Relevant bibliographies by topics / Anoxic environments

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  2. Dissertations / Theses
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Academic literature on the topic 'Anoxic environments'

Author: Grafiati
Published: 4 June 2021
Last updated: 9 February 2022

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Journal articles on the topic "Anoxic environments"

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Rogov, MA, EV Shchepetova, and VA Zakharov. "Late Jurassic – earliest Cretaceous prolonged shelf dysoxic–anoxic event and its possible causes." Geological Magazine 157, no. 10 (2020): 1622–42. http://dx.doi.org/10.1017/s001675682000076x.

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AbstractThe Late Jurassic – earliest Cretaceous time interval was characterized by a widespread distribution of dysoxiс–anoxiс environments in temperate- and high-latitude epicontinental seas, which could be defined as a shelf dysoxic–anoxic event (SDAE). In contrast to black shales related to oceanic anoxic events, deposits generated by the SDAE were especially common in shelf sites in the Northern Hemisphere. The onset and termination of the SDAE was strongly diachronous across different regions. The SDAE was not associated with significant disturbances of the carbon cycle. Deposition of organic-carbon-rich sediment and the existence of dysoxic–anoxic conditions during the SDAE lasted up to c. 20 Ma, but this event did not cause any remarkable biotic extinction. Temperate- and high-latitude black shale occurrences across the Jurassic–Cretaceous boundary have been reviewed. Two patterns of black shale deposition during the SDAE are recognized: (1) Subboreal type, with numerous thin black shale beds, bounded by sediments with very low total organic carbon (TOC) values; and (2) Boreal type, distinguished by predominantly thick black shale successions showing high TOC values and prolonged anoxic–dysoxic conditions. These types appear to be unrelated to differences in accommodation space, and can be clearly recognized irrespective of the thickness of shale-bearing units. Black shales in high-latitude areas in the Southern Hemisphere strongly resemble Boreal types of black shale by their mode of occurrence. The causes of this SDAE are linked to long-term warming and changes in oceanic circulation. Additionally, the long-term disturbance of planktonic communities may have triggered overall increased productivity in anoxia-prone environments.
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Child, R. E. "Anoxic Environments in Archive Conservation." Journal of the Society of Archivists 23, no. 2 (2002): 171–78. http://dx.doi.org/10.1080/0037981022000006354.

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Nardelli, M. P., C. Barras, E. Metzger, et al. "Experimental evidence for foraminiferal calcification under anoxia." Biogeosciences 11, no. 14 (2014): 4029–38. http://dx.doi.org/10.5194/bg-11-4029-2014.

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Abstract. Benthic foraminiferal tests are widely used for paleoceanographic reconstructions from a range of different environments with varying dissolved oxygen concentrations in the bottom water. There is ample evidence that foraminifera can live in anoxic sediments. For some species, this is explained by a switch to facultative anaerobic metabolism (i.e. denitrification). Here we show for the first time that adult specimens of three benthic foraminiferal species are not only able to survive, but are also able to calcify under anoxic conditions, at various depths in the sediment, and with or without nitrates. In fact, several specimens of Ammonia tepida (1–4%), Bulimina marginata (8–24%) and Cassidulina laevigata (16–23%) were able to calcify at different redox fronts of sediment cores, under laboratory conditions. This demonstrates ongoing metabolic processes, even in micro-environments where denitrification is not possible. Earlier observations suggest that the disappearance of foraminiferal communities after prolonged anoxia is not due to instantaneous or strongly increased adult mortality. Here we show that it cannot be explained by an inhibition of growth through chamber addition either. Our observations of ongoing calcification under anoxic conditions mean that geochemical proxy data obtained from benthic foraminifera in settings experiencing intermittent anoxia have to be reconsidered. The analysis of whole single specimens or of their successive chambers may provide essential information about short-term environmental variability and/or the causes of anoxia.
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Nardelli, M. P., C. Barras, E. Metzger, et al. "Experimental evidence for foraminiferal calcification under anoxia." Biogeosciences Discussions 11, no. 3 (2014): 4669–94. http://dx.doi.org/10.5194/bgd-11-4669-2014.

