GROWTH CONTROL OF TRIBONEMA MINUS (WILLE) HAZEN AND SPIROGYRA SINGULARIS NORDSTEDT BY LIGHT AND TEMPERATURE

Abstract

Optimum growth in uni-algal cultures of Tribonema minus (Wille) Hazen, a dominant alga in blanketing algal mats in the early spring, was obtained at temperatures between 15–25°C and light intensities above 18 μ Einstein m–2 s–1. Uni-algal cultures of Spirogyra singularis Nordstedt, dominant in algal mats during summer, grew well between 20–25°C and the highest light intensities tested (62 μ Einstein m–2 s–1). In mixed cultures T. minus outgrows S. singularis below 13 μ Einstein m–2 s–1 and 15°C. At higher light intensities and temperatures levels S. singularis dominates, which agrees with field observations. The growth reduction of T. minus at these higher levels is discussed.