Deeper waters are changing less consistently than surface waters in a global analysis of 102 lakes

Citation

Pilla R, Williamson CE, Adamovich BV, Adrian R, Anneville O, Chandra S, Colom-Montero W, Devlin SP, Dix MA, Dokulil MT, Gaiser EE, Girdner SF, Hambright KD, Hamilton DP & Jones ID (2020) Deeper waters are changing less consistently than surface waters in a global analysis of 102 lakes. Scientific Reports, 10 (1), Art. No.: 20514. https://doi.org/10.1038/s41598-020-76873-x

Abstract
Globally, lake surface water temperatures have warmed rapidly relative to air temperatures, but changes in deepwater temperatures and vertical thermal structure are still largely unknown. We have compiled the most comprehensive data set to date of long-term (1970-2009) summertime vertical temperature profiles in lakes across the world to examine trends and drivers of whole-lake vertical thermal structure. We found significant increases in surface water temperatures across lakes at an average rate of +0.37°C decade-1, comparable to changes reported previously for other lakes, and similarly consistent trends of increasing water column stability (+0.08 kg m-3 decade-1). In contrast, however, deepwater temperature trends showed little change on average (+0.06°C decade-1 ), but had high variability across lakes, with trends in individual lakes ranging from -0.68°C decade-1 to +0.65°C decade-1 . The variability in deepwater temperature trends was not explained by trends in either surface water temperatures or thermal stability within lakes, and only 8.4% was explained by lake thermal region or local lake characteristics in a random forest analysis. These findings suggest that external drivers beyond our tested lake characteristics are important in explaining long-term trends in thermal structure, such as local to regional climate patterns or additional external anthropogenic influences.

Keywords
Freshwater ecology; Limnology

Notes
Additional co-authors: Karl Havens, Dag O Hessen, Scott N Higgins, Timo H Huttula, Hannu Huuskonen, Peter D F Isles, Klaus D Joehnk, Wendel Bill Keller, Lesley B Knoll, Johanna Korhonen, Benjamin M Kraemer, Peter R Leavitt, Fabio Lepori, Martin S Luger, Stephen C Maberly, John M Melack, Stephanie J Melles, Döerthe C Müller-Navarra, Don C Pierson, Helen V Pislegina, Pierre-Denis Plisnier, David C Richardson, Alon Rimmer, Michela Rogora, James A Rusak, Steven Sadro, Nico Salmaso, Jasmine E Saros, Émilie Saulnier-Talbot, Daniel E Schindler, Martin Schmid, Svetlana V Shimaraeva, Eugene A Silow, Lewis M Sitoki, Ruben Sommaruga, Dietmar Straile, Kristin E Strock, Wim Thiery, Maxim A Timofeyev, Piet Verburg, Rolf D Vinebrooke, Gesa A Weyhenmeyer, Egor Zadereev

Journal
Scientific Reports: Volume 10, Issue 1