in many cases both," first author Joanne Littlefair, a researcher at Queen Mary University of London, said in a statement. "This could solve a global problem of how to measure biodiversity at a massive scale."
Together, the amplified sequences identified in the eDNA identified more than 180 species of fungi, plants, insects, birds, amphibians, and mammals. Among them were trees, grasses, and crop plants, for example, along with nearly three dozen bird species, newts, badgers, and hedgehogs.
In addition to showing that they could successfully obtain DNA from the Scottish air filter samples stored at room temperature for several months, the researchers also determined that they could pick up DNA from a growing number of vertebrate species by stretching out sampling times, potentially providing more time for the animals to return to the air quality monitoring site and deposit DNA.
"The idea that these stations have been quietly collecting this sort of ecological data as a byproduct of their regular operation is amazing," Clare said, noting that the current results suggest that it will be possible to "use the same material they collect for air quality as a way to measure biodiversity."