Literatura académica sobre el tema "Cycle of iron and other trace metals"
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Artículos de revistas sobre el tema "Cycle of iron and other trace metals"
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Tan, Maxine H., Sarah R. Smith, Kim K. Hixson, Justin Tan, James K. McCarthy, Adam B. Kustka y Andrew E. Allen. "The Importance of Protein Phosphorylation for Signaling and Metabolism in Response to Diel Light Cycling and Nutrient Availability in a Marine Diatom". Biology 9, n.º 7 (6 de julio de 2020): 155. http://dx.doi.org/10.3390/biology9070155.
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Diatoms are major contributors to global primary production and their populations in the modern oceans are affected by availability of iron, nitrogen, phosphate, silica, and other trace metals, vitamins, and infochemicals. However, little is known about the role of phosphorylation in diatoms and its role in regulation and signaling. We report a total of 2759 phosphorylation sites on 1502 proteins detected in Phaeodactylum tricornutum. Conditionally phosphorylated peptides were detected at low iron (n = 108), during the diel cycle (n = 149), and due to nitrogen availability (n = 137). Through a multi-omic comparison of transcript, protein, phosphorylation, and protein homology, we identify numerous proteins and key cellular processes that are likely under control of phospho-regulation. We show that phosphorylation regulates: (1) carbon retrenchment and reallocation during growth under low iron, (2) carbon flux towards lipid biosynthesis after the lights turn on, (3) coordination of transcription and translation over the diel cycle and (4) in response to nitrogen depletion. We also uncover phosphorylation sites for proteins that play major roles in diatom Fe sensing and utilization, including flavodoxin and phytotransferrin (ISIP2A), as well as identify phospho-regulated stress proteins and kinases. These findings provide much needed insight into the roles of protein phosphorylation in diel cycling and nutrient sensing in diatoms.
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Chang, Xuan y Yingxia Li. "Using a Multimedia Aquivalence Model to Evaluate the Environmental Fate of Fe, Mn and Trace Metals in an Industrial City, China". Water 12, n.º 6 (2 de junio de 2020): 1580. http://dx.doi.org/10.3390/w12061580.
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The rapid expansion of urban impervious surface areas complicates urban-scale heavy metal circulation among various environmental compartments (air, soil, sediment, water, and road dust). Herein, a level III steady-state aquivalence model evaluated the fate of heavy metals in Nanjing, China. Iron was the most abundant heavy metal in all environmental compartments, while cadmium was the rarest. Most simulated concentrations agreed with measured values within three logarithmic residuals. In the simulated heavy metal cycle, industrial emission contributed almost the entire input, whereas sediment burial was the dominant output pathway. The transfer fluxes between bottom sediment and water were the highest. Thereinto, the contribution of sediment resuspension for Fe and Mn was significantly higher than that to the other metal elements, which could partly explain why Fe and Mn are the major blackening ingredients in malodorous black rivers. Road dust was also an important migration destination for heavy metals, accounting for 3–45%, although soil and sediment were the main repositories of heavy metals in the urban environment. The impact of road dust on surface water should not be neglected, with its contribution reaching 4–31%. The wash-off rate constant W for road dust–water process was proved to be consistent with that for film–water and was independent of the type of heavy metals. Sensitivity analysis highlighted the notable background value effect on Fe and Mn.
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Rahman, Md Lutfor, Zhi Jian Wong, Mohd Sani Sarjadi, Sabrina Soloi, Sazmal E. Arshad, Kawi Bidin y Baba Musta. "Heavy Metals Removal from Electroplating Wastewater by Waste Fiber-Based Poly(amidoxime) Ligand". Water 13, n.º 9 (30 de abril de 2021): 1260. http://dx.doi.org/10.3390/w13091260.
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An efficient and economical treatment technology for heavy metal removal from the electroplating wastewaters is needed for the water purification. Therefore, pure cellulosic materials were derived from two waste fiber (pandanus fruit and durian rind) and conversion of the cellulose into the poly(acrylonitrile)-grafted material was accomplished by free radical grafting system. Thereafter, poly(amidoxime) ligand was produced from the grafted materials. Sorption capacity (qe) of several toxic metals ions was found to be high, e.g., copper capacity (qe) was 298.4 mg g−1 at pH 6. In fact, other metal ions, such as cobalt chromium and nickel also demonstrated significant sorption capacity at pH 6. Sorption mechanism played acceptable meet with pseudo second-order rate of kinetic pattern due to the satisfactory correlation with the experimental sorption values. A significant correlation coefficient (R2 > 0.99) with Langmuir model isotherm showed the single or monolayer sorption occurred on the surfaces. The reusability study showed that the polymer ligand can be useful up to six cycles with minimum loss (7%) of efficiency and can be used in the extraction of toxic metal ions present in the wastewaters. Therefore, two types of electroplating wastewater were used in this study, one containing high concentration of copper (23 ppm) and iron (32 ppm) with trace level of others heavy metals (IWS 1) and another containing high concentration of copper (85.7 ppm) only with trace level of others heavy metals (IWS 2). This polymeric ligand showed acceptable removal magnitude, up to 98% of toxic metal ions can be removed from electroplating wastewater.
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Sánchez-España, Javier y Jesús Reyes. "Comparing Schwertmannite and Hydrobasaluminite Dissolution in Ammonium Oxalate (pH 3.0): Implications for Metal Speciation Studies by Sequential Extraction". Minerals 9, n.º 1 (17 de enero de 2019): 57. http://dx.doi.org/10.3390/min9010057.
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The “poorly crystalline iron oxy-hydroxides” are one of the most reactive and environmentally important fractions in soils and sediments due to the association of many toxic elements associated with these minerals. The metal content of this fraction in sequential extraction procedures is usually evaluated by dissolution in ammonium oxalate ([NH4]2C2O4·H2O) at pH 3.0 and 25 ᵒC [1–12]. Such chemical treatment, however, may also dissolve other mineral phases of comparable reactivity, which can lead to wrong interpretations of mineral carriers for specific metals. In this study, we compare the dissolution kinetics of schwertmannite and hydrobasaluminite, two minerals of comparable crystallinity and reactivity that play a major role in the mobility of many trace metals in waters and sediments affected by acid mine drainage (AMD). We first synthesized these two minerals in the laboratory by partial neutralization of two different metal-rich mine waters, and then we applied the standard protocol of ammonium oxalate dissolution to different specimens; the solutions were periodically sampled at intervals of 2, 5, 10, 15, 30 and 60 min to compare (i) the kinetics of mineral dissolution, and (ii) the metals released during dissolution of these two minerals. The results indicate a very similar kinetics of mineral dissolution, though hydrobasaluminite exhibited a faster rate. Some toxic elements such as As, Cr or V were clearly bonded to schwertmannite, while many others such as Cu, Zn, Si, Co, Ni and Y were clearly linked to hydrobasaluminite. These results suggest that studies linking the mobility of many elements with the Fe cycle in AMD-affected soils and sediments could be inaccurate, since these elements could actually be associated with Al minerals of poor crystallinity. The step of ammonium oxalate dissolution in sequential extraction studies should be best described with a more general term such as “low-crystallinity oxy-hydroxides”.
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Facey, Jordan A., Simon C. Apte y Simon M. Mitrovic. "A Review of the Effect of Trace Metals on Freshwater Cyanobacterial Growth and Toxin Production". Toxins 11, n.º 11 (5 de noviembre de 2019): 643. http://dx.doi.org/10.3390/toxins11110643.
