Lyautey Emilie, Bonnineau Chloé, Billard Patrick, Loizeau Jean-Luc, Naffrechoux Emmanuel, Tlili Ahmed, Topp Edward, Ferrari Benoît J D, Pesce Stéphane
INRAE UR RiverLy, Villeurbanne, France.
INRAE, Université Savoie Mont Blanc, CARRTEL, Thonon-les-Bains, France.
Front Microbiol. 2021 Oct 18;12:738629. doi: 10.3389/fmicb.2021.738629. eCollection 2021.
Lake sediments are natural receptors for a wide range of anthropogenic contaminants including organic matter and toxicants such as trace metals, polycyclic aromatic hydrocarbons, polychlorinated biphenyls that accumulate over time. This contamination can impact benthic communities, including microorganisms which play a crucial role in biogeochemical cycling and food-webs. The present survey aimed at exploring whether anthropogenic contamination, at a large lake scale, can influence the diversity, structure and functions of microbial communities associated to surface sediment, as well as their genetic potential for resistance to metals and antibiotics. Changes in the characteristics of these communities were assessed in surface sediments collected in Lake Geneva from eight sampling sites in October 2017 and May 2018. These sampling sites were characterized by a large concentration range of metal and organic compound contamination. Variation between the two sampling periods were very limited for all sampling sites and measured microbial parameters. In contrast, spatial variations were observed, with two sites being distinct from each other, and from the other six sites. Benthic communities from the most contaminated sampling site (Vidy Bay, near the city of Lausanne) were characterized by the lowest bacterial and archaeal diversity, a distinct community composition, the highest abundance of antibiotic resistance genes and functional (respiration, denitrification, methanogenesis, phosphatase, and beta-glucosidase) activity levels. The second sampling site which is highly influenced by inputs from the Rhône River, exhibited low levels of diversity, a distinct community composition, high abundance of antibiotic resistance genes and the highest bacterial abundance. Overall, our results suggest that local anthropogenic contamination, including organic matter and toxicants, is a major driver of the diversity and functioning of sediment-microbial communities in Lake Geneva. This highlights the need to consider benthic microbial communities and a suite of complementary ecotoxicological endpoints for more effective environmental risk assessments of contaminants in lake sediments.
湖泊沉积物是多种人为污染物的天然受体，这些污染物包括有机物质和有毒物质，如微量金属、多环芳烃、多氯联苯等，它们会随着时间的推移而积累。这种污染会影响底栖生物群落，包括在生物地球化学循环和食物网中起关键作用的微生物。本次调查旨在探讨在大湖泊尺度上，人为污染是否会影响与表层沉积物相关的微生物群落的多样性、结构和功能，以及它们对金属和抗生素的抗性遗传潜力。2017年10月和2018年5月，在日内瓦湖的八个采样点采集表层沉积物，评估这些群落特征的变化。这些采样点的特点是金属和有机化合物污染浓度范围很大。所有采样点和测量的微生物参数在两个采样期之间的变化非常有限。相比之下，观察到了空间变化，有两个采样点彼此不同，也与其他六个采样点不同。污染最严重的采样点（洛桑市附近的维迪湾）的底栖生物群落具有最低的细菌和古菌多样性、独特的群落组成、最高的抗生素抗性基因丰度以及最高的功能（呼吸、反硝化、甲烷生成、磷酸酶和β-葡萄糖苷酶）活性水平。受罗纳河输入影响很大的第二个采样点，多样性水平较低，群落组成独特，抗生素抗性基因丰度高，细菌丰度最高。总体而言，我们的结果表明，包括有机物质和有毒物质在内的局部人为污染是日内瓦湖沉积物微生物群落多样性和功能的主要驱动因素。这凸显了在对湖泊沉积物中的污染物进行更有效的环境风险评估时，需要考虑底栖微生物群落和一系列补充性生态毒理学终点。
