scholarly journals Modeling the physiology of the aquatic temnospondyl <i>Archegosaurus decheni</i> from the early Permian of Germany

Fossil Record ◽  
2017 ◽  
Vol 20 (2) ◽  
pp. 105-127 ◽  
Author(s):  
Florian Witzmann ◽  
Elizabeth Brainerd
Keyword(s):  
Metabolic Rate ◽  
Body Length ◽  
Lung Ventilation ◽  
Standard Metabolic Rate ◽  
Nitrogen Excretion ◽  
Early Permian ◽  
O2 Uptake ◽  
Energy Demands ◽  
Interspecific Allometry ◽  
Tropical Freshwater

Abstract. Physiological aspects like heat balance, gas exchange, osmoregulation, and digestion of the early Permian aquatic temnospondyl Archegosaurus decheni, which lived in a tropical freshwater lake, are assessed based on osteological correlates of physiologically relevant soft-tissue organs and by physiological estimations analogous to air-breathing fishes. Body mass (M) of an adult Archegosaurus with an overall body length of more than 1 m is estimated as 7 kg using graphic double integration. Standard metabolic rate (SMR) at 20 °C (12 kJ h−1) and active metabolic rate (AMR) at 25 °C (47 kJ h−1) were estimated according to the interspecific allometry of metabolic rate (measured as oxygen consumption) of all fish (VO2 = 4. 8 M0. 88) and form the basis for most of the subsequent estimations. Archegosaurus is interpreted as a facultative air breather that got O2 from the internal gills at rest in well-aerated water but relied on its lungs for O2 uptake in times of activity and hypoxia. The bulk of CO2 was always eliminated via the gills. Our estimations suggest that if Archegosaurus did not have gills and released 100 % CO2 from its lungs, it would have to breathe much more frequently to release enough CO2 relative to the lung ventilation required for just O2 uptake. Estimations of absorption and assimilation in the digestive tract of Archegosaurus suggest that an adult had to eat about six middle-sized specimens of the acanthodian fish Acanthodes (ca. 8 cm body length) per day to meet its energy demands. Archegosaurus is regarded as an ammonotelic animal that excreted ammonia (NH3) directly to the water through the gills and the skin, and these diffusional routes dominated nitrogen excretion by the kidneys as urine. Osmotic influx of water through the gills had to be compensated for by production of dilute, hypoosmotic urine by the kidneys. Whereas Archegosaurus has long been regarded as a salamander-like animal, there is evidence that its physiology was more fish- than tetrapod-like in many respects.

Respiration in relation to ion uptake in the crayfish Austropotamobius pallipes (Lereboullet)

1975 ◽  
Vol 63 (3) ◽  
pp. 689-699
Author(s):  
D. W. Sutcliffe ◽  
T. R. Carrick
Keyword(s):  
Metabolic Rate ◽  
Ion Transport ◽  
Standard Metabolic Rate ◽  
Ion Uptake ◽  
Energetic Cost ◽  
O2 Uptake ◽  
Thermodynamic Work ◽  
Salt Depletion ◽  
The Mean ◽  
Free Media

1. O2 uptake was determined for periods of 23–46 h in salt-depleted crayfish held in deionized water (DW) or Na-free media at 10 degrees C. These media were replaced by artificial lakewater media (ALW) containing 0-2-0-6 mM Na and O2 uptake was again determined for periods of 24–66 h. 2. During net ion uptake in ALW the metabolic rate was either elevated or depressed. Standard metabolism in ALW altered by amounts equivalent to 0-1 - 15–5% (mean 6-4 (15) +/− 4–4% S. D.) of the metabolic rate measured during salt-depletion. On three occasions the metabolic rate was elevated by 22-0 - 66–7%, but some of this increase may have been due to locomotor activity. 3. The calculated values for thermodynamic work involved in ion transport were 0–056 - 0–268 J/10 g. h at 10 degrees C, or 1-5 - 7-2% of the mean standard metabolic rate. Most of the observed changes in metabolic rate lie within the limits of experimental error (ca. +/− 7%). Hence the energetic cost of ion transport is too small for direct measurement in intact crayfish.

Foliage of Eucalyptus-Punctata and the Maintenance Nitrogen Requirements of Koalas, Phascolarctos-Cinereus

1986 ◽  
Vol 34 (1) ◽  
pp. 17 ◽  
Author(s):  
SJ Cork
Keyword(s):  
Metabolic Rate ◽  
Standard Metabolic Rate ◽  
Nitrogen Excretion ◽  
Staple Food ◽  
Phascolarctos Cinereus ◽  
Microbial Nitrogen ◽  
Faecal Nitrogen ◽  
Feeding Trials ◽  
Urinary Nitrogen Excretion ◽  
Urinary Nitrogen

