Search Results - (Author, Cooperation:R. S. Sletten)
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1Latest Papers from Table of Contents or Articles in PressJ. P. Grotzinger ; D. Y. Sumner ; L. C. Kah ; K. Stack ; S. Gupta ; L. Edgar ; D. Rubin ; K. Lewis ; J. Schieber ; N. Mangold ; R. Milliken ; P. G. Conrad ; D. DesMarais ; J. Farmer ; K. Siebach ; F. Calef, 3rd ; J. Hurowitz ; S. M. McLennan ; D. Ming ; D. Vaniman ; J. Crisp ; A. Vasavada ; K. S. Edgett ; M. Malin ; D. Blake ; R. Gellert ; P. Mahaffy ; R. C. Wiens ; S. Maurice ; J. A. Grant ; S. Wilson ; R. C. Anderson ; L. Beegle ; R. Arvidson ; B. Hallet ; R. S. Sletten ; M. Rice ; J. Bell, 3rd ; J. Griffes ; B. Ehlmann ; R. B. Anderson ; T. F. Bristow ; W. E. Dietrich ; G. Dromart ; J. Eigenbrode ; A. Fraeman ; C. Hardgrove ; K. Herkenhoff ; L. Jandura ; G. Kocurek ; S. Lee ; L. A. Leshin ; R. Leveille ; D. Limonadi ; J. Maki ; S. McCloskey ; M. Meyer ; M. Minitti ; H. Newsom ; D. Oehler ; A. Okon ; M. Palucis ; T. Parker ; S. Rowland ; M. Schmidt ; S. Squyres ; A. Steele ; E. Stolper ; R. Summons ; A. Treiman ; R. Williams ; A. Yingst
American Association for the Advancement of Science (AAAS)
Published 2013Staff ViewPublication Date: 2013-12-11Publisher: American Association for the Advancement of Science (AAAS)Print ISSN: 0036-8075Electronic ISSN: 1095-9203Topics: BiologyChemistry and PharmacologyComputer ScienceMedicineNatural Sciences in GeneralPhysicsKeywords: Bays ; Carbon/analysis ; *Exobiology ; *Extraterrestrial Environment ; Geologic Sediments/analysis/classification ; Hydrogen/analysis ; Hydrogen-Ion Concentration ; Iron/analysis/chemistry ; *Mars ; Nitrogen/analysis ; Oxidation-Reduction ; Oxygen/analysis ; Phosphorus/analysis ; Salinity ; Sulfur/analysis/chemistry ; *WaterPublished by: -
2Articles: DFG German National LicensesStaff View
ISSN: 1751-8369Source: Blackwell Publishing Journal Backfiles 1879-2005Topics: GeographyGeosciencesNotes: Soils at well-drained sites near Kongsfjorden, Spitsbergen, are described in terms of morphology as well as solid and solution phase chemistry. Decarbonation is the dominant soil process and results in high Mg and Ca concentrations in soil solutions, in negative enrichment of Fe, Al, and non-carbonate clasts in near-surface horizons, and in the accumulation of dolomitic silt horizons at depth. Coatings of reprecipitated carbonates extend into the C horizon. Several developmental pathways are suggested for well-drained carbonate soils at Kongsfjorden. In vegetation-rich areas, with calcite-rich parent material, relatively rapid (∼ 10, 000 years) carbonate dissolution precedes silicate mineral weathering. In areas of Polar Desert climate and dolomitic parent material, decarbonation is slower and the continued accumulation of dolomite silt may eventually transform the soil system to a periglacial one.Type of Medium: Electronic ResourceURL: -
3Articles: DFG German National LicensesStaff View
ISSN: 1573-2932Keywords: arsenic ; sequential extraction ; soil size fractionsSource: Springer Online Journal Archives 1860-2000Topics: Energy, Environment Protection, Nuclear Power EngineeringNotes: Abstract Five soils from Austria that have high contents of arsenic (As)due to anthropogenic and/or geogenic sources were separated intosand, silt, and clay fractions. The distribution of As among theparticle-size fractions was clay 〉〉 silt 〉 sand. Theparticle-size fractions were analysed according to an 8-stepsequential extraction procedure (SEP) designed to assess theprimary reservoirs and extractability of As. Steps 1 and 2,(i.e. NH4NO3 and (NH4)2SO4) extractedthe least As, while considerably greater amounts were extractedin steps 3, 4 and 5 (i.e. NH4H2PO4,NH2OH-HCl, and NH4F). The greatest amounts of As wereextracted in steps 6 and 7, both NH4-oxalate extractantstargeting the amorphous and crystalline oxide fractions. Theresidual fraction (step 8) was typically low. The extraction ofthe clays contained generally more As in steps 3 to 8, while Asrelease in the first two steps was typically highest in the sandand silt fractions. These findings are in accord with factoranalysis indicating that the extractants of the SEP areseparated into weak (steps 1 and 2) and strong (steps 3 to 8)extractants. SEP data along with microprobe analyses (X-raymicroanalyses) indicate that most As is associated with Fe andis therefore not readily mobile. Anyhow, As could be releasedupon changes in redox potential or pH. The greaterextractability of As from sand fractions using weak extractantsmay explain the higher toxicity of As in coarse-textured soils,as found in previous studies.Type of Medium: Electronic ResourceURL: