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.

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.

THE INFLUENCE OF ENVIRONMENTAL TEMPERATURE ON THYROID, ADRENAL, AND WATER METABOLISM IN THE NEWBORN HUMAN INFANT

PEDIATRICS ◽  
1966 ◽  
Vol 37 (4) ◽  
pp. 583-591
Author(s):  
D. A. Fisher ◽  
T. H. Oddie ◽  
E. J. Makoski
Keyword(s):  
Creatinine Clearance ◽  
Methylene Chloride ◽  
Caloric Intake ◽  
Urine Osmolality ◽  
Ambient Air ◽  
Human Infant ◽  
Water Metabolism ◽  
Term Infants ◽  
Air Temperatures ◽  
Tsh Secretion

Measurements of fluid and caloric intake, urine output, urine osmolality, creatinine clearance, weight change, 48-hour PBI and thyroid radioiodine clearance, 4-hour hematocrit increment, and 12-hour urinary 17-OH-CS excretion have been conducted in newborn term infants exposed to relatively cold ambient temperature (23-29°C) and contrasted with values in infants incubated at ambient air temperatures of 31-40°C during the first 36-48 hours of life. Deep rectal and skin temperatures were consistently lower in the infants in the cooler environment. Non-incubated infants showed significantly higher PB! values and higher thyroid radioiodine clearance at 48 hours than did the incubated infants, suggesting that the usual feedback suppression of TSH secretion is inoperative in the infants in the colder environment. These observations are in agreement with the hypothesis that the neonatal hyperthyroid state is the result of thermal receptor stimulation of TSH secretion by the relatively cold extrauterine environment. The cooler non-incubated infants showed significantly greater urine volumes with significantly lower (urine) osmolality than did the incubated infants. Mean osmolal and creatinine clearance were similar in the two groups of infants. Although this cold induced water diuresis seems most likely due to a larger fluid intake in the non-incubated infants in response to a greater metabolic rate, the observation of similar non-renal water metabolism in cold and warm infants suggests the possibility of a primary "cold diuresis" similar to that observed during acute cold exposure in adults. A significantly greater increment in hematocrit was observed during the first 4 hours in the colder infants. The mechanism of this response, presumably due to a displacement of plasma volume from the vascular compartment, remains to be defined. Urinary methylene chloride extractable 17-OH-CS excretion was similar in the cold exposed and the incubated infants.

Sweating in cattle. II. Cutaneous evaporative loss measured from limited areas and its relationship with skin, rectal, and air temperatures

1959 ◽  
Vol 52 (1) ◽  
pp. 50-61 ◽  
Author(s):  
G. C. Taneja
Keyword(s):  
Skin Temperature ◽  
Air Temperature ◽  
Rectal Temperature ◽  
Water Losses ◽  
Air Temperatures ◽  
Evaporative Loss ◽  
Cutaneous Evaporation ◽  
The University ◽  
Skin Temperatures

1. Three female calves (Shorthorn, Zebux Australian Illawara Shorthorn, and American Brahman) of about 7–8 months old were exposed to different combinations of wet- and dry-bulb temperatures in the psychrometric chamber at the Physiology Department of the University of Queensland.2. A capsule method has been developed for measurement of cutaneous evaporation from limited areas. This method has been described in detail.3. Cutaneous evaporation from the shoulder area of the Zebu cross was significantly higher than that of the Shorthorn. There was, however, no difference between the two animals in their cutaneous evaporation from the belly area.4. In the Zebu cross the cutaneous water losses from the shoulder area, on the average, increased linearly with increase in skin temperature. In the Shorthorn, there was no important increase in the cutaneous evaporation from the shoulder area, although the skin temperature increased by about 2–3/ F.5. The Zebu cross had lower skin temperatures of the shoulder area when compared with that of the Shorthorn. These lower skin temperatures were associated with higher cutaneous evaporation.6. Increase in rectal temperature was not accompanied by increase in cutaneous evaporation in all the three animals studied.7. In all the three calves the cutaneous evaporation increased with increase in air temperature.

