Nasal heat and water exchange in gray seals

1987 ◽  
Vol 253 (6) ◽  
pp. R883-R889 ◽  
Author(s):  
L. P. Folkow ◽  
A. S. Blix
Keyword(s):  
Water Exchange ◽  
Ambient Air ◽  
Minute Volume ◽  
Halichoerus Grypus ◽  
Evaporative Water ◽  
Air Temperatures ◽  
Respiratory Heat Loss ◽  
Average Maximum ◽  
Lower Critical Temperature ◽  
Gray Seals

Metabolic rate (MR), expired air temperature (Tex), respiratory frequency (f), respiratory minute volume (V), and skin (Ts) and body (Tb) temperatures were recorded in three gray seals (Halichoerus grypus) at ambient air temperatures (Ta) between -40 and +20 degrees C. At Ta within the thermoneutral zone, MR averaged 3.7 W.kg-0.75, while mean V was 0.26 1.min-1.kg-0.75. At Ta below -11 degrees C [apparent lower critical temperature (Tlc)], both MR and V increased linearly with decreasing Ta. Average maximum MR (9.6 W.kg-0.75) and V (0.57 1.min-1.kg-0.75) were both recorded at Ta of -40 degrees C. Tex decreased with decreasing Ta to an average minimum value of 8 degrees C at Ta of -30 degrees C. The highest Tex recorded was 32 degrees C at Ta of +20 degrees C. At Ta of -20 degrees C, both total respiratory heat loss, with one exception, and respiratory evaporative water loss reached their lowest values. At this Ta, 66% of the heat and 80% of the water added to the inspired air were regained on expiration. We suggest that nasal heat exchange may be of considerable importance for thermal and water balance in many pinnipeds.

Physiological responses of a rodent to heliox reveal constancy of evaporative water loss under perturbing environmental conditions

2014 ◽  
Vol 307 (8) ◽  
pp. R1042-R1048 ◽  
Author(s):  
Christine Elizabeth Cooper ◽  
Philip Carew Withers
Keyword(s):  
Water Vapor ◽  
Metabolic Rate ◽  
Environmental Conditions ◽  
Water Loss ◽  
Physiological Responses ◽  
Ambient Air ◽  
Minute Volume ◽  
Evaporative Water Loss ◽  
Evidence Based ◽  
Evaporative Water

Total evaporative water loss of endotherms is assumed to be determined essentially by biophysics, at least at temperatures below thermoneutrality, with evaporative water loss determined by the water vapor deficit between the animal and the ambient air. We present here evidence, based on the first measurements of evaporative water loss for a small mammal in heliox, that mammals may have a previously unappreciated ability to maintain acute constancy of total evaporative water loss under perturbing environmental conditions. Thermoregulatory responses of ash-grey mice ( Pseudomys albocinereus) to heliox were as expected, with changes in metabolic rate, conductance, and respiratory ventilation consistent with maintaining constancy of body temperature under conditions of enhanced heat loss. However, evaporative water loss did not increase in heliox. This is despite our confirmation of the physical effect that heliox augments evaporation from nonliving surfaces, which should increase cutaneous water loss, and increases minute volume of live ash-grey mice in heliox to accommodate their elevated metabolic rate, which should increase respiratory water loss. Therefore, mice had not only a thermoregulatory but also a hygroregulatory response to heliox. We interpret these results as evidence that ash-grey mice can acutely control their evaporative water loss under perturbing environmental conditions and suggest that hygroregulation at and below thermoneutrality is an important aspect of the physiology of at least some small mammals.

Thermoregulation of juvenile grey seals, Halichoerus grypus, in air

1996 ◽  
Vol 74 (2) ◽  
pp. 201-208 ◽  
Author(s):  
Patrice Boily ◽  
David M. Lavigne
Keyword(s):  
Metabolic Rate ◽  
Core Temperature ◽  
Low Temperatures ◽  
Heat Load ◽  
Cold Water ◽  
Internal Heat ◽  
Ambient Air ◽  
Halichoerus Grypus ◽  
Metabolic Depression ◽  
Air Temperatures

Metabolic rate, core temperature, and duration of sleep-related apnea events were monitored in three juvenile grey seals (Halichoerus grypus) aged 7–19 months (49–78 kg), at ambient air temperatures ranging from −18 °C to 35 °C. At low temperatures, only one seal increased its metabolic rate (at −18 °C), whereas at high temperatures (up to 35 °C) none of the three animals increased its metabolic rate. Nonetheless, seals usually became hyperthermic when they were subjected to air temperatures of 30 °C or higher. There was no indication that the duration of sleep-related apnea was greater at higher temperatures. The sleeping metabolic rate was significantly lower (20%) than the resting level. A metabolic depression associated with sleep may be advantageous at higher temperatures, reducing the internal heat load of the animal. These results suggest that cold-water adaptations of juvenile grey seals do not interfere with their ability to cope with higher air temperatures. Also, such animals should not be directly limited in their distribution by either high or low ambient air temperatures.

