Much of the world around us is dying. We’re in the midst of a mass extinction event, driven by human activity, and at this point it’s unclear exactly how this event will compare to its predecessors. We don’t need an answer to that to know that it’s in our own interest to stop it, but I think that the effort to do so would be aided by a more accurate understanding of exactly what is going on. We measure the mass extinctions of the past by the fossil record- each event was discovered because a huge number of species simply stopped appearing, because there were no more of them to leave remains. We can’t do that for our present crisis, because it’ll be a while before our era has something that could be called a fossil record.
No, if we want to understand the full horror of what we’re doing to our world, we have to find a way to figure out what’s alive now, and track declines or disappearances, species by species. Once Upon A Time, the only way to do that was to go out and literally count individual organisms. A while back I posted about the use of environmental DNA (eDNA) to determine the presence of alligator snapping turtles, simply by testing the water. Obviously, it’s a bit ridiculous to call the process “simple”, but it’s safer for scientists, less invasive for the turtles, and this technology means that instead of the time and effort spent laying hands on the organism in question, someone can collect water sample, label it, and send it to a lab. This might be bad news for those of us who like doing that kind of field work (certainly more than I like lab work or data analysis), but it’s great news for our overall ability to understand what’s happening in the ecosystems of which we’re a part. I called that process “scrying for turtles”, because while DNA testing isn’t magic, it sure as hell resembles some forms of it. You use powerful energies, dangerous potions, and complicated rituals, and you gain knowledge of what that water has touched, if you know the right questions to ask.
Well, it turns out we can scry the wind, as well as the water. More than that, it seems that we may even be able to ask questions of wind that was trapped in bottles, long ago:
In their new study, researchers including Clare, Allerton, and Brown along with Nina Garrett, York University Toronto, and first author Joanne Littlefair, Queen Mary University of London, tested whether airborne eDNA containing information about the local plant, insect, and other animal life is captured on filters as a by-product of regularly operating air quality monitoring networks that are intended to monitor heavy metals and other pollutants in the atmosphere. After extracting and amplifying DNA from filters sampled at monitoring stations at two locations in the UK, they found an astonishing record of biodiversity trapped on the filters.
Their analyses recovered eDNA from more than 180 different plants, fungi, insects, mammals, birds, amphibians, and other groups. They report that the species list included many “charismatic species such as badgers, dormice, little owls, and smooth newts, species of special conservation interest such as hedgehogs and songbirds, trees including ash, linden, pine, willow, and oak, plants like yarrows, mallows, daisy, nettles, and grasses, arable crops such as wheat, soybean, and cabbage.”
They also note that the filters had DNA from 34 species of birds. The data showed that longer sampling times captured an increased number of vertebrate species, presumably as more mammals and birds visited the area over time.
The researchers contend, based on their findings, that air quality monitoring networks have been gathering local biodiversity data in a standardized way and on continental scales routinely for many years but that “the ecological significance of these samples has gone unnoticed.” In some places, samples are kept for decades, suggesting that existing samples capturing ecological data over time already exist. With only minor changes to current air quality monitoring protocols, the researchers say that these samples could be used for detailed monitoring of terrestrial biodiversity, relying entirely on a network that is already in operation.
Arthur C. Clarke said that “any sufficiently advanced technology is indistinguishable from magic”, and it really feels like that applies to this sort of eDNA stuff. I’ve seen the work that has historically gone into environmental monitoring, and it can be brutal. Now, apparently, we can just ask the wind. To be clear – field work will still be needed. We’re able to get this much information from eDNA because people have already collected DNA samples from all those species. It may be that we’ll be able to discover the presence of new species this way, similar to how it’s possible to discover new bird species by pinpointing unidentified songs, but I think it’s likely that we’ll still need people to go lay eyes and/or hands on individuals to get the whole picture. That said, the amount that we can learn through this air sampling is almost certain to be revolutionary.
“The most important finding, to my mind, is the demonstration that aerosol samplers typically used in national networks for ambient air quality monitoring can also collect eDNA,” Allerton said. “One can infer that such networks — for all their years of operation and in other countries around the world — must have been inadvertently picking up eDNA from the very air we breathe.”
“The potential of this cannot be overstated,” Littlefair said. “It could be an absolute gamechanger for tracking and monitoring biodiversity. Almost every country has some kind of air pollution monitoring system or network, either government owned or private, and in many cases both. This could solve a global problem of how to measure biodiversity at a massive scale.”
The team is now working to preserve as many samples as possible with eDNA in mind. While the samples have already been collected, they say it will take a global effort to take full advantage of the biodiversity information they contain.
Because this is not magic, it will require a great deal of work to fully realize the potential that has been discovered here. DNA analysis may be quicker and easier, but the samples still have to be collected and analyzed. I don’t know how long it will be before we really see what this can bring us, but I find it very hard to believe that we won’t be hearing more about it soon. The technology for DNA analysis is everywhere, at this point, and scientists all over the world are going to be itching to get to work on this. Getting started on it will probably be pretty easy for most universities, because everyone already has almost everything they need.
Given the state of the world, I expect that a lot of the news we get from this will be somewhat dire. We’re going to get a lot of new information, but it’s not going to suddenly show that the mass extinction isn’t happening, and scientists just got worse at counting things or something. This won’t change the pre-existing need for rapid political and economic change around the globe, because having more knowledge ends up meaning little, if that knowledge isn’t put to work. That said, the movements for that change continue, and the information that comes from air monitoring stations will almost certainly be of use in that effort. It’s a scary world out there, but it’s not all man-made horrors beyond our comprehension. There are man-made wonders, too.
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