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https://www.readbyqxmd.com/read/28190688/antimony-as-a-global-dilemma-geochemistry-mobility-fate-and-transport
#1
REVIEW
Indika Herath, Meththika Vithanage, Jochen Bundschuh
Elevated concentrations of antimony (Sb) in environmental, biological and geochemical systems originating from natural, geological and anthropogenic sources are of particular global concern. This review presents a critical overview of natural geochemical processes which trigger the mobilization of Sb from its host mineral phases and related rocks to the surrounding environments. The primary source of Sb contamination in the environment is geogenic. The geochemical characteristics of Sb are determined by its oxidation states, speciation and redox transformation...
February 9, 2017: Environmental Pollution
https://www.readbyqxmd.com/read/28181800/vanadium-geochemistry-of-oil-sands-fluid-petroleum-coke
#2
Jake A Nesbitt, Matthew B J Lindsay
Vanadium has previously been linked to elevated toxicity of leachates derived from oil sands petroleum coke. However, geochemical controls on V mobility within coke deposits remain poorly constrained. Detailed examinations of porewater and solid-phase V geochemistry were therefore performed on oil sands fluid petroleum coke deposits in Alberta, Canada. Sample collection focused on both active and reclaimed deposits, which contained more than 3 × 10(7) m(3) of fluid petroleum coke. Dissolved V concentrations were highest (up to 3...
February 17, 2017: Environmental Science & Technology
https://www.readbyqxmd.com/read/28179898/metatranscriptomic-analysis-reveals-unexpectedly-diverse-microbial-metabolism-in-a-biogeochemical-hot-spot-in-an-alluvial-aquifer
#3
Talia N M Jewell, Ulas Karaoz, Markus Bill, Romy Chakraborty, Eoin L Brodie, Kenneth H Williams, Harry R Beller
Organic matter deposits in alluvial aquifers have been shown to result in the formation of naturally reduced zones (NRZs), which can modulate aquifer redox status and influence the speciation and mobility of metals, affecting groundwater geochemistry. In this study, we sought to better understand how natural organic matter fuels microbial communities within anoxic biogeochemical hot spots (NRZs) in a shallow alluvial aquifer at the Rifle (CO) site. We conducted a 20-day microcosm experiment in which NRZ sediments, which were enriched in buried woody plant material, served as the sole source of electron donors and microorganisms...
2017: Frontiers in Microbiology
https://www.readbyqxmd.com/read/28176842/clay-mineralogical-and-geochemical-proxies-of-the-east-asian-summer-monsoon-evolution-in-the-south-china-sea-during-late-quaternary
#4
Quan Chen, Zhifei Liu, Catherine Kissel
The East Asian summer monsoon controls the climatic regime of an extended region through temperature and precipitation changes. As the East Asian summer monsoon is primarily driven by the northern hemisphere summer insolation, such meteorological variables are expected to significantly change on the orbital timescale, influencing the composition of terrestrial sediments in terms of both mineralogy and geochemistry. Here we present clay mineralogy and major element composition of Core MD12-3432 retrieved from the northern South China Sea, and we investigate their relationship with the East Asian summer monsoon evolution over the last 400 ka...
February 8, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28158920/the-geobiological-nitrogen-cycle-from-microbes-to-the-mantle
#5
A L Zerkle, S Mikhail
Nitrogen forms an integral part of the main building blocks of life, including DNA, RNA, and proteins. N2 is the dominant gas in Earth's atmosphere, and nitrogen is stored in all of Earth's geological reservoirs, including the crust, the mantle, and the core. As such, nitrogen geochemistry is fundamental to the evolution of planet Earth and the life it supports. Despite the importance of nitrogen in the Earth system, large gaps remain in our knowledge of how the surface and deep nitrogen cycles have evolved over geologic time...
February 3, 2017: Geobiology
https://www.readbyqxmd.com/read/28139267/when-is-a-terrace-not-a-terrace-the-importance-of-understanding-landscape-evolution-in-studies-of-terraced-agriculture
#6
C Ferro-Vázquez, C Lang, J Kaal, D Stump
Before the invention of modern, large-scale engineering projects, terrace systems were rarely built in single phases of construction, but instead developed gradually, and could even be said to have evolved. Understanding this process of landscape change is therefore important in order to fully appreciate how terrace systems were built and functioned, and is also pivotal to understanding how the communities that farmed these systems responded to changes; whether these are changes to the landscape brought about by the farming practices themselves, or changes to social, economic or climatic conditions...
