Scientists for the first time have used DNA as a “time machine” to illuminate a century of environmental change, including temperature rises and pollution, in a freshwater lake, highlighting an irreversible loss of biodiversity.
An international team from the University of Birmingham in the UK, in collaboration with Goethe University in Frankfurt, Germany, employed artificial intelligence to study biodiversity based on DNA and variables of climate and pollution. This approach could aid regulators in protecting or potentially improving current levels of biodiversity on Earth.
DNA analysis provides vital data on the complex functions and cycles within groundwater systems, revealing the transformation of “almost” pristine environments from the beginning of the industrial revolution to present-day impacts.
The researchers utilized sediment from the bottom of a Danish lake to reconstruct a 100-year record of biodiversity, chemical pollution, and climate change levels. This lake has a well-documented history of water quality transformations, making it an ideal natural experiment for testing the biodiversity time machine concept.
Published in the journal “eLife,” their findings show that the sediments carry a continuous record of biological and environmental signals that have evolved over time. Using environmental DNA (genetic material left by plants, animals, and bacteria), they constructed a picture of the entire freshwater community. With AI, they analyzed this information alongside climate and pollution data to identify factors contributing to the historical species loss in the lake.
The researchers found that pollutants such as pesticides and fungicides, along with increases in minimum temperatures (a rise of 1.2-1.5 degrees), caused the most damage to biodiversity levels.
The primary author, Niamh Eastwood, a Ph.D. student at the University of Birmingham, stated that the biodiversity loss due to pollution and increased water temperatures may be irreversible, with species found in the lake 100 years ago and now lost possibly unable to return. The lake cannot be restored to its original state, even though it is recovering. This research shows that if we fail to protect biodiversity, we may lose much of it forever.DNA as a “time machine”
Dr. Iliana Bista, co-author and lecturer in environmental bioinformatics at the University of Birmingham, expressed that they have demonstrated the value of AI-based methods in understanding historical causes of biodiversity loss. By learning from the past, their comprehensive models can help predict future biodiversity loss.
The researchers are now expanding their initial study from one lake to include lakes in England and Wales. This new study will help them understand how repeatable the patterns they observed are, thus generalizing their findings on pollution and climate change’s impacts on lake biodiversity.