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Abstract. Benthic foraminiferal tests are widely used for paleoceanographic reconstructions. There is ample evidence that foraminifera can live in anoxic sediments. For some species, this is explained by a switch to facultative anaerobic metabolism (i.e. denitrification). Here we show for the first time that adult specimens of three benthic foraminiferal species are not only able to survive but are also able to calcify in anoxic conditions, at various depths in the sediment, with and without nitrates. This demonstrates ongoing metabolic processes, even in micro-environments where denitrification is not possible. Earlier observations suggest that the disappearance of foraminiferal communities after prolonged anoxia is not due to instantaneous or strongly increased adult mortality. Here we show that it cannot be explained by an inhibition of growth through chamber addition either. Our observations of ongoing calcification under anoxic conditions means that geochemical proxy data obtained from benthic foraminifera in settings experiencing intermittent anoxia have to be reconsidered. The analysis of whole single specimens or of their successive chambers may provide essential information about short-term environmental variability and/or the causes of anoxia.
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Orsi, William D., Raphaël Morard, Aurele Vuillemin, et al. "Anaerobic metabolism of Foraminifera thriving below the seafloor." ISME Journal 14, no. 10 (2020): 2580–94. http://dx.doi.org/10.1038/s41396-020-0708-1.

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Abstract Foraminifera are single-celled eukaryotes (protists) of large ecological importance, as well as environmental and paleoenvironmental indicators and biostratigraphic tools. In addition, they are capable of surviving in anoxic marine environments where they represent a major component of the benthic community. However, the cellular adaptations of Foraminifera to the anoxic environment remain poorly constrained. We sampled an oxic-anoxic transition zone in marine sediments from the Namibian shelf, where the genera Bolivina and Stainforthia dominated the Foraminifera community, and use metatranscriptomics to characterize Foraminifera metabolism across the different geochemical conditions. Relative Foraminifera gene expression in anoxic sediment increased an order of magnitude, which was confirmed in a 10-day incubation experiment where the development of anoxia coincided with a 20–40-fold increase in the relative abundance of Foraminifera protein encoding transcripts, attributed primarily to those involved in protein synthesis, intracellular protein trafficking, and modification of the cytoskeleton. This indicated that many Foraminifera were not only surviving but thriving, under the anoxic conditions. The anaerobic energy metabolism of these active Foraminifera was characterized by fermentation of sugars and amino acids, fumarate reduction, and potentially dissimilatory nitrate reduction. Moreover, the gene expression data indicate that under anoxia Foraminifera use the phosphogen creatine phosphate as an ATP store, allowing reserves of high-energy phosphate pool to be maintained for sudden demands of increased energy during anaerobic metabolism. This was co-expressed alongside genes involved in phagocytosis and clathrin-mediated endocytosis (CME). Foraminifera may use CME to utilize dissolved organic matter as a carbon and energy source, in addition to ingestion of prey cells via phagocytosis. These anaerobic metabolic mechanisms help to explain the ecological success of Foraminifera documented in the fossil record since the Cambrian period more than 500 million years ago.
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Kartal, Boran, Hans J. C. T. Wessels, Erwin van der Biezen, et al. "Effects of Nitrogen Dioxide and Anoxia on Global Gene and Protein Expression in Long-Term Continuous Cultures of Nitrosomonas eutropha C91." Applied and Environmental Microbiology 78, no. 14 (2012): 4788–94. http://dx.doi.org/10.1128/aem.00668-12.

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ABSTRACTNitrosomonas eutrophais an ammonia-oxidizing betaproteobacterium found in environments with high ammonium levels, such as wastewater treatment plants. The effects of NO2on gene and protein expression under oxic and anoxic conditions were determined by maintainingN. eutrophastrain C91 in a chemostat fed with ammonium under oxic, oxic-plus-NO2, and anoxic-plus-NO2culture conditions. Cells remained viable but ceased growing under anoxia; hence, the chemostat was switched from continuous to batch cultivation to retain biomass. After several weeks under each condition, biomass was harvested for total mRNA and protein isolation. Exposure ofN. eutrophaC91 to NO2under either oxic or anoxic conditions led to a decrease in proteins involved in N and C assimilation and storage and an increase in proteins involved in energy conservation, including ammonia monooxygenase (AmoCAB). Exposure to anoxia plus NO2resulted in increased representation of proteins and transcripts reflective of an energy-deprived state. Several proteins implicated in N-oxide metabolism were expressed and remained unchanged throughout the experiment, except for NorCB nitric oxide reductase, which was not detected in the proteome. Rather, NorY nitric oxide reductase was expressed under oxic-plus-NO2and anoxic-plus-NO2conditions. The results indicate that exposure to NO2results in an energy-deprived state ofN. eutrophaC91 and that anaerobic growth could not be supported with NO2as an oxidant.
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Meilijson, Aaron, Sarit Ashckenazi-Polivoda, Peter Illner, et al. "Evidence for specific adaptations of fossil benthic foraminifera to anoxic–dysoxic environments." Paleobiology 42, no. 1 (2015): 77–97. http://dx.doi.org/10.1017/pab.2015.31.

