Recent research, published in Nature Communications, has unveiled how DNA trapped on air filters since the 1960s serves as an ecological time capsule. The study highlights the potential of airborne DNA to reveal the dynamics of ecosystems over time and underscores a significant decline in biodiversity observed over a span of 34 years.
The filters in question were originally employed to monitor radioactive fallout and have been preserved in an archive at the Swedish Defense Research Agency, located outside Kiruna, Sweden. Researchers, led by Per Stenberg from Umeå University, seized the opportunity to analyze these filters, which collected DNA from a diverse array of organisms weekly, including plants, fungi, insects, and even large mammals.
The team identified a remarkable 2,700 organism groups in the vicinity of the monitoring station. By sequencing the DNA captured in the filters, they traced how the populations of these organisms fluctuated over time. Stenberg noted, “It was a stroke of luck that the filters had been kept—and that they were made of a material that preserves DNA. The archive turned out to be a time machine, allowing us to revisit the past and watch an ecosystem changing in almost real time.”
The research revealed a troubling trend: biodiversity in the area has been on the decline since the 1970s, with specific losses noted in organisms such as birch and associated lichens and fungi. This decrease cannot solely be attributed to climate change; rather, it appears to be linked to human activities, particularly forest management practices.
A Novel Approach to Airborne DNA Analysis
While studies on airborne DNA have been conducted previously, this research represents a pioneering and comprehensive approach spanning several decades. The research team utilized advanced DNA sequencing techniques, machine-learning algorithms for organism identification, and air-flow modeling to trace the origins of the DNA found on the filters.
Comparative analyses with traditional field surveys have confirmed the reliability of this new methodology for both organism identification and monitoring population changes. Co-author Daniel Svensson expressed enthusiasm for the future applications of this research, stating, “This work is the result of nine years of intense research and development. I look forward to applying these data, together with ongoing sequencing of additional filters, to a wide range of questions.”
The findings underscore the value of existing air-filter networks for monitoring biodiversity trends and reconstructing ecosystems in regions where baseline data is lacking. This capability is crucial for predicting future changes and developing effective management and restoration strategies. Stenberg added, “The method can also detect and track genetic variation, as well as the presence of invasive species and pathogens.”
In conclusion, the analysis of airborne DNA from decades-old filters not only sheds light on the past but also equips researchers with vital tools for understanding and protecting ecosystems. As biodiversity continues to face significant challenges, such innovative approaches will be essential for informing conservation efforts.