丰登大坝的破坏,巴西历史上最严重的环境灾难,通过多斯河发射了5000万立方米的铁矿石尾矿泥浆,到达大西洋。一般来说,尾矿增加了沉积物的流入,导致表栖大型动物的泥葬,以及金属(oid)浓度的提高导致大型动物的长期变化。在将近四年之后,尾矿泥浆仍在多西河架子上蔓延,虽然对海洋大型动物的影响仍然未知。在这里,IMS指数(Fundão大坝尾矿泥浆的示踪剂),沉积物变量,有机污染物,和金属(oid)被集成在一起,以揭示从CostasdaAlgas到Abrolhos银行MPA的大型动物结构的驱动力。尾矿泥浆只存在于多西河口和德格雷多,高于安全水平的有机污染物和金属(oid)集中在这些地区。尾矿泥浆(IMS指数)大大降低了物种丰富度和多样性,有利于机会物种的丰富。泥浆,IMS指数和Al,Ba,V,与大坝破坏有关的金属(oid),这个受影响地区的结构化大型动物组成,以Nuculidae等抗性群体为主,Spionidae,和Magelonidae.相反,对于CaCO3含量和总氮含量高的更远和更深的地点,发现了相反的模式,这也显示出较大的晶粒尺寸,在已知有生物结构的地区,维持与受影响地区不同的大型动物组成,以Syllidae和Crassatellidae为主,对影响敏感。大型动物的组成大多由沉积物变量构成,其次是金属(oid)s-IMS和泥浆之间的交点,这两个梯度几乎完全作用在广泛的空间尺度上。Doce河架的底栖大型动物仍然受到Fundão大坝尾矿泥浆的影响,即使在经历了将近四年的灾难之后,并可能继续,由于尾矿的涌入并没有停止,沉积物再悬浮是这些影响的经常性来源。
The Fundão dam failure, the worst environmental disaster in Brazilian history, launched 50 million m3 of iron ore tailings mud through the Doce River, reaching the Atlantic Ocean. Generally, mine tailings increase the sediment inflow, leading to mud burial of epibenthic macrofauna, and the raise of metal(oid)s concentration causing macrofauna long-term changes. After almost four years, tailings mud was still spreading on the Doce River Shelf, while impacts on marine macrofauna were still unknown. Herein, the IMS index (a tracer of Fundão dam tailings mud), sediment variables, organic pollutants, and metal(oid)s were integrated to uncover the drives of macrofauna structure from Costas da Algas to Abrolhos bank MPAs. Tailings mud was present only in Doce River Mouth and Degredo, organic pollutants and metal(oid)s above safety levels were concentrated in those same areas. Tailings mud (IMS index) drastically reduced species richness and diversity, favoring the abundance of opportunistic species. Mud, IMS index and Al, Ba, and V, metal(oid)s linked to dam failure, structured macrofauna composition in this impacted area, dominated by resistant groups as Nuculidae, Spionidae, and Magelonidae. Conversely, an opposite pattern was found for further and deeper sites with high CaCO3 content and total nitrogen that also showed large grain size, in areas known to harbour biogenic structures, sustaining a macrofauna composition distinct from the impacted areas, dominated by Syllidae and Crassatellidae, sensitives to impacts. Macrofauna composition was most structured by sediment variables, followed by the intersection between metal(oid)s-IMS and Mud, both gradients acting almost entirely on a broad spatial scale. Benthic macrofauna at the Doce River Shelf is still impacted by Fundão dam tailings mud, even after almost four years of the disaster, and may continue to, since the influx of tailings does not stop, and sediment resuspension is a recurrent source for those impacts.