Abstract:

Benthic diatoms were productive culture using three kinds of measures (Ⅰ. Illuminance 2500-3000lx, one day over the baskets; Ⅱ. Illuminance 2500-3000lx, 3 days over the baskets; Ⅲ. Illuminance 1500-2000lx, 3 days over the baskets). The results show that: Species composition of benthic diatoms (per cent in the density of large species of Naviculaceae, small species of Naviculaceae, species of Diatomaceae, species of Nitzschiaceae, species of Melosira and species of Cocconeis were 11.56 ± 4.64, 78.27 ± 9.63, 0.823 ± 0.25, 2.57 ± 1.06, 0.01 ± 0.01,6.78 ± 1.34 and 0.15 ± 0.03, 79.71 ± 12.72, 0.23 ± 0.09, 0.64 ± 0.12, 0.01 ± 0.01, 19.262 ± 6.64 respectively) cultured using measures Ⅰ and Ⅲ than develop measures Ⅱ (per cent in the density of large species of Naviculaceae, small species of Naviculaceae, species of Diatomaceae, species of Nitzschiaceae, species of Melosira and species of Cocconeis were 23.56 ± 10.47, 38.47 ± 9.85, 22.51 ± 9.86, 10.24 ± 2.86, 5.22 ± 1.68, 0.007 ± 0.002), but total density of benthic diatoms cultured using measures Ⅲ were significantly lower. This study indicated that stronger illuminance (Optimum illumination theoretic of small species of Naviculaceae is 1000-1500 lx) combined with daily turn baskets both ensure more high-quality and also enhance the growth rate of benthic diatom, so as meeting need of seed for more quantity of benthic diatoms of aquatic economic animals.