Fecal-related anthropogenic sources are key determinants of lake microbiomes through microbial source tracking

Zhongfu Zhang; Jinfeng Qi; Qingguo Yu; Shenglong Wang; Hang Wang

doi:10.1016/j.envpol.2023.122507

Fecal-related anthropogenic sources are key determinants of lake microbiomes through microbial source tracking

Environ Pollut. 2023 Nov 1:336:122507. doi: 10.1016/j.envpol.2023.122507. Epub 2023 Sep 4.

Authors

Zhongfu Zhang¹, Jinfeng Qi², Qingguo Yu³, Shenglong Wang³, Hang Wang⁴

Affiliations

¹ Yunnan Key Laboratory of Plateau Wetland Conservation, Restoration and Ecological Services, Southwest Forestry University, Kunming, 650224, People's Republic of China; Yunnan Key Laboratory for Integrative Conservation of Plant Species with Extremely Small Populations, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, People's Republic of China.
² Department of Economic Plants and Biotechnology, Yunnan Key Laboratory for Wild Plant Resources, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, People's Republic of China.
³ Yunnan Key Laboratory of Plateau Wetland Conservation, Restoration and Ecological Services, Southwest Forestry University, Kunming, 650224, People's Republic of China.
⁴ Yunnan Key Laboratory of Plateau Wetland Conservation, Restoration and Ecological Services, Southwest Forestry University, Kunming, 650224, People's Republic of China; Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, 361021, People's Republic of China. Electronic address: hwang17@163.com.

PMID: 37673318
DOI: 10.1016/j.envpol.2023.122507

Abstract

Lake microbiomes are essential indicators of lake health and are strongly influenced by allochthonous microbial communities from various sources within the watershed. However, quantifying the contributions of multiple inputs to lake microbiomes is challenging because of the complex nature of river‒lake systems and the presence of many untraceable sources. Here, Jianhu Lake‒‒a geographically simple and closed plateau lake in southwestern China, was surveyed to disentangle the contributions of five distinct sources (three input rivers that receive town sewage, stormwater runoff, and creek spring water, as well as two nonpoint sources, duck ponds and dry farmland) to the overall lake microbiomes. We found that feces-loading sources, namely town sewage and duck aquaculture, accounted for 48.7% of the total variations in lake microbiomes. In contrast, the combined contribution of the remaining three sources amounted to 13.21%, despite these less-influential sources (e.g., stormwater runoff) may introduce an even larger volume of allochthonous materials into the lake. In addition, approximately 38.1% of the variations in the lake microbiomes were attributed to unknown sources. Sewage effluents also caused a significant loss of lake microbial diversity, and there was a tendency for large-scale microbial homogeneity in lake sediments that resembled those from duck ponds. We then used a targeted approach to track host-specific fecal pollution, and found that human feces were the primary source, followed by ruminant and chicken/duck feces, all of which can be successfully traced back to the feces-loading sources. In our further modelling of sediment transport from three rivers into the whole lake, we observed a significant relationship between sediment accumulation and adsorbed microorganisms only for the sewage-receiving river. Together, lines of evidence indicate that both point and nonpoint fecal-related anthropogenic sources possess discriminatory power for shaping microbial geographic patterns of the lake, posing threats to the survival of local indigenous lake microbiomes.

Keywords: Anthropogenic impact; Lake; Microbial geography; Plateau region; Sewage; Source tracking.