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Cyanobacterial blooms are becoming more common in freshwater systems, causing ecological degradation and human health risks through exposure to cyanotoxins. The role of phosphorus and nitrogen in cyanobacterial bloom formation is well documented and these are regularly the focus of management plans. There is also strong evidence that trace metals are required for a wide range of cellular processes, however their importance as a limiting factor of cyanobacterial growth in ecological systems is unclear. Furthermore, some studies have suggested a direct link between cyanotoxin production and some trace metals. This review synthesises current knowledge on the following: (1) the biochemical role of trace metals (particularly iron, cobalt, copper, manganese, molybdenum and zinc), (2) the growth limitation of cyanobacteria by trace metals, (3) the trace metal regulation of the phytoplankton community structure and (4) the role of trace metals in cyanotoxin production. Iron dominated the literature and regularly influenced bloom formation, with 15 of 18 studies indicating limitation or colimitation of cyanobacterial growth. A range of other trace metals were found to have a demonstrated capacity to limit cyanobacterial growth, and these metals require further study. The effect of trace metals on cyanotoxin production is equivocal and highly variable. Better understanding the role of trace metals in cyanobacterial growth and bloom formation is an essential component of freshwater management and a direction for future research.
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Baraj, Besnik, Luis Felipe Niencheski, Gilberto Fillmann y Luciano Hermanns. "Biochemical normalization of trace metals in Arctocephalus australis". Brazilian Journal of Oceanography 57, n.º 1 (marzo de 2009): 1–6. http://dx.doi.org/10.1590/s1679-87592009000100001.
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Initially, the heart concentration data does not seem relevant for use as a bioindicator, mainly due to its low concentration level. After applying a normalizing procedure, the heart results were a better Hg bioindicator (preconcentration coefficient 43.1) than those of the kidney (preconcentration coefficient 8.6). Cadmium preconcentration coefficients were 128.1, 195.3 and 5.2 for liver, kidney and heart, respectively, demonstrating the high accumulative capacity especially for the liver and kidneys. Iron is proposed as a normalizing element for the definiton of the regional natural biochemical population of the metals. In general, positive correlation coefficients were found between Fe and other metals.
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Scales, W. E., A. J. Vander, M. B. Brown y M. J. Kluger. "Human circadian rhythms in temperature, trace metals, and blood variables". Journal of Applied Physiology 65, n.º 4 (1 de octubre de 1988): 1840–46. http://dx.doi.org/10.1152/jappl.1988.65.4.1840.
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The literature supports the concept that circadian changes in body temperature reflect changes in the thermoregulatory set point. We were interested in studying the relationship between the circadian rhythm in body temperature and 24-h variations in plasma concentrations of iron, zinc, circulating leukocyte counts, and plasma interleukin 1 (IL-1) activity. Eight healthy men were studied for two separate 48-h sessions. Rectal temperature, plasma iron and zinc concentrations, plasma IL-1 activity, circulating leukocyte counts, and several other blood variables were monitored. Circadian rhythms in temperature, trace metals, and various leukocyte populations were demonstrated. The 24-h pattern of changes in plasma concentrations of iron and zinc approximate an inverse relationship with rectal temperature. Although we were unable to detect any IL-1 activity in human plasma collected at 4-h intervals, the daily changes in plasma trace metal concentrations and the variations in leukocyte populations may provide indirect evidence for a daily variation in local (e.g., in liver) or central nervous system release of IL-1.
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Bowell, Rob, Christopher Brough, Andrew Barnes y Arman Vardanyan. "Geometallurgy of Trace Elements in the Hrazdan Iron Deposit". Minerals 11, n.º 10 (2 de octubre de 2021): 1085. http://dx.doi.org/10.3390/min11101085.
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This study presents an evaluation of arsenic and other trace metals in the Hrazdan Iron-Ore project in Armenia using a methodology typically associated with Geometallurgical characterization. The principal host of the trace elements is pyrite and oxidized equivalents. Pyrite is a mineral of elemental concern as it has the potential to generate acidic pH in water that it contacts and thus mobilize metals of concern. In the Hrazdan deposit, there is a general excess of neutralizing carbonate minerals that result in adequate buffering of generated acid and limiting the mobility of metal cations in solution. However, metalloids that form oxyanions species such as those of arsenic or chromium tend to be more mobile in neutral to alkaline mine drainage. From the geometallurgical assessment of the mine waste, the results of the geochemical testwork can be explained and the information used to assess potential issues with mine waste storage, timing of metal release and provide a baseline for mitigation strategies.
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Makević, Vedrana, Luka de y Anđelija Ilić. "Essential trace metals in health and disease". Medicinski podmladak 74, n.º 5 (2023): 1–8. http://dx.doi.org/10.5937/mp74-43573.
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Essential trace metals (Fe, Zn, Cu, Mn, Mo, Co) are involved in high number of physiological and metabolic activities and therefore have a substantial role in organisms. Thus, their balance is tightly regulated by levels of absorption, transport, and storage in the organism. They can alter human health in both deficiency and overload conditions. On one hand, deficiency health problems are due to reduction of their physiological activities. On the other hand, Fe, Cu and Co are redox active metals and their increase can cause severe tissue damage through oxidative stress. Numerous well-established diseases like iron and copper deficiency anemia, hemochromatosis, Menkes and Wilson disease, acrodermatitis enteropathica are consequence of essential metal alterations. Nowadays, trace metals alterations are also found to be implicated in neurodegenerative disease, cancers, atherosclerosis, and diabetes. Those diseases represent enormous health problems in contemporary society and trace metals might help to further elucidate their pathogenesis and potentially even treatment. In the present study, essential trace metals kinetic and physiology are reviewed, as well as their roles in disease pathophysiology.
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Forsch, Kiefer O., Lisa Hahn-Woernle, Robert M. Sherrell, Vincent J. Roccanova, Kaixuan Bu, David Burdige, Maria Vernet y Katherine A. Barbeau. "Seasonal dispersal of fjord meltwaters as an important source of iron and manganese to coastal Antarctic phytoplankton". Biogeosciences 18, n.º 23 (13 de diciembre de 2021): 6349–75. http://dx.doi.org/10.5194/bg-18-6349-2021.
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Abstract. Glacial meltwater from the western Antarctic Ice Sheet is hypothesized to be an important source of cryospheric iron, fertilizing the Southern Ocean, yet its trace-metal composition and factors that control its dispersal remain poorly constrained. Here we characterize meltwater iron sources in a heavily glaciated western Antarctic Peninsula (WAP) fjord. Using dissolved and particulate ratios of manganese to iron in meltwaters, porewaters, and seawater, we show that surface glacial melt and subglacial plumes contribute to the seasonal cycle of iron and manganese within a fjord still relatively unaffected by climate-change-induced glacial retreat. Organic ligands derived from the phytoplankton bloom and the glaciers bind dissolved iron and facilitate the solubilization of particulate iron downstream. Using a numerical model, we show that buoyant plumes generated by outflow from the subglacial hydrologic system, enriched in labile particulate trace metals derived from a chemically modified crustal source, can supply iron to the fjord euphotic zone through vertical mixing. We also show that prolonged katabatic wind events enhance export of meltwater out of the fjord. Thus, we identify an important atmosphere–ice–ocean coupling intimately tied to coastal iron biogeochemistry and primary productivity along the WAP.
Tesis sobre el tema "Cycle of iron and other trace metals"
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Tilliette, Chloé. "Influence du fer et autres éléments traces issus des sources hydrothermales peu profondes sur la biogéochimie marine dans le Pacifique Sud-Ouest". Electronic Thesis or Diss., Sorbonne université, 2023. http://www.theses.fr/2023SORUS046.