Thermoregulation in mule deer and elk

1984 ◽  
Vol 62 (7) ◽  
pp. 1409-1422 ◽  
Author(s):  
Katherine L. Parker ◽  
Charles T. Robbins
Keyword(s):  
Respiratory Rate ◽  
Air Temperature ◽  
Cervus Elaphus ◽  
Heat Dissipation ◽  
Mule Deer ◽  
Incident Radiation ◽  
Air Temperatures ◽  
Primary Means ◽  
Cutaneous Evaporation ◽  
Operative Temperatures

Thermoregulatory responses of mule deer (Odocoileus hemionus hemionus) and elk (Cervus elaphus nelsoni) were analyzed for air temperatures outdoors between 2 and 34 °C in summer and −38 and +24 °C in winter. Body temperatures differed between species, seasons, and ages. Surface skin temperatures varied with air temperature, incident radiation, and seasonal pelage. Respiratory rate and water loss increased exponentially while exhaled air temperatures varied sigmoidally as air temperature increased. Expired air volume increased logarithmically with increasing respiratory rate. Cutaneous evaporation (grams per square metre per hour) in summer was significantly greater in elk than in mule deer, which used panting as the primary means of heat dissipation in hot environments. Nonevaporative respiratory heat loss varied parabolically as a function of air temperature in both species. Thermally critical environments for mule deer occurred at operative temperatures of less than −20 °C and greater than 5 °C in winter and greater than 25 °C in summer. Energy expenditures increased for elk at operative temperatures below −20 °C and above +20 °C in winter, with metabolic rates decreasing between 10 and −20 °C. Maximum thermal resistances for mule deer and elk in winter were 1400 and 2000 s/m, respectively, compared with 600 and 400 s/m in summer.

The effect of the dietary plane upon the reactions of two breeds of sheep during short exposures to hot environments

1950 ◽  
Vol 1 (2) ◽  
pp. 217 ◽  
Author(s):  
RF Riek ◽  
MH Hardy ◽  
DHK Lee ◽  
HB Carter
Keyword(s):  
Respiratory Rate ◽  
Air Temperature ◽  
Rectal Temperature ◽  
Vapour Pressure ◽  
Experimental Period ◽  
Water Losses ◽  
Evaporative Water ◽  
Respiratory Volume ◽  
Average Maximum ◽  
C 30

Five Camden Park Merino and six Corriedale ewes, each breed divided into three groups and offered the food corresponding respectively to high, medium, and low dietary levels, were exposed for seven hours a day, one to three days a week, to each of several selected hot atmospheres over a range of temperatures 30 to 45°C, and a range of vapour pressures 15 to 40 mm.Hg. Observations were made on the rectal temperature, pulse rate, respiratory rate, respiratory volume, evaporative water loss, food and water consumption, body weight, and behaviour. These sheep were relatively tolerant of the hot conditions, only the highplane Corriedales having to be removed before the completion of the seven hours' exposure from the atmosphere 40°C./40 mm.Hg., with a rectal temperature over 107° F. A sharp rise in respiratory rate followed commencement of the exposure, the rate in the Merino being the higher under all hot conditions above the mildest (300 °C./30 mm.Hg.). The average maximum rates obtained for four sheep were 370/min. for the Merinos and 290/min. for the Corriedales. Pulse rates showed little change from normal rates of 60-65min. until air temperate or humidity reached high levels. The rise in vapour pressure at an air temperature of 40°C., which produced the same effect as a rise of 1°C. in air temperature at a vapour pressure of 30 mm.Hg., was 0.25 mm.Hg. for rectal temperature, 1.7 mm.Hg. for respiratory rate, and 2.3 mm.Hg. for respiratory volume. A high-plane diet reduced the heat tolerance of sheep, and heavy individuals actually lost weight during the experimental period. A very low diet, on the other hand, also impaired heat regulation, probably as part of a general depression of function. Sheep on a medium-plane diet fared best. It is difficult to account for observed water losses under hot conditions unless sweating is admitted.

Inhibiting ventilatory evaporation produces an adaptive increase in cutaneous evaporation in mourning doves Zenaida macroura

1999 ◽  
Vol 202 (21) ◽  
pp. 3021-3028 ◽  
Author(s):  
T.C. Hoffman ◽  
G.E. Walsberg
Keyword(s):  
Skin Surface ◽  
The Body ◽  
Evaporative Heat Loss ◽  
Evaporative Water ◽  
Zenaida Macroura ◽  
Ambient Temperatures ◽  
Rapid Adjustment ◽  
Mourning Doves ◽  
A Minor ◽  
Cutaneous Evaporation

We tested the hypothesis that birds can rapidly change the conductance of water vapor at the skin surface in response to a changing need for evaporative heat loss. Mourning doves (Zenaida macroura) were placed in a two-compartment chamber separating the head from the rest of the body. The rate of cutaneous evaporation was measured in response to dry ventilatory inflow at three ambient temperatures and in response to vapor-saturated ventilatory inflow at two ambient temperatures. At 35 degrees C, cutaneous evaporation increased by 72 % when evaporative water loss from the mouth was prevented, but no increase was observed at 45 degrees C. For both dry and vapor-saturated treatments, cutaneous evaporation increased significantly with increased ambient temperature. Changes in skin temperature made only a minor contribution to any observed increase in cutaneous evaporation. This indicates that Z. macroura can effect rapid adjustment of evaporative conductance at the skin in response to acute change in thermoregulatory demand.

