Hairs, phosphatase activity and environmental chemistry inStigeoclonium, ChaetophoraandDraparnaldia(Chaetophorales)

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Abstract
A study of environmental chemistry, algal morphology, algal N and P compositions and phosphatase activity was made for 32 samples of Chaetophorales (30 Stigeoclonium, one Chaetophora, one Draparnaldia) at 15 sites in NE England. Algal N ranged from 1·52–8·41% dry weight, algal P from 0·097–1·87% dry weight and the N : P ratio (by weight) from 3·65 to 35·6. Significant positive correlations (P < 0·001) were found between algal P and aqueous P and N, amount of hair formation and N : P ratio, and between phosphatase activity and hair formation. Significant negative correlations were found between algal N : P ratio and aqueous P, amount of hair formation and aqueous P, and between phosphatase activity and algal P. Algal samples with N : P ratios (by weight) of 5·58 and below lacked hairs; those with ratios of 6·46 and above had hairs. A study of the influence of pH on phosphatase activity of six populations showed three markedly different types of response. Use of the lead capture technique revealed localization of phosphatase activity on hairs of Chaetophora and Draparnaldia, but the results were not clear-cut for Stigeoclonium. It is suggested that hair formation in these genera usually occurs in nature under conditions of relative phosphorus deficiency, but that occasionally it may also occur due to the influence of other factors.