Transparency, Geomorphology and Mixing Regime Explain Variability in Trends in Lake Temperature and Stratification across Northeastern North America (1975–2014)
David C. Richardson,
Stephanie J. Melles,
Rachel M. Pilla,
Amy L. Hetherington,
Lesley B. Knoll,
Craig E. Williamson,
Benjamin M. Kraemer,
James R. Jackson,
Elizabeth C. Long,
Karen Moore,
Lars G. Rudstam,
James A. Rusak,
Jasmine E. Saros,
Sapna Sharma,
Kristin E. Strock,
Kathleen C. Weathers,
Courtney R. Wigdahl-Perry
Affiliations
David C. Richardson
Department of Biology, SUNY New Paltz, 1 Hawk Drive, New Paltz, NY 12561, USA
Stephanie J. Melles
Department of Chemistry and Biology, Ryerson University, 350 Victoria Street, Toronto, ON M5B 2K3, Canada
Rachel M. Pilla
Department of Biology, Miami University, 700 E High Street, Oxford, OH 45056, USA
Amy L. Hetherington
Department of Biological Sciences, Virginia Polytechnic Institute and State University, 2011 Derring Hall, 926 West Campus Drive, Blacksburg, VA 24061, USA
Lesley B. Knoll
Itasca Biological Station and Laboratories, University of Minnesota Twin Cities, 28131 University Circle, Lake Itasca, MN 56470, USA
Craig E. Williamson
Department of Biology, Miami University, 700 E High Street, Oxford, OH 45056, USA
Benjamin M. Kraemer
Center for Limnology, University of Wisconsin-Madison, 680 North Park Street, Madison, WA 53706, USA
James R. Jackson
Department of Natural Resources, Cornell University Biological Field Station, 900 Shackelton Point Road, Bridgeport, NY 13030, USA
Elizabeth C. Long
Mohonk Preserve, Daniel Smiley Research Center, P.O. Box 715, New Paltz, NY 12561, USA
Karen Moore
New York City Department of Environmental Protection, 71 Smith Avenue, Kingston, NY 12401, USA
Lars G. Rudstam
Department of Natural Resources, Cornell University Biological Field Station, 900 Shackelton Point Road, Bridgeport, NY 13030, USA
James A. Rusak
Dorset Environmental Science Centre, Ontario Ministry of the Environment and Climate Change, P.O. Box 39, Dorset, ON P0A1E0, Canada
Jasmine E. Saros
Climate Change Institute, University of Maine, 137 Sawyer Research Center, Orono, ME 04401, USA
Sapna Sharma
Department of Biology, York University, Toronto, ON M3P1J3, Canada
Kristin E. Strock
Environmental Studies, Dickinson College, 28 North College Street, Carlisle, PA 17013, USA
Kathleen C. Weathers
Cary Institute of Ecosystem Studies, Box AB, Millbrook, NY 12545, USA
Courtney R. Wigdahl-Perry
Department of Biology, State University of New York at Fredonia, 280 Central Avenue, Fredonia, NY 14063, USA
Lake surface water temperatures are warming worldwide, raising concerns about the future integrity of valuable lake ecosystem services. In contrast to surface water temperatures, we know far less about what is happening to water temperature beneath the surface, where most organisms live. Moreover, we know little about which characteristics make lakes more or less sensitive to climate change and other environmental stressors. We examined changes in lake thermal structure for 231 lakes across northeastern North America (NENA), a region with an exceptionally high density of lakes. We determined how lake thermal structure has changed in recent decades (1975–2012) and assessed which lake characteristics are related to changes in lake thermal structure. In general, NENA lakes had increasing near-surface temperatures and thermal stratification strength. On average, changes in deepwater temperatures for the 231 lakes were not significantly different than zero, but individually, half of the lakes experienced warming and half cooling deepwater temperature through time. More transparent lakes (Secchi transparency >5 m) tended to have higher near-surface warming and greater increases in strength of thermal stratification than less transparent lakes. Whole-lake warming was greatest in polymictic lakes, where frequent summer mixing distributed heat throughout the water column. Lakes often function as important sentinels of climate change, but lake characteristics within and across regions modify the magnitude of the signal with important implications for lake biology, ecology and chemistry.