Gómez-Martínez Daniela, Selvin Mary A, Nilsson Anders K, Carmona Eric, Ngou Judith Sorel, Kristiansson Erik, Nilsson R Henrik, Corcoll Natàlia
Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, Sweden; Department of Biological and Environmental Sciences, Centre for Future Chemical Risk Assessment and Management Strategies (FRAM) and Gothenburg Global Biodiversity Center (GGBC), University of Gothenburg, Gothenburg, Sweden.
Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, Sweden.
Chemosphere. 2024 Dec;369:143854. doi: 10.1016/j.chemosphere.2024.143854. Epub 2024 Dec 4.
Freshwater microbial communities are integral components of riverine biodiversity. The ecological effects of toxic chemical pollutants, such as fungicides (e.g., tebuconazole), on microbial abundance and diversity are needed for risk assessment and regulation. The emergence of RNA metabarcoding approaches allow us to describe at unprecedented resolution the microbial diversity of the active part of a microbial community. Our study assesses the ecotoxicological impact of chronic and acute tebuconazole exposures on fungal, bacterial, and algal biomass and biodiversity of aquatic fungi and bacteria in stream biofilms using an RNA metabarcoding approach. In addition, the study uses HPLC-MS to evaluate the capability of biofilms to metabolize tebuconazole. Natural biofilm communities from a Swedish stream were exposed chronically (24 days) and acutely (96 h) to environmental concentrations of tebuconazole (10 and 100 μg/L) in microcosms conditions. The diversity and community structure of fungi and bacteria was assessed by ITS2 and 16S cDNA amplicon-sequencing, respectively. Biofilms chronically exposed to tebuconazole produced and released unidentified transformation products into the water column, suggesting a biotransformation capability following 24 days of uninterrupted exposure. The fungal biomass markedly decreased by a biomass loss of 40% when chronically exposed to 10 μg/L, and 60% when chronically exposed to 100 μg/L. Bacterial and algal biomass remained comparable with the controls in all tebuconazole treatments. Fungal and bacterial alpha diversity metrics were not significantly impacted, although a decreasing trend in fungal richness was observed with the treatments. However, beta diversity was significantly impacted in both fungal and bacterial compartments. Chronic exposures resulted in a shift in community composition, where taxa potentially more tolerant to tebuconazole (i.e. Lecanoromycetes) replaced more sensitive taxa (i.e. Malasseziomycetes). This study indicates that tebuconazole at environmental concentrations might pose a risk to freshwater systems, mainly due to its high toxicity to fungi.
淡水微生物群落是河流生物多样性的重要组成部分。为了进行风险评估和监管，需要了解有毒化学污染物（如杀菌剂，例如戊唑醇）对微生物丰度和多样性的生态影响。RNA宏条形码技术的出现使我们能够以前所未有的分辨率描述微生物群落活性部分的微生物多样性。我们的研究使用RNA宏条形码技术评估了戊唑醇慢性和急性暴露对溪流生物膜中水生真菌和细菌的真菌、细菌和藻类生物量以及生物多样性的生态毒理学影响。此外，该研究使用高效液相色谱 - 质谱联用技术评估生物膜代谢戊唑醇的能力。在微宇宙条件下，将来自瑞典一条溪流的天然生物膜群落长期（24天）和急性（96小时）暴露于环境浓度的戊唑醇（10和100μg/L）中。分别通过ITS2和16S cDNA扩增子测序评估真菌和细菌的多样性及群落结构。长期暴露于戊唑醇的生物膜产生并向水柱中释放了未鉴定的转化产物，这表明在24天的连续暴露后具有生物转化能力。长期暴露于10μg/L时，真菌生物量显著下降，生物量损失40%；长期暴露于100μg/L时，生物量损失60%。在所有戊唑醇处理中，细菌和藻类生物量与对照相当。真菌和细菌的α多样性指标没有受到显著影响，尽管在处理中观察到真菌丰富度有下降趋势。然而，β多样性在真菌和细菌区室中均受到显著影响。长期暴露导致群落组成发生变化，其中对戊唑醇可能更具耐受性的类群（即茶渍纲）取代了更敏感的类群（即马拉色菌纲）。这项研究表明环境浓度的戊唑醇可能对淡水系统构成风险，主要是因为它对真菌具有高毒性。
