Joint 56th Annual North-Central/ 71st Annual Southeastern Section Meeting - 2022

Paper No. 2-9
Presentation Time: 10:20 AM


CORCORAN, Megan1, DIEFENDORF, Aaron1, LOWELL, Thomas1, WIESENBERG, Nicholas2, WILES, Gregory2, WILSON, Mark A.2, DIETRICH, Watts1 and BERINA, Justine Paul2, (1)Department of Geology, University of Cincinnati, Cincinnati, OH 45221, (2)Department of Earth Sciences, The College of Wooster, Wooster, OH 44691

The hydrogen isotopic composition of lake water (δ2Hlw) contains hydrologic information, and when combined with other proxies that record the δ2H of precipitation, lake water hydrology and extent of evaporation can be determined. Initial studies indicate that highly branched isoprenoids (HBIs), synthesized by lake diatoms and preserved in lake sediments, are a promising proxy for δ2Hlw. However, there are several aspects of this proxy, such as the seasonality of HBI production, that are poorly understood and need to be constrained before reconstructions of δ2Hlw using the δ2H of HBIs (δ2HHBI) are possible. The season when HBIs are produced may bias δ2HHBI records depending on the extent that δ2Hlw changes throughout the year due to precipitation δ2H, evaporation, ground water contribution and the amount of precipitation falling into the lake and surrounding catchment. The timing of when HBIs are produced is difficult to determine from sediment archives because HBIs found in lake sediments reflect the time and flux integrated accumulation of HBIs. We deployed two sediment traps at Brown’s Lake, in northeastern Ohio, to determine when HBIs are produced and whether δ2H changes throughout the year. We present HBI concentration and δ2H from the sediment traps collected monthly for the past 12+ months. In addition, we plan to determine the diatom groups that are producing HBIs throughout the year. This record of HBI concentration and δ2H throughout the year will highlight if there should be any seasonal adjustments when interpreting hydroclimate records using HBIs.