Grupo de Ecologia Bentônica, Department of Oceanography, Universidade Federal do Espírito Santo, Vitória, Espírito Santo, Brazil.
Plataforma de Bioinformática, Instituto René Rachou, FIOCRUZ/Minas, Belo Horizonte, Minas Gerais, Brazil.
PeerJ. 2023 Mar 14;11:e14992. doi: 10.7717/peerj.14992. eCollection 2023.
Estuaries are transitional coastal ecosystems that are threatened by multiple sources of human pollution. In 2015, mining tailings from an upstream dam failure caused massive metal contamination that impacted benthic assemblages on the Brazilian Rio Doce estuary.
In this study, we investigate and compare meiofaunal assemblages with eDNA metabarcoding 1.7 years (2017) and 2.8 years (2018) after the initial contamination by mine tailings in order to evaluate the continued impact of sediment mine tailing contaminants on the structure of benthic assemblages after the disaster.
The community was dominated by Arthropoda and Nematoda 1.7 yr after the impacts (42 and 29% of meiofaunal sequence reads, respectively) but after 2.8 years Arthropoda (64.8% of meiofaunal sequence reads) and Rotifera (11.8%) were the most common taxa. This continued impact on meiofaunal assemblage revealed a lower phylogenetic diversity (7.8-fold) in 2018, despite overall decrease in metal concentration (Al, Ba, Cr, As, Fe, Zn, Mn, Pb, Cd, Co) in sediments. Our data suggests that differences in benthic assemblages and loss of diversity may be influenced by contaminants in sediments of this estuary, and indicate that broad eDNA assessments are greatly useful to understand the full range of biodiversity changes in dynamic estuarine ecosystems.
河口是受多种人为污染威胁的过渡性沿海生态系统。2015 年，上游大坝决堤产生的采矿尾矿造成了大规模的金属污染，影响了巴西里奥多斯河口的底栖生物组合。
在本研究中，我们使用 DNA metabarcoding 技术，在尾矿最初污染后的 1.7 年（2017 年）和 2.8 年（2018 年）调查和比较了小型生物群落，以评估尾矿污染物对灾难后底栖生物群落结构的持续影响。
1.7 年后，群落主要由节肢动物和线虫组成（分别占小型生物序列读数的 42%和 29%），但 2.8 年后，节肢动物（占小型生物序列读数的 64.8%）和轮虫（占 11.8%）是最常见的类群。尽管沉积物中的金属浓度（Al、Ba、Cr、As、Fe、Zn、Mn、Pb、Cd、Co）总体下降，但这种对小型生物群落的持续影响导致其系统发育多样性降低了 7.8 倍。
本研究表明，尽管沉积物中金属浓度总体下降，但底栖生物群落的差异和多样性的丧失可能受到该河口沉积物中污染物的影响，并且表明广泛的 eDNA 评估对于了解动态河口生态系统中生物多样性变化的全貌非常有用。
