. The algae. Algae. 4 5 6 Time in Hours Fig. 207 Loss of water, as represented by loss in weight, in Pelvetia canaliculata during intertidal exposure. (After Isaac.) during periods of exposure is quite clearly an important causal factor. On salt marshes it is undoubtedly responsible for the oc- currence of gelatinous Myxophyceae at the higher levels where the exposure periods are long. Among others Pringsheim (1923), Zaneveld (1937)3 Isaac (i933) and Kanwisher (1957) have studied rate of water loss in intertidal algae. Much of the work has centred around the principal fucoids found on Euro
. The algae. Algae. 4 5 6 Time in Hours Fig. 207 Loss of water, as represented by loss in weight, in Pelvetia canaliculata during intertidal exposure. (After Isaac.) during periods of exposure is quite clearly an important causal factor. On salt marshes it is undoubtedly responsible for the oc- currence of gelatinous Myxophyceae at the higher levels where the exposure periods are long. Among others Pringsheim (1923), Zaneveld (1937)3 Isaac (i933) and Kanwisher (1957) have studied rate of water loss in intertidal algae. Much of the work has centred around the principal fucoids found on European shores. In Pelvetia canaliculata the main water loss occurs in the first six hours of exposure (Fig. 207) whilst in Fucus spiralis var. platycarpus, F. vesiculosus, F. serratus and Asco- phyllum the maximum water loss can be spread over 18 hours (Fig. 208): in F. vesiculosus as much as 90 per cent of the total initial water can be lost in i| hours. Fucus spiralis var. platycarpus loses its water the slowest of these last four species, and a definite in- crease in the rate of water loss can be observed with the different species as each occupies a successively lower zone on the shore, but it must be noted that F. spiralis var. platycarpus ultimately loses a rather higher percentage of water than the other three. Haas and Hill (1933) have also shown that the higher the alga grows the greater is the fat content (Table 15). 387. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Chapman, V. J. (Valentine Jackson), 1910-. London, Macmillan; New York, St. Martin's Press
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Keywords: ., bo, bookcentury1900, bookcollectionbiodiversity, booksubjectalgae
