Growth response to temperature and light in Nostoc spongiaeforme (Cyanobacteria)

Cyanobacteria and algae are problematic in California rice fields that are typically shallow and have high nutrient levels, providing ideal growing conditions. Nostoc spongiaeforme is a problem because extensive floating mats dislodge rice seedlings or smother them when the mats accumulate in windward areas. There is little published information on growth requirements for N. spongiaeforme. We grew N. spongiaeforme in BG-11 medium at 24 combinations of light (22, 87, 162, and 400 µM m−2 s−1) and temperatures (10°C, 15°C, 20°C, 25°C, 30°C, and 35°C). Results were summarized as a quadratic equation relating light and temperature to growth and indicate that optimal growth occurred at 26°C and 227 µM m−2 s−1 of light. Thus, N. spongiaeforme grows well at water temperatures and light levels similar to those measured in rice fields during the critical 30 days following initial flooding of the field.