Nutrients and pH regulate algicide accumulation in cultures of the cyanobacterium Oscillatoria laetevirens

摘要: Summary • The change in algicide synthesis response to nutrients and pH axenic cultures of the planktonic cyanobacterium, Oscillatoria laetevirens is reported. • Analytical bioassay techniques were used determine effects nitrogen (N), sulpher (S), phosphorus (P), magnesium (Mg2+), calcium (Ca2+) hydrogen (H+) on growth, secondary metabolite accumulation minimum inhibitory concentration culture filtrates. • Growth production affected by nutrient addition. High production, which was not dependent optimal correlated with deficiences phosphate, high pH. Algicidal activity medium detected following organic addition while growth sustained; however, ammonia reduced biomass yield but did affect formation. The differential inside cells indicated secretion an efflux mechanism rather than leakage from aging cells. • Algicide negatively regulated both phosphate magnesium, interactive influence allelopathy discussed species succession dominance maintenance freshwater blooms.