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Researchers from Tallinn University of Technology‘s Department of Geology, Quaternary Geology Research Group, have published an innovative study in Boreas. The team developed a new Chironomidae-based inference model to reconstruct mean July air temperatures of the past 14,000 years in the eastern Baltic area.
It fills a crucial gap in climate reconstructions for Estonia, Latvia, and Lithuania by providing a reliable, independent proxy that complements existing methods. By providing the most accurate reconstructions of July air temperatures in the eastern Baltic, this model significantly advances our understanding of historical climate variations and their impact on regional ecosystems.
Chironomidae are non-biting midges, which larvae live in the lake’s bottom sediments, where they can be sampled and identified. Each Chironomidae taxon prefers to live in a specific July air temperature range. By analyzing modern Chironomidae communities and the temperatures where they are found, researchers have developed a mathematical model linking each species to its preferred temperature range.
This model can then be applied to fossil Chironomidae communities to reconstruct past temperatures. Similar models have been successfully implemented in Switzerland, Norway, Poland, Finland, Northern America, and Canada. However, the accuracy of Chironomidae-based models is highest when applied within the same region where the Chironomids were collected. Thus, resolving the mystery of Chironomidae distribution, specifically in the eastern Baltic, was crucial to produce reliable reconstructions of July air temperatures in Estonia, Latvia, or Lithuania.
The researchers’ team collected samples from 35 lakes across Estonia, Latvia, and Lithuania and merged them with existing Finnish and Polish datasets into a regional Finno-Baltic-Polish dataset (121 lakes). This broad dataset covers a wide geographical and temperature range, ensuring the model’s robustness and reliability. The Finno-Baltic-Polish inference model boasts the lowest reconstruction error among all published Chironomidae-based models, achieving a precision of 0.7°C in reconstructing July air temperatures.
Some of the eastern Baltic taxa revealed different distribution patterns and ecological preferences compared to Central and Northern Europe. Interestingly, some Chironomidae species in the eastern Baltic exhibit different distribution patterns and ecological preferences compared to those in Central and Northern Europe, underscoring the uniqueness of the region’s ecosystems and the importance of their conservation.
Bakumenko, V., Poska, A., Płociennik, M., Gasteviciene, N., Kotrys, B., Luoto, T. P., Belle, S. & Veski, S.: Chironomidae-based inference model for mean July air temperature reconstructions in the eastern Baltic area. Boreas.
This article was originally published on the webpage of TalTech (Tallinn University of Technology).
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