Salting our freshwater lakes

HILARY DUGAN; SARAH BARTLETT; SAMANTHA BURKE; JONATHAN DOUBEK; FLORA E. KRIVAK-TETLEY; NICHOLAS SKAFF; JAMIE SUMMERS; KAITLIN FARRELL; IAN MCCULLOUGH; ANA MORALES-WILLIAMS; DEREK ROBERTS; FACUNDO SCORDO; ZUTAO OUYANG; PAUL HANSON; KATHLEEN WEATHERS

Lunz

Workshop; GLEON 18 Lunz & Gaming, Austria; 2016

Global Lake Ecological Observatory Network - SUNY New Paltz, Mohonk Preserve - Cary Institute of Ecosystem Studies - NYC Department of Environmental Protection

Worldwide, the greatest concentration of lakes is in north temperate ecosystems (Verpooter et al. 2014). As urban development and the percentage of people living in urban areas continue to grow in these regions, the potential deterioration of lakeshore habitats and urban runoff poses a threat to lake water quality. In north temperate climates, a known threat to water quality is runoff from road salt application, which can lead to the steady and long-term salinization of freshwaters.To determine if urbanization was a leading driver of lake salinization, we amassed a global dataset of lake chloride concentrations from numerous national and local sources. Our dataset contains over 500 lakes, situated in North America and Europe, with chloride records spanning at least ten years. For each site, we calculated landscape metrics, including percent impervious surface and road density in 100 to 1500 m buffers surrounding the lake perimeter, mean temperatures, monthly precipitation, and sea salt deposition. The result of tree-based models constructed using the entire dataset, continental subsets, and a subset of semi annual continuous data from 1985-2010 reveals that the percentage of impervious surface surrounding the lake was the most important predictor of chloride trends. In Northern Europe, this response is more muted, as long term trends were also driven by regional climate patterns. This study identifies areas of lake salinization, and draws attention to the lack of long term monitoring around the world.