底泥与衰亡植物营养释放及细菌群落演替差异的比较分析

Comparative analysis of nutrient release and bacterial community succession difference between sediment and withering plant

为揭示两种“湖泛”因素对水质影响及细菌群落演替差异,对泸沽湖草海底泥和衰亡植物营养释放过程进行对比研究,并通过冗余分析阐明影响细菌群落不同阶段变化的主要环境因子.结果表明,前期是衰亡植物与底泥营养释放及细菌演替差异显著的主要阶段.植物腐解过程中,细菌前期厌氧发酵更剧烈,水体迅速处于低pH、低DO和低ORP(O_(x)idation Reduction Potential)状态,使得细菌丰度和多样性明显低于底泥.同时,衰亡植物前期营养释放浓度和速率相较于中后期远远高于底泥.在92 d营养释放过程中,底泥菌群相对稳定,而植物菌群明显分为3个时期:前期以厌氧发酵为主,中后期以纤维降解和硫氧化还原为主.冗余分析表明,底泥与植物菌群演变主要受TP和ORP影响.在不同阶段,底泥菌群前期受NH_(3)^(-)N影响,中期受TN、pH和COD影响,后期受TP、ORP和DO影响.而衰亡植物菌群前期受除pH外各理化因子和水质指标影响,中后期则受pH影响.衰亡植物前期对水质各方面影响最大,应及时打捞收割.

To uncover the influence of two black bloom factors on water quality,and the differences of bacterial community succession,a comparative study of the nutrient release process of sediment and withering plant in grass sea of Lugu Lake was carried out.Redundancy analysis was used to reveal major environmental factors affecting the variation of bacterial community in different stages.The results indicated that the prophase was the main stage in which the nutrient release and bacterial succession of withering plants and sediment were remarkably different.More acute anaerobic fermentation during plant prophase decomposing led to low pH、low DO and low oxidation reduction potential in overlying water,which dramatically decreased the bacterial abundance and diversity.In the meantime,the concentration and rate of nutrient release in the prophase of withering plant were much higher than that in sediment.During the 92 day simulated nutrient release process,the sediment bacterial community was relatively stable,while the plant bacterial community was obviously divided into three stages:The anaerobic fermentative bacteria were dominant in the early stage,while the cellulolytic bacteria and sulfur redox bacteria were dominant in the middle and late stages.Redundancy analysis showed that the bacterial community succession of sediment and plant was mainly affected by TP and ORP.The bacterial community of sediment was affected by NH_(3)^(-)N in the early stage,TN、pH and COD in the middle stage,TP、ORP and DO in the late stage.For withering plant,the bacterial community was affected by all the investigated factors except pH in the early stage,and pH was the main impact factor in the middle and late stages.Withering plants show great impact on all aspects of the water quality in the early stage,so they should be salvaged and harvested in time.