Gómez-Villegas Patricia, Guerrero José Luis, Pérez-Rodriguez Miguel, Bolívar Juan Pedro, Morillo Antonio, Vigara Javier, Léon Rosa
Laboratory of Biochemistry, Center for Natural Resources, Health and Environment (RENSMA), University of Huelva, Avda. de las Fuerzas Armadas s/n, Huelva 21071, Spain.
Department of Integrated Sciences, Center for Natural Resources, Health and Environment (RENSMA), University of Huelva, Avda. de las Fuerzas Armadas s/n, Huelva 21071, Spain.
Aquat Toxicol. 2022 Apr;245:106103. doi: 10.1016/j.aquatox.2022.106103. Epub 2022 Jan 24.
Around 100 Mt of phosphogypsum (PG) have been deposited in large stacks on the salt marshes of the Tinto River estuary in Huelva (SW Spain), covering about 1000 ha. These stacks contain extremely acidic water (pH < 2) with high concentrations of pollutants which can cause emissions into their surroundings, generating important environmental concerns. Despite many chemical, geological or hydrological studies have been conducted to characterize the PG stacks of Huelva, the microbial community inhabiting this extreme environment remains unexplored. Using a 16S/18S-rRNA-high throughput sequencing approach, we have uncovered the main taxonomic groups able to live in the acidic metal-contaminated water, which is in direct contact with the PG, demonstrating for the first time the existence of a huge diversity of microbial species in these extreme conditions. In addition, the physicochemical characteristics of the water sampled have been analyzed. These studies have revealed that the most abundant bacteria found in two different leachate samples of the PG stacks belong to the genera Acidiphilium, Pseudomonas, Leptosprillum, Acidithrix, or Acidithiobacillus, typically found in acid mine drainage (AMD) environments, which in total represent around 50% of the total bacterial community. Biodiversity of eukaryotes in PG water is lower than that of prokaryotes, especially in the water collected from the perimeter channel that surrounds the PG stacks, where the pH reaches a value of 1.5 and the activity concentrations exceed 300 Bq L for U or 20 Bq L for Po, values which are from four to five orders of magnitude higher than those usually found in unperturbed surface waters. Even so, an unexpected diversity of algae, fungi, and ciliates have been found in the PG stacks of Huelva, where chlorophyte microalgae and basidiomycetes fungi are the most abundant eukaryotes. Additional bioinformatics tools have been used to perform a functional analysis and predict the most common metabolic pathways in the PG microbiota. The obtained data indicate that the extreme conditions of these PG stacks hide an unexpected microbial diversity, which can play an important role in the dynamics of the contaminating compounds of the PG and provide new strains with unique biotechnological applications.
约1亿吨磷石膏（PG）被堆积在韦尔瓦（西班牙西南部）廷托河河口的盐沼中，占地面积约1000公顷。这些磷石膏堆含有极酸性的水（pH值<2），且污染物浓度很高，可能会排放到周围环境中，引发了重要的环境问题。尽管已经进行了许多化学、地质或水文研究来描述韦尔瓦的磷石膏堆，但栖息在这种极端环境中的微生物群落仍未得到探索。我们采用16S/18S - rRNA高通量测序方法，发现了能够生活在与磷石膏直接接触的酸性金属污染水中的主要分类群，首次证明了在这些极端条件下存在着极其多样的微生物物种。此外，还分析了所采集水样的理化特性。这些研究表明，在磷石膏堆的两个不同渗滤液样本中发现的最丰富细菌属于嗜酸菌属、假单胞菌属、纤发菌属、嗜酸丝菌属或嗜酸硫杆菌属，这些细菌通常存在于酸性矿山排水（AMD）环境中，它们总共约占细菌群落总数的50%。磷石膏水中真核生物的生物多样性低于原核生物，特别是在围绕磷石膏堆的周边渠道采集的水中，那里的pH值达到1.5，铀的活度浓度超过300 Bq/L，钋的活度浓度超过20 Bq/L，这些值比未受干扰的地表水通常发现的值高出四到五个数量级。即便如此，在韦尔瓦的磷石膏堆中仍发现了意想不到的藻类、真菌和纤毛虫多样性，其中绿藻微藻和担子菌真菌是最丰富的真核生物。还使用了其他生物信息学工具进行功能分析，并预测磷石膏微生物群中最常见的代谢途径。获得的数据表明，这些磷石膏堆的极端条件隐藏着意想不到的微生物多样性，这可能在磷石膏污染化合物的动态变化中发挥重要作用，并为具有独特生物技术应用的新菌株提供来源。
