Use of operative temperature and standard operative temperature models in thermal biology

Dzialowski, Edward M.

doi:10.1016/j.jtherbio.2005.01.005

Cited by 187 publications

(157 citation statements)

References 125 publications

(245 reference statements)

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“…Nonetheless, it is not clear whether ectotherms can adjust their within-body temperature heterogeneity to maintain several physiological functions near their optimal temperature in different body compartments. Third, ecologists have developed physical models that are useful in mapping body temperatures across space and time (Bakken and Gates, 1975;Fitzhenry et al, 2004;Dzialowski, 2005;Angilletta, 2009). These biomimetic loggers give estimates of body temperature, i.e.…”

Section: Discussionmentioning

confidence: 99%

Survival and arm abscission are linked to regional heterothermy in an intertidal sea star

Pincebourde

Sanford

Helmuth

2013

Journal of Experimental Biology

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SUMMARYBody temperature is a more pertinent variable to physiological stress than ambient air temperature. Modeling and empirical studies on the impacts of climate change on ectotherms usually assume that body temperature within organisms is uniform. However, many ectotherms show significant within-body temperature heterogeneity. The relationship between regional heterothermy and the response of ectotherms to sublethal and lethal conditions remains underexplored. We quantified withinbody thermal heterogeneity in an intertidal sea star (Pisaster ochraceus) during aerial exposure at low tide to examine the lethal and sublethal effects of temperatures of different body regions. In manipulative experiments, we measured the temperature of the arms and central disc, as well as survival and arm abscission under extreme aerial conditions. Survival was related strongly to central disc temperature. Arms were generally warmer than the central disc in individuals that survived aerial heating, but we found the reverse in those that died. When the central disc reached sublethal temperatures of 31-35°C, arms reached temperatures of 33-39°C, inducing arm abscission. The absolute temperature of individual arms was a poor predictor of arm abscission, but the arms lost were consistently the hottest at the within-individual scale. Therefore, the vital region of this sea star may remain below the lethal threshold under extreme conditions, possibly through water movement from the arms to the central disc and/or evaporative cooling, but at the cost of increased risk of arm abscission. Initiation of arm abscission seems to reflect a whole-organism response while death occurs as a result of stress acting directly on central disc tissues. Supplementary material available online at

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Section: Discussionmentioning

confidence: 99%

Survival and arm abscission are linked to regional heterothermy in an intertidal sea star

Pincebourde

Sanford

Helmuth

2013

Journal of Experimental Biology

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“…Operative temperature incorporates energy flow between an animal and the environment and is primarily dependent upon radiation, air temperature, wind, and humidity (Dzialowski 2005). Collectively, these environmental variables determine the actual thermal environment experienced by an animal and influences their body temperature, loss of moisture, and metabolic rate.…”

Section: Introductionmentioning

confidence: 99%

Landscapes as a moderator of thermal extremes: a case study from an imperiled grouse

et al. 2014

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Abstract. The impacts of climate driven change on ecosystem processes and biodiversity are pervasive and still not fully understood. Biodiversity loss, range shifts, and phenological mismatches are all issues associated with a changing climate that are having significant impacts on individuals and ecosystems alike. Investigating and identifying effective management strategies that can conserve vulnerable species should be the focus of current and future climate change research. We investigated thermal properties of habitat for an imperiled grouse (Greater Prairie-chicken; Tympanuchus cupido) in tallgrass prairie characterized by heterogeneous fire and grazing (the fire-grazing interaction). We examined operative temperature at varying scales relevant to grouse and used historic and forecasted climate data to estimate thermal stress during nesting activities. We found that heterogeneous grasslands have high thermal variability with operative temperature ranging as much as 238C across the landscape. Grouse exhibited strong selection for cooler thermal environments as nest sites were as much as 88C cooler than the surrounding landscape, and fine-scale differences in thermal environments were nearly 48C cooler than sites within 2 m of nests. Additionally, forecasted climate scenarios indicate grouse will experience 2-4 times the number of hours above thermal stress thresholds, emphasizing the need for informed conservation management. Overall, these data provide evidence that variation in grassland structure resulting from the fire-grazing interaction may be important in moderating thermal environments and highlights the complex and interactive effects of restored ecological processes on ecosystems.

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“…Costa & Kooyman 1984;Markussen et al 1994;Hawkins et al 1997). However, for species that normally eat lowprotein foods in smaller intermittent meals, peaks of HIF and thermal substitution tend to be low relative to the typically high variance in Vo 2 (Kaseloo & Lovvorn 2003, 2005. Thus, the substitution of HIF may be occurring, but the signal-to-noise ratio might be low for certain diets and consumption patterns.…”

Section: Methods For Calculating Thermal Substitutionmentioning

confidence: 99%

“…Results have been mixed, often with unacceptably large errors (Walsberg & Wolf 1996;Dzialowski 2005). In water, such physical models have the same problems as heatflux sensors in duplicating the insulative air layers that are so carefully maintained by live birds and some mammals.…”

Section: Approaches To Measuring Heat Generation and Loss (A) Direct mentioning

confidence: 99%

Thermal substitution and aerobic efficiency: measuring and predicting effects of heat balance on endotherm diving energetics

Lovvorn

2007

Phil. Trans. R. Soc. B

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For diving endotherms, modelling costs of locomotion as a function of prey dispersion requires estimates of the costs of diving to different depths. One approach is to estimate the physical costs of locomotion (P mech ) with biomechanical models and to convert those estimates to chemical energy needs by an aerobic efficiency (hZP mech /Vo 2 ) based on oxygen consumption (Vo 2 ) in captive animals. Variations in h with temperature depend partly on thermal substitution, whereby heat from the inefficiency of exercising muscles or the heat increment of feeding (HIF) can substitute for thermogenesis. However, measurements of substitution have ranged from lack of detection to nearly complete use of exercise heat or HIF. This inconsistency may reflect (i) problems in methods of calculating substitution, (ii) confounding mechanisms of thermoregulatory control, or (iii) varying conditions that affect heat balance and allow substitution to be expressed. At present, understanding of how heat generation is regulated, and how heat is transported among tissues during exercise, digestion, thermal challenge and breath holding, is inadequate for predicting substitution and aerobic efficiencies without direct measurements for conditions of interest. Confirming that work rates during exercise are generally conserved, and identifying temperatures at those work rates below which shivering begins, may allow better prediction of aerobic efficiencies for ecological models.

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Use of operative temperature and standard operative temperature models in thermal biology

Cited by 187 publications

References 125 publications

Survival and arm abscission are linked to regional heterothermy in an intertidal sea star

Survival and arm abscission are linked to regional heterothermy in an intertidal sea star

Landscapes as a moderator of thermal extremes: a case study from an imperiled grouse

Thermal substitution and aerobic efficiency: measuring and predicting effects of heat balance on endotherm diving energetics

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