Consistent temperature dependence of respiration across ecosystems contrasting in thermal history

Abstract

Ecosystem respiration is a primary component of the carbon cycle and understanding the mechanisms that determine its temperature dependence will be important for predicting how rates of carbon efflux might respond to global warming. We used a rare model system, comprising a network of geothermally heated streams ranging in temperature from 5 °C to 25 °C, to explore the nature of the relationship between respiration and temperature. Using this ‘natural experiment’, we tested whether the natal thermal regime of stream communities influenced the temperature dependence of respiration in the absence of other potentially confounding variables. An empirical survey of 13 streams across the thermal gradient revealed that the temperature dependence of whole‐stream respiration was equivalent to the average activation energy of the respiratory complex (0.6–0.7 eV). This observation was also consistent for in‐situ benthic respiration. Laboratory experiments, incubating biofilms from four streams across the thermal gradient at a range of temperatures, revealed that the activation energy and Q10 of respiration were remarkably consistent across streams, despite marked differences in their thermal history and significant turnover in species composition. Furthermore, absolute rates of respiration at standardised temperature were also unrelated to ambient stream temperature, but strongly reflected differences in biofilm biomass. Together, our results suggest that the core biochemistry, which drives the kinetics of oxidative respiratory metabolism, may be well conserved among diverse taxa and environments, and that the intrinsic sensitivity of respiration to temperature is not influenced by ambient environmental temperature.

Influence of watershed‐climate interactions on stream temperature, sediment yield, and metabolism along a land use intensity gradient in Indonesian Borneo

“…These conditions likely enabled high ER rates during the 2009 drought. The temperature dependence of respiration is a topic of considerable debate [Perkins et al, 2012]. We found no significant influence of stream temperature on ER in these warm headwater catchments.…”

Mesocosm Experiments as a Tool for Ecological Climate-Change Research

“…(1) Finkel et al (2006), (2) Ward et al (2012), (15) Blanchard et al (2012), (16) Poloczanska et al (2008), (17) Cheung et al (2009), (18) Sheldon et al (2011), (19) Henry and Molau (1997), (20) Perkins et al (2012), (21) Stephen et al (2004), (22) Meerhoff et al (2007), (23) Friberg et al (2009), (24) Woodward et al (2010a), and (25) Gudmundsdottir et al (2011a). Reference numbers are the same as in the text and Table 1.…”

Ecosystem respiration increases with biofilm growth and bed forms: Flume measurements with resazurin

“…We also know that ER is controlled by temperature [Sinsabaugh, 1997;Acuña et al, 2004;Demars et al, 2011;Perkins et al, 2012] and that the change in respiration with temperature is well described by the Arrhenius equation . We know that ER is controlled by the standing crop of biomass [Jones et al, 1995;Cardinale et al, 2002;Acuña et al, 2004], sometimes made more labile by disturbance [Jones et al, 1995;O'Connor et al, 2012].…”