INFLUENCE OF IONIC PARAMETERS ON THE GROWTH AND DISTRIBUTION OF BOEKELOVIA-HOOGLANDII (CHROMOPHYTA)

The small, flagellated monad Boekelovia hooglandii Nicolai et Baas Becking (Chromophyta) has not been reported in the literature since its initial discovery in a saline swimming pool in the Netherlands in 1935. This alga was recently observed in several temporary saline ponds in the central and western USA. The water where the alga was most abundant was characterized by a high concentration of sodium and bicarbonate ions, and a high monovalent:divalent (M:D) ionic ratio. Results of experiments to evaluate the growth and photosynthetic efficiency of B. hooglandii in several water types indicated that the alga exhibited its optimum growth rate and photosynthetic efficiency in water types with high M:D ratios. Growth rates tended to decline when divalent cation concentrations exceeded 20 mM. Despite exhibiting optimum growth in high M:D waters, the data also indicated that B. hooglandii could grow relatively well in lower M:D saline waters, such as seawater. Factors other than ionic composition appear to be limiting the distribution of this species in such waters. However, this alga appears to be much more abundant, particularly in temporary saline waters, than previously reported.