Mineralogical In-situ Investigation of Acid-Sulfate Samples from the Rio Tinto River, Spain, with a Portable XRD/XRF Instrument

A field campaign was organized in September 2006 by Centro de Astobiologica (Spain) and Washington University (St Louis, USA) for the geological study of the Rio Tinto river bed sediments using a suite of in-situ instruments comprising an ASD reflectance spectrometer, an emission spectrometer, panoramic and close-up color imaging cameras, a life detection system and NASA's CheMin 4 XRD/XRF prototype. The primary objectives of the field campaign were to study the geology of the site and test the potential of the instrument suite in an astrobiological investigation context for future Mars surface robotic missions. The results of the overall campaign will be presented elsewhere. This paper focuses on the results of the XRD/XRF instrument deployment. The specific objectives of the CheMin 4 prototype in Rio Tinto were to 1) characterize the mineralogy of efflorescent salts in their native environments; 2) analyze the mineralogy of salts and oxides from the modern environment to terraces formed earlier as part of the Rio Tinto evaporative system; and 3) map the transition from hematite-dominated terraces to the mixed goethite/salt-bearing terraces where biosignatures are best preserved

Bacterial diversity of autotrophic enriched cultures from remote, glacial Antarctic, Alpine and Andean aerosol, snow and soil samples

International audienceFour different communities and one culture of autotrophic microbial assemblages were obtained by incubation of samples collected from high elevation snow in the Alps (Mt. Blanc area) and the Andes (Nevado Illimani summit, Bolivia), from Antarctic aerosol (French station Dumont d'Urville) and a maritime Antarctic soil (King George Island, South Shetlands, Uruguay Station Artigas), in a minimal mineral (oligotrophic) media. Molecular analysis of more than 200 16S rRNA gene sequences showed that all cultured cells belong to the Bacteria domain. Phylogenetic comparison with the currently available rDNA database allowed sequences belonging to Proteobacteria (Alpha-, Betaand Gamma-proteobacteria) , Actinobacteria and Bacteroidetes phyla to be identified. The Andes snow culture was the richest in bacterial diversity (eight microorganisms identified) and the marine Antarctic soil the poorest (only one). Snow samples from Col du Midi (Alps) and the Andes shared the highest number of identified microorganisms (Agrobacterium, Limnobacter, Aquiflexus and two uncultured Alphaproteobacteria clones). These two sampling sites also shared four sequences with the Antarctic aerosol sample (Limnobacter, Pseudonocardia and an uncultured Alphaproteobacteria clone). The only microorganism identified in the Antarctica soil (Brevundimonas sp.) was also detected in the Antarctic aerosol. Most of the identified microorganisms had been detected previously in cold environments, marine sediments soils and rocks. Air current dispersal is the best model to explain the presence of very specific microorganisms, like those identified in this work, in environments very distant and very different from each other

Characterization of a Subsurface Biosphere in a Massive Sulfide Deposit At Rio Tinto, Spain: Implications For Extant Life On Mars

The recent discovery of abundant sulfate minerals, particularly Jarosite by the Opportunity Rover at Sinus Merdiani on Mars has been interpreted as evidence for an acidic lake or sea on ancient Mars [1,2], since the mineral Jarosite is soluble in liquid water at pH above 4. The most likely mechanism to produce sufficient protons to acidify a large body of liquid water is near surface oxidation of pyrite rich deposits [3]. The acidic waters of the Rio Tinto, and the associated deposits of Hematite, Goethite, and Jarosite have been recognized as an important chemical analog to the Sinus Merdiani site on Mars [4]. The Rio Tinto is a river in southern Spain that flows 100 km from its source in the Iberian pyrite belt, one of the Earth's largest Volcanically Hosted Massive Sulfide (VHMS) provinces, into the Atlantic ocean. The river originates in artesian springs emanating from ground water that is acidified by the interaction with subsurface pyrite ore deposits. The Mars Analog Rio Tinto Experiment (MARTE) has been investigating the hypothesis that a subsurface biosphere exists at Rio Tinto living within the VHMS deposit living on chemical energy derived from sulfur and iron minerals. Reduced iron and sulfur might provide electron donors for microbial metabolism while in situ oxidized iron or oxidants entrained in recharge water might provide electron acceptors

Mars Sulfate Formation Sourced in Sulfide-Enriched Subsurface Fluids: The Rio Tinto Model

