Seasonal dynamics of epiphytic algal growth in a marsh pond: composition, metabolism, and nutrient availability

Abstract

Seasonal growth and succession of epiphytic algae on artificial substrates in a marsh pond were related to nutrient levels (N, P, and Si) and to various physiological indicators of nutrient availability, including chlorophyll content, protein to carbohydrate and lipid ratio, Si debt, storage phosphate levels, alkaline phosphatase activity, and nitrogenase activity. Low standing crops in June and early July coincided with indications of deficiency in terms of chlorophyll a content and protein to carbohydrate and lipid ratios at chosen Scirpus and Potamogeton sites. Low available N may have been limiting growth. In July and August, when available N, P, and Si were low, there was evidence of Si limitation of diatom growth at both sites. Growth of heterocystous, N2-fixing. blue-green algae and high alkaline phosphatase activity occurred in July at the Potanwgeton site. Increased standing crop of epiphytic algae in September and October at the Scirpus site coincided with higher nutrient levels and an absence of deficiency symptoms. A delay in the standing crop increase at the Potamogeton site correlated with low nutrient levels and various physiological deficiency symptoms.