Abstract：
Identifying sediment phosphorus sources, the key to control eutrophication, is hindered in multi-source polluted urban rivers by the lack of appropriate methods and data resolution. Community-based microbial source tracking (MST) offers new insight, but the bacterial communities could be affected by environmental fluctuations during the migration with sediments, which might induce instability of MST results. Therefore, the effects of environmental-induced community succession on the stability of MST were compared in this study. Liangxi River, a highly eutrophic urban river, was selected as the study area where sediment phosphorus sources are difficult to track because of multi-source pollution and complicated hydrodynamic conditions. Spearman correlation analysis (P < 0.05) was conducted to recognize a close relationship between sediment, bacterial communities and phosphorus, verifying the feasibility of MST for identify sediment phosphorus sources. Two distinct microbial community fingerprints were constructed based on whether excluded 113 vulnerable species, which were identified by analyzing the differences of microorganisms across a concentration gradient of exogenous phosphorus input in microbial environmental response experiment. Because of the lower unknown proportion and relative standard deviations, MST results were more stable and reliable when based on the fingerprints excluding species vulnerable to phosphorus. This study presents a novel insight on how to identify sediment phosphorus sources in multi-source polluted urban river, and would help to develop preferential control strategies for eutrophication management.
摘要：
确定沉积物磷源，控制富营养化的关键，由于缺乏适当的方法和数据分辨率，在多源污染的城市河流中受到阻碍。基于社区的微生物源跟踪（MST）提供了新的见解，但是细菌群落可能会受到沉积物迁移过程中环境波动的影响，这可能会导致MST结果的不稳定性。因此,比较了环境诱导群落演替对MST稳定性的影响。梁溪河,一条高度富营养化的城市河流，由于多源污染和复杂的水动力条件，选择了沉积物磷源难以追踪的研究区域。进行Spearman相关分析(P<0.05)以识别沉积物之间的密切关系,细菌群落和磷，验证了MST识别沉积物磷源的可行性。基于是否排除113个脆弱物种，构建了两个不同的微生物群落指纹图谱，通过分析微生物环境响应实验中外源磷输入的浓度梯度上微生物的差异来鉴定。由于未知比例和相对标准偏差较低，当基于指纹图谱排除易受磷影响的物种时，MST结果更稳定和可靠。这项研究为如何识别多源污染的城市河流中的沉积物磷源提供了新的见解，并将有助于制定富营养化管理的优先控制策略。