Nitrogen metabolism and balance were investigated in captive koalas fed mature foliage of a staple food tree, Eucalyptus punctata, in six feeding trials at various times of year. Winter foliage contained less nitrogen than summer foliage but koalas compensated by eating more in winter. Thus, nitrogen balance did not differ significantly between seasons. Urinary nitrogen excretion similarly showed no seasonal trend but losses of non-dietary (i.e. endogenous and microbial) faecal nitrogen were greater in winter than in summer, presumably because of the higher food intake. Estimates of the requirements of dietary and truly digestible nitrogen for maintenance of nitrogen equilibrium (283 mg . kg-0.75 . d-� and 271 mg . kg-0.75 . d-� respectively) were comparable with several estimates for other marsupials. Although urinary nitrogen.excretion by koalas was low compared with that by other marsupials, consistent with the koala's standard metabolic rate, losses of non-dietary faecal nitrogen were relatively high. It was concluded that relatively high losses of endogenous andlor microbial nitrogen in faeces are a consequence of feeding on Eucalyptus foliage and that the koala's low standard metabolic rate is an important adaptation permitting it to utilize this diet by partly compensating for faecal nitrogen losses.

Field-Testing a Standard Metabolic Rate Estimation Technique for Eastern Red-Backed Salamanders

2016 ◽  
Vol 50 (1) ◽  
pp. 138-144
Author(s):  
Patrick J Ruhl ◽  
Robert N Chapman ◽  
John B. Dunning
Keyword(s):  
Metabolic Rate ◽  
Field Testing ◽  
Standard Metabolic Rate ◽  
Estimation Technique ◽  
Rate Estimation

Measurement of metabolic rate in hyperoxia

1981 ◽  
Vol 51 (3) ◽  
pp. 725-731 ◽  
Author(s):  
H. G. Welch ◽  
P. K. Pedersen
Keyword(s):  
Metabolic Rate ◽  
Submaximal Exercise ◽  
Co2 Production ◽  
O2 Uptake ◽  
Vo2 Max ◽  
Conventional Calculation ◽  
Mixing Chamber ◽  
Douglas Bag ◽  
Douglas Bag Method ◽  
Fick Equation

The conventional Douglas bag calculation for estimating O2 uptake (VO2) during exercise in normoxia and hyperoxia, VO2 = VE . (FIO2 . FEN2/FIN2 - FEO2), was tested against two other valid calculations: the Fick equation, VO2 = VI . FIO2 - VE . FEO2, and the equation VO2 = VI - VE - VCO2 (VE and VI are expired and inspired ventilation, respectively; FEO2 and FIO2 are expired and inspired O2 contents, respectively; FEN2 and FIN2 are expired and inspired N2 contents, respectively; and VCO2 is CO2 production.). These calculations are based on different assumptions, in part, and are affected to a varying degree of errors in volume or gas fraction measurements. With the conventional Douglas bag technique, we found evidence of an overestimate of VO2 during hyperoxia. After the introduction of a mixing chamber for sampling expired air, the means of the three methods were not significantly different. The variability among the methods was least with the conventional calculation but increased with higher O2 fractions. The average VO2 for submaximal exercise in hyperoxia was not significantly different from that of normoxia. VO2 max was significantly higher in hyperoxia. The increased variability of the Douglas bag method in hyperoxia may lead to overestimates of VO2 max unless special precautions are taken.

Intestinal capillary blood flow during metabolic hyperemia.

1979 ◽  
Vol 237 (6) ◽  
pp. E548 ◽  
Author(s):  
A P Shepherd
Keyword(s):  
Blood Flow ◽  
Metabolic Rate ◽  
Constant Pressure ◽  
Oxygen Demand ◽  
Capillary Density ◽  
Control Mechanisms ◽  
O2 Uptake ◽  
O2 Extraction ◽  
Circulatory Control ◽  
Parenchymal Cells

It has been postulated that local circulatory control mechanisms regulate the O2 flux to parenchymal cells by two vascular mechanisms: changes in blood flow that minimize capillary PO2 variations and changes in the density of the perfused capillary bed through which O2 extraction is regulated. To test this prediction, isolated loops of canine jejenum and ileum were perfused at either constant blood flow or constant pressure, and intraluminal glucose was used to increase metabolic rate. In the constant-flow series, glucose increased O2 extraction, O2 uptake, and rubidium extraction. Resistance fell when the metabolic rate was elevated. In the constant-pressure series, glucose increased blood flow, O2 extraction, O2 uptake, and capillary filtration coefficients. These results show that vascular resistance falls and that capillary density increases following an increase in oxygen demand. Thus, the glucose-stimulated gut loop seems to be a valid model of metabolic hyperemia, and its behavior would be difficult to reconcile with a purely myogenic theory of intestinal blood flow autoregulation.

scholarly journals Multigenerational exposure to elevated temperatures leads to a reduction in standard metabolic rate in the wild

2020 ◽  
Vol 34 (6) ◽  
pp. 1205-1214 ◽  
Author(s):  
Natalie Pilakouta ◽  
Shaun S. Killen ◽  
Bjarni K. Kristjánsson ◽  
Skúli Skúlason ◽  
Jan Lindström ◽  
...  
Keyword(s):  
Metabolic Rate ◽  
Elevated Temperatures ◽  
Standard Metabolic Rate ◽  
In The Wild

