LI Wenhai, YIN Dongpeng, ZHAO Wen, ZHANG Rongkun, WEI Jie, LIU Xingshi, ZHAO Shuang, WANG Wei
The phytoplankton community structure and functional characteristics of Chaihe Reservoir (Liaoning, China) were investigated using field ecological surveys conducted from 2023 to 2024. Data were compared to assess the differences in analytical results obtained using two functional group classification methods. 112 species plankton algae were detected in the Chaihe Reservoir, including 41 species from Chlorophyta, accounting for 36.61%; 36 species from Bacillariophyta (32.14%); 13 species from Euglenophyta division (11.61%); 10 species from Cyanophyta (8.93%); 4 species from Xanthophyta (3.57%); 3 species from repectively Chrysophyta and Cryptophyta (2.68% each); and 2 species from Dinophyta (1.79%). The average density of phytoplankton was 2.77 × 106 ind./L, and the densities of cyanobacteria, green algae, and diatoms were generally high. The average biomass was 2.82 mg/L, and those of green algae, diatoms and cyanobacteria was dominant. The Shannon-Wiener diversity index was 3.99 and was highest in winter and lowest in summer. The Pielou evenness index was 0.75, with a higher value in spring than that in winter, summer, and autumn successively. The canonical correspondence analysis results between phytoplankton and environmental factors indicated that the annual phytoplankton density was positively correlated with total phosphorus, active phosphorus, nitrite nitrogen, temperature, and water depth; biomass was positively correlated with nitrate nitrogen and water transparency; and the diversity and evenness indexes were both positively correlated with total nitrogen. These relationships also exhibited seasonal differences. Phytoplankton in the Chaihe Reservoir were divided into 15 functional communities. The relative density method was used to classity them into F, H1, J, K, MP, N, NA, S1, Wo, X3, X2, and X1, with seasonal succession from summer (K/Wo/X1/X2/X3/F) → autumn (K/Wo/X1/X2/X3/H1/S1/J) → winter (K/Wo/X1/X2/X3/H1/S1/J/MP) → spring (K/Wo/X1/X2/X3/N/NA/J/S1/F/H1/MP). The relative biomass method was used to classified them into B, MP, Wo, W1, X2, and Y, with seasonal succession from summer (Wo/W1/X2/Y) → autumn (Wo/W1/X2/MP) → winter (Wo/W1/X2/MP/B) → spring (Wo/W1/X2/MP). The results shows that the combination of these two methods was much more suitable to the actual status of the Chaihe Reservoir.
