Abstract

Most of Earth’s fresh surface water is consolidated in just a few of its largest lakes, and because of their unique response to environmental conditions, lakes have been identified as climate change sentinels. While the response of lake surface water temperatures to climate change is well documented from satellite and summer in situ measurements, our understanding of how water temperatures in large lakes are responding at depth is limited, as few large lakes have detailed long-term subsurface observations. We present an analysis of three decades of high frequency (3-hourly and hourly) subsurface water temperature data from Lake Michigan. This unique data set reveals that deep water temperatures are rising in the winter and provides precise measurements of the timing of fall overturn, the point of minimum temperature, and the duration of the winter cooling period. Relationships from the data show a shortened winter season results in higher subsurface temperatures and earlier onset of summer stratification. Shifts in the thermal regimes of large lakes will have profound impacts on the ecosystems of the world’s surface freshwater.

This study presents hourly data from a thermistor string in Lake Michigan, inspecting its response at depth to surface warming. Based on the data, the study suggests bottom lake temperatures respond to changes in turnover and re-stratification, with the ultimate possibility of the lake shifting from dimictic to monomictic.

Details

Title
Seasonal overturn and stratification changes drive deep-water warming in one of Earth’s largest lakes
Author
Anderson, Eric J 1   VIAFID ORCID Logo  ; Stow, Craig A 1   VIAFID ORCID Logo  ; Gronewold, Andrew D 2 ; Mason, Lacey A 1 ; McCormick, Michael J 1 ; Qian, Song S 3   VIAFID ORCID Logo  ; Ruberg, Steven A 1 ; Beadle, Kyle 1 ; Constant, Stephen A 1 ; Hawley, Nathan 1 

 National Oceanic and Atmospheric Administration, Great Lakes Environmental Research Laboratory, Office of Oceanic and Atmospheric Research, Ann Arbor, USA (GRID:grid.3532.7) (ISNI:0000 0001 1266 2261) 
 University of Michigan, School for Environment and Sustainability, Ann Arbor, USA (GRID:grid.214458.e) (ISNI:0000000086837370) 
 The University of Toledo, Department of Environmental Sciences, Toledo, USA (GRID:grid.267337.4) (ISNI:0000 0001 2184 944X) 
Publication year
2021
Publication date
2021
Publisher
Nature Publishing Group
e-ISSN
20411723
Source type
Scholarly Journal
Language of publication
English
ProQuest document ID
2501654810
Copyright
© This is a U.S. government work and not under copyright protection in the U.S.; foreign copyright protection may apply 2021. This work is published under http://creativecommons.org/licenses/by/4.0/ (the “License”). Notwithstanding the ProQuest Terms and Conditions, you may use this content in accordance with the terms of the License.