The extensive evidence for sulfate deposits on Mars provided by analyses of MER and Mars Express data shows that the sulfur played an essential role in the geochemical cycles of the planet, including reservoirs in the atmosphere, hydro-sphere and geosphere. Overall the data are consistent with a fluvial/lacustrine-evaporative origin of at least some of the sulfate deposits, with mineral precipitation through oversaturation of salty acidic fluids enriched in sulfates. This scenario requires reservoirs of sulfur and associated cations, as well as an acidic and oxidizing hydrochemistry which could be provided by surface and subsurface catching of meteoric waters resulting in the presence of sulfur-bearing gases and steam photochemistry. In this work we suggest a new scenario for the extensive generation of sulfates in Mars based on the observation of seasonal changes in the redox and pH of subsurface waters enriched in sulfur that supply the acidic Mars process analog of Rio Tinto. This model considers the long-term subsurface storage of sulfur during most of Noachian and its release from the late Noachian to Hesperian time through weathering by meteoric fluids that would acidify and oxidize the sulfur bearing compounds stored in the subsurface

Draft genome sequence of the deep-subsurface Ciceribacter sp. strain T2.26MG-112.2, a second Rhizobiaceae isolated from the Iberian Pyrite Belt at 492.6 mbs

T2.26MG-112.2 is a Ciceribacter strain that has been isolated from the deep subsurface of the Iberian Pyrite Belt. We report its draft genome consisting of a chromosome of ≈4.9 Mb and a plasmid of 357 kb. The annotation reveals 4,824 coding sequences, 48 tRNA genes, and 1 rRNA operonThis work was supported by MCINN grants PID2019-104812GB-I00 and TED2021-129563B-I0

BIOTECHNOLOGICAL SEQUESTERING OF CHROMIUM(III) FROM POST-TANNING EFFLUENTS: FIRST RESULTS

Heavy metals in waste waters and sludge may cause significant environmental problems, and it is known that conventional recovery technologies cannot always achieve satusfactort treatment. For example, they are inappropriate to completely recover the chromium in the case of waste waters from the tanning process. Chromium can be recovered (by precipitation) from effluents that contain high concentrations of this metal. However, effluents from the later stages in present day tanning process often have a low concentration of chromium that cannot be recovered and is found in the sludge of the waste water treatment plant (WWTP). The aim of our research is to recover and reuse the chromium (III) from post-tanning effluents by means of a biotechnological sequestering method using acidophilic fungi. In this study, we tested acidophilic fungi capable to grow in the presence of chromium in waste waters from various stages of a real post-tanning process. When the post-tanning process was carried out on a pilot plant scale in which conventional rechroming and neutralization stages were undertaken and the use of additional chemicals was avoided, chromium (III) sequestration values of above 95% were obtained. As these results are so promising, further studies will focus on searching for more resistant fungal strains and determining which of the chemicals used in the post-tanning process can be avoided or replaced by alternatives. Resumen Metales pesados en efluentes y lodos podrían causar significantes problemas al medio ambiente, y es conocido que la recuperación por medio de tecnologías convencionales no puede siempre ser un tratamiento satisfactorio. Por ejemplo, son inapropiados para la recuperación completa de cromo en ciertos casos de los desechos hídricos en el proceso de curtición. Cromo puede ser recuperado (por precipitación) de efluentes conteniendo altos niveles de concentración de este metal. Sin embargo, efluentes de las etapas posteriores provenientes del proceso de curtición de hoy en día, que muy a menudo contienen concentraciones tan bajas, que no es recuperable y se encuentra entonces el cromo en el lodo de la planta de tratamiento de desechos líquidos (WWTP). El objetivo de nuestras investigaciones es recuperar y reutilizar el cromo (III) en los efluentes del recurtido por medio de un método secuestrante biotecnológico empleando hongos acidófílos. En este estudio, probamos hongos acidofílos capaces de reproducirse en presencia de desperdicios líquidos de las varias etapas reales del recurtido. Cuando se efectuó a escala de planta piloto el proceso en las operaciones de recromado y neutralizado convencionales y el empleo de agentes químicos adicionales fue obviado, se obtuvieron resultados de secuestro del cromo (III) superiores al 95%. Ya que los resultados prometen tanto, estudios posteriores se enfocarían en la búsqueda de cepas micóticas más resistentes y determinando cuales de los productos químicos usados en los procesos posteriores al curtido pueden ser evitados o sustituidos por alternativos

Methanogenesis at high temperature, high ionic strength and low pH in the volcanic area of Dallol, Ethiopia

