title: Global patterns in lake ecosystem responses to warming based on the temperature dependence of metabolism.
abstract: Climate warming is expected to have large effects on ecosystems in part due to the temperature dependence of metabolism. The responses of metabolic rates to climate warming may be greatest in the tropics and at low elevations because mean temperatures are warmer there and metabolic rates respond exponentially to temperature (with exponents >1). However, if warming rates are sufficiently fast in higher latitude/elevation lakes, metabolic rate responses to warming may still be greater there even though metabolic rates respond exponentially to temperature. Thus, a wide range of global patterns in the magnitude of metabolic rate responses to warming could emerge depending on global patterns of temperature and warming rates. Here we use the Boltzmann-Arrhenius equation, published estimates of activation energy, and time series of temperature from 271 lakes to estimate long-term (1970-2010) changes in 64 metabolic processes in lakes. The estimated responses of metabolic processes to warming were usually greatest in tropical/low-elevation lakes even though surface temperatures in higher latitude/elevation lakes are warming faster. However, when the thermal sensitivity of a metabolic process is especially weak, higher latitude/elevation lakes had larger responses to warming in parallel with warming rates. Our results show that the sensitivity of a given response to temperature (as described by its activation energy) provides a simple heuristic for predicting whether tropical/low-elevation lakes will have larger or smaller metabolic responses to warming than higher latitude/elevation lakes. Overall, we conclude that the direct metabolic consequences of lake warming are likely to be felt most strongly at low latitudes and low elevations where metabolism-linked ecosystem services may be most affected.
authors: Center for Limnology, University of Wisconsin-Madison, Madison, WI, USA.
authors: Benjamin M
authors: BM
authors: Kraemer
authors: Department of Natural Resources and Environmental Science, University of Nevada-Reno, Reno, NV, USA.
authors: Sudeep
authors: S
authors: Chandra
authors: National Great Rivers Research and Education Center, Alton, IL, USA.|Department of Biology, Washington University, St Louis, MO, USA.
authors: Anthony I
authors: AI
authors: Dell
authors: Centro de Estudios Atitlán, Universidad del Valle de Guatemala, Altiplano Campus, Sololá, Guatemala.
authors: Margaret
authors: M
authors: Dix
authors: Freshwater Centre, Finnish Environment Institute, Mechelininkatu, Helsinki, Finland.
authors: Esko
authors: E
authors: Kuusisto
authors: Department of Water Resources and Drinking Water, Eawag, Swiss Federal Institute of Aquatic Science and Technology, Dübendorf, Switzerland.
authors: David M
authors: DM
authors: Livingstone
authors: Tahoe Environmental Research Center, University of California-Davis, Davis, CA, USA.
authors: S Geoffrey
authors: SG
authors: Schladow
authors: Institute of Biology, Irkutsk State University, Irkutsk, Russia.
authors: Eugene
authors: E
authors: Silow
authors: Technical University of Kenya, Nairobi, Kenya.
authors: Lewis M
authors: LM
authors: Sitoki
authors: Department of Fisheries and Aquatic Sciences, University of Dar es Salaam, Dar es Salaam, Tanzania.
authors: Rashid
authors: R
authors: Tamatamah
authors: Center for Limnology, University of Wisconsin-Madison, Madison, WI, USA.
authors: Peter B
authors: PB
authors: McIntyre
mesh_terms: D002980:Climate; D057231:Climate Change; D017753:Ecosystem; D057232:Global Warming; D060106:Lakes; D013696:Temperature
keywords: aquatic; carbon; climate change; fish; long-term; methane; temperature; tropics