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L’océan Pacifique Sud-Ouest a été identifié comme un point chaud de fixation de diazote (N2) par les organismes diazotrophes, arborant des taux de fixation parmi les plus élevés des océans du globe. Le succès de ces espèces repose sur les concentrations non limitantes en fer dissous (DFe) dans la couche photique de la région, dont l’origine demeure méconnue. Dans le cadre de ce travail de thèse, la distribution du DFe a été étudiée le long d’un transect de 6100 km, allant de Nouméa jusqu’aux eaux de la gyre et traversant le Bassin de Lau et l’Arc des Tonga (175 °E à 166 °W, le long de 19–21 °S). Combinées avec une analyse optimale multiparamétrique des masses d’eau, les anomalies de DFe ont été déterminées sur la zone du transect, les plus notables étant présentes le long de l’Arc des Tonga. Les résultats ont démontré que les masses d’eau d’origine lointaine alimentant le Bassin de Lau ne peuvent expliquer les concentrations observées en surface dans cette région, permettant de conclure avec certitude que le DFe provient de sources hydrothermales peu profondes présentes le long de l’arc. Bien qu’une portion non négligeable de cet apport de DFe soit transportée sur de longues distances, une large majorité est rapidement éliminée à proximité des sources sous l’action de divers processus mis en lumière à l’aide d’un modèle en boîte. Outre le fer, les fluides hydrothermaux sont enrichis en de nombreux autres métaux susceptibles d’être toxiques pour les organismes. Ces fluides, directement introduits dans la couche photique, pourraient impacter le phytoplancton. Leur effet a été évalué lors d’une expérience innovante pendant laquelle des communautés planctoniques naturelles ont été soumises à un gradient d’enrichissement en fluides hydrothermaux. Malgré un effet toxique initial de quelques jours, les apports hydrothermaux ont finalement induit des taux de fixation de N2, de productivité et d’export de matière organique deux à trois fois plus élevés que dans le contrôle non enrichi. Cet effet fertilisant résulte probablement de la détoxification de l’environnement, riche en de nombreux éléments potentiellement toxiques, par des écotypes résistants capables de produire des ligands forts, les thiols, limitant la biodisponibilité de certains métaux. L’apport additionnel d’éléments fertilisants par les fluides, en particulier le DFe, a ainsi permis la croissance ultérieure des espèces les plus sensibles. Ces résultats expérimentaux, reproduisant fidèlement les observations in-situ, confirment l’implication des fluides hydrothermaux peu profonds dans la forte productivité observée dans la région. Les sources hydrothermales ont pu être tracées à différentes échelles spatiales et temporelles par le déploiement de pièges à sédiments dérivants (durant quelques jours, le long de l’Arc des Tonga) et fixe (durant une année, le long de la dorsale de Lau) et par le carottage des sédiments du fond marin aux sites de déploiement des pièges (échelle de temps géologique). Le traçage Al-Fe-Mn a révélé que le matériel lithogénique exporté à petite et large échelle spatiale dans la région provenait de sources hydrothermales peu profondes et/ou profondes localisées le long de l’Arc des Tonga. Cette empreinte hydrothermale a également été détectée dans les sédiments, notamment à proximité de la dorsale de Lau où la présence d’une importante source active est fortement suspectée. Finalement, les dynamiques similaires observées pour l’export de particules d’origine biologique et hydrothermale suggèrent que la production de surface serait liée aux apports hydrothermaux dans la couche photique. En conclusion, ce travail de thèse a démontré l’impact de sources hydrothermales peu profondes sur le cycle des éléments traces, notamment du fer, dans la colonne d’eau et les sédiments, ainsi que leur lien avec la productivité biologique dans la région du Pacifique Sud-OuestThe Western Tropical South Pacific Ocean has been identified as a hotspot for dinitrogen (N2) fixation by diazotrophic organisms, with some of the highest rates recorded in the global ocean. The success of these species relies on non-limiting concentrations of dissolved iron (DFe) in the photic layer of the region, whose origin remains unclear. In this thesis work, the distribution of DFe was studied along a 6100-km transect from Noumea to the gyre waters, crossing the Lau Basin and the Tonga Arc (175°E to 166°W, along 19-21°S). Combined with an optimal multiparametric water mass analysis, DFe anomalies were determined over the transect area, the most notable being present along the Tonga Arc. The results demonstrated that water masses of remote origin entering the Lau Basin could not explain the concentrations observed at the surface in this region, leading to the confident conclusion that DFe originates from shallow hydrothermal sources present along the arc. Although a non-negligeable portion of this DFe input is transported over long distances, a large majority is rapidly removed near the sources through a variety of processes highlighted by a box model. Besides iron, hydrothermal fluids are enriched in numerous other metals that may be toxic to organisms. These fluids, introduced directly into the photic layer, could have an impact on phytoplankton. Their effect was evaluated in an innovative experiment during which natural plankton communities were subjected to an enrichment gradient of hydrothermal fluids. Despite an initial toxic effect of a few days, hydrothermal inputs ultimately induced N2 fixation, productivity and organic matter export rates two to three times higher than those of the non-enriched control. This fertilizing effect probably results from the detoxification of the environment, rich in numerous potentially toxic elements, by resistant ecotypes able to produce strong ligands, such as thiols, limiting the bioavailability of certain metals. The additional supply of fertilizing elements by the fluids, in particular DFe, thus allowed the subsequent growth of the most sensitive species. These experimental results, faithfully reproducing the in-situ observations, confirm the involvement of shallow hydrothermal fluids in the high productivity observed in the region. Hydrothermal sources could be traced at different spatial and temporal scales through the deployment of drifting (for a few days, along the Tonga Arc) and fixed (for a year, along the Lau Ridge) sediment traps and through the coring of seafloor sediments at the trap deployment sites (geological time scale). Al-Fe-Mn tracing revealed that the lithogenic material exported at small and large spatial scales in the region originated from shallow and/or deep hydrothermal sources located along the Tonga Arc. This hydrothermal signature has also been detected in the seafloor sediments, particularly in the vicinity of the Lau Ridge where the presence of a major active source is strongly suspected. Finally, the similar patterns observed for the export of biological and hydrothermal particles suggest that surface production is closely linked to hydrothermal inputs into the photic layer. In conclusion, this thesis work has demonstrated the influence of shallow hydrothermal sources on the fate of trace elements, particularly iron, in the water column and seafloor sediments, and their link to biological productivity in the Western Tropical South Pacific region
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Trapp, John Michael. "Chemistry of Iron and Other Trace Elements in Trade Wind Aerosols and Precipitation". Scholarly Repository, 2009. http://scholarlyrepository.miami.edu/oa_dissertations/323.
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The atmospheric transport of various substances from the continents to the oceans plays an important role in biogeochemical processes. Trace metals, iron in particular is of great interest as its availability regulates the growth of phytoplankton over large areas of the ocean. This dissertation focuses on examining and characterizing the factors that affect the solubility of trace metals in Miami and Barbados aerosols and precipitation, in particular species that could play a role in surface seawater biogeochemistry (Fe and trace metals such as Al, V, Cr, Mn, Cu, Co, Ni, Zn, As, Tl, Ba, Cd, Pb, Th, Ti, Zr, and REE's). To enable this study existing methods of colorimetric spectroscopic and inductively coupled plasma mass spectrometry analysis were improved and modified. This dissertation examines several issues related to source inputs: 1.) Are single spot sources within the North African dust source distinguishable after long transport by their bulk metal composition and thus important in the characteristics of individual mineral dust samples? 2.) What is the temporal variability and controlling factors in trace metal solubility in trade wind aerosols collected over Barbados? 3.) Which factors control the observed trend of speciation and increasing iron solubility in decreasing aerosol loading? Additionally a kinetic model of species specific iron (II) to iron(III) oxidation kinetics in NaCl Brines was conducted at nano-molar levels. This study greatly expands the ability to predict rates of iron oxidation at concentrations closer to those observed in natural systems.
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Duprat, LPADM. "Role of sea ice as a biogeochemically active reservoir of iron and other trace metals". Thesis, 2021. https://eprints.utas.edu.au/38318/1/Duprat_whole_thesis.pdf.