January 28, 2017: Journal of Environmental Management
https://www.readbyqxmd.com/read/28122279/-210-pb-137-cs-and-7-be-in-the-sediments-of-coastal-lakes-on-the-polish-coast-implications-for-sedimentary-processes
#7
Michał Woszczyk, Grzegorz Poręba, Łukasz Malinowski
In this study we combined radioisotopes ((210)Pb, (137)Cs and (7)Be) and hydrodynamic modeling to investigate sedimentary processes in three coastal lakes on the Polish Baltic coast. The research aimed at establishing the depth of sediment mixing and its effects on sediment geochemistry as well as showing the relationship between lake water salinity and radionuclide distribution in the sediment cores. We established that the intensity of mixing displayed appreciable variability throughout the lakes and the thickness of sediment mixing layer was between <2 and 22 cm...
January 22, 2017: Journal of Environmental Radioactivity
https://www.readbyqxmd.com/read/28122036/temporal-and-spatial-variations-of-bacterial-and-faunal-communities-associated-with-deep-sea-wood-falls
#8
Petra Pop Ristova, Christina Bienhold, Frank Wenzhöfer, Pamela E Rossel, Antje Boetius
Sinking of large organic food falls i.e. kelp, wood and whale carcasses to the oligotrophic deep-sea floor promotes the establishment of locally highly productive and diverse ecosystems, often with specifically adapted benthic communities. However, the fragmented spatial distribution and small area poses challenges for the dispersal of their microbial and faunal communities. Our study focused on the temporal dynamics and spatial distributions of sunken wood bacterial communities, which were deployed in the vicinity of different cold seeps in the Eastern Mediterranean and the Norwegian deep-seas...
2017: PloS One
https://www.readbyqxmd.com/read/28117550/abundant-carbon-substrates-drive-extremely-high-sulfate-reduction-rates-and-methane-fluxes-in-prairie-pothole-wetlands
#9
Paula Dalcin Martins, David W Hoyt, Sheel Bansal, Christopher T Mills, Malak Tfaily, Brian A Tangen, Raymond G Finocchiaro, Michael D Johnston, Brandon C McAdams, Matthew J Solensky, Garrett J Smith, Yu-Ping Chin, Michael J Wilkins
Inland waters are increasingly recognized as critical sites of methane emissions to the atmosphere, but the biogeochemical reactions driving such fluxes are less well understood. The Prairie Pothole Region (PPR) of North America is one of the largest wetland complexes in the world, containing millions of small, shallow wetlands. The sediment pore waters of PPR wetlands contain some of the highest concentrations of dissolved organic carbon (DOC) and sulfur species ever recorded in terrestrial aquatic environments...
January 24, 2017: Global Change Biology
https://www.readbyqxmd.com/read/28096405/selenium-isotopes-record-extensive-marine-suboxia-during-the-great-oxidation-event
#10
Michael A Kipp, Eva E Stüeken, Andrey Bekker, Roger Buick
It has been proposed that an "oxygen overshoot" occurred during the early Paleoproterozoic Great Oxidation Event (GOE) in association with the extreme positive carbon isotopic excursion known as the Lomagundi Event. Moreover, it has also been suggested that environmental oxygen levels then crashed to very low levels during the subsequent extremely negative Shunga-Francevillian carbon isotopic anomaly. These redox fluctuations could have profoundly influenced the course of eukaryotic evolution, as eukaryotes have several metabolic processes that are obligately aerobic...
January 31, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28088549/redistribution-of-elements-between-wastes-and-organic-bearing-material-in-the-dispersion-train-of-gold-bearing-sulfide-tailings-part-i-geochemistry-and-mineralogy
#11
B Yu Saryg-Ool, I N Myagkaya, I S Kirichenko, M A Gustaytis, O V Shuvaeva, S M Zhmodik, E V Lazareva
Migration and redistribution of elements during prolonged interaction of cyanide wastes with the underlying natural organic-bearing material have been studied in two ~40cm deep cores that sample primary ores and their weathering profile (wastes I and II, respectively) in the dispersion train of gold-bearing sulfide tailings in Siberia. Analytical results of SR-XRF, whole-rock XRF, AAS, CHNS, and SEM measurements of core samples show high K, Sr, Ti, and Fe enrichments and correlation of P2O5 and Mn with LOI and Corg...
