899 resultados para ruthenium acetate clusters
Resumo:
Fil: Belloni, Paula. Universidad Nacional de La Plata. Facultad de Humanidades y Ciencias de la Educación; Argentina.
Resumo:
Fil: Langard, Federico. Universidad Nacional de La Plata. Facultad de Humanidades y Ciencias de la Educación; Argentina.
Resumo:
Acetate and hydrogen concentrations in pore fluids were measured in samples taken at seven sites from southern Hydrate Ridge (SHR) offshore Oregon, USA. Acetate concentrations ranged from 3.17 to 2515 µM. The maximum acetate concentrations occurred at Site 1251, which was drilled on a slope basin to the east of SHR at depths just above the bottom-simulating reflector (BSR) that marks the boundary of gas hydrate stability. Acetate maxima and localized high acetate concentrations occurred at the BSR at all sites and frequently corresponded with areas of gas hydrate accumulation, suggesting an empirical relationship. Acetate concentrations were typically at a minimum near the seafloor and above the sulfate/methane interface, where sulfate-reducing bacteria may consume acetate. Hydrogen concentrations in pressure core samples ranged from 16.45 to 1036 parts per million by volume (ppmv). In some cases, hydrogen and acetate concentrations were elevated concurrently, suggesting a positive correlation. However, sampling of hydrogen was limited in comparison to acetate, so any relationships between the two analytes, if present, were difficult to discern.
Resumo:
Clusters of sponge spicules found in Quaternary deep-water sediments at Sites 685 and 688 off Peru represent single individuals of small sponges or fragments of larger sponges. The spicule assemblages constituting these clusters probably represent a few demosponge species of the subclass Tetractinomorpha and order Astrophorida, because triaenes and microscleric euasters, as well as abundant monaxons, are present. As proved by incorporated Neogene diatoms, these spicule clusters are allochthonous. The sponge individuals probably inhabited deeper neritic environments during late Neogene time.
Resumo:
These data are from a field experiment conducted in a shallow alluvial aquifer along the Colorado River in Rifle, Colorado, USA. In this experiment, bicarbonate-promoted uranium desorption and acetate amendment were combined and compared to an acetate amendment-only experiment in the same experimental plot. Data include names and location data for boreholes, geochemical data for all the boreholes between June 1, 2010 and January 1, 2011, microarray data provided as signal to noise ratio (SNR) for individual microarray probes, microarray data provided as signal to noise ratio (SNR) by Genus.
Resumo:
The microbial population in samples of basalt drilled from the north of the Australian Antarctic Discordance (AAD) during Ocean Drilling Program Leg 187 were studied using deoxyribonucleic acid (DNA)-based methods and culturing techniques. The results showed the presence of a microbial population characteristic for the basalt environment. DNA sequence analysis revealed that microbes grouping within the Actinobacteria, green nonsulfur bacteria, the Cytophaga/Flavobacterium/Bacteroides (CFB) group, the Bacillus/Clostridium group, and the beta and gamma subclasses of the Proteobacteria were present in the basalt samples collected. The most dominant phylogenetic group, both in terms of the number of sequences retrieved and the intensities of the DNA bands obtained with the denaturing gradient gel electrophoresis analysis, was the gamma Proteobacteria. Enrichment cultures showed phylogenetic affiliation with the Actinobacteria, the CFB group, the Bacillus/Clostridium group, and the alpha, beta, gamma, and epsilon subclasses of the Proteobacteria. Comparison of native and enriched samples showed that few of the microbes found in native basalt samples grew in the enrichment cultures. Only seven clusters, two clusters within each of the CFB and Bacillus/Clostridium groups and five clusters within the gamma Proteobacteria, contained sequences from both native and enriched basalt samples with significant similarity. Results from cultivation experiments showed the presence of the physiological groups of iron reducers and methane producers. The presence of the iron/manganese-reducing bacterium Shewanella was confirmed with DNA analysis. The results indicate that iron reducers and lithotrophic methanogenic Archaea are indigenous to the ocean crust basalt and that the methanogenic Archaea may be important primary producers in this basaltic environment.