Measurement of evaporative water loss in small animals by dew-point hygrometry

1977 ◽  
Vol 43 (2) ◽  
pp. 382-385 ◽  
Author(s):  
M. H. Bernstein ◽  
D. M. Hudson ◽  
J. M. Stearns ◽  
R. W. Hoyt
Keyword(s):  
Water Vapor ◽  
Water Loss ◽  
Water Vapor Pressure ◽  
Columba Livia ◽  
Evaporative Water Loss ◽  
Dew Point ◽  
Small Animals ◽  
Evaporative Water ◽  
Open Flow ◽  
Two Temperatures

This paper presents the procedures and equations to be utilized for measurement of evaporative water loss (mw), by use of the dew-point hygrometer, in small animals exposed to air containing water vapor in an open-flow system. The system accounted accurately for the water evaporated from a bubble flask. In addition, hygrometric measurements of pulmocutaneous mw in pigeons (Columba livia, mean mass 0.31 kg) agreed closely with simultaneous gravimetric measurements, utilizing a desiccant in the sample stream, in a manner independently of air temperature (Ta, 20 or 40 degrees C), ambient water vapor pressure (PW, 4–16 10(2) Pa), or mw (5–66 mg-min-1). Evaporation in pigeons was independent of PW at 20 degrees C, but increased with decreasing PW at 40 degrees C, suggesting differences in ventilatory adjustments to changes in PW at the two temperatures.

Dew-point hygrometry system for measurement of evaporative water loss in infants

1997 ◽  
Vol 82 (3) ◽  
pp. 1008-1017 ◽  
Author(s):  
Ronald L. Ariagno ◽  
Steven F. Glotzbach ◽  
Roger B. Baldwin ◽  
David M. Rector ◽  
Susan M. Bowley ◽  
...  
Keyword(s):  
Water Loss ◽  
Water Vapor Pressure ◽  
Skin Surface ◽  
Term Infant ◽  
Evaporative Water Loss ◽  
Dew Point ◽  
Ambient Conditions ◽  
Evaporative Water ◽  
Clinical Investigations ◽  
Vapor Pressure Gradient

Ariagno, Ronald L., Steven F. Glotzbach, Roger B. Baldwin, David M. Rector, Susan M. Bowley, and Robert J. Moffat.Dew-point hygrometry system for measurement of evaporative water loss in infants. J. Appl. Physiol.82(3): 1008–1017, 1997.—Evaporation of water from the skin is an important mechanism in thermal homeostasis. Resistance hygrometry, in which the water vapor pressure gradient above the skin surface is calculated, has been the measurement method of choice in the majority of pediatric investigations. However, resistance hygrometry is influenced by changes in ambient conditions such as relative humidity, surface temperature, and convection currents. We have developed a ventilated capsule method that minimized these potential sources of measurement error and that allowed second-by-second, long-term, continuous measurements of evaporative water loss in sleeping infants. Air with a controlled reference humidity (dew-point temperature = 0°C) is delivered to a small, lightweight skin capsule and mixed with the vapor on the surface of the skin. The dew point of the resulting mixture is measured by using a chilled mirror dew-point hygrometer. The system indicates leaks, is mobile, and is accurate within 2%, as determined by gravimetric calibration. Examples from a recording of a 13-wk-old full-term infant obtained by using the system give evaporative water loss rates of ∼0.02 mgH2O ⋅ cm−2 ⋅ min−1for normothermic baseline conditions and values up to 0.4 mgH2O ⋅ cm−2 ⋅ min−1 when the subject was being warmed. The system is effective for clinical investigations that require dynamic measurements of water loss.