January 11, 2017: Science of the Total Environment
https://www.readbyqxmd.com/read/28076393/alder-nitrogen-and-lake-ecology-terrestrial-aquatic-linkages-in-the-postglacial-history-of-lone-spruce-pond-southwestern-alaska
#12
Bianca B Perren, Yarrow Axford, Darrell S Kaufman
Diatoms, combined with a multiproxy study of lake sediments (organic matter, N, δ15N, δ13C, biogenic silica, grain size, Cladocera and chironomids, Alnus pollen) from Lone Spruce Pond, Alaska detail the late-glacial to Holocene history of the lake and its response to regional climate and landscape change over the last 14.5 cal ka BP. We show that the immigration of alder (Alnus viridis) in the early Holocene marks the rise of available reactive nitrogen (Nr) in the lake as well as the establishment of a primarily planktonic diatom community...
2017: PloS One
https://www.readbyqxmd.com/read/28063656/effect-of-cyclic-redox-oscillations-on-water-quality-in-freshwater-acid-sulfate-soil-wetlands
#13
Niloofar Karimian, Scott G Johnston, Edward D Burton
Restoration of acid sulfate soil (ASS) wetlands by freshwater re-flooding can lead to the reformation of various Fe(II) and reduced inorganic sulfur (RIS) species in surface soil layers. However, in many locations, wetland water levels undergo large seasonal fluctuations that drive extreme redox oscillations. Newly formed RIS species [e.g. greigite, mackinawite, nano-pyrite and S(0)] and Fe(II) are vulnerable to rapid oxidation during dry periods and may generate substantial acidity. Rainfall following a dry period may then mobilise acidity and metal cations in surface waters prior to eventual recovery in pH by re-establishment of reducing conditions...
January 4, 2017: Science of the Total Environment
https://www.readbyqxmd.com/read/28045509/metal-ion-modeling-using-classical-mechanics
#14
Pengfei Li, Kenneth M Merz
Metal ions play significant roles in numerous fields including chemistry, geochemistry, biochemistry, and materials science. With computational tools increasingly becoming important in chemical research, methods have emerged to effectively face the challenge of modeling metal ions in the gas, aqueous, and solid phases. Herein, we review both quantum and classical modeling strategies for metal ion-containing systems that have been developed over the past few decades. This Review focuses on classical metal ion modeling based on unpolarized models (including the nonbonded, bonded, cationic dummy atom, and combined models), polarizable models (e...
February 8, 2017: Chemical Reviews
https://www.readbyqxmd.com/read/28040254/source-distribution-and-ecotoxicological-assessment-of-multielements-in-superficial-sediments-of-a-tropical-turbid-estuarine-environment-a-multivariate-approach
#15
M J Watts, S Mitra, A L Marriott, S K Sarkar
The work examined the distribution, possible sources and ecotoxicological assessment of 51 trace elements covering 13 sampling stations in surface sediments of coastal regions of Sundarban mangrove wetland and adjacent Hugli river estuary. The element concentrations exhibited an increasing trend towards downstream of the estuary (except lanthanides) with maximum enrichment for 22 elements at Gangadharpur (Sundarban region). According to Sediment Quality Guidelines (SQGs), the concentrations of Cu, As, Cr and Cd exceeded the Effects-Range-Low values, while Ni at certain stations exceeded the Effects-Range-Medium suggesting adverse effects on the sediment-dwelling organisms...
December 28, 2016: Marine Pollution Bulletin
https://www.readbyqxmd.com/read/28034542/shifts-in-microbial-community-structure-and-function-in-surface-waters-impacted-by-unconventional-oil-and-gas-wastewater-revealed-by-metagenomics
#16
N L Fahrenfeld, Hannah Delos Reyes, Alessia Eramo, Denise M Akob, Adam C Mumford, Isabelle M Cozzarelli
Unconventional oil and gas (UOG) production produces large quantities of wastewater with complex geochemistry and largely uncharacterized impacts on surface waters. In this study, we assessed shifts in microbial community structure and function in sediments and waters upstream and downstream from a UOG wastewater disposal facility. To do this, quantitative PCR for 16S rRNA and antibiotic resistance genes along with metagenomic sequencing were performed. Elevated conductivity and markers of UOG wastewater characterized sites sampled downstream from the disposal facility compared to background sites...