The Dallol geothermal area originated as a result of seismic activity and the presence of a shallow underground volcano, both due to the divergence of two tectonic plates. In its ascent, hot water dissolves and drags away the subsurface salts. The temperature of the water that comes out of the chimneys is higher than 100C, with a pH close to zero and high mineral concentration. These factors make Dallol a polyextreme environment. So far, nanohaloarchaeas, present in the salts that form the walls of the chimneys, have been the only living beings reported in this extreme environment. Through the use of complementary techniques: culture in microcosms, methane stable isotope signature and hybridization with specific probes, the methanogenic activity in the Dallol area has been assessed. Methane production in microcosms, positive hybridization with the Methanosarcinales probe and the δC-values measured, show the existence of extensive methanogenic activity in the hydrogeothermic Dallol system. A methylotrophic pathway, carried out by Methanohalobium and Methanosarcina-like genera, could be the dominant pathway for methane production in this environment.Agencia Estatal de Investigación (AEI), grant MDM-2017-0737 (Unidad de Excelencia “María de Maeztu”-Centro de Astrobiología INTA-CSIC) and the Spanish Ministerio de Ciencia e Innovación (MICINN

Distribution and seasonal variability in the benthic eukaryotic community of Río Tinto (SW, Spain), an acidic, high metal extreme environment

Author Posting. © The Author(s), 2007. This is the author's version of the work. It is posted here by permission of Elsevier B.V. for personal use, not for redistribution. The definitive version was published in Systematic and Applied Microbiology 30 (2007): 531-546, doi:10.1016/j.syapm.2007.05.003.The eukaryotic community of Río Tinto (SW, Spain) was surveyed fall, winter, and spring through the combined use of traditional microscopy and molecular approaches including Denaturing Gradient Gel Electrophoresis (DGGE) and sequence analysis of 18S rRNA gene fragments. We compared eukaryotic assemblages of surface sediment biofilms collected in January, May and September 2002 from 13 sampling stations along the river. Physicochemical data revealed extremely acidic conditions (pH ranged from 0.9 to 2.5) with high concentrations of heavy metals including up to 20 g l-1 Fe, 317 mg l-1 Zn, 47 mg l-1 As, 42 mg l-1 Cd, and 4 mg l-1 Ni. In total, 20 taxa were identified, including members of the Bacillariophyta, Chlorophyta, and Euglenophyta phyla as well as ciliates, cercomonads, amoebae, stramenopiles, fungi, heliozoan and rotifers. In general, total cell abundances were highest in fall and spring decreasing drastically in winter and the sampling stations with the most extreme conditions showed the lowest number of cells as well as the lowest diversity. Species diversity does not vary much during the year. Only the filamentous algae showed a dramatic seasonal change almost disappearing in winter and reaching the highest biomass during the summer. PCA showed a high inverse correlation between pH and most of the heavy metals analyzed as well as Dunaliella sp., while Chlamydomonas sp. is directly related to pH during May and September. Three heavy metals (Zn, Cu and Ni) remained separate from the rest and showed an inverse correlation with most of the species analyzed except for Dunaliella sp.A.A was supported by the Spanish Ministry of Education and Science through the Ramón y Cajal program. This work has been supported by grant CGL2005-05470/BOS and grants to the Centro de Astrobiología at the Instituto National de Técnica Aeroespacial

Editorial: Archaea in the Environment: Views on Archaeal Distribution, Activity, and Biogeography

On the occasion of the 10-year anniversary of Frontiers in Microbiology, this Research Topic was launched to highlight the linkages between extreme and archaeal microbiology (Teske, 2020). Archaea adapt to the physical and chemical characteristics of their habitat—such as organic matter availability, electron donor redox status, salinity, temperature, and pH—in terms of metabolic activity, community composition, gene expression patterns, and evolutionary diversification (Baker et al., 2020). Here, cultivation- and genome-based studies highlight linkages between archaea and their habitats (Figure 1)

Visualizing microorganism-mineral interaction in the iberian pyrite belt subsurface: the acidovorax case

Despite being considered an extreme environment, several studies have shown that life in the deep subsurface is abundant and diverse. Microorganisms inhabiting these systems live within the rock pores and, therefore, the geochemical and geohydrological characteristics of this matrix may influence the distribution of underground biodiversity. In this study, correlative fluorescence and Raman microscopy (Raman-FISH) was used to analyze the mineralogy associated with the presence of members of the genus Acidovorax, an iron oxidizing microorganisms, in native rock samples of the Iberian Pyrite Belt subsurface. Our results suggest a strong correlation between the presence of Acidovorax genus and pyrite, suggesting that the mineral might greatly influence its subsurface distributionThe authors acknowledge financial support from the Spanish AEI, Project MDM-2017-0737 Unidad de Excelencia “María de Maeztu”- Centro de Astrobiología (INTA-CSIC), the Spanish MINECO, Project MAT2017-86450-C4-1-R and the Spanish MICINN, Projects PID2019-104812GB-I00 and RTI2018-099794-B-I00