Classifying Mixing Regimes in Ponds and Shallow Lakes

Meredith A. Holgerson, David C. Richardson, Joseph Roith, Lauren E. Bortolotti, Kerri Finlay, Daniel J. Hornbach, Kshitij Gurung, Andrew Ness, Mikkel R. Andersen, Sheel Bansal, Jacques C. Finlay, Jacob A. Cianci-Gaskill, Shannon Hahn, Benjamin D. Janke, Cory McDonald, Jorrit P. Mesman, Rebecca L. North, Cassandra O. Roberts, Jon N. Sweetman, Jackie R. Webb

Research output: Contribution to journalArticlepeer-review

22 Scopus citations

Abstract

Lakes are classified by thermal mixing regimes, with shallow waterbodies historically categorized as continuously mixing systems. Yet, recent studies demonstrate extended summertime stratification in ponds, underscoring the need to reassess thermal classifications for shallow waterbodies. In this study, we examined the summertime thermal dynamics of 34 ponds and shallow lakes across temperate North America and Europe to categorize and identify the drivers of different mixing regimes. We identified three mixing regimes: rarely (n = 18), intermittently (n = 10), and often (n = 6) mixed, where waterbodies mixed an average of 2%, 26%, and 75% of the study period, respectively. Waterbodies in the often mixed category were larger (≥4.17 ha) and stratification weakened with increased wind shear stress, characteristic of “shallow lakes.” In contrast, smaller waterbodies, or “ponds,” mixed less frequently, and stratification strengthened with increased shortwave radiation. Shallow ponds (<0.74 m) mixed intermittently, with daytime stratification often breaking down overnight due to convective cooling. Ponds ≥0.74 m deep were rarely or never mixed, likely due to limited wind energy relative to the larger density gradients associated with slightly deeper water columns. Precipitation events weakened stratification, even causing short-term mixing (hours to days) in some sites. By examining a broad set of shallow waterbodies, we show that mixing regimes are highly sensitive to very small differences in size and depth, with potential implications for ecological and biogeochemical processes. Ultimately, we propose a new framework to characterize the variable mixing regimes of ponds and shallow lakes.

Original languageEnglish (US)
Article numbere2022WR032522
JournalWater Resources Research
Volume58
Issue number7
DOIs
StatePublished - Jul 2022

Bibliographical note

Funding Information:
This project emerged during a brainstorming session at the Global Lake Ecological Observatory Network (GLEON) 19 meeting at Mohonk Lake, New York, when the Pond Observation aNd Discovery in GLEON (PONDING) group formed. We thank all municipalities and landowners who granted us access to study sites, including the Katharine Ordway Natural History Study Area of Macalester College, the St. Olaf College Natural Lands, Mohonk Preserve, Minnewaska State Park Preserve, Curran Homestead, and the Service de la Biodiversité of the Canton of Geneva. We acknowledge funding support from the St. Olaf College Collaborative Undergraduate Research and Inquiry program (MAH), St. Olaf College Helterbrand/Varshavsky Center for Integrated Research (MAH, JR, KG, and AN), Macalester College Collaborative Summer Research Program (SH), the BEYOND 2020 project funded under the Marine Research Programme by the Irish Government (grant PBA/FS/16/02, MRA), the Minnesota Stormwater Research and Technology Transfer Program via the University of Minnesota Water Resources Center and the Minnesota Stormwater Research Council (JCF and BDJ), the MANTEL ITN through the European Union’s Horizon 2020 Research and Innovation Programme under the Marie Skłodowska-Curie (grant 722518, JPM), the University of Missouri School of Natural Resources (RLN), the North Central Region Water Network (grant 0057039, RLN), National Science Foundation: 1559769 (to Alan Berkowitz, funding COR), Ducks Unlimited Canada (LEB), the Saskatchewan Ministry of Agriculture’s Agricultural Development Fund (grant 20160015, KF and JRW) and the Great Plains Cooperative Ecosystems Study Unit (grant G16AC00003, JNS). Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government. We are grateful to the following people for assistance during field work: Eliane Demierre, Lianna Goldstein, Margot Groskreutz, Kathryn Hoffman, Sarah Hoffman, Kui Hu, Sydney Jensen, Olivia Johnson, Emily Kinzinger, Paige Kowal, Ally Kruper, Jacob Meier, Megan Napoli, Beat Oertli, Jean Pengra, and Jillian St. George. We thank Alana Barnhart for assistance with data cleaning and preliminary analyses. We appreciate the thoughtful reviews by Hilary Dugan and anonymous reviewers, which improved this manuscript. We acknowledge, with respect, that the study ponds in North America are located on the homelands of Indigenous peoples including the Anishinaabe, Anihšināpēk, Lenape, Métis, Nipmuc, Nêhiyawak, Oceti Sakowin, Osage, Penobscot, and Peoria. We make this acknowledgment to honor all Indigenous people, ancestors, and descendants, as well as the land itself.

