Maximum Metabolic Rate, Thermal Insulation and Aerobic Scope in a Small-Sized Chilean Hummingbird (Sephanoides sephanoides)

The Auk ◽  
1995 ◽  
Vol 112 (4) ◽  
pp. 1034-1036 ◽  
Author(s):  
Francisco Bozinovic
Keyword(s):  
Metabolic Rate ◽  
Thermal Insulation ◽  
Aerobic Scope ◽  
Maximum Metabolic Rate

scholarly journals Changes in body temperature influence the scaling of and aerobic scope in mammals

2006 ◽  
Vol 3 (1) ◽  
pp. 100-103 ◽  
Author(s):  
James F Gillooly ◽  
Andrew P Allen
Keyword(s):  
Body Size ◽  
Metabolic Rate ◽  
Size Dependence ◽  
Maximal Activity ◽  
Scaling Exponent ◽  
Temperature Influence ◽  
Aerobic Scope ◽  
Metabolic Scope ◽  
Single Power ◽  
Maximum Metabolic Rate

Debate on the mechanism(s) responsible for the scaling of metabolic rate with body size in mammals has focused on why the maximum metabolic rate ( ) appears to scale more steeply with body size than the basal metabolic rate (BMR). Consequently, metabolic scope, defined as /BMR, systematically increases with body size. These observations have led some to suggest that and BMR are controlled by fundamentally different processes, and to discount the generality of models that predict a single power-law scaling exponent for the size dependence of the metabolic rate. We present a model that predicts a steeper size dependence for than BMR based on the observation that changes in muscle temperature from rest to maximal activity are greater in larger mammals. Empirical data support the model's prediction. This model thus provides a potential theoretical and mechanistic link between BMR and .

scholarly journals Temperature acclimation rate of aerobic scope and feeding metabolism in fishes: implications in a thermally extreme future

2014 ◽  
Vol 281 (1794) ◽  
pp. 20141490 ◽  
Author(s):  
Erik Sandblom ◽  
Albin Gräns ◽  
Michael Axelsson ◽  
Henrik Seth
Keyword(s):  
Metabolic Rate ◽  
Time Course ◽  
Standard Metabolic Rate ◽  
Temperature Acclimation ◽  
Specific Dynamic Action ◽  
Energetic Cost ◽  
Aerobic Scope ◽  
Postprandial Metabolism ◽  
Myoxocephalus Scorpius ◽  
Maximum Metabolic Rate

Temperature acclimation may offset the increased energy expenditure (standard metabolic rate, SMR) and reduced scope for activity (aerobic scope, AS) predicted to occur with local and global warming in fishes and other ectotherms. Yet, the time course and mechanisms of this process is little understood. Acclimation dynamics of SMR, maximum metabolic rate, AS and the specific dynamic action of feeding (SDA) were determined in shorthorn sculpin ( Myoxocephalus scorpius ) after transfer from 10°C to 16°C. SMR increased in the first week by 82% reducing AS to 55% of initial values, while peak postprandial metabolism was initially greater. This meant that the estimated AS during peak SDA approached zero, constraining digestion and leaving little room for additional aerobic processes. After eight weeks at 16°C, SMR was restored, while AS and the estimated AS during peak SDA recovered partly. Collectively, this demonstrated a considerable capacity for metabolic thermal compensation, which should be better incorporated into future models on organismal responses to climate change. A mathematical model based on the empirical data suggested that phenotypes with fast acclimation rates may be favoured by natural selection as the accumulated energetic cost of a slow acclimation rate increases in a warmer future with exacerbated thermal variations.

scholarly journals Analytical methods matter too: Establishing a framework for estimating maximum metabolic rate for fishes

2021 ◽  
Author(s):  
Tanya S. Prinzing ◽  
Yangfan Zhang ◽  
Nicholas C. Wegner ◽  
Nicholas K. Dulvy
Keyword(s):  
Metabolic Rate ◽  
Analytical Methods ◽  
Maximum Metabolic Rate

scholarly journals Do method and species lifestyle affect measures of maximum metabolic rate in fishes?

2016 ◽  
Vol 90 (3) ◽  
pp. 1037-1046 ◽  
Author(s):  
S. S. Killen ◽  
T. Norin ◽  
L. G. Halsey
Keyword(s):  
Metabolic Rate ◽  
Maximum Metabolic Rate

Coastal pH variability and the eco-physiological and behavioural response of a coastal fish species in light of future ocean acidification

2021 ◽  
Author(s):  
◽  
Carla Edworthy
Keyword(s):  
South Africa ◽  
Metabolic Rate ◽  
Continuous Monitoring ◽  
Activity Level ◽  
Metabolic Rates ◽  
Feeding Rates ◽  
Aerobic Scope ◽  
Carbonate Chemistry ◽  
Near Future

