Physiological responses of Nodularia harveyana to osmotic stress

The effects of salinity stress on biomass yield, photosynthetic O sub(2) evolution and nitrogenase activity were investigated using axenic cultures of N. harveyana). Biomass yields, as chlorophyll alpha per culture, were highest in the O to 100% seawater (0 to 35ppt. sea salt) range with negligible growth in 200% seawater; growth on NH super(+)d4 was greater than on N sub(2) and NO sub(3)u-, which did not differ significantly from each other. In short-term experiments, photosynthetic O sub(2) evolution remained high at salinities up to 150% seawater (52.5ppt. sea salt); nitrogenase activity remained high at salinities up to 100% seawater (35ppt. sea salt).