Funding Information:
This project emerged during a brainstorming session at the Global Lake Ecological Observatory Network (GLEON) 19 meeting at Mohonk Lake, New York, when the Pond Observation aNd Discovery in GLEON (PONDING) group formed. We thank all municipalities and landowners who granted us access to study sites, including the Katharine Ordway Natural History Study Area of Macalester College, the St. Olaf College Natural Lands, Mohonk Preserve, Minnewaska State Park Preserve, Curran Homestead, and the Service de la Biodiversité of the Canton of Geneva. We acknowledge funding support from the St. Olaf College Collaborative Undergraduate Research and Inquiry program (MAH), St. Olaf College Helterbrand/Varshavsky Center for Integrated Research (MAH, JR, KG, and AN), Macalester College Collaborative Summer Research Program (SH), the BEYOND 2020 project funded under the Marine Research Programme by the Irish Government (grant PBA/FS/16/02, MRA), the Minnesota Stormwater Research and Technology Transfer Program via the University of Minnesota Water Resources Center and the Minnesota Stormwater Research Council (JCF and BDJ), the MANTEL ITN through the European Union’s Horizon 2020 Research and Innovation Programme under the Marie Skłodowska‐Curie (grant 722518, JPM), the University of Missouri School of Natural Resources (RLN), the North Central Region Water Network (grant 0057039, RLN), National Science Foundation: 1559769 (to Alan Berkowitz, funding COR), Ducks Unlimited Canada (LEB), the Saskatchewan Ministry of Agriculture’s Agricultural Development Fund (grant 20160015, KF and JRW) and the Great Plains Cooperative Ecosystems Study Unit (grant G16AC00003, JNS). Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government. We are grateful to the following people for assistance during field work: Eliane Demierre, Lianna Goldstein, Margot Groskreutz, Kathryn Hoffman, Sarah Hoffman, Kui Hu, Sydney Jensen, Olivia Johnson, Emily Kinzinger, Paige Kowal, Ally Kruper, Jacob Meier, Megan Napoli, Beat Oertli, Jean Pengra, and Jillian St. George. We thank Alana Barnhart for assistance with data cleaning and preliminary analyses. We appreciate the thoughtful reviews by Hilary Dugan and anonymous reviewers, which improved this manuscript. We acknowledge, with respect, that the study ponds in North America are located on the homelands of Indigenous peoples including the Anishinaabe, Anihšināpēk, Lenape, Métis, Nipmuc, Nêhiyawak, Oceti Sakowin, Osage, Penobscot, and Peoria. We make this acknowledgment to honor all Indigenous people, ancestors, and descendants, as well as the land itself.

Publisher Copyright:
© 2022 The Authors.

Keywords

  • density gradient
  • lake
  • mixing
  • morphology
  • pond
  • precipitation
  • stratification
  • surface area
  • temperature
  • thermal dynamics

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