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An increasing body of work has underlined the importance of Antarctic sea ice as a reservoir and source of iron (Fe) to the Southern Ocean, boosting local primary production and carbon export during spring and summer. The impact of Fe in controlling sea-ice and ocean productivity is unequivocal, but other trace metals (TMs) can also regulate productivity. Nevertheless, considerable uncertainty with respect to the pathways, fate and bioavailability of TMs in the sea-ice environment prevents us to accurately model the impact of predicted future changes in sea-ice extent and thickness on Southern Ocean ecosystems and our global climate. The aim of this PhD is to bring new evidence to our present understanding of the biogeochemical cycling of Fe and other bioactive TMs(Cd, Co, Cu, Mn, Ni and Zn) in Antarctic coastal land-fast (i.e. sea ice fastened to the coastline, ice shelves or to grounded icebergs) and pack ice (free drifting) and their relationship with regional primary productivity. The main findings from the analyses of TM distributions in sea ice from three field campaigns (SIPEX-2, 2012; Davis, 2015 and AAV2, 2016/17) along the East Antarctic coast are as follows: 1) Primary production in coastal land-fast ice is not Fe-limited during late-spring/early summer, potentially due to the high input of Fe from suspended sediment entrapped during ice formation; 2) Windblown dust from ice-free coastal landmasses can significantly contribute to the total Fe pool in land-fast ice and could become an important source of Fe and potentially other TMs, considering the projected expansion of ice-free areas across the Antarctic landmass by the end of the century; 3) Primary production in East Antarctic (fast and pack) ice is also not Fe-limited during mid-summer. Instead, low concentrations of inorganic nitrogen sources could be the main nutrient limiting sea-ice algal growth at this time of the year; 4) The formation of Fe-rich platelet ice underneath pack ice in proximity to glacial systems with negative ice mass balance (Totten Glacier basin) indicates the potentially large contribution of glacial meltwater to Fe and TM pools in sea ice collected near the coast; and finally, 5) TMs other than Fe are enriched in sea ice relative to seawater from winter/spring to summer. However, this enrichment is not consistent across the TMs analysed. Zinc, Cu and Ni display higher enrichment than Mn, Co and Cd, potentially because of different levels of complexation with organic ligands. High concentrations of dissolved Zn and Cu in sea ice suggest both elements are unlikely to limit sea-ice algae growth. Contrary, their levels could be toxic if they are not appreciably chelated. Free Zn and Cu ion measurements are needed to confirm this hypothesis. This study shows that sea ice serves as a biogeochemically active reservoir not only for Fe but potentially for Zn as well.
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Kao, Shu-Yang y 高書暘. "Diel Cycle of Iron, Aluminum and Other Heavy Metals in a Volcano Watershed in Northern Taiwan". Thesis, 2014. http://ndltd.ncl.edu.tw/handle/08851498510136278109.
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碩士國立中正大學
應用地球物理研究所
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Diel changes in concentration of trace elements were investigated in North Huanghsi River, which is located at Tatun Volcanic Group and drains the volcanic geothermal spring water northward to the coastal area. A 24-h sampling procedure was conducted at two sites: BY (the upstream site) and SH (the downstream site). According to the results of chemical analysis, only Fe, As and V show considerable diel concentration cycle while the others including rare earth elements demonstrate insignificant diel change. Along with the increase of pH value at night, the concentration of Fe decreases due to the transformation from Fe2+ (higher solubility) to Fe3+ (much lower solubility). Therefore, iron hydroxide would be significantly generated at night and would probably dominate the adsorption behavior of ions. In general, iron hydroxide is in the form of positive charged ion under the low pH environment. On the contrary, As is an anionic complex. It is expected that As can be adsorbed and consequently precipitated with iron hydroxide in the form of negative charged ion. Therefore, a lower concentration of As was observed in the late afternoon in this study. In addition, it is interesting that V demonstrates an opposite behavior with As during the diel cycle. This implies that V is in the form of positive charged ionic complex under the low pH environment and shows a quite different cycle from As.
Libros sobre el tema "Cycle of iron and other trace metals"
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Gómez-Consarnau, Laura y Sergio A. Sañudo-Wilhelmy, eds. Beyond the Iron age: the ecological relevance of bioactive trace metals other than Fe and organic growth factors in aquatic systems. Frontiers Media SA, 2015. http://dx.doi.org/10.3389/978-2-88919-546-6.
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Kirchman, David L. Introduction to geomicrobiology. Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780198789406.003.0013.
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Geomicrobiology, the marriage of geology and microbiology, is about the impact of microbes on Earth materials in terrestrial systems and sediments. Many geomicrobiological processes occur over long timescales. Even the slow growth and low activity of microbes, however, have big effects when added up over millennia. After reviewing the basics of bacteria–surface interactions, the chapter moves on to discussing biomineralization, which is the microbially mediated formation of solid minerals from soluble ions. The role of microbes can vary from merely providing passive surfaces for mineral formation, to active control of the entire precipitation process. The formation of carbonate-containing minerals by coccolithophorids and other marine organisms is especially important because of the role of these minerals in the carbon cycle. Iron minerals can be formed by chemolithoautotrophic bacteria, which gain a small amount of energy from iron oxidation. Similarly, manganese-rich minerals are formed during manganese oxidation, although how this reaction benefits microbes is unclear. These minerals and others give geologists and geomicrobiologists clues about early life on Earth. In addition to forming minerals, microbes help to dissolve them, a process called weathering. Microbes contribute to weathering and mineral dissolution through several mechanisms: production of protons (acidity) or hydroxides that dissolve minerals; production of ligands that chelate metals in minerals thereby breaking up the solid phase; and direct reduction of mineral-bound metals to more soluble forms. The chapter ends with some comments about the role of microbes in degrading oil and other fossil fuels.
Capítulos de libros sobre el tema "Cycle of iron and other trace metals"
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Sander, S. G. y A. Koschinsky. "The Export of Iron and Other Trace Metals from Hydrothermal Vents and the Impact on Their Marine Biogeochemical Cycle". En The Handbook of Environmental Chemistry, 9–24. Cham: Springer International Publishing, 2016. http://dx.doi.org/10.1007/698_2016_4.
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Gerlach, Manfred, Moussa B. H. Youdim y Peter Riederer. "Brain Iron and other Trace Metals in Neurodegenerative Diseases". En Neurotoxic Factors in Parkinson’s Disease and Related Disorders, 259–76. Boston, MA: Springer US, 2000. http://dx.doi.org/10.1007/978-1-4615-1269-1_25.
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Werner, Markus, Rico Haase y Christian Hermeling. "reProd® – Resource-Autarkic Production Based on Secondary Semi-finished Products". En Lecture Notes in Mechanical Engineering, 51–59. Cham: Springer International Publishing, 2023. http://dx.doi.org/10.1007/978-3-031-28839-5_6.
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AbstractThis paper presents a novel approach of a smart shortened material loop for producing second-life metallic components by saving a significant amount of energy and CO2 emissions. The focus is on metallic components and manufacturing chains based on adapted forming technologies. Sourcing and using secondary semi-finished products instead of virgin metallic materials facilitates the omission of process steps, such as iron smelting, steel making, continuous casting, hot and cold rolling, which involve the highest energy consumption and the highest CO2 emissions. Besides the positive impacts on sustainability, there are still scientific and technological challenges. One challenge lies in matching providers of secondary semi-finished material to market needs; the other comprises engineering the forming process chain while some material characteristics are not clearly specified or vary in a wide range. In contrast to the heavily restricted properties of virgin material, the characteristics of secondary semi-finished materials vary in a wider range and need to be elaborated. In the end, a new component will be produced, differing in design, function, and properties from conventional, single-life cycle products. Therefore, this paper introduces a novel, circular material loop for metals. The paper finishes with a short concept note on digital material and product passports to store and provide the required information on properties.
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McCleverty, Jon. "Metals and solid compounds". En Chemistry of the First-row Transition Metals. Oxford University Press, 1999. http://dx.doi.org/10.1093/hesc/9780198501510.003.0002.
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This chapter describes the elements encountered within the crust, wherein iron is fourth after oxygen, silicon, and aluminum that comprises about 6% of the total crustal composition. It discusses first-row transition elements, which includes titanium and manganese. It also talks about the majority of the elements that occur in minerals, such as oxides, hydrated oxides, and carbonates, including principal minerals and other sources of the elements. The chapter talks about vanadium that is found naturally in some living systems, particularly sea squirts, tunicates, and some mushrooms. It looks at trace amounts of chromium, which are responsible for the characteristic colours of ruby and emerald.