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 The ship of the desert. The dromedary camel (Camelus dromedarius), a domesticated animal species well adapted to extreme conditions of aridness and heat

Rangifer ◽  
1990 ◽  
Vol 10 (3) ◽  
pp. 231 ◽  
Author(s):  
S. Bornstein
Keyword(s):  
Animal Species ◽  
Physiological Adaptation ◽  
Dromedary Camel ◽  
Large Animal ◽  
Water Losses ◽  
Evaporative Water ◽  
Ambient Temperatures ◽  
Adaptive Mechanisms ◽  
Adaptation To Heat ◽  
Arabian Camel

The dromedary camel (Camel dromedarius) is extremely well adapted to life in hot and arid lands. In terms of physiological adaptation to heat and water deprivation it surpasses by far every other large animal of which data have been collected. None of the adaptive mechanisms to cope with the environmental stresses are unique to the Arabian camel, but the efficiency of its adaptation is superior. At high ambient temperatures the camels adapt to the scarcity of water by reducing their faecal, urinary and evaporative water losses. During dehydration, the kidneys reduce water losses both by decreasing the glomerual filtration rate and by increasing the tubular reabsorption of water. Also their ability of regulating their body temperature from 34.5-40.7 °C conserves a lot of water, when most needed.

scholarly journals Variability of the water availability in a river lake system – A case study of Lake Symsar

2016 ◽  
Vol 31 (1) ◽  
pp. 87-96 ◽  
Author(s):  
Angela B. Kuriata-Potasznik ◽  
Sławomir Szymczyk
Keyword(s):  
Climate Change ◽  
Water Availability ◽  
Water Retention ◽  
Water Exchange ◽  
Water Losses ◽  
Local Conditions ◽  
Local Climate ◽  
Lake System ◽  
Catchment Areas ◽  
The Impact

AbstractIt is predicted that climate change will result in the diminution of water resources available both on global and regional scales. Local climate change is harder to observe and therefore, while counteracting its effects, it seems advisable to undertake studies on pertinent regional and local conditions. In this research, our aim was to assess the impact of a river and its catchment on fluctuations in the water availability in a natural lake which belongs to a post-glacial river and lake system. River and lake systems behave most often like a single interacting hydrological unit, and the intensity of water exchange in these systems is quite high, which may cause temporary water losses. This study showed that water in the analyzed river and lake system was exchanged approx. every 66 days, which resulted from the total (horizontal and vertical) water exchange. Also, the management of a catchment area seems to play a crucial role in the local water availability, as demonstrated by this research, where water retention was favoured by wooded and marshy areas. More intensive water retention was observed in a catchment dominated by forests, pastures and wetlands. Wasteland and large differences in the land elevation in the tested catchment are unfavourable to water retention because they intensify soil evaporation and accelerate the water run-off outside of the catchment. Among the actions which should be undertaken in order to counteract water deficiencies in catchment areas, rational use and management of the land resources in the catchment are most often mentioned.

Germination strategy of the East African savanna tree Acacia tortilis

2005 ◽  
Vol 21 (5) ◽  
pp. 509-517 ◽  
Author(s):  
Paul E. Loth ◽  
Willem F. de Boer ◽  
Ignas M. A. Heitkönig ◽  
Herbert H. T. Prins
Keyword(s):  
National Park ◽  
Laboratory Experiments ◽  
Perennial Grass ◽  
Soil Surface ◽  
Bare Soil ◽  
Acacia Tortilis ◽  
East African ◽  
Tree Canopies ◽  
Arable Fields ◽  
Germination Success

Germination of Acacia tortilis seeds strongly depends on micro-site conditions. In Lake Manyara National Park, Tanzania, Acacia tortilis occurs abundantly in recently abandoned arable fields and in elephant-mediated gaps in acacia woodland, but does not regenerate in grass swards or beneath canopies. We examined the germination of Acacia tortilis using field and laboratory experiments. Seeds placed on top of the soil rarely germinated, while seeds covered with elephant dung or buried under the soil surface had a germination success between 23–43%. On bare soil 39% of both the dung-covered and buried seeds germinated, in perennial grass swards 24–43%, and under tree canopies 10–24% respectively. In laboratory experiments, seed water absorption correlated positively with temperature up to 41 °C, while subsequent germination was optimal at lower (21–23 °C) temperatures. Seeds that had absorbed water lost their viability when kept above 35.5 °C. The absence of light did not significantly influence germination success. Acacia tortilis does not actively disperse its seeds, but regeneration outside tree canopies was substantial. The regeneration potential thus strongly depends on the physiognomy of the vegetation.

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