A new study conducted by researchers at Harvard University in the United States suggests that changes in the behavior of microscopic marine organisms could serve as an early warning of a possible mass extinction. These microorganisms, which have been around for millions of years, have left an extensive fossil record that allows scientists to trace important climate events in the past.
Planktonic foraminifera are small animals with shells that have inhabited the oceans for hundreds of thousands of years. These microorganisms form the basis of the marine food chain and their fossils were essential for the Harvard University team to analyze changes in biodiversity during the Eocene climatic optimum, about 50 million years ago. This period was the last significant period of high temperatures since the age of the dinosaurs, compared to the worst-case scenarios expected with current global warming.
“Can we use the past to understand what might happen in the future, in the context of global climate change?” asks Anshuman Swain, a researcher in the Department of Organismic and Evolutionary Biology at Harvard University and one of the authors of the study published in the journal Nature. “Our work provides new insights into how biodiversity responds spatially to global climate change, especially during periods of warming, which is relevant to future projections.”
To conduct this research, the researchers used the Triton Database, the largest source of spatiotemporal records for foraminifera, developed by Adam Woodhouse, a researcher at the University of Bristol and co-author of the study. Using these data, the team was able to determine how the composition of foraminiferal communities changed over millions of years, a much longer period than has typically been studied at this scale.
The data revealed that before the mass extinction that occurred 34 million years ago, marine communities became highly specialized and began to lose their physical diversity, and began to resemble each other. This phenomenon, coupled with mass migration to higher latitudes and away from the tropics, suggests that these societies were adapting to an environment about to change radically.
The researchers believe these findings could indicate community-level changes, similar to observed migration patterns, long before extinctions and actual losses of biodiversity due to global warming occur. According to the team, it is necessary to monitor the structure of biological communities, as changes in their behavior can predict major extinctions in the future.
Moreover, the results of this study on foraminifera open the way for research on other groups of marine organisms, such as sharks and insects. According to Swain, this work is one of the cornerstones of an emerging field called paleoinformatics, which uses large databases of spatiotemporal-resolution fossil records to gain new knowledge about the future of the planet.
This pioneering study not only provides a new perspective for predicting mass extinctions, but also highlights the importance of understanding historical patterns of biodiversity to better prepare us to meet future challenges posed by global climate change.
