Geoquímica microbiana del lago ácido y salino de la corta de la mina Brunita (La Unión, SE España)

Translated title of the contribution: Microbial Geochemistry of the Acidic Saline Pit Lake of Brunita Mine (La Unión, SE Spain)

Javier Sánchez-España*, Iñaki Yusta, Andrey Ilin, Charlotte van der Graaf, Irene Sánchez-Andrea

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

2 Citations (Scopus)

Abstract

We present the first study of a unique acidic lake formed in the Brunita open pit (La Unión mines, Cartagena, SE Spain). This pit lake exhibits chemical characteristics typical of AMD, such as low pH (pH 2.2–5.0) and high iron content (500–6400 mg/L total Fe). It also has some of the highest sulfate concentrations reported to date in pit lakes (26,000–38,400 mg/L SO42-) and transition metals like Mn (up to 2000 mg/L), Zn (500 mg/L), or Cu (250 mg/L). In addition, we found abnormally high concentrations of salt-forming ions (e.g. 5500 mg/L Mg, 750–1300 mg/L Cl, and 300–630 mg/L Na). The resulting high salinity (58‰) at the bottom creates a meromictic lake despite the lake’s low relative depth (9%), with an anoxic, reducing monimolimnion isolated from the oxygenated mixolimnion. In the monimolimnion, we observed decreased metal concentrations (e.g. Cu, Zn, Cd, Cr, Pb, Th). We hypothesize that these metals are being removed by interaction with biogenic H2S and subsequent precipitation as metal sulfides. Scanning electron microscopy shows sub-micron, spherical particles of ZnS in close association with cocci and rod-like bacteria. Analysis of the microbial community composition through 16S rRNA gene amplicon sequencing revealed different genera of sulfate-reducing bacteria (SRB) in the monimolimnion, including Desulfobacca, Desulfomonile, Desulfurispora, and Desulfosporosinus. Their apparent ability to reduce sulfate and selectively precipitate potentially toxic metals, and their resistance to this lake’s extreme geochemical conditions, makes these bacteria of great interest for biotechnological applications (e.g. bioremediation and biomining).

Original languageSpanish
Pages (from-to)535-555
Number of pages21
JournalMine Water and the Environment
Volume39
DOIs
Publication statusPublished - 25 Jan 2020

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