title: Salting our freshwater lakes.
abstract: The highest densities of lakes on Earth are in north temperate ecosystems, where increasing urbanization and associated chloride runoff can salinize freshwaters and threaten lake water quality and the many ecosystem services lakes provide. However, the extent to which lake salinity may be changing at broad spatial scales remains unknown, leading us to first identify spatial patterns and then investigate the drivers of these patterns. Significant decadal trends in lake salinization were identified using a dataset of long-term chloride concentrations from 371 North American lakes. Landscape and climate metrics calculated for each site demonstrated that impervious land cover was a strong predictor of chloride trends in Northeast and Midwest North American lakes. As little as 1% impervious land cover surrounding a lake increased the likelihood of long-term salinization. Considering that 27% of large lakes in the United States have >1% impervious land cover around their perimeters, the potential for steady and long-term salinization of these aquatic systems is high. This study predicts that many lakes will exceed the aquatic life threshold criterion for chronic chloride exposure (230 mg L-1), stipulated by the US Environmental Protection Agency (EPA), in the next 50 y if current trends continue.
authors.affiliation: Center for Limnology, University of Wisconsin-Madison, Madison, WI 53706; hdugan@wisc.edu.|Cary Institute of Ecosystem Studies, Millbrook, NY 12545.
authors.forename: Hilary A
authors.identifier: 0000-0003-4674-1149
authors.initials: HA
authors.lastname: Dugan
authors.affiliation: School of Freshwater Sciences, University of Wisconsin-Milwaukee, Milwaukee, WI 53204.
authors.forename: Sarah L
authors.initials: SL
authors.lastname: Bartlett
authors.affiliation: Department of Biology, University of Waterloo, Waterloo, ON, N2L 3G1, Canada.
authors.forename: Samantha M
authors.initials: SM
authors.lastname: Burke
authors.affiliation: Department of Biological Sciences, Virginia Tech, Blacksburg, VA 24061.
authors.forename: Jonathan P
authors.initials: JP
authors.lastname: Doubek
authors.affiliation: Department of Biological Sciences, Dartmouth College, Hanover, NH 03755.
authors.forename: Flora E
authors.initials: FE
authors.lastname: Krivak-Tetley
authors.affiliation: Department of Fisheries and Wildlife, Michigan State University, East Lansing, MI 48824.
authors.forename: Nicholas K
authors.initials: NK
authors.lastname: Skaff
authors.affiliation: Department of Biology, Queen's University, Kingston, ON, K7L 3N6, Canada.
authors.forename: Jamie C
authors.initials: JC
authors.lastname: Summers
authors.affiliation: Odum School of Ecology, University of Georgia, Athens, GA 30602.
authors.forename: Kaitlin J
authors.initials: KJ
authors.lastname: Farrell
authors.affiliation: Bren School of Environmental Science and Management, University of California, Santa Barbara, CA 93106.
authors.forename: Ian M
authors.initials: IM
authors.lastname: McCullough
authors.affiliation: Department of Ecology, Evolution and Organismal Biology, Iowa State University, Ames, IA 50011.
authors.forename: Ana M
authors.initials: AM
authors.lastname: Morales-Williams
authors.affiliation: Department of Civil & Environmental Engineering, University of California, Davis, CA 95616.|UC Davis Tahoe Environmental Research Center, Incline Village, NV 89451.
authors.forename: Derek C
authors.initials: DC
authors.lastname: Roberts
authors.affiliation: Center for Global Change and Earth Observations, Michigan State University, East Lansing, MI 48823.
authors.forename: Zutao
authors.initials: Z
authors.lastname: Ouyang
authors.affiliation: Instituto Argentino de Oceanografía, Universidad Nacional del Sur-CONICET, Bahia Blanca Bs As, B8000BFW, Argentina.
authors.forename: Facundo
authors.initials: F
authors.lastname: Scordo
authors.affiliation: Center for Limnology, University of Wisconsin-Madison, Madison, WI 53706.
authors.forename: Paul C
authors.initials: PC
authors.lastname: Hanson
authors.affiliation: Cary Institute of Ecosystem Studies, Millbrook, NY 12545.
authors.forename: Kathleen C
authors.initials: KC
authors.lastname: Weathers
mesh_terms: D060106:Lakes / Q000737:chemistry*; D054712:Salinity; D012965:Sodium Chloride / Q000737:chemistry*; D014481:United States; D014484:United States Environmental Protection Agency; D014873:Water Pollutants / Q000737:chemistry*
chemical_list: D014873:Water Pollutants; D012965:Sodium Chloride
keywords: chloride; ecosystem services; impervious surface; limnology; road salt