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Kumar, Ajay y Rakesh Kumar Singh. "Water Quality Assessment in Terms of Major and Minor Elements in Surface, Ground and Sea Water and Correlating the Presence with Associated Problems". En Trace Metals in the Environment [Working Title]. IntechOpen, 2023. http://dx.doi.org/10.5772/intechopen.1001129.
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Distribution of major and minor element concentrations in the surface and ground was evaluated in one of the districts of India, Moradabad lies between 28◦21’ to 28◦16’ north latitude and 78◦4’ to 79◦ east longitude in western Uttar Pradesh. The city is known for its export of brass handicrafts to various countries across the world including North America and Europe. A field survey was conducted in district Moradabad along with a public interaction program on water related problems. A total of 108 representative villages covering all eight blocks of Moradabad district were visited and interactions were held with the local population to find out the status of drinking water quality and associated problems. Water quality of surface and groundwater has been assessed with respect to metal concentration using ICP-OES technique. In the collected water samples, copper, arsenic, lead and chromium concentrations were found within the permissible limits. Iron concentration was observed beyond permissible limit in more than 50% of the samples collected. Maximum iron level in groundwater sample was 3820 ppb and that in surface water sample was 6294 ppb whereas the permissible limit is 300 ppb. Seawater samples were collected from eight sampling location in Southern Ocean from latitude S 67º16´10.9´´ and longitude E 28º39´64.5´´ to latitude S 69º17´42.9´´ and longitude E 76º13´23.3´´ and analyzed for various heavy metals like copper (Cu), lead (Pb), cadmium (Cd), zinc (Zn), nickel (Ni), chromium (Cr). The concentrations of heavy metals Cu, Pb, Cd, Zn, Ni, Cr and other major elements like sodium, potassium, calcium, magnesium, boron were measured in selected seawater samples using Inductively Coupled Plasma Optical Emission spectroscopy (ICP-OES). The results indicated that the concentrations of metals in seawater were found uniformly in entire selected stretch of Southern Ocean. Sodium, potassium, calcium, magnesium, boron and iron metals were found as the dominant constituents among the sea water. Aluminum (0.3-15.0 µg/cc), zinc (0.27-1.9 µg/cc), copper (0.04-0.23 µg/cc) and molybdenum (0.10- 0.77 µg/cc) were also found in sufficient concentrations in all the seawater samples. Strontium was also one of the dominant alkaline earth metals in sea water. However, the concentration of strontium (22.8-53.0 µg/cc) was found to be evenly distributed from Indian Bay to Larsemann Hills in east Antarctica. Selenium and chromium were the rarest metals in seawater as these were below detection limit in all samples. The overload of these major and minor elements beyond the permissible limits causes severe health problems such as liver cancer, diabetes, cirrhosis of liver, diseases related to heart and central nervous system, infertility etc. and thus needs to be monitored on regular basis.
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Dalton, David R. "The Soil". En The Chemistry of Wine. Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780190687199.003.0012.
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The widespread practices of viniculture (the study of production of grapes for wine) and oenology (the study of winemaking) affirm the generalization that grapevines have fewer problems with mineral deficiency than many other crops. Only occasionally is the addition of iron (Fe), phosphorus (P), magnesium (Mg), and manganese (Mn) supplements to the soil needed. Addition of potassium (K), zinc (Zn), and boron (B) to the soil is more common. And, of course, nitrogen (N) is critical for the production of proteins. Over the years, various transition metals (metals in groups three through twelve [3– 12] of the periodic table, Appendix 1) have been shown to be generally important. These groups include iron (Fe), magnesium (Mg), manganese (Mn), zinc (Zn), and copper (Cu). Many metals are bound to organic molecules that are important for life. Some of the metals, such as copper (Cu) and iron (Fe), are important in electron transport while others, including manganese (Mn) and iron (Fe), inhibit reactive oxygen (O) species (ROSs) that can destroy cells. Metals serve both to cause some reactions to speed up, called positive catalysis while caus¬ing others (e.g., unwanted oxidation) to slow down (negative catalysis). It is not uncommon to add nitrogen (N), in the form of ammonium salts such as ammonium nitrate (NH4NO3), as fertilizer to the soil in which the vines are growing. It is also common to increase the nitrogen (N) content in the soil by planting legumes (legumes have roots that are frequently colonized by nitrogen-fixing bacteria). Nitrogen- fixing bacteria convert atmospheric nitrogen (N2), which plants cannot use, to forms, such as ammonia (NH3) or its equivalent, capable of absorption by plants. Nitrogen, used in plant proteins, tends to remain in the soil after harvest or decomposition. With sufficient nitrogen present in the soil the growth cycle can begin again in the following season without adding too much fertilizer. In a more general sense, however, it is clear (as mentioned earlier) that the soil must be capable of good drainage so the sub-soil parts of the plant do not rot and it must be loose enough to permit oxygen to be available to the growing roots.
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Emsley, John. "Testing your metal: An exhibition of the metals which our body must have". En Molecules at an Exhibition. Oxford University Press, 1998. http://dx.doi.org/10.1093/oso/9780198502661.003.0006.
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Ask people which metals are essential for healthy living and I suspect most would say zinc and iron. Some might mention sodium and potassium, although sodium is often regarded as something deleterious to healthy living; and a few people will know that calcium is a metal also, and important. In fact the human body needs fourteen metal elements to function properly. But for every metal that we do need, there is another that our body contains that we could well do without. These metals serve no known purpose, but they come with the food we eat, the water we drink, and the air we breathe and our body absorbs them, mistaking them for more useful elements. As a result we find that the average adult contains measurable amounts of aluminium, barium, cadmium, caesium, lead, silver and strontium. There are also trace amounts of many others, including gold and uranium. Because strontium so closely resembles calcium we absorb a lot of this element, and the average person has about 320 mg in their body, far more than of many of the essential elements. On the other hand the weight of gold in the average person is only 7 mg, worth but a few pence, and the weight of uranium is only 0.07 mg, although turned into pure energy this could drive your car for five kilometres. Our body tends to retain these unwanted intruders either in our skeleton, as in the case of uranium which has a special propensity to bind to phosphate, or in our liver which has proteins that can trap metals like gold. The table below lists the amounts of the essential 14 metals in the average adult—someone who weighs 70 kg (155 pounds). As we would expect, calcium heads the list because, along with phosphate, it is what makes up the bones of our skeleton, which weighs 9 kg on average. Of this, i kg is calcium and 2.5 kg is phosphate. In fact 99% of the body's calcium and 85% of its phosphate is in the skeleton. Bone also contains water and the protein collagen, plus the elements sodium, potassium, iron, copper and chlorine.
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Bajželj, Ana. "When Earth Comes Alive: Earth-Bodied Beings in Jain Tradition". En Soulless Matter, Seats of Energy: Metals, Gems and Minerals in South Asian Traditions, 255–74. Equinox Publishing, 2016. http://dx.doi.org/10.1558/equinox.29660.
