Phytoplankton in Mitika Wetland, Tibet, China:2. Characteristics of functional groups and their relationship with environmental factors

Abstract

为揭示青藏高原湿地浮游植物功能群时空分布特征与环境因子的关系,本文于2019年7月(丰水期)和2019年10月(枯水期)在麦地卡湿地调查浮游植物功能群组成和生物量,并运用Spearman相关性分析、冗余分析(RDA)和典范对应分析(CCA)等方法,对麦地卡湿地浮游植物功能群时空分布特征及其与环境因子的关系进行分析.结果表明:1)根据功能群分类方法,麦地卡湿地浮游植物可划分为27个功能群,分别为A、B、C、D、E、F、G、H1、J、K、L_M、L_O、M、MP、N、P、S1、S2、T、T_B、T_C、W1、W2、X1、X2、X3和Z;在时间维度上,丰水期有26个功能群,枯水期有23个功能群;在空间维度上,河流湿地有24个功能群,湖泊湿地有23个功能群,沼泽湿地有12个功能群.2)丰水期,以功能群A、D、L_M、L_O、MP、N、P、T、T_B和X3为主,枯水期以功能群A、D、J、L_M、L_O、MP、N、P、T和T_B为主,其中A和T功能群为2个水情期的共有绝对优势功能群,功能群J仅为枯水期的绝对优势功能群.3)生态状态指数(Q)范围为1.80～4.86,平均值为3.80,表明麦地卡湿地水质状态为“好”.4)相关性分析表明,浊度、COD_Cr、总磷和硝态氮与部分优势功能群生物量具有显著相关性;RDA分析表明,盐度和总氮是影响丰水期优势功能群生物量的主要环境因子.CCA分析表明,总氮和硝态氮是影响枯水期优势功能群生物量的主要环境因子.;In order to reveal the relationship between temporal and spatial distribution characteristics of phytoplankton functional groups and environmental factors in Qinghai-Tibet Plateau in wetlands, the composition and biomass of phytoplankton functional groups were investigated in the Mitika Wetland in July 2019 (wet season) and October 2019 (dry season). The Spearman correlation analysis, redundancy analysis (RDA) and canonical correspondence analysis (CCA) were used to analyse the temporal and spatial distribution characteristics of phytoplankton functional groups and their relationship with environmental factors in the Mitika Wetland. The results showed that:1) According to the functional group classification method, the phytoplankton in the Mitika Wetland can be divided into 27 functional groups, which were A, B, C, D, E, F, G, H1, J, K, L_M, L_O, M, MP, N, P, S1, S2, T, T_B, T_C, W1, W2, X1, X2, X3, Z. In the time dimension, there were 26 functional groups in the wet season, 23 functional groups in the dry season. In the spatial dimension, there were 24 functional groups in river wetland, 23 functional groups in lake wetland and 12 functional groups in swamp wetland. 2) In the wet season, functional groups A, D, L_M, L_O, MP, N, P, T, T_B and X3 dominated. In the dry season, functional groups A, D, J, L_M, L_O, MP, N, P, T and T_B dominated. Functional groups A and T were the common absolute dominant functional groups in two hydrological periods, and functional group J was the absolute dominant functional group only in dry period. 3) Ecological status index values ranged from 1.80 to 4.86, with an average value of 3.80, indicating that the water quality of the Mitika Wetland was good. 4) Correlation analysis showed that turbidity, COD_Cr, total phosphorus and nitrate nitrogen were significantly correlated with the biomass of partial dominant functional groups. RDA analysis showed that salinity and total nitrogen were the main environmental factors affecting the biomass of dominant functional groups in the wet season. CCA analysis showed that total nitrogen and nitrate nitrogen were the main environmental factors affecting the biomass of dominant functional groups in the dry season.