Vast amounts of eDNA captured in air quality monitoring stations

Global ecosystems are under threat, facing a rapidly escalating biodiversity crisis with an alarmingly increasing rate of species extinction. Until now, tracking this loss on a large scale has been an elusive goal, primarily hindered by infrastructure inadequacies. A new study published in Current Biology, however, introduces a surprising solution: environmental DNA (eDNA) that has been unintentionally captured in filters of air quality monitoring stations around the world.

“One of the biggest challenges in biodiversity is monitoring at landscape scales – and our data suggest this could be addressed using the already existing networks of air quality monitoring stations,” said Elizabeth Clare, a scholar at York University Toronto, Canada.

These stations, she highlights, have been managed by both public and private entities for decades, but the ecological value of the samples collected has been largely overlooked.

Accidental eDNA jackpot discovered

Andrew Brown from the National Physical Laboratory (NPL) backs this up, arguing that these established air quality networks are “potentially a huge untapped source of biodiversity data.”

While these monitoring stations have a long-standing history, the techniques to extract and analyze eDNA from the air have only recently been developed. This game-changing methodology was initially introduced in two prior studies, which provided preliminary evidence of its potential to identify zoo species through air sampling.

James Allerton, also from NPL, recalls how these early findings ignited a spark of curiosity within his team. Intrigued by the possibility that air quality data filters could serve as valuable DNA collectors, they approached Littlefair and Clare for further collaboration.

Objective of the study

Together with Nina Garrett from York University Toronto, Joanne Littlefair from Queen Mary University of London, and other researchers, the experts embarked on a novel research endeavor. The objective was to explore whether these filters, used primarily to monitor heavy metals and other pollutants, could capture airborne eDNA reflective of local flora and fauna biodiversity.

The pioneering investigation revealed a remarkable biodiversity record trapped within the filters of two monitoring stations in the UK. Extraction and amplification of DNA from these filters identified eDNA from over 180 various species – from plants and fungi to insects, mammals, birds, amphibians, and more.

The species list was extensive, featuring “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.”

The researchers noted that longer sampling periods resulted in the identification of more vertebrate species, which suggests an increased visitation of mammals and birds over time.

According to the study results, air quality monitoring networks have inadvertently been gathering standardized, large-scale biodiversity data for many years, though the ecological significance of these samples has been grossly underestimated.

Some samples are decades old

The longevity of these samples, which in some places have been stored for decades, implies that they already embody a time capsule of ecological data. The researchers propose that with minor modifications to current monitoring practices, these samples could be instrumental in monitoring terrestrial biodiversity on a massive scale.

James Allerton expressed his enthusiasm for this discovery: “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. One can infer that such networks…must have been inadvertently picking up eDNA from the very air we breathe.”

“The potential of this cannot be overstated. It could be an absolute gamechanger for tracking and monitoring biodiversity,” said Littlefair.

Next step – how to use this eDNA data treasure trove

The team is now focused on preserving as many samples as possible with this newfound purpose. Although these samples have already been collected, the team emphasizes that a coordinated global effort will be needed to fully harness the wealth of biodiversity information they contain.

Notably, this discovery has the potential to revolutionize our understanding of the world around us. Air pollution monitoring networks exist in nearly every country, both in the form of government-operated or privately-owned systems, and often a combination of both. If utilized effectively, these existing infrastructures could provide an unprecedented solution to the global challenge of measuring biodiversity at a large scale.

“Almost every country has some kind of air pollution monitoring system or network…This could solve a global problem of how to measure biodiversity at a massive scale,” said Littlefair.

The team is highly motivated to proceed with their research, eager to unlock the full potential of these underappreciated samples. Their findings offer an exciting breakthrough in the fight against biodiversity loss, redefining our ability to monitor and understand the world’s ecological health on an unprecedented scale. 

However, to realize this promise, the researchers insist on the urgent need for a collaborative international effort. This could potentially lead to a global paradigm shift in biodiversity monitoring and conservation, turning the tide on a looming ecological crisis.

More about eDNA

Environmental DNA, or eDNA, is genetic material that is collected directly from environmental samples such as soil, sediment, water, or air, rather than from an individual organism. 

Organisms constantly shed cells and genetic material into their environment in the form of skin, hair, feces, urine, and even just the process of breathing out. These traces can be collected and analyzed to detect the presence of the organism that shed them.

New uses found for eDNA

eDNA has gained significant attention in recent years due to its wide range of applications, particularly in biodiversity monitoring and ecology. It can be used to detect species presence in a non-invasive manner, without needing to physically capture or observe the organisms. This is especially useful in aquatic environments, where traditional sampling methods can be challenging and invasive.

Moreover, eDNA can be used to detect elusive or rare species that are difficult to find using traditional methods. For instance, it has been used to detect the presence of endangered or invasive species in various environments, providing critical information for conservation and management efforts.

In the field of paleoecology, eDNA from sediments has been used to reconstruct past biodiversity, ecosystems, and climate. It’s also used in forensic science, agriculture, and in the search for new pharmaceuticals.

Tech advances brings new uses

Recent technological advancements, particularly in high-throughput DNA sequencing and bioinformatics, have made it possible to not only detect the presence of specific organisms, but also to characterize entire communities of organisms from eDNA samples. This is often referred to as metabarcoding.

However, the field of eDNA research is still developing, and there are challenges and limitations to its use. These include issues with DNA degradation, contamination, the uneven distribution of eDNA in the environment, and the need for accurate reference databases to match eDNA sequences.

Nevertheless, eDNA holds great promise for advancing our understanding of biodiversity and ecosystems, particularly in the context of global environmental change.

More about the global biodiversity crisis

The term “biodiversity crisis” refers to the rapid, human-induced loss of plant and animal species at the global scale. This rate of loss is so high that it’s often compared to the five mass extinction events in Earth’s history, leading many scientists to refer to the current era as the sixth mass extinction.

Biodiversity, the variety of life in a particular habitat or on Earth as a whole, is critical to the health of ecosystems and human survival. It contributes to everything from food security and medical research to climate regulation and recreational benefits.

According to the United Nations’ Global Assessment Report on Biodiversity and Ecosystem Services released in 2019, around one million animal and plant species are threatened with extinction. The report points to five main drivers of this biodiversity loss:

Changes in land and sea use

This includes deforestation for agriculture, logging, mining, and urban expansion, as well as damage to coral reefs from fishing.

Direct exploitation of organisms

Overfishing, overhunting, and illegal wildlife trade are major contributors to species decline.

Climate change

Rising temperatures, sea level rise, increased frequency and severity of natural disasters, and ocean acidification all disrupt habitats and species survival.

Pollution

Pesticides, plastics, oil spills, heavy metals, and other pollutants can harm or kill various species.

Invasive alien species

Non-native species can outcompete native species for resources, change habitats, or directly prey on native species.

Solving the biodiversity crisis will require addressing these drivers. This could include everything from stronger regulation and enforcement against illegal wildlife trade, to shifts in agriculture to reduce deforestation, to global action on climate change.

The consequences of inaction are dire. Biodiversity loss threatens food security, as fewer species mean fewer resources for human consumption. It also threatens the discovery of new medicines, as many are found by studying various species. 

Biodiversity loss can lead to the collapse of ecosystems, which could increase the risk of natural disasters, negatively impact climate regulation, and reduce nature’s recreational, cultural, and spiritual benefits.

It’s important to note that while the situation is severe, it’s not hopeless. Changes in policies, practices, and behaviors can protect and restore biodiversity. Numerous conservation efforts around the world are underway to address this issue, but it will take a global, concerted effort to effectively combat the biodiversity crisis.

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