Energy expenditure for thermoregulation and locomotion in emperor penguins

1976 ◽  
Vol 231 (3) ◽  
pp. 903-912 ◽  
Author(s):  
B Pinshow ◽  
MA Fedak ◽  
DR Battles ◽  
K Schmidt-Nielsen
Keyword(s):  
Metabolic Rate ◽  
Energy Requirement ◽  
Thermal Conductance ◽  
Standard Metabolic Rate ◽  
High Energy ◽  
Breeding Cycle ◽  
Emperor Penguin ◽  
Energy Reserves ◽  
Ambient Temperatures ◽  
Emperor Penguins

During the antarctic winter emperor penguins (Aptenodytes forsteri) spend up to four mo fasting while they breed at rookeries 80 km or more from the sea, huddling close together in the cold. This breeding cycle makes exceptional demands on their energy reserves, and we therefore studied their thermoregulation and locomotion. Rates of metabolism were measured in five birds (mean body mass, 23.37 kg) at ambient temperatures ranging from 25 to -47 degrees C. Between 20 and -10 degrees C the metabolic rate (standard metabolic rate (SMR)) remained neraly constant, about 42.9 W. Below -10 degrees C metabolic rate increased lineraly with decreasing ambient temperature and at -47 degrees C it was 70% above the SMR. Mean thermal conductance below -10 degrees C was 1.57 W m-2 degrees C-1. Metabolic rate during treadmill walking increased linearly with increasing speed. Our data suggest that walking 200 km (from the sea to the rookery and back) requires less than 15% of the energy reserves of a breeding male emperor penguin initially weighing 35 kg. The high energy requirement for thermoregulation (about 85%) would, in the absence of huddling, probably exceed the total energy reserves.

Mitochondrial Proton Conductance, Standard Metabolic Rate and Metabolic Depression

2000 ◽  
pp. 413-430 ◽  
Author(s):  
Martin D. Brand ◽  
Tammie Bishop ◽  
Robert G. Boutilier ◽  
Julie St-Pierre
Keyword(s):  
Metabolic Rate ◽  
Standard Metabolic Rate ◽  
Metabolic Depression ◽  
Proton Conductance

scholarly journals Aerobic capacity influences the spatial position of individuals within fish schools

2011 ◽  
Vol 279 (1727) ◽  
pp. 357-364 ◽  
Author(s):  
Shaun S. Killen ◽  
Stefano Marras ◽  
John F. Steffensen ◽  
David J. McKenzie
Keyword(s):  
Metabolic Rate ◽  
Aerobic Capacity ◽  
Leading Edge ◽  
Standard Metabolic Rate ◽  
Fish Schools ◽  
Liza Aurata ◽  
Schooling Behaviour ◽  
In The Wild ◽  
Focal Fish ◽  
Spatial Positioning

The schooling behaviour of fish is of great biological importance, playing a crucial role in the foraging and predator avoidance of numerous species. The extent to which physiological performance traits affect the spatial positioning of individual fish within schools is completely unknown. Schools of juvenile mullet Liza aurata were filmed at three swim speeds in a swim tunnel, with one focal fish from each school then also measured for standard metabolic rate (SMR), maximal metabolic rate (MMR), aerobic scope (AS) and maximum aerobic swim speed. At faster speeds, fish with lower MMR and AS swam near the rear of schools. These trailing fish required fewer tail beats to swim at the same speed as individuals at the front of schools, indicating that posterior positions provide hydrodynamic benefits that reduce swimming costs. Conversely, fish with high aerobic capacity can withstand increased drag at the leading edge of schools, where they could maximize food intake while possibly retaining sufficient AS for other physiological functions. SMR was never related to position, suggesting that high maintenance costs do not necessarily motivate individuals to occupy frontal positions. In the wild, shifting of individuals to optimal spatial positions during changing conditions could influence structure or movement of entire schools.

Aspects of the Use of Den Trees by Arboreal and Scansorial Marsupials Inhabiting Montane Ash Forests in Victoria

1991 ◽  
Vol 39 (1) ◽  
pp. 57 ◽  
Author(s):  
DB Lindenmayer ◽  
RB Cunningham ◽  
MT Tanton ◽  
HA Nix
Keyword(s):  
Metabolic Rate ◽  
Standard Metabolic Rate ◽  
The Body ◽  
Large Species ◽  
Strongly Correlated ◽  
Emergence Time ◽  
Significant Preference ◽  
Field Metabolic Rate ◽  
Arboreal Marsupials ◽  
Selection Of

The time and height of emergence from den trees occupied by various species of arboreal marsupials inhabiting the montane ash forests of the Central Highlands of Victoria, in south-east Australia, were recorded from September 1988 to January 1989. There were significant differences in emergence time among most species of arboreal marsupials. Emergence time was strongly correlated with published values of body weight, field metabolic rate and standard metabolic rate. The entrance to the nest was higher in gliding species than those which are non-volant. Small species exhibited a significant preference for den sites with a hole as the entrance. The entrance of a den occupied by large species was typically a hole in a hollow branch or spout. The selection of den sites was related to the body size of the occupant. Differences in the type and height of the entrance to the nest, together with the time of emergence from the den, indicate partitioning of the nest tree resource between the various species inhabiting montane ash forests.

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