Respiratory water loss in free-flying pigeons

2001 ◽  
Vol 204 (21) ◽  
pp. 3803-3814 ◽  
Author(s):  
Gilead Michaeli ◽  
Berry Pinshow
Keyword(s):  
Water Vapor ◽  
Air Temperature ◽  
Water Loss ◽  
Beat Frequency ◽  
Ambient Air ◽  
Columba Livia ◽  
Evaporative Water Loss ◽  
Diffusion Resistance ◽  
Breathing Frequency ◽  
Evaporative Water

SUMMARY We assessed respiratory and cutaneous water loss in trained tippler pigeons (Columba livia) both at rest and in free flight. In resting pigeons, exhaled air temperature Tex increased with ambient air temperature Ta (Tex=16.3+0.705Ta) between 15°C and 30°C, while tidal volume VT (VT=4.7±1.0 ml, mean ± s.d. at standard temperature and pressure dry) and breathing frequency fR (fR=0.46±0.06 breaths s–1) were independent of Ta. Respiratory water loss, RWL, was constant over the range of Ta (RWL=1.2±0.4 mg g–1 h–1) used. In flying pigeons, Tex increased with Ta (Tex=25.8+0.34Ta), while fR was independent of Ta (fR=5.6±1.4 breaths s–1) between 8.8°C and 27°C. Breathing frequency varied intermittently between 2 and 8 breaths s–1 during flight and was not always synchronized with wing-beat frequency. RWL was independent of air temperature (RWL=9.2±2.9 mg g–1 h–1), but decreased with increasing inspired air water vapor density (ρin) (RWL=12.5–0.362ρin), whereas cutaneous water loss, CWL, increased with air temperature (CWL=10.122+0.898Ta), but was independent of ρin. RWL was 25.7–32.2 %, while CWL was 67.8–74.3 % of the total evaporative water loss. The data indicate that pigeons have more efficient countercurrent heat exchange in their anterior respiratory passages when at rest than in flight, allowing them to recover more water at rest at lower air temperatures. When evaporative water loss increases in flight, especially at high Ta, the major component is cutaneous rather than respiratory, possibly brought about by reducing the skin water vapor diffusion resistance. Because of the tight restrictions imposed by gas exchange in flight, the amount of water potentially lost through respiration is limited.

Evaporative water loss in domestic fowls and its partition in relation to ambient temperature

1976 ◽  
Vol 87 (3) ◽  
pp. 527-532 ◽  
Author(s):  
S. A. Richards
Keyword(s):  
Ambient Temperature ◽  
Water Loss ◽  
Absolute Humidity ◽  
Evaporative Water Loss ◽  
Linear Functions ◽  
Whole Body ◽  
Water Vapour Pressure ◽  
Evaporative Water ◽  
Open Flow ◽  
Low Levels

SummaryThe rate of evaporative water loss has been studied in domestic fowls in the ambient temperature range from 0 to 40°C.Results for whole-body evaporation were similar when obtained by the open-flow and direct-weighing methods. At low levels of absolute humidity the rate increased by 0·03 mg/(g.h.°C) from 0 to 22 °C and by 0·17 mg/(g.h.°C) from 23 to 40 °C. Wholebody evaporation decreased with rising ambient water vapour pressure by 0·7 mg/(g.h.kPa).Cutaneous water loss was greater than respiratory water loss below 21 °C; it accounted for 78% of whole-body evaporation at 0 °C, falling to 25% at 40 °C.The rates of respiratory and whole-body evaporation could both be expressed as linear functions of respiratory frequency.

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.

Shell Resistance and Evaporative Water Loss from Bird Eggs: Effects of Wind Speed and Egg Size

1981 ◽  
Vol 54 (2) ◽  
pp. 195-202 ◽  
Author(s):  
James R. Spotila ◽  
Christina J. Weinheimer ◽  
Charles V. Paganelli
Keyword(s):  
Wind Speed ◽  
Water Loss ◽  
Egg Size ◽  
Evaporative Water Loss ◽  
Evaporative Water ◽  
Bird Eggs

Scaling of Evaporative Water Loss in Marsupials

1986 ◽  
Vol 59 (1) ◽  
pp. 1-9 ◽  
Author(s):  
David S. Hinds ◽  
Richard E. MacMillen
Keyword(s):  
Water Loss ◽  
Evaporative Water Loss ◽  
Evaporative Water
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