Diatom-inferred Hydroclimate Variability in Marl Lake, WI Over the Past 2,000 Years
Hydroclimate variability in the Midwest has witnessed an increase over recent decades, marked by rises in average precipitation and the frequency of extreme hydroclimate events. A comprehensive understanding of natural climate variability in this region is crucial for better preparation and mitigation of risks associated with extreme hydroclimate variability. Natural lakes in the Midwest serve as effective archives of hydroclimate, demonstrating direct responses to climate changes at both local and regional scales. We extracted a 4.5-meter sediment core from the deepest part of Marl Lake in Waushara County, Wisconsin, representing approximately 2,000 years of sediment accumulation. In this study, we focused on a 2-meter segment to identify fossil diatoms, documenting assemblage shifts over time. Changes in the dominant diatom species of Marl Lake reflect significant environmental changes, including lake-level fluctuations and alterations in lake stratification. Current data indicates distinct wet periods and hydrologic shifts throughout the 2,000-year record. These shifts are evident through increases in the relative abundance of planktonic taxa such as Lindavia michiganiana and Discostella pseudostelligera. Robust hydroclimate records from the Midwestern United States are sparse, so expanding the number of millennial-scale records will provide policymakers with additional critical information necessary for future planning.
Figure 1 Cymbellafalsa diluviana
Figure 2 Lindavia michiganiana
I am Christian Sizemore, an MS student at Indiana State University, conducting research in the Paleolimnology Research Lab under the supervision of Dr. Jeffery Stone. Alongside my master’s research, I actively contribute taxonomic data to the DONA website and am currently involved in describing a new diatom species of Cyclotella from Lake Malawi in Africa. My master’s research is part of a larger project funded by an NSF grant from the P2C2 program, with award #1903607. The project focuses on understanding Midcontinental hydroclimate dynamics in response to atmospheric teleconnections such as the Pacific North American Teleconnection, and notable climate phenomena like the Little Ice Age and the Medieval Climate Anomaly.