Seasonal size changes in certain diatoms and their possible significance

Cell sizes of two species of diatoms, Stephanodiscus astraea and Asterionella formosa, were determined in algal populations in four water bodies at various times of the year. Changes in the average cell diameter or length were observed throughout the growing seasons. The possible effects of these cell size changes are discussed in relation to parameters such as rate of sinking, nutrient absorption, temperature, viscosity and turbulence.