底生付着珪藻Nitzschia sp.の増殖に対する付着基質サイズの影響

Effects of grain size of substrate on the growth of a benthic microalgae Nitzschia sp. (diatoms) were experimentally investigated with commercial glass beads. The growth of Nitzschia sp. was enhanced with addition of glass beads, with the highest growth rate of 0.39 day-1 and the maximum estimated yield of 2.2×105 cells ml-1 at the smallest glass beads (mean diameter=0.115 mm). On the other hand, with the largest glass beads (mean diameter=1.244 mm), the growth rate was lowest (0.23 day-1), which was not significantly different from the blank experiment with no glass beads (0.25 day-1). The results in the present study indicate that not only the small glass beads are suitable for the growth of Nitzschia sp. but also the size of substrate is an important environmental factor for the growth of benthic microalgae.