Influence of nitrate and phosphate on the growth of Schizomeris leibleinii Kützing (Chaetophorales, Chlorophyta)

Abstract

Schizomeris leibleinii Kützing is an algal species commonly found in eutrophic freshwater or in water polluted by organic nutrients and shows high potential as an organic pollution indicator. S. leibleinii was grown at different nitrate and phosphate concentrations for 50 days. Biomass was determined by quantifying chlorophyll a concentrations for different cultivation periods. Besides growth-curve analysis, data were evaluated by ANOVA (one way) and by Tukey's test for comparing treatments. The study revealed that S. leibleinii grew rapidly at low concentrations of nitrate and phosphate, but the best development occurred at high nitrate concentrations. Environmental stress initially promoted fast growth in this species, possibly accompanied by intense reproduction. In spite of the rapid growth of S. leibleinii, growth curves suggested that this species is probably a k-strategist. In addition, the alga was more dependent on nitrate than on phosphate concentration, indicating nitrogen as the limiting nutrient of growth in culture.