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.

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.

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.

Respiratory Exchange and Evaporative Water Loss in the Flying Budgerigar

1968 ◽  
Vol 48 (1) ◽  
pp. 67-87 ◽  
Author(s):  
VANCE A. TUCKER
Keyword(s):  
Carbon Dioxide ◽  
Oxygen Consumption ◽  
Respiratory Rate ◽  
Water Loss ◽  
Beat Frequency ◽  
Evaporative Water Loss ◽  
Wing Beat ◽  
Evaporative Water ◽  
Wing Beat Frequency ◽  
Level Flight

1. Oxygen consumption of 2 budgerigars (Melopsittacus undulatus) was measured during level, ascending and descending nights lasting 5-20 min. in a wind-tunnel at speeds between 19 and 48 km./hr. In level flight oxygen consumption was lowest at 35 km./hr. with a mean value of 21.9 ml. (g. hr.)-1 or 12.8 times the standard value calculated for these birds (weight = 35 g.). At a given speed oxygen consumption was highest for ascending flight and lowest for descending flight. 2. Carbon dioxide production was measured on one bird flying level at 35 km./hr.for 20 min. The ratio of carbon dioxide production to oxygen consumption was 0.780, indicating that the bird was oxidizing primarily fat. 3. The efficiencies of level, ascending and descending flight are discussed. The measurements indicate that for the budgerigar 42 km./hr. is the most economical speed for covering distance, and below 27 km./hr. undulating flight is more economical than flight at a constant altitude. 4. Evaporative water loss in level flight was measured in two birds for 20 min. at 35 km./hr. at temperatures of 18-200 and 29-31° C. At 36-37° C. the birds became overheated and would not fly for as long as 20 min. Evaporative water loss at 18-20° C. was 20.4 mg. (g. hr.)-1. It increased to 63.9 mg. (g. hr.)-1 at 36-37° C. After accounting for metabolic water production and faecal water loss, budgerigars flying at 18-20°C. had a net water loss of 11 mg. (g. hr.)-1. At this temperature 15% of the estimated heat production in flight was lost by evaporation of water, while 47% was lost by evaporation of water at 36-37°C. 5. Lung ventilation, tidal volume and partial pressure of carbon dioxide in expired air were estimated for flying budgerigars from evaporative water-loss data. In level flight at 18-20° C and 35 km./hr. these quantities had values of 398 ml. (g. hr.)-1, 0.033 ml. (g- breath)-1 and 37 mm. Hg. respectively. 6. Respiratory rate in level flight was measured in 2 birds at speeds between 19 and 48 km./hr. Respiratory rate depended on speed and was lowest at 35 km./hr. Since wing-beat frequency was constant at 840 beats/min. at all speeds, respiratory rate and wing-beat frequency were not synchronized. Published data and analysis of dimensional relations of birds suggest that in birds the size of a budgerigar or smaller a respiratory rate equal to the wing-beat frequency would be too high for efficient ventilation of the lungs. Birds the size of a pigeon or larger probably have synchronous wing beats and respirations.

Transient Analysis of Microorganism Temperature and Evaporative Losses in an Algae Biofilm Photobioreactor

2011 ◽  
Author(s):  
Thomas E. Murphy ◽  
Halil Berberoglu
Keyword(s):  
Ambient Temperature ◽  
Water Loss ◽  
High Surface ◽  
Volume Ratio ◽  
Ambient Air ◽  
Evaporative Water Loss ◽  
Environmental Data ◽  
Biofuel Production ◽  
Solar Irradiation ◽  
Evaporative Water

This study describes the thermal modeling of a novel algal biofilm photobioreactor aimed at cultivating algae for biofuel production. The thermal model is developed to assess the photo-bioreactor’s thermal profile and evaporative water loss rate for a range of environmental parameters, including relative humidity, ambient air temperature, solar irradiation, and wind speed. First, a 24 hour simulation of the system has been performed using environmental data for Memphis, TN, USA on a typical spring day to assess the diurnal variations in system performance. Then, a sensitivity analysis is performed to assess the effect of each environmental parameter on the temperature and evaporative losses of the photobioreactor. It is observed that because of the high surface area-to-volume ratio of the system, the temperature of the system exceeds that of the maximum ambient temperature during daylight hours by approximately 0.5 °C and is lower than the minimum ambient temperature at night by approximately 1.4 °C because of evaporative and radiative cooling. Furthermore, without active cooling, the characteristic evaporative water loss from the system is approximately 4.8 L/m2-day.

scholarly journals Can birds do it too? Evidence for convergence in evaporative water loss regulation for birds and mammals

2017 ◽  
Vol 284 (1867) ◽  
pp. 20171478 ◽  
Author(s):  
E. C. Eto ◽  
P. C. Withers ◽  
C. E. Cooper
Keyword(s):  
Water Vapour ◽  
Water Loss ◽  
Vapour Pressure ◽  
Vapour Pressure Deficit ◽  
Ambient Air ◽  
Evaporative Water Loss ◽  
Water Vapour Pressure ◽  
Evaporative Heat Loss ◽  
Evaporative Water ◽  
Water Vapour Pressure Deficit

Birds have many physiological characteristics that are convergent with mammals. In the light of recent evidence that mammals can maintain a constant insensible evaporative water loss (EWL) over a range of perturbing environmental conditions, we hypothesized that birds might also regulate insensible EWL, reflecting this convergence. We found that budgerigars ( Melopsittacus undulatus ) maintain EWL constant over a range of relative humidities at three ambient temperatures. EWL, expressed as a function of water vapour pressure deficit, differed from a physical model where the water vapour pressure deficit between the animal and the ambient air is the driver of evaporation, indicating physiological control of EWL. Regulating EWL avoids thermoregulatory impacts of varied evaporative heat loss; changes in relative humidity had no effect on body temperature, metabolic rate or thermal conductance. Our findings that a small bird can regulate EWL are evidence that this is a common feature of convergently endothermic birds and mammals, and may therefore be a fundamental characteristic of endothermy.

Temperature Fluctuation and Evaporative Loss Rate in an Algae Biofilm Photobioreactor

2011 ◽  
Vol 134 (1) ◽  
Author(s):  
Thomas E. Murphy ◽  
Halil Berberoğlu
Keyword(s):  
Water Loss ◽  
Loss Rate ◽  
Environmental Parameters ◽  
Ambient Air ◽  
Evaporative Water Loss ◽  
Environmental Data ◽  
Biofuel Production ◽  
Solar Irradiation ◽  
Evaporative Water ◽  
Evaporative Loss

This study describes the thermal modeling of a novel algal biofilm photobioreactor aimed at cultivating algae for biofuel production. The thermal model is developed to assess the photobioreactor’s thermal profile and evaporative water loss rate for a range of environmental parameters, including ambient air temperature, solar irradiation, relative humidity, and wind speed. First, a week-long simulation of the system has been performed using environmental data for Memphis, TN, on a typical week during the spring, summer, fall, and winter. Then, a sensitivity analysis was performed to assess the effect of each weather parameter on the temperature and evaporative loss rate of the photobioreactor. The range of the daily algae temperature variation was observed to be 12.2  °C, 13.2 °C, 11.7 °C, and 8.2 °C in the spring, summer, fall, and winter, respectively. Furthermore, without active cooling, the characteristic evaporative water loss from the system is approximately 6.0 L/m2 day, 7.3 L/m2 day, 3.4 L/m2 day, and 1.0 L/m2 day in the spring, summer, fall, and winter, respectively.

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