December 26, 2016: Science of the Total Environment
https://www.readbyqxmd.com/read/28004913/geochemical-parameters-and-reductive-dechlorination-determine-aerobic-cometabolic-vs-aerobic-metabolic-vinyl-chloride-biodegradation-at-oxic-anoxic-interface-of-hyporheic-zones
#17
Siavash Atashgahi, Yue Lu, Javier Ramiro-Garcia, Peng Peng, Farai Maphosa, Detmer Sipkema, Winnie Dejonghe, Hauke Smidt, Dirk Springael
Hyporheic zones mediate vinyl chloride (VC) biodegradation in groundwater discharging into surface waters. At the oxic/anoxic interface (OAI) of hyporheic zones subjected to redox oscillations, VC is degraded via coexisting aerobic ethenotrophic and anaerobic reductive dechlorination pathways. However, the identity of aerobic VC degradation pathways (cometabolic vs metabolic) and their interactions with reductive dechlorination in relation to riverbed sediment geochemistry remain ill-defined. We addressed this using microcosms containing OAI sediments incubated under fluctuating oxic/anoxic atmosphere...
January 11, 2017: Environmental Science & Technology
https://www.readbyqxmd.com/read/27995953/anthropogenic-and-natural-sources-of-dust-in-peatland-during-the-anthropocene
#18
B Fiałkiewicz-Kozieł, B Smieja-Król, M Frontasyeva, M Słowiński, K Marcisz, E Lapshina, D Gilbert, A Buttler, V E J Jassey, K Kaliszan, F Laggoun-Défarge, P Kołaczek, M Lamentowicz
As human impact have been increasing strongly over the last decades, it is crucial to distinguish human-induced dust sources from natural ones in order to define the boundary of a newly proposed epoch - the Anthropocene. Here, we track anthropogenic signatures and natural geochemical anomalies in the Mukhrino peatland, Western Siberia. Human activity was recorded there from cal AD 1958 (±6). Anthropogenic spheroidal aluminosilicates clearly identify the beginning of industrial development and are proposed as a new indicator of the Anthropocene...
December 20, 2016: Scientific Reports
https://www.readbyqxmd.com/read/27960117/factors-controlling-groundwater-salinization-and-hydrogeochemical-processes-in-coastal-aquifers-from-southern-spain
#19
M Argamasilla, J A Barberá, B Andreo
In detrital coastal aquifers, seawater and surface water may interact with groundwater in multiple ways. Understanding the interference of water fluxes in this type of environment is essential to effectively manage the groundwater resources in water-stressed regions, such as the Mediterranean coastal fringe. In this research, the characterization of the main hydrogeochemical processes and the interaction between surface water and groundwater in the Marbella-Estepona coastal aquifers (southern Spain) have been carried out by means of the combined use of different hydrogeochemical indicators along with isotope data...
December 9, 2016: Science of the Total Environment
https://www.readbyqxmd.com/read/27960056/chemical-identification-at-the-solid-liquid-interface
#20
Hagen Söngen, Christoph Marutschke, Peter Spijker, Eric Holmgren, Ilka Hermes, Ralf Bechstein, Stefanie Klassen, John Tracey, Adam S Foster, Angelika Kühnle
Solid-liquid interfaces are decisive for a wide range of natural and technological processes, including fields as diverse as geochemistry and environmental science as well as catalysis and corrosion protection. Dynamic atomic force microscopy nowadays provides unparalleled structural insights into solid-liquid interfaces, including the solvation structure above the surface. In contrast, chemical identification of individual interfacial atoms still remains a considerable challenge. So far, an identification of chemically alike atoms in a surface alloy has only been demonstrated under well-controlled ultrahigh vacuum conditions...
December 22, 2016: Langmuir: the ACS Journal of Surfaces and Colloids
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