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The primary objective of this paper is to explore the notion of earth-beings as proposed by the Jain tradition. Akin to divine (deva), hellish (nāraki), human (manuṣya) and animal beings (tiryañc) Jains consider plants (vanaspati), water- (āpo-kāyika), air- (vāyu-kāyika), fire- (tejo-kāyika) and earth-bodied (pṛthivῑ-kāyika) beings to be alive as well, the criterion for life being the possession and application of the attribute of consciousness (caitanya). More precisely, non-material living substances (jῑva), which constitute the essence of every living being, are the ones that are regarded as conscious. As a result of passion-motivated bodily, verbal, and mental activities these living substances are said to attract subtle matter (pudgala), which comes to form different bodies that bind them to the cycle of rebirths, restraining their natural movement upwards. Every embodied being is therefore composed of both living and material substance. Earth-beings represent one kind of possible embodiment, in which living substances are bound by bodies that have the nature of earth. Upon the completion of one particular embodiment in the earth-form, living substances leave the old earth-bodies and proceed to attract new body-forming matter. Apart from earth-matter which functions as a bonding body there is then also earth-matter which is not related to any living substance and is currently not utilized as a body, even though it may have previously been or will potentially become one. However, earth-matter is considered to be non-living (ajῑva) and non-conscious (acetana), no matter what its connection to living substances. The interaction between living substances and earth-matter as well as the distinction between earth utilized as a body and earth without a current embodying function will be carefully studied. The class of earth-beings is a pluralistic category just as the general ontology of life and matter in Jainism is pluralistic. Jainism does not put forward a notion of earth as such but instead refers to a multitude of earth-beings. These include raw soil, particles of dust, sand, raw minerals, pebbles, sand, salt, iron, copper, lead, silver, gold, diamonds, etc. This paper will look at various accounts of these subcategories in Jain literature, namely, basic descriptions of their smallest and biggest possible sizes, their characteristic of immobility, their single sense of touch, their instincts, and their experience of pleasure and pain. Their status within the broader ontological-cosmological doctrine will also be discussed as well as the character of their interactions with other living beings, the karmic contexts within which embodiments in the form of earth-beings are possible, the life-span of these embodiments, and the possible future rebirths following them. Additionally, this paper will point out and critically examine the implications of the described doctrines of earth-beings for the practical life of Jain laity and mendicants. The attitudes towards as well as the actual exploitation of earthly resources with a particular reference to the differences and similarities between Jains in the past and today will be analysed.
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Lindvall, A. y R. Hudecek. "Nuclear Accumulation of Mercury in Neutrophil Granulocytes Associated with Exposure from Dental Amalgam". En Geology and Health. Oxford University Press, 2003. http://dx.doi.org/10.1093/oso/9780195162042.003.0017.
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Corrosion and wear of dental amalgam may be associated with unexpectedly high levels of endogenous exposure to heavy metals. According to WHO, the resulting uptake of mercury exceeds that from all other sources in persons not occupationally exposed (WHO 1991) and a daily uptake level of 100 μg has been reported (Barregard et al. 1995). Due to the distribution patterns of mercury, standard blood and urine analyses give meager information on the response of the organism to this exposure. We here present data from nuclear microscopy analysis of neutrophil granulocytes (short-lived cells in the immune system cascade) in peripheral blood. Blood samples were drawn from patients suffering from possible side effects from dental amalgam. Their symptoms resembled those of the Chronic Fatigue Syndrome (Fukuda 1994), and the onset or intensity of the symptoms were related to occasional increased exposure to dental amalgam e.g., unprotected placing/drilling of the material. Data showed profound derangement of several cellular trace elements in the patient group and in some cases the substitution of mercury for zinc in the nuclear area. This supports the contention that systemic side effects from dental amalgam may occur. Venous blood samples were drawn from a cohort of Caucasian patients (n = 25) with a chronic debilitating illness, possibly related to the exposure from dental amalgam, and cell preparations were done as previously described (Johansson 1984, Lindh 1997). The same procedure was performed on blood samples from an age- and sex-matched healthy control group (n = 22) with similar numbers of amalgam fillings. A freeze-dried monolayer preparation of neutrophil granulocytes from each subject was investigated by means of nuclear microscopy (Zidenberg-Cherr). Thirty cells from each subject were analyzed in a subsequent manner and means and variances of the elemental concentrations of calcium (Ca), manganese (Mn), iron (Fe), zinc (Zn), and mercury (Hg) were calculated. In addition, the intracellular distribution of zinc and mercury was investigated in a few cells from both patients and controls by means of a nuclear microscopy elemental mapping technique. Cells with mercury levels above the detection limit (0.5 μg/kg dry weight) were investigated as well as cells with no detectable mercury.
Actas de conferencias sobre el tema "Cycle of iron and other trace metals"
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Bates, Eleanor y Nick Hawco. "Seasonal variability in the budgets of iron and other trace metals at Station ALOHA". En Goldschmidt2022. France: European Association of Geochemistry, 2022. http://dx.doi.org/10.46427/gold2022.12462.
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Natsuike, Masafumi, Masafumi Natsuike, Tetsuro Kikuchi, Tetsuro Kikuchi, Ying Ping Lee, Ying Ping Lee, Yuta Endo et al. "IRON AVAILABILITY BY COASTAL DIATOM CHAETOCEROS SP. IN THE SHIZUGAWA BAY, JAPAN". En Managing risks to coastal regions and communities in a changing world. Academus Publishing, 2017. http://dx.doi.org/10.31519/conferencearticle_5b1b938597fbe4.90495900.
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This study aimed to investigate the spatial distribution of dissolved iron from river to coastal waters and iron bioavailability for coastal phytoplankton. Dissolved iron concentrations and other water quality parameters (e.g., pH, concentrations of dissolved organic carbon and trace metals, etc.) were determined in the Shizugawa Bay and its adjacent rivers, northeast Japan. Coastal dominant diatom (Chaetoceros sp.) isolated from the bay was used for incubational assay to examine growth kinetics in a range of iron concentrations. As a result, total dissolved iron concentrations of inland waters (75 ± 80 nM) were substantially higher than those of coastal waters (7.2 ± 4.8 nM). Among inland waters, iron concentrations from anthropogenic waters were relatively higher than those for forested river waters. In the bay, relatively higher concentrations of iron were observed in the inner part. From the growth experiment, half-saturation constant of iron for the growth of Chaetoceros sp. was determined to be 1.8 - 3.5 nM. The observed dissolved iron concentrations combined with growth response indicate that growth of Chaetoceros sp. is in some cases limited by iron availability. However, this study generally suggests that, while dissolved iron concentration largely decreased from river to coastal waters, terrestrial iron inputs potentially including both natural and anthropogenic sources contribute sufficient growth and iron availability by Chaetoceros sp. in the Shizugawa Bay.
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Natsuike, Masafumi, Masafumi Natsuike, Tetsuro Kikuchi, Tetsuro Kikuchi, Ying Ping Lee, Ying Ping Lee, Yuta Endo et al. "IRON AVAILABILITY BY COASTAL DIATOM CHAETOCEROS SP. IN THE SHIZUGAWA BAY, JAPAN". En Managing risks to coastal regions and communities in a changing world. Academus Publishing, 2017. http://dx.doi.org/10.21610/conferencearticle_58b43167ae68c.
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This study aimed to investigate the spatial distribution of dissolved iron from river to coastal waters and iron bioavailability for coastal phytoplankton. Dissolved iron concentrations and other water quality parameters (e.g., pH, concentrations of dissolved organic carbon and trace metals, etc.) were determined in the Shizugawa Bay and its adjacent rivers, northeast Japan. Coastal dominant diatom (Chaetoceros sp.) isolated from the bay was used for incubational assay to examine growth kinetics in a range of iron concentrations. As a result, total dissolved iron concentrations of inland waters (75 ± 80 nM) were substantially higher than those of coastal waters (7.2 ± 4.8 nM). Among inland waters, iron concentrations from anthropogenic waters were relatively higher than those for forested river waters. In the bay, relatively higher concentrations of iron were observed in the inner part. From the growth experiment, half-saturation constant of iron for the growth of Chaetoceros sp. was determined to be 1.8 - 3.5 nM. The observed dissolved iron concentrations combined with growth response indicate that growth of Chaetoceros sp. is in some cases limited by iron availability. However, this study generally suggests that, while dissolved iron concentration largely decreased from river to coastal waters, terrestrial iron inputs potentially including both natural and anthropogenic sources contribute sufficient growth and iron availability by Chaetoceros sp. in the Shizugawa Bay.
