. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 516 J-P. TRUCHOT 7-8 Q. E _>» o E 0> I 76 • • • \ .•. 20 25 Water temperature 30 C FIGURE 3. Individual pH values measured on 61 crabs Carcinus maenas breathing water in the artificial pool in low-tide conditions, plotted as a function of water temperature. Open symbol with error bars represents the mean pH value for 11 crabs breathing air at Pw^ < 20 Torr. Regression line calculated for values of crabs breathing water only. Correlation coefficient r = ; P 20 Torr. The scatter of these data is much larger t
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 516 J-P. TRUCHOT 7-8 Q. E _>» o E 0> I 76 • • • \ .•. 20 25 Water temperature 30 C FIGURE 3. Individual pH values measured on 61 crabs Carcinus maenas breathing water in the artificial pool in low-tide conditions, plotted as a function of water temperature. Open symbol with error bars represents the mean pH value for 11 crabs breathing air at Pw^ < 20 Torr. Regression line calculated for values of crabs breathing water only. Correlation coefficient r = ; P 20 Torr. The scatter of these data is much larger than usually found in laboratory experiments. This is not surprising because environmental changes were not exactly the same from one low tide session to another and because different Pw0, and Pwc02 levels thus prevailed at a given temperature in the artificial pool. However, the pH-temperature slope calculated by linear regression amounts to — pH unit- °C~' in the range 20 to 30°C with a highly significant correlation coefficient (r = —; P < ). The slope value fits the imidazole alphastat theory satisfactorily and approaches that required for a constant relative alkalinity ( in the same temperature range). Practically the same slope was observed previously in laboratory experiments at constant water P02 and PCo2 m crabs Carcinus acclimated several days at various temperatures, (Truchot, 1973a; Dejours # a/., 1985). Customarily it is thought that pH-temperature adjustments in aquatic animals rely on changes of the blood bicarbonate concentration and thus require a relatively long acclimation period. The present data suggest that the same result can be attained rapidly in natural conditions when water P02 and PCo2 simultaneously change with temperature. Whether this represents a particular adaptive pattern in intertidal rockpool animals awaits further studies. But, since no changes of hemolymph bicarbonate con- centration are apparent in ti
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
