Abstract
A CHANGE in the pH value of the surrounding water has been observed to have a marked influence on the life and growth of trout eggs and larvæ. Normally, they are reared in water of pH 7.30 ± 0.05 at 10.5° C. The pH value of the yolk in living eggs and larvæ is 6.50–6.55, and after death it has the same pH value as that of the surrounding water. As a starting point for an investigation of the effect of different pH values on eggs and larvæ, they were reared in tap water adjusted to different pH's with hydrochloric acid and sodium hydroxide. Such a system would not remain at constant pH. Since it was found that a particular quantity of water in a glass vessel containing fifty eggs did not change its pH in 6 hr. by more than 1.0 towards the acid side, the water of the experimental container was replaced after 6 hr. with fresh water adjusted to the original pH. Buffer solutions were not used to avoid the action of other ions. All the containers were kept in the same hatchery tray at a constant temperature of 10.5° ± 0.5°C., and each container received 50 eggs. The larvæ need more oxygen and give out more carbon dioxide than the same number of eggs, so the quantity of water in each container was increased to five times the original to ensure the proper aeration of the larvæ. A simple average of the mortality percentage of four experiments is shown in the graph. All pH values were measured with a glass electrode and Cambridge pH-meter at 10.5° C.
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Young, R. T., Ecology, 19, 126 (1938).
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KRISHNA, D. Effect of Changing pH on Developing Trout Eggs and Larvæ. Nature 171, 434 (1953). https://doi.org/10.1038/171434a0
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DOI: https://doi.org/10.1038/171434a0
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