水質對東江流域附生矽藻群落的影響

運用相關分析(CA),典型對應分析(CCA),加權平均分析(WA)研究了影響東江流域附生矽藻的主要水質因數及對應的最適生態範圍。CA顯示,13項水質指標中溶解氧(Dissolved Oxygen,DO)、氨氮(NH₄-N)、亞硝氮(NO₂-N)、氯化物(Cl)、五日生化需氧量(BOD₅)、磷酸鹽(PO₄-P)與其它指標間的相關性較強(P < 0.05),其餘指標間相關性較低(P < 0.05)。以相關性較弱的pH、電導率(Cond.)、矽酸鹽(SiO₂)、總磷(TP)、總氮(TN)、硝氮(NO₃-N)、化學需氧量(CODKMnO₄)進行CCA分析,排序顯示影響附生矽藻的水質因數依次為Cond.、NO₃-N、CODKMnO₄、TP、TN,對應的生態最適範圍分別為39.20-642.00μs/cm、0.46-2.77mg/L、1.0-5.5mg/L、0.02-0.64mg/L、0.48-3.43mg/L。研究表明,Cond、NO₃-N、CODKMnO₄、TP、TN是影響東江附生矽藻分佈的主要水質因數,Cyclostephanos invisitatus、Gomphonema olivaceum、Nitzschia acicularis、N. capitellata、N. intermedia可以指示東江較高的電導率,Aulacoseira ambigua、A. lirata、Cyclotella meneghiniana、Cyclostephanos invisitatus、Eunotia minor、Nitzschia acicularis、N. Clausii、Pinnularia subcapitata是東江TN、TP污染的指示種。Nitzschia acicularis對TN、TP的耐受性最高,Navicula eidrigiana對TN、TP敏感性最強。
The effects of thirteen water quality parameters(Conductivity, pH, Dissolved Oxygen, Biochemistry Oxygen Demand, Chemistry Oxygen Demand, Total Nitrogen, NH₄-N, NO₃-N, NO₂-N, Total Phosphorus, PO₄-P, SiO₂ and Cl) on the distribution of epilithic diatoms in the Dongjiang basin were investigated by correlation analysis (CA), canonical correspondence analysis (CCA) and weighted average (WA). Correlation analysis showed that NH₄-N, NO₂-N, PO₄-P, Cl, DO and BOD₅ had significant correlations with the other seven water quality parameters, while CCA analysis revealed that the impacts level of the five environmental variables. Cond., COD_KMnO₄, NO₃-N, TN and TP on the variation in community composition of epilithic diatoms were in the order of Cond.> NO₃-N > COD_KMnO₄ > TP > TN. Furthermore, the optimum ecological values of Cond., NO₃-N, COD_KMnO₄, TP and TN for epilithic diatoms were calculated using weighted average regression method to be 39.20-642.00μs/cm, 0.46-2.77mg/L, 1.0-5.5mg/L, 0.02-0.64 mg/L and 0.48-3.43mg/L, respectively. The results indicated that Cond., COD_KMnO₄, NO₃-N, TN and TP were the major water quality parameters affecting the distribution of diatom assemblages. Cyclostephanos invisitatus, Nitzschia acicularis, N. capitellata and N. intermedia could be used as bioindicators for the higher conductivity in the Dongjiang river basin. Aulacoseira ambigua, A. lirata, Cyclotella meneghiniana, Cyclostephanos invisitatus, Eunotia minor, Nitzschia acicularis, N. clausii and Pinnularia subcapitata were indicative species for TN and TP in the Dongjiang river basin. Moreover, Nitzschia acicularis is the best bioindicator for TN and TP in the Dongjiang basin, while Navicula eidrigiana is the least sensitive bioindicator for TN and TP. Copyright © 2015 Ecological Society of China.