The water metabolism of a small East African antelope: the dik-dik

1973 ◽  
Vol 184 (1075) ◽  
pp. 167-178 ◽  
Keyword(s):  
Respiratory Rate ◽  
Laboratory Experiments ◽  
Water Exchange ◽  
Urine Osmolality ◽  
Water Metabolism ◽  
East African ◽  
Water Losses ◽  
Evaporative Water ◽  
Air Temperatures ◽  
Cutaneous Evaporation

1. In controlled laboratory experiments, rectal temperature, cutaneous moisture evapora­tion, and respiratory rate were studied in the dik-dik. The water balance of the dik-dik was investigated when the antelope were either fully hydrated or dehydrated at the environ­mental temperature of 22 °C or at temperatures alternating between 22 °C and 40 °C at 12 h intervals. 2. Faecal, urinary and evaporative water losses were all reduced by varying degrees during dehydration at 22 °C and 22 to 40 °C. The highest urine osmolality recorded was 4318 ± 105 mosmol/kg H 2 O which occurred when the antelopes were severely dehydrated. 3. At the high air temperatures (40 to 45 °C) cutaneous evaporation measured with a non-ventilated sweat capsule was 19 g H 2 O m -2 h -1 and the respiratory rate over 360/min. Thus the respiratory tract seems to be the major avenue for dissipating excess heat in dik-dik exposed to thermal stress. Injection of adrenaline, intravenously, stimulated sweat dis­charges similar to those observed in the small gazelles, and sheep and goats. 4. The low-water exchange and an efficient kidney helps explain the ability of this small antelope to inhabit hot arid areas.

Respiration in exercising fowl. II. Respiratory water loss and heat balance

1981 ◽  
Vol 93 (1) ◽  
pp. 327-332
Author(s):  
J. H. Brackenbury ◽  
M. Gleeson ◽  
P. Avery
Keyword(s):  
Rectal Temperature ◽  
Water Loss ◽  
Heat Balance ◽  
Domestic Fowl ◽  
Metabolic Energy ◽  
Air Temperatures ◽  
Respiratory Heat Loss ◽  
All Speeds ◽  
Body Heat ◽  
Respiratory Evaporation

1. Respiratory water loss and rectal temperature were measured in domestic fowl running for 10 min on a treadmill at speeds of 1.24-4.3 km h-1 in air temperatures of 20 +/− 2 degrees C or 32 +/− 2 degrees C. 2. At given speeds the water loss at 32 +/− 2 degrees C was approximately twice that at 20 +/− 2 degrees C and the end-exercise rectal temperature was 0.5-0.8 degrees C higher. 3. At 20 +/− 2 degrees C, respiratory evaporation accounted for 10–12% of the total metabolic energy used at all speeds. At 32 +/− 2 degrees C, the fractional respiratory heat loss fell from 26.5% at 1.24 km h-1 to 17% at 3.6 km h-1. The fraction of the total metabolic energy stored as body heat rose progressively with air temperature.

Physical fitness and thermoregulatory reactions in a cold environment in men

1988 ◽  
Vol 65 (5) ◽  
pp. 1984-1989 ◽  
Author(s):  
J. H. Bittel ◽  
C. Nonotte-Varly ◽  
G. H. Livecchi-Gonnot ◽  
G. L. Savourey ◽  
A. M. Hanniquet
Keyword(s):  
Physical Fitness ◽  
Cold Stress ◽  
Heat Production ◽  
Ambient Air ◽  
Metabolic Heat Production ◽  
Adult Males ◽  
Fitness Level ◽  
Metabolic Heat ◽  
Air Temperatures ◽  
Thermoregulatory Reactions

