Characteristics of Communities in the Extracts of Different Purple Soils in the Sichuan Basin, China

Abstract

Pond soils play a fundamental role determining nutrient availability and regulate the characteristics of phytoplankton communities. This study investigated the change of phytoplankton communities in three types (alkaline, neutral, and acid) of purple soil. There were 107 species of phytoplankton detected in three purple soils belonging to 52 genera of 6 phyla (68 species in acid group, 69 species in neutral group and 64 species in alkaline group). The highest percentage of phytoplankton in three purple soil groups is Chlorophyta, followed by Bacillariophyta, and Euglenophyta. There were 23 species of 5 phyla in three purple soil ponds as the dominant species of phytoplankton, and the dominance varied from 0.05 to 0.67. The dominant species in neutral and alkaline purple soil groups were more than those in acid purple soil. Phytoplankton density varied from 43 to 7360 × 106 ind/L in the acid purple soil group, and the ratio of the highest value to the lowest one was 170. The variation range of phytoplankton density in neutral and alkaline purple soil ponds was 83 to 565 × 106 and 56 to 437 × 106 ind/L, and the ratio of the highest value to the lowest one was 6.8 and 7.8 respectively. The variation of biodiversity indices (Shannon—Wiener index, Pielous evenness index and Margalef richness index), were higher in the acid purple soil group than in the neutral and alkaline purple soil groups, similar to the result of phytoplankton density. Our results indicate that the phytoplankton community was more stable in the neutral and alkaline purple soil groups than in the acid soil group, and these two soil types are recommended for site-selection to build aquaculture ponds.