Role Of Water Temperature Research Articles

Benutting van landbouneweprodukte en gesuiwerde rioolwater in akwakultuur in ontwikkelende gebiede van Suid-Afrika

The serious shortage of potable water supplies for domestic, agricultural and industrial requirements necessitates an investigation into the optimal utilization of this scarce commodity in South Africa. The multipurpose use of water in agriculture through its effective utilization in integrated aquaculture-agriculture food production systems is one way of optimising the application of such water. In the present series of investigations, agricultural wastes such as chicken, cattle and duck manure were applied as organic nutrient in freshwaterfish ponds with and without supplementary feeds. Fish used in polyculture production for the optimal utilization of the various trophic levels in manured fishpond ecosystems included the European and Chinese carp species and the sharptooth catfish. Supplementary food consisted of 18-45% protein fish pellets. As an alternative to organic manures, treated sewage effluent with fish pellets was used to evaluate its fish-production potential. Fish species used in monoculture and polyculture production included the European common carp and the sharptooth catfish. The role of water temperature on the fish-production potential of these systems was also investigated. The possible value of integrated aquaculture-agriculture systems in protein production in rural community development in South Africa is discussed.

The role of water temperature and laundry procedures in reducing house dust mite populations and allergen content of bedding

The effects of various laundry procedures on house dust mites and their allergens have been established. All mites were killed by water temperatures 55 ° C or greater. Killing at lower temperatures was not enhanced by any of the pure detergents or laundry products tested. A cold cycle of laundry washing with or without laundry powder did not remove most live mites from bedding, however, the allergen concentration ( Der p I/gm fine dust) was reduced by more than 90%. Dry cleaning did not reduce the allergen concentration of the dust, although most, if not all, mites were killed.

Perception of drinking water temperature and effects for humans after exercise

Subjects rated the perceived temperature and hedonic values of four samples of drinking water (5°, 16°, 22°, 38°C) after exercise and on a control day. Ad lib drinking of any of the four samples was permitted for 20 minutes after exercise and intake was measured. Subjects completed questionnaires pertaining to their subjective states. Sensory thermal neutral water was found to be close to 22°C which was also judged to be affectively neutral. Subjects rated 16°C water higher on the hedonic scale after exercise than they did on a control day, despite the fact that no change in the perception of this temperature was observed. Responses to the symptoms questionnaire showed a marked effect of exercise on the perception of thirst, sweating, body warmth and dryness in the mouth. Sensations of stomach fullness could not account for the incomplete rehydration of most subjects in the time allotted. It was suggested that a rapid reduction in symptoms which initiate drinking was responsible for drinking termination. The role of water temperature in the reduction of thirst symptoms was discussed.

Influence of Water Temperature on the Electric Organ Discharge (Eod) of the Weakly Electric Fish Marcusenius Cyprinoides (Mormyridae)

1. The influence of different water temperatures on the electric organ discharge (EOD) of a mormyrid fish Marcusenius cyprinoïdes was studied. The range of the water temperatures was fixed according to the seasonal temperature variations of the rivers in Central Africa, the natural habitat of this species. 2. The EOD activity was characterized using the following parameters: mean EOD rate, EOD pattern in the form of Interpulse Interval Histograms (IIH), IIH range, and shortest pulse interval. These parameters remained constant during control experiments at constant temperature (27 degrees C) for 4 days. 3. The mean EOD rate increases with increasing water temperatures. The lowest mean EOD rate is always found at 17 degrees C, the highest between 26 and 33 degrees C. The characteristics of the IIH are modified by stepwise temperature increases. These IIH show during high temperatures (26-33 degrees C) similar patterns to those previously observed during high level motor activity and excitement. The IIH range diminishes with stepwise temperature increases. The shortest pulse interval has a negative, linear correlation with water temperature. 4. The possible role of water temperature in the reproduction of the mormyrids is discussed. The high discharge rate of M. cyprinoïdes produced by high water temperatures during the rainy season could serve to improve the resolution of the electroreceptors during this period.

Effect of water temperature on a herpesvirus infection of sea turtles

The role of water temperature in the induction and maintenance of a dermal herpesvirus infection (gray-patch disease) of young, green sea turtles (Chelonia mydas) was studied under carefully controlled experimental conditions, in which the influence of other recognized stress factors was negligible. A nimals that were subjected to a gradual temperature increase from 25 to 30 degrees C, with subsequent maintenance at 30 degrees C, and those that were abruptly shifted from water at 25 degrees C to water at 30 degrees C showed a significantly shorter period before the onset of clinical signs and an increase in the severity of the lesions when compared with control animals. Animals that were subjected to a gradual increase in water temperature from 25 to 30 degrees C and a subsequent decrease to 25 degrees C, where they were maintained, had a period before onset of clinical signs and severity closer to that of control animals. Our findings indicate that both the induction of clinical gray-patch disease and the severity of the lesions are affected by water temperature and suggest that one possible means of control of this herpesvirus infection under intensive aquaculture conditions might be water temperature manipulation.

Role of water temperature in the regulation of water intake.

Role of water temperature in the regulation of water intake.