The relationship between the physical fitness level (maximal O2 consumption, VO2max) and thermoregulatory reactions was studied in 17 adult males submitted to an acute cold exposure. Standard cold tests were performed in nude subjects, lying for 2 h in a climatic chamber at three ambient air temperatures (10, 5, and 1 degrees C). The level of physical fitness conditioned the intensity of thermoregulatory reactions to cold. For all subjects, there was a direct relationship between physical fitness and 1) metabolic heat production, 2) level of mean skin temperature (Tsk), 3) level of skin conductance, and 4) level of Tsk at the onset of shivering. The predominance of thermogenic or insulative reactions depended on the intensity of the cold stress: insulative reactions were preferential at 10 degrees C, or even at 5 degrees C, whereas colder ambient temperature (1 degree C) triggered metabolic heat production abilities, which were closely related to the subject's physical fitness level. Fit subjects have more efficient thermoregulatory abilities against cold stress than unfit subjects, certainly because of an improved sensitivity of the thermoregulatory system.

scholarly journals Direct Calculation of Thermodynamic Wet-Bulb Temperature as a Function of Pressure and Elevation

2013 ◽  
Vol 30 (8) ◽  
pp. 1757-1765 ◽  
Author(s):  
Sayed-Hossein Sadeghi ◽  
Troy R. Peters ◽  
Douglas R. Cobos ◽  
Henry W. Loescher ◽  
Colin S. Campbell
Keyword(s):  
Air Temperature ◽  
Mean Absolute Error ◽  
Direct Calculation ◽  
Ambient Air ◽  
Absolute Error ◽  
Mean Square ◽  
Air Temperatures ◽  
Order Polynomial ◽  
The Mean ◽  
Very High

Abstract A simple analytical method was developed for directly calculating the thermodynamic wet-bulb temperature from air temperature and the vapor pressure (or relative humidity) at elevations up to 4500 m above MSL was developed. This methodology was based on the fact that the wet-bulb temperature can be closely approximated by a second-order polynomial in both the positive and negative ranges in ambient air temperature. The method in this study builds upon this understanding and provides results for the negative range of air temperatures (−17° to 0°C), so that the maximum observed error in this area is equal to or smaller than −0.17°C. For temperatures ≥0°C, wet-bulb temperature accuracy was ±0.65°C, and larger errors corresponded to very high temperatures (Ta ≥ 39°C) and/or very high or low relative humidities (5% < RH < 10% or RH > 98%). The mean absolute error and the root-mean-square error were 0.15° and 0.2°C, respectively.

scholarly journals Quantitative and qualitative constraints on hind-casting the formation of multiyear lake-ice covers at Lake El'gygytgyn

2013 ◽  
Vol 9 (3) ◽  
pp. 1253-1269 ◽  
Author(s):  
M. Nolan
Keyword(s):  
Water Exchange ◽  
Sediment Cores ◽  
Ice Cover ◽  
Lake Ice ◽  
Ice Growth ◽  
Temperature Reduction ◽  
Air Temperatures ◽  
Lake El’Gygytgyn ◽  
Oxygen Conditions ◽  
Multiyear Ice

Abstract. Analysis of the 3.6 Ma, 318 m long sediment core from Lake El'gygytgyn suggests that the lake was covered by ice for millennia at a time for much of its history and therefore this paper uses a suite of existing, simple, empirical degree-day models of lake-ice growth and decay to place quantitative constraints on air temperatures needed to maintain a permanent ice cover on the lake. We also provide an overview of the modern climatological and physical processes that relate to lake-ice growth and decay as a basis for evaluating past climate and environmental conditions. Our modeling results indicate that modern annual mean air temperature would only have to be reduced by 3.3 °C ± 0.9 °C to initiate a multiyear ice cover and a temperature reduction of at least 5.5 °C ± 1.0 °C is likely needed to completely eliminate direct air–water exchange of oxygen, conditions that have been inferred at Lake El'gygytgyn from the analysis of sediment cores. Once formed, a temperature reduction of only 1–3 °C relative to modern may be all that is required to maintain multiyear ice. We also found that formation of multiyear ice covers requires that positive degree days are reduced by about half the modern mean, from about +608 to +322. A multiyear ice cover can persist even with summer temperatures sufficient for a two-month long thawing period, including a month above +4 °C. Thus, it is likely that many summer biological processes and some lake-water warming and mixing may still occur beneath multiyear ice-covers even if air–water exchange of oxygen is severely restricted.

scholarly journals EVAPORATIVE WATER AND AIR COOLERS FOR SOLAR COOLING SYSTEMS. ANALYSIS AND PERSPECTIVES

2017 ◽  
Vol 52 (5) ◽  
Author(s):  
A. Doroshenko ◽  
K. Shestopalov ◽  
I. Mladionov
Keyword(s):  
Systems Analysis ◽  
Ambient Air ◽  
Dew Point ◽  
Cooling Process ◽  
Evaporative Water ◽  
Cooling Systems ◽  
Solar Cooling ◽  
Multistage System ◽  
Process Implementation ◽  
Polymeric Structures

