Papers by Keyword: Sulfur Cycle

Abstract: The geomicrobiological characterization of Río Tinto, an extreme acidic environment, has proven the importance of the iron cycle, not only in generating the extreme conditions of the habitat (low pH, high concentration of toxic heavy metals) but also in maintaining the high level of microbial diversity detected in the water column and the sediments. The extreme conditions detected in the Tinto basin are not the product of industrial contamination but the consequence of the presence of an underground bioreactor that obtains its energy from the massive sulfide minerals of the Iberian Pyrite Belt (IPB). To test this hypothesis, a drilling project (IPBSL) to intersect ground waters interacting with the mineral ore is under way, to provide evidence of subsurface microbial activities. A dedicated geophysical characterization of the area selected two drilling sites due to the possible existence of water with high ionic content. Two wells have been drilled in Peña de Hierro, BH11 and BH10, with depths of 340 and 630 meters respectively, with recovery of cores and generation of samples in anaerobic and sterile conditions. The geological analysis of the retrieved cores showed an important alteration of mineral structures associated with the presence of water, with production of expected products from the bacterial oxidation of pyrite. Ion chromatography of water soluble compounds from uncontaminated samples showed the existence of putative electron donors, electron acceptors, as well as variable concentration of metabolic organic acids, which suggest the presence of an active subsurface ecosystem associated to the high sulfidic mineral content of the IPB. Enrichment cultures from selected samples showed evidences of an active iron and sulfur cycle, together with unexpected methanogenic, methanotrophic and acetogenic activities. The geological, geomicrobiological and molecular biology analyses which are under way, should allow the characterization of this ecosystem of biohydrometallurgical interest

Abstract: A 1.2 km long effluent from La Zarza-Perrunal mine (Iberian Pyritic Belt, IPB) was characterized and compared with Río Tinto. In La Zarza effluent microbial oxidation of ferrous iron is responsible for the drastic increase in ferric iron, from a ratio of Fe(III)/Fetotal of 0.11 at the origin, up to 0.99 downstream. Prokaryotic and eukaryotic diversity throughout the effluent were determined. Bacteria related to the sulfur cycle as well as iron-reducing bacteria were mainly detected near the anoxic origin. Iron-oxidizing microorganisms increased along the course of the effluent following an increase in the oxygen content in the water column. Eukaryotic diversity varied drastically along the effluent. Rio Tinto (92 km length) is a natural extreme acidic environment with a rather constant acidic pH (mean pH value 2.3) and a high concentration of heavy metals. The Tinto ecosystem is under the control of iron [1]. The geomicrobiological comparisons of both habitats were performed to unravel some basic questions of biohydrometallurgical interest.

Abstract: Rio Tinto (Iberian Pyritic Belt, SW Spain) is a natural extreme acidic environment with a rather constant acidic pH (mean pH value 2.3) and a high concentration of heavy metals. The Tinto ecosystem is under the control of iron. The geomicrobiological characterization of Río Tinto has unravelled some basic questions of biohydrometallurgical interest. The methodologies developed for this study were applied successfully to monitor different bioleaching processes of the BioMinE project.