4
Codreanu, Liviu. "Chromium bioaccumulation potential of edaphic cyanobacterium nostoc linckia grown on multimetallic systems". En 5th International Scientific Conference on Microbial Biotechnology. Institute of Microbiology and Biotechnology, Republic of Moldova, 2022. http://dx.doi.org/10.52757/imb22.16.
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Over the past few decades, chromium contamination of both terrestrial and aquatic ecosystems has increased as a result of various anthropogenic activities. In this regard, various useful and practical remediation technologies have been emerging to control chromium content in water, soil and other resources. Chromium remediation through microorganisms may be the best technology currently available for cleaning up Cr contaminated sites. These technologies using biological agents are cheaper, safer and ecofriendly than chemical treatment methods. Cr exists in several oxidation states, but the most stable and common forms are Cr(0), Cr(III) and Cr(VI) species. Chromium toxicity depends on its valence state. Hexavalent chromium is a highly mobile and toxic contaminant. Cr(III) being less mobile is much less toxic than Cr(VI). The purpose of this study was to assess the potential of cyanobacterium Nostoc linckia to accumulate hexavalent chromium during three successive cultivation cycles on multimetallic systems. Cyanobacterium Nostoc linckia (Roth) Born et Flah CNM-CB-03 was grown in a mineral medium and metal ions in different combinations. Cultivation was carried out in Erlenmayer flasks of 1000 mL with a working volume of 700 mL. The following parameters were used: pH of the medium 6.8-7.2, temperature 25-27oC, light intensity of 37-55 μmol photons m-2 s-1, continuous illumination, slow periodic shaking. The amount of inoculum was 0.4 g/L. Each cultivation cycle lasted 12 days. Multimetallic systems Cr/Fe, Cr/Fe/Ni, Cr/Fe/Ni/Zn and Cr/Fe/Ni/Zn/Cu were added to culture medium on the exponential phase of nostoc growth. In this study, the bioaccumulation of Cr(VI) from multimetallic systems was performed - a situation that is closer to real conditions, since in most cases the contamination of certain areas occurs due to the presence of several pollutants. Among the four studied systems, in Cr/Fe, Cr/Fe/Ni, and Cr/Fe/Ni/Zn/Cu, the rate of chromium uptake by nostoc was very similar and varied with the cultivation cycle. Thus, in these three systems, chromium uptake in the first cultivation cycle was 35.8-40.2% of the initial level of metal; in the second cycle - 27.2-32.7%, and in the third cycle - 19.7-27.1%. In Cr/Fe/Ni/Zn system, the bioaccumulation capacity of nostoc biomass was significantly higher and amounted to 63.1%, 56.0% and 34.8% of Cr(VI), which corresponds to three cultivation cycles. Moreover, Fe, Ni, Zn and Cu were also taken up during the cultivation of nostoc biomass from one cycle to another. For instance, iron uptake in the first cycle was 59-78% and it was accumulated almost completely in the next two cycles. Nickel uptake in the first cycle was 43.2-62.6%, in the next two - 49.7-83.1%. The percentage of zinc recovery by nostoc biomass was at the same level in all three cycles and amounted to 37.1-39.8% of its initial content in the Cr/Fe/Ni/Zn system. In the Cr/Fe/Zn/Ni/Cu system, zinc uptake increased from 25.8% in the first cycle to 54.5% in the third one. Copper uptake was 46.5-57.8%, and its maximum amount was accumulated in the second cycle of nostoc cultivation. Thus, the culture of Nostoc linckia demonstrated resistance to multimetallic systems and a high potential for bioaccumulation of Cr(VI) and other metals present. The capacity of cyanobacterium Nostoc linckia to bioaccumulate Cr(VI) from the contaminated medium remained high over three generations, while the uptake of Fe, Ni, Cu and Zn in the biomass increased from generation to generation. In conclusion, edaphic cyanobacterium Nostoc linkia is a good accumulator of chromium, but also of other metals in multimetallic systems. Due to its biological nature, Nostoc linckia is a suitable matrix for remediation processes that offers a vast competition ground for metal cations. Therefore, the use of microorganisms for heavy metal removal is a sustainable remediation approach that must be adopted in order to balance the environment and nature.
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Baviskar, Ajay, Pankaj Khera, Ashish Telgote, Himanshu Dhuria y Amit Sharma. "An Experimental Approach Towards Sustainable Solution for Material Recycling of ELV Plastic Bumpers and EV Batteries". En Symposium on International Automotive Technology. 400 Commonwealth Drive, Warrendale, PA, United States: SAE International, 2024. http://dx.doi.org/10.4271/2024-26-0164.
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<div class="section abstract"><div class="htmlview paragraph">A general automotive car is majorly composed of high strength steel (6%), other steel (50%), Iron (15%), Plastics (7%), Aluminum (4%) and others (Rubber, Glass, Textile) about 18%. End-of-life vehicles (ELVs) are a significant source of waste and pollution in the automotive industry.</div><div class="htmlview paragraph">Recycling ELVs, particularly their plastic components, Li-ion batteries, catalytic converters, and critical technology components such as alternators, semi-conductor chips, and high tensile strength steel can reduce their environmental impact and conserve valuable raw materials. The paper conducts a SWOT analysis and a life cycle assessment (LCA) to evaluate the long-term viability and potential of ELV recycling, environmental impact, and carbon footprint.</div><div class="htmlview paragraph">This paper examines the current state and challenges of ELV recycling in India and proposes a sustainable recycling solution for waste bumpers that includes paint removal, modification, reprocessing & recovery of precious metals from xEV Li-ion batteries.<ol class="list nostyle"><li class="list-item"><span class="li-label">i</span><div class="htmlview paragraph">Plastic recycling – Mainly PP from bumpers and other components.</div></li><li class="list-item"><span class="li-label">ii</span><div class="htmlview paragraph">Precious metals recovery – Lithium, Cobalt, Nickel, Mn etc.</div></li></ol></div><div class="htmlview paragraph">Based on pilot line experiment sustainable recycling solution was established and validated through lab testing to compare the changes in physical properties.</div><div class="htmlview paragraph">The paper also discusses the progress and challenges of achieving Carbon neutrality and circular economy objectives in the automotive industry and provides insights on sustainable material developments like e.g., long cellulose fiber reinforced thermoplastic for bumpers, reusability of raw materials in automobile parts manufacturing without compromising on quality requirements & provides data for rational decision-making and policy-making for ELV recycling in India.</div></div>
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Russell, Michael J. "On Irish bacteriometallogenesis and its wider connotations". En Irish-type Zn-Pb deposits around the world. Irish Association for Economic Geology, 2023. http://dx.doi.org/10.61153/pbic1076.
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Rapid and widespread access of surface waters to jostling segments of the upper crust marks the first step to metallogenesis in the Irish early Carboniferous. Overall, siting of these ore-forming systems involves two types of fluid-charged autocatalytic cracking engines. The more obvious is a province-wide diffuse type, excavating downward from the generally submarine surface to where waters are heated, dissolve metals and become buoyant enough to exploit channel ways back to the surface. Another, rather more obscure engine, starts near the mantle-crust boundary and either produces a through-going crustal structure to vectorially guide pressurized mantle volatiles and perhaps accompanying magma toward the surface, or it autonomously drills its way through the entire crust by penetrative convection, as in a diatreme. Either way ore-forming solutions are perhaps best incubated where both engines interact within the crust. But precipitation of minable metal requires structural down warp basins and associated saline, sulphate-reducing microbiome traps. So, whilst there is no unique ex-planation for the distribution of the orebodies, the Navan orebody, its southwest extension (SWEX) and its neigh-bour to the south, Tara Deep, do fall on a putative N-S Geofracture (Gf 3) first proposed in 1968/1969. But the N-S Geofracture hypothesis runs strongly against the “academic” grain! Moreover, no further discoveries can be unequivocally assigned to the hypothesis. So why persist with the notion at all? Well, there have been some other indications of such structures in adjacent countries and, most notably and farthest afield, on Mars which acts as a time machine for our planet! There the seismically active Cerberus Fossae structures have similar crustal joint aspect ratios of 40 to 55km, as with the putative Irish (and Scottish) examples. And five cold springs, sequentially younger to the east, happen to lie well-spaced along a 250km stretch of the northernmost Fossa. Yet there are no signs of mineral sulphide accumulations on Mars. Perhaps lacking there were sulphate-reducing bacteria required for the deposition of economic ores as in Ireland. Indeed, it was the discovery of light sulphate sulphur in the Irish ores, along with lithochemical and geological evidence for an exhalative aspect to them, that inspired the submarine alkaline vent theory (AVT) for the emergence of life. In this theory exothermic serpentinization drives hydrothermal convection cells to produce the exhalations into the Hadean Ocean. Here the free-energy convert-ing iron minerals (oxyhydroxides and sulphides) act as nano-engines in spontaneously precipitated membranes to generate the appropriate organic molecules required for life’s onset from volatile and hydrothermal delivery of CO2, H2, CH4 and the trace elements. These prebiotic nanoengines are powered by the electrical and pH disequilibria focused across the mineral membranes amounting to ~1 volt.