The concept of evaporative coolers of gases and fluids on the basis of monoblock multichannel polymeric structures is presented. Different schemes of indirect evaporative coolers, in which the natural cooling limit is the dew point of the ambient air  are discussed. In such systems the cooling temperature is lower than the wet bulb temperature of the ambient air. Special attention is paid to the recondensation of water vapor for deep evaporative cooling. It is shown that for the solution of the recondensation problem it is necessary to vary the ratio of the contacting air and water flows, particularly in each stage of the multistage system. Recommendations for the deep cooling process implementation in the evaporative coolers of gases and liquids are given.

scholarly journals Measurement report: Chemical characteristics of PM<sub>2.5</sub> during typical biomass burning season at an agricultural site of the North China Plain

2021 ◽  
Vol 21 (4) ◽  
pp. 3181-3192
Author(s):  
Linlin Liang ◽  
Guenter Engling ◽  
Chang Liu ◽  
Wanyun Xu ◽  
Xuyan Liu ◽  
...  
Keyword(s):  
Biomass Burning ◽  
Inorganic Ions ◽  
Northern China ◽  
Ambient Air ◽  
Rural Site ◽  
Biomass Combustion ◽  
Chemical Components ◽  
The North ◽  
Air Temperatures ◽  
Agricultural Site

Abstract. Biomass burning activities are ubiquitous in China, especially in northern China, where there is a large rural population and winter heating custom. Biomass burning tracers (i.e., levoglucosan, mannosan and potassium (K+)), as well as other chemical components, were quantified at a rural site (Gucheng, GC) in northern China from 15 October to 30 November, during a transition heating season, when the field burning of agricultural residue was becoming intense. The measured daily average concentrations of levoglucosan, mannosan and K+ in PM2.5 (particulate matter with aerodynamic diameters less than 2.5 µm) during this study were 0.79 ± 0.75, 0.03 ± 0.03 and 1.52 ± 0.62 µg m−3, respectively. Carbonaceous components and biomass burning tracers showed higher levels during nighttime than daytime, while secondary inorganic ions were enhanced during daytime. An episode with high levels of biomass burning tracers was encountered at the end of October 2016, with high levoglucosan at 4.37 µg m−3. Based on the comparison of chemical components during different biomass burning pollution periods, it appeared that biomass combustion can obviously elevate carbonaceous component levels, whereas there was essentially no effect on secondary inorganic aerosols in the ambient air. Moreover, the levoglucosan / mannosan ratios during different biomass burning pollution periods remained at high values (in the range of 18.3–24.9); however, the levoglucosan / K+ ratio was significantly elevated during the intensive biomass burning pollution period (1.67) when air temperatures were decreasing, which was substantially higher than in other biomass burning periods (averaged at 0.47).

Respiration in Exercising Fowl. III. Ventilation

1982 ◽  
Vol 96 (1) ◽  
pp. 315-324
Author(s):  
J. H. BRACKENBURY ◽  
M. GLEESON ◽  
P. AVERY
Keyword(s):  
Steady State ◽  
State Level ◽  
Minute Volume ◽  
Oxygen Extraction ◽  
Respiratory Pattern ◽  
Heavy Exercise ◽  
Predominant Role ◽  
Air Temperatures ◽  
Maximum Work ◽  
All Speeds

1. Minute volume (V), respiratory frequency (f) and tidal volume (VT) were continuously measured in domestic fowl running on a treadmill at speeds of 1.24–4.3 km h−1 in air temperatures of 18±2 °C and 35±2 °C. Oxygen extraction (E) was estimated using previously measured values of oxygen consumption. 2. At 18±2 °C V, f and VT rose abruptly at the start of exercise and V and f continued to rise except at the slower running speeds. V and f continued to rise throughout exercise at all speeds in the heat-stressed birds. In both groups VT reached a maximum at the start of exercise then fell to a new steady-state level. Steady-state V, f and VT increased with exercise speed at 18±2 °C. At 35–37 °C steady-state V and VT increased with speed but f changed relatively little. 3. E remained close to resting (0.21) at low speeds in room temperatures but decreased to 0.17 at 4.3 km h−1. In contrast E rose from 0.05 at rest in heat-stressed birds to 0.14 at 3.6 km h−1. The changes in oxygen extraction and respiratory pattern in the two groups during exercise are discussed in connexion with the control of ventilation by thermal and non-thermal factors. It is suggested that the latter play a predominant role during heavy exercise and that this accounts for the convergence of respiratory patterns in both heat-stressed and non heat-stressed birds at maximum work rates.

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