Ocean acidification (OA) is a global phenomenon referring to a decrease in ocean pH and a perturbation of the seawater carbonate system due to ever-increasing atmospheric CO2 concentrations. In coastal environments, identifying the impacts of OA is complex due to the multiple contributors to pH variability by coastal processes, such as freshwater inflow, upwelling, hydrodynamic processes, and biological activity. The aim of this PhD study was to quantify the local processes occurring in a temperate coastal embayment, Algoa Bay in South Africa, that contribute to pH and carbonate chemistry variability over time (monthly and 24-hour) and space (~10 km) and examine how this variability impacts a local fish species, Diplodus capensis, also commonly known as ‘blacktail’. Algoa Bay, known for its complex oceanography, is an interesting location in which to quantify carbonate chemistry variability. To assess this variability, monitoring sites were selected to coincide with the Algoa Bay Sentinel Site long-term ecological research (LTER) and continuous monitoring (CMP) programmes. The average pH at offshore sites in the bay was 8.03 ± 0.07 and at inshore sites was 8.04 ± 0.15. High pH variability (~0.55–0.61 pH units) was recorded at both offshore (>10 m depth) and inshore sites (intertidal surf zones). Many sites in the bay, especially the atypical site at Cape Recife, exhibit higher than the average pH levels (>8.04), suggesting that pH variability may be biologically driven. This is further evidenced by high diurnal variability in pH (~0.55 pH units). Although the specific drivers of the high pH variability in Algoa Bay could not be identified, baseline carbonate chemistry conditions were identified, which is necessary information to design and interpret biological experiments. Long-term, continuous monitoring is required to improve understanding of the drivers of pH variability in understudied coastal regions, like Algoa Bay. A local fisheries species, D. capensis, was selected as a model species to assess the impacts of future OA scenarios in Algoa Bay. It was hypothesized that this temperate, coastally distributed species would be adapted to naturally variable pH conditions and thus show some tolerance to low pH, considering that they are exposed to minimum pH levels of 7.77 and fluctuations of up to 0.55 pH units. Laboratory perturbation experiments were used to expose early postflexion stage of D. capensis to a range of pH treatments that were selected based on the measured local variability (~8.0–7.7 pH), as well as future projected OA scenarios (7.6–7.2 pH). Physiological responses were estimated using intermittent flow respirometry by quantifying routine and active metabolic rates as well as relative aerobic scope at each pH treatment. The behavioural responses of the larvae were also assessed at each pH treatment, as activity levels, by measuring swimming distance and speed in video-recording experiments, as well as feeding rates. D. capensis had sufficient physiological capacity to maintain metabolic performance at pH levels as low as 7.27, as evidenced by no changes in any of the measured metabolic rates (routine metabolic rate, active metabolic rate, and relative aerobic scope) after exposure to the range of pH treatments (8.02–7.27). Feeding rates of D. capensis were similarly unaffected by pH treatment. However, it appears that subtle increases in activity level (measured by swimming distance and swimming speed experiments) occur with a decrease in pH. These changes in activity level were a consequence of a change in behaviour rather than metabolic constraints. This study concludes, however, that based on the parameters measured, there is no evidence for survival or fitness related consequences of near future OA on D. capensis. OA research is still in its infancy in South Africa, and the potential impacts of OA to local marine resources has not yet been considered in local policy and resource management strategies. Integrating field monitoring and laboratory perturbation experiments is emerging as best practice in OA research. This is the first known study on the temperate south coast of South Africa to quantify local pH variability and to use this information to evaluate the biological response of a local species using relevant local OA scenarios as treatment levels for current and near future conditions. Research on local conditions in situ and the potential impacts of future OA scenarios on socio-economically valuable species, following the model developed in this study, is necessary to provide national policy makers with relevant scientific data to inform climate change management policies for local resources.

Dual core and shell temperature regulation during sea acclimatization in Gentoo penguins (Pygoscelis papua)

1994 ◽  
Vol 266 (4) ◽  
pp. R1319-R1326 ◽  
Author(s):  
E. Dumonteil ◽  
H. Barre ◽  
J. L. Rouanet ◽  
M. Diarra ◽  
J. Bouvier
Keyword(s):  
Body Temperature ◽  
Metabolic Rate ◽  
Thermal Insulation ◽  
Cold Water ◽  
Threshold Temperature ◽  
Ambient Temperatures ◽  
Adaptation To Cold ◽  
Marine Life ◽  
Shell Temperature ◽  
Skin Temperatures

Penguins are able to maintain a high and constant body temperature despite a thermally constraining environment. Evidence for progressive adaptation to cold and marine life was sought by comparing body and peripheral skin temperatures, metabolic rate, and thermal insulation in juvenile and adult Gentoo penguins exposed to various ambient temperatures in air (from -30 to +30 degrees C) and water (3-35 degrees C). Juvenile penguins in air showed metabolic and insulative capacities comparable with those displayed by adults. Both had a lower critical temperature (LCT) close to 0 degree C. In both adults and juveniles, the intercept of the metabolic curve with the abscissa at zero metabolic rate was far below body temperature. This was accompanied by a decrease in thermal insulation below LCT, allowing the preservation of a threshold temperature in the shell. However, this shell temperature maintenance was progressively abandoned in immersed penguins as adaptation to marine life developed, probably because of its prohibitive energy cost in water. Thus adaptation to cold air and to cold water does not rely on the same kind of reactions. Both of these strategies fail to follow the classical sequence linking metabolic and insulative reactions in the cold.

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