Giongo Adriana, Dos Anjos Borges Luiz Gustavo, Marconatto Letícia, de Lara Palhano Pâmela, Serbent Maria Pilar, Moreira-Silva Eduardo, de Abreu Siqueira Tiago, Martinho Caroline Thais, Barili Rosalia, Paz Lisiê Valéria, Moser Letícia Isabela, De Marco Veríssimo Carolina, Ketzer João Marcelo Medina, Medina-Silva Renata
Geobiology Laboratory, Instituto do Petróleo e dos Recursos Naturais (IPR), Pontifícia Universidade Católica do Rio Grande do Sul (PUCRS), Porto Alegre, Brazil.
Environmental Engineering Graduate Program, Universidade Regional de Blumenau (FURB), Blumenau, Brazil.
Heliyon. 2020 Aug 27;6(8):e04778. doi: 10.1016/j.heliyon.2020.e04778. eCollection 2020 Aug.
In November 2015, two iron ore tailing dams collapsed in the city of Mariana, Brazil. The dams' collapse generated a wave of approximately 50 million m of a mixture of mining waste and water. It was a major environmental tragedy in Brazilian history, which damaged rivers, and cities 660 km away in the Doce River basin until it reached the ocean coast. Shortly after the incident, several reports informed that the concentration of metals in the water was above acceptable legal limits under Brazilian laws. Here the microbial communities in samples of water, mud, foam, and rhizosphere of from Doce River were analyzed for 16S and 18S rRNA-based amplicon sequencing, along with microbial isolation, chemical and mineralogical analyses. Samples were collected one month and thirteen months after the collapse. Prokaryotic communities from mud shifted drastically over time (33% Bray-Curtis similarity), while water samples were more similar (63% Bray-Curtis similarity) in the same period. After 12 months, mud samples remained with high levels of heavy metals and a reduction in the diversity of microeukaryotes was detected. Amoebozoans increased in mud samples, reaching 49% of microeukaryote abundance, with Discosea and Lobosa groups being the most abundant. The microbial communities' structure in mud samples changed adapting to the new environment condition. The characterization of microbial communities and metal-tolerant organisms from such impacted environments is essential for understanding the ecological consequences of massive anthropogenic impacts and strategies for the restoration of contaminated sites such as the Doce River.
2015年11月，巴西马利亚纳市的两座铁矿石尾矿坝坍塌。坝体坍塌产生了一股约5000万立方米的采矿废料与水的混合物浪潮。这是巴西历史上一场重大的环境悲剧，它破坏了河流，并影响到多西河盆地660公里外的城市，直至到达海岸。事故发生后不久，几份报告指出，水中金属浓度高于巴西法律规定的可接受法定限值。在此，对多西河的水、泥、泡沫和根际样本中的微生物群落进行了基于16S和18S rRNA的扩增子测序分析，同时进行了微生物分离、化学和矿物学分析。样本在坍塌后一个月和十三个月采集。泥中的原核生物群落随时间发生了剧烈变化（Bray-Curtis相似度为33%），而同期水样的相似度更高（Bray-Curtis相似度为63%）。12个月后，泥样中重金属含量仍然很高，并且检测到微型真核生物多样性降低。泥样中的变形虫类增加，占微型真核生物丰度的49%，其中盘状亚目和叶足亚目群体最为丰富。泥样中的微生物群落结构发生变化以适应新的环境条件。表征此类受影响环境中的微生物群落和耐金属生物对于理解大规模人为影响的生态后果以及多西河等受污染场地的修复策略至关重要。