Informes sobre el tema "Cycle of iron and other trace metals"
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Banin, Amos, Joseph Stucki y Joel Kostka. Redox Processes in Soils Irrigated with Reclaimed Sewage Effluents: Field Cycles and Basic Mechanism. United States Department of Agriculture, julio de 2004. http://dx.doi.org/10.32747/2004.7695870.bard.
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The overall objectives of the project were: (a) To measure and study in situ the effect of irrigation with reclaimed sewage effluents on redox processes and related chemical dynamics in soil profiles of agricultural fields. (b) To study under controlled conditions the kinetics and equilibrium states of selected processes that affect redox conditions in field soils or that are effected by them. Specifically, these include the effects on heavy metals sorption and desorption, and the effect on pesticide degradation. On the basis of the initial results from the field study, increased effort was devoted to clarifying and quantifying the effects of plants and water regime on the soil's redox potential while the study of heavy metals sorption was limited. The use of reclaimed sewage effluents as agricultural irrigation water is increasing at a significant rate. The relatively high levels of suspended and, especially, dissolved organic matter and nitrogen in effluents may affect the redox regime in field soils irrigated with them. In turn, the changes in redox regime may affect, among other parameters, the organic matter and nitrogen dynamics of the root zone and trace organic decomposition processes. Detailed data of the redox potential regime in field plots is lacking, and the detailed mechanisms of its control are obscure and not quantified. The study established the feasibility of long-term, non-disturbing monitoring of redox potential regime in field soils. This may enable to manage soil redox under conditions of continued inputs of wastewater. The importance of controlling the degree of wastewater treatment, particularly of adding ultrafiltration steps and/or tertiary treatment, may be assessed based on these and similar results. Low redox potential was measured in a field site (Site A, KibutzGivat Brenner), that has been irrigated with effluents for 30 years and was used for 15 years for continuous commercial sod production. A permanently reduced horizon (Time weighted averaged pe= 0.33±3.0) was found in this site at the 15 cm depth throughout the measurement period of 10 months. A drastic cultivation intervention, involving prolonged drying and deep plowing operations may be required to reclaim such soils. Site B, characterized by a loamy texture, irrigated with tap water for about 20 years was oxidized (Time weighted average pe=8.1±1.0) throughout the measurement period. Iron in the solid phases of the Givat Brenner soils is chemically-reduced by irrigation. Reduced Fe in these soils causes a change in reactivity toward the pesticide oxamyl, which has been determined to be both cytotoxic and genotoxic to mammalian cells. Reaction of oxamyl with reduced-Fe clay minerals dramatically decreases its cytotoxicity and genotoxicity to mammalian cells. Some other pesticides are affected in the same manner, whereas others are affected in the opposite direction (become more cyto- and genotoxic). Iron-reducing bacteria (FeRB) are abundant in the Givat Brenner soils. FeRB are capable of coupling the oxidation of small molecular weight carbon compounds (fermentation products) to the respiration of iron under anoxic conditions, such as those that occur under flooded soil conditions. FeRB from these soils utilize a variety of Fe forms, including Fe-containing clay minerals, as the sole electron acceptor. Daily cycles of the soil redox potential were discovered and documented in controlled-conditions lysimeter experiments. In the oxic range (pe=12-8) soil redox potential cycling is attributed to the effect of the daily temperature cycle on the equilibrium constant of the oxygenation reaction of H⁺ to form H₂O, and is observed under both effluent and freshwater irrigation. The presence of plants affects considerably the redox potential regime of soils. Redox potential cycling coupled to the irrigation cycles is observed when the soil becomes anoxic and the redox potential is controlled by the Fe(III)/Fe(II) redox couple. This is particularly seen when plants are grown. Re-oxidation of the soil after soil drying at the end of an irrigation cycle is affected to some degree by the water quality. Surprisingly, the results suggest that under certain conditions recovery is less pronounced in the freshwater irrigated soils.
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Kanner, Joseph, Edwin Frankel, Stella Harel y Bruce German. Grapes, Wines and By-products as Potential Sources of Antioxidants. United States Department of Agriculture, enero de 1995. http://dx.doi.org/10.32747/1995.7568767.bard.
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Several grape varieties and red wines were found to contain large concentration of phenolic compounds which work as antioxidant in-vitro and in-vivo. Wastes from wine production contain antioxidants in large amounts, between 2-6% on dry material basis. Red wines but also white wines were found to prevent lipid peroxidation of turkey muscle tissues stored at 5oC. The antioxidant reaction of flavonoids found in red wines against lipid peroxidation were found to depend on the structure of the molecule. Red wine flavonoids containing an orthodihydroxy structure around the B ring were found highly active against LDL and membrane lipid peroxidation. The antioxidant activity of red wine polyphenols were also found to be dependent on the catalyzer used. In the presence of H2O2-activated myoglobin, the inhibition efficiency was malvidin 3-glucoside>catechin>malvidin>resveratol. However, in the presence of an iron redox cycle catalyzer, the order of effectiveness was resveratol>malvidin 3-glucoside = malvidin>catechin. Differences in protein binding were found to affect antioxidant activity in inhibiting LDL oxidation. A model protein such as BSA, was investigated on the antioxidant activity of phenolic compounds, grape extracts, and red wines in a lecithin-liposome model system. Ferulic acid followed by malvidin and rutin were the most efficient in inhibiting both lipid and protein oxidation. Catechin, a flavonal found in red-wines in relatively high concentration was found to inhibit myoglobin catalyzed linoleate membrane lipid peroxidation at a relatively very low concentration. This effect was studied by the determination of the by-products generated from linoleate during oxidation. The study showed that hydroperoxides are catalytically broken down, not to an alcohol but most probably to a non-radical adduct. The ability of wine-phenolics to reduce iron and from complexes with metals were also demonstrated. Low concentration of wine phenolics were found to inhibit lipoxygenase type II activity. An attempt to understand the bioavailability in humans of antocyanins from red wine showed that two antocyanins from red wine were found unchanged in human urine. Other antocyanins seems to undergo molecular modification. In hypercholesterolemic hamsters, aortic lipid deposition was significantly less in animals fed diets supplemented with either catechin or vitamin E. The rate of LDL accumulation in the carotid arteries was also significantly lower in the catechin and vitamin E animal groups. These results suggested a novel mechanism by which wine phenolics are associated with decreased risk of coronary heart diseases. This study proves in part our hypothesis that the "French Paradox" could be explained by the action of the antioxidant effects of phenolic compounds found at high concentration in red wines. The results of this study argue that it is in the interest of public health to increase the consumption of dietary plant falvonoids. Our results and these from others, show that the consumption of red wine or plant derived polyphenolics can change the antioxidant tone of animal and human plasma and its isolated components towards oxidative reactions. However, we need more research to better understand bioavailability and the mechanism of how polyphenolics affect health and disease.