Key differences between lakes and reservoirs modify climate signals: A case for a new conceptual model

Abstract

Lakes and reservoirs are recognized as important sentinels of climate change, integrating catchment and atmospheric climate change drivers. Climate change conceptual models generally consider lakes and reservoirs together despite the possibility that these systems respond differently to climate-related drivers. Here, we synthesize differences between lake and reservoir characteristics that are likely important for predicting waterbody response to climate change. To better articulate these differences, we revised the energy mass flux framework, a conceptual model for the effects of climate change on lentic ecosystems, to explicitly consider the differential responses of lake versus reservoir ecosystems. The model predicts that catchment and management characteristics will be more important mediators of climate effects in reservoirs than in natural lakes. Given the increased reliance on reservoirs globally, we highlight current gaps in our understanding of these systems and suggest research directions to further characterize regional and continental differences among lakes and reservoirs. Author Contribution Statement: NMH and BRD co-led the manuscript effort and contributed equally. JRC and BRD conducted the statistical analyses. KES and JRC designed the lake pairing analysis. NMH, NRR, and KES developed the climate change conceptual model. This paper was a highly collaborative effort and all authors contributed equally to the development of the research question and study design as well as the writing of the paper. This is an open access article under the terms of the Creative Commons Attribution NonCommercial License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes. Scientific Significance StatementClimate change poses a significant threat to freshwater ecosystems, though the exact nature of these threats can vary by waterbody type. An existing conceptual model describes how altered fluxes of mass and energy will affect standing waterbodies, but it does not differentiate reservoirs from lakes. Here, we synthesize evidence suggesting that lakes and reservoirs differ in fundamental ways that are likely to influence their response to climate change. We then present a revised conceptual model that contrasts climate change effects on reservoirs versus lakes. 47Limnology and Oceanography Letters 2, 2017, 47-62

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