An Experimental Validation of Heat Loss Models for Marine Mammals

Autor: P.H. Kvadsheim, Arnoldus Schytte Blix, Lars P. Folkow, Anne R.L. Gotaas
Rok vydání: 1997
Předmět:
Zdroj: Journal of Theoretical Biology. 184:15-23
ISSN: 0022-5193
Popis: Various heat loss models have been used to predict metabolic rates or lower critical temperatures of marine mammals. We have evaluated the accuracy of four models by making detailed measurements of all input parameters, while simultaneously recording the metabolic rate in two resting harp seals (Phoca groenlandica) in ice water. We subtracted respiratory heat loss from metabolic rate and compared the resulting value with estimated heat loss rates. The models overestimated heat loss rate by between 28% and 76% on average. Measurements of body and body core surface areas of four other harp seals showed that the large overestimation resulting from the use of the flat plate model, is due to the large difference between body and body core surface area. The bad performance of the three other models, which all describe the seals as cylindrical in shape, appears to be due to the fact that the blubber envelope and the body core of seals are not two perfect and concentrically positioned cylinders. Model experiments with a cylindrical heat element placed eccentrically inside an insulating polyethylene pipe showed that the established use of these models overestimates the true heat loss rate, unless data input are based on direct morphometrical measurements on the core. When making a correction for this for the best performing cylinder model, the overestimation of heat loss rate ranged between 3% and 18%.
Databáze: OpenAIRE
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