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AbstractIt has generally been argued that the majority of fossil benthic foraminifera, the most common proxy for paleo bottom oceanic conditions, could not tolerate anoxia. Here we present evidence that fossil foraminifera were able to successfully colonize anoxic–dysoxic bottom waters, by using adaptations similar to those found in living species. Our study is based on a multi proxy micropaleontological and geochemical investigation of the Upper Cretaceous sediments from the Levant upwelling regime. A shift from buliminid to diverse trochospiral dominated assemblages was recorded in an interval with a distinct anoxic geochemical signature coinciding with a regional change in lithology. This change was triggered by an alteration in the type of primary producers from diatoms to calcareous nannoplankton, possibly causing modifications in benthic foraminiferal morphological and physiological adaptations to life in the absence of oxygen.Our data show that massive blooms of triserial (buliminid) benthic foraminifera with distinct apertural and test morphologies during the Campanian were enabled by their ability to sequester diatom chloroplasts and associate with bacteria, in a similar manner as their modern analogs. Diverse trochospiral forms existed during the Maastrichtian by using nitrate instead of oxygen for their respiratory pathways in a denitrifying environment. Species belonging to the Stilostomellidae and Nodosariidae families might have been affected by the change in food type arriving to the seafloor after the phytoplankton turnover at the Campanian/Maastrichtian boundary, in a similar manner as their mid Pleistocene descendants prior to their extinction. This study promotes the need for a re-evaluation of the current models used for interpreting paleoceanographic data and demonstrates that the identification of adaptations and mechanisms involved in promoting sustained life under anoxic to dysoxic conditions should become a standard in faunal paleoceanographic studies.
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Senior, Nicholas A., Taylor Martino, and Nikitas Diomidis. "The anoxic corrosion behaviour of carbon steel in anoxic alkaline environments simulating a Swiss L/ILW repository environment." Materials and Corrosion 72, no. 1-2 (2020): 131–40. http://dx.doi.org/10.1002/maco.202011780.

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de Beer, Dirk, Andreas Schramm, Cecilia M. Santegoeds, and Helle K. Nielsen. "Anaerobic processes in activated sludge." Water Science and Technology 37, no. 4-5 (1998): 605–8. http://dx.doi.org/10.2166/wst.1998.0726.

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We found anoxic zones in aerated activated sludge flocs, and demonstrated denitrification under normal operating conditions. Sulfate reduction was not found. Micro-environments and microbial conversions in flocs from bulking and non-bulking activated sludge were determined with microsensors for H2S, O2, NO2− and NO3−. Denitrification and sulfate reduction rates were mmeasured with 15N- and 35S-tracer techniques. We showed that under normal reactor conditions (ca. 20% air saturation) anoxic zones develop within flocs allowing denitrification. The denitrification rates amounted to 40% of the rates under anoxic conditions. At 100% air saturation no anoxic zones were found and no denitrification occurred. However, in flocs from bulking sludge (at 20% air saturation) anoxic zones were absent and denitrification did not occur. In bulking sludge only at total anoxia was denitrification found. Confocal microscopy showed that flocs from bulking sludge were much looser than those from non-bulking sludge. The absence of anoxic zones and of denitrification was attributed to the open floc structure, allowing advective oxygen transport. Sulfate reduction was not detected in any of the sludges tested by microsensors or by tracer techniques even under anoxic conditions. this indicates that the sulfur cycle (sulfate reduction and sulfide oxidation) does not play a role in mineralization processes and bulking in activated sludge. Preliminary molecular work (in situ hybridization with the 16S-rRNA probe SRB385) indicated the presence of small amounts of sulfate reducing bacteria in all sludges. Either the probe is not specific or the sulfate reducers present are not active under reactor conditions.
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Rausch, Richard N., Larry I. Crawshaw, and Helen L. Wallace. "Effects of hypoxia, anoxia, and endogenous ethanol on thermoregulation in goldfish, Carassius auratus." American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 278, no. 3 (2000): R545—R555. http://dx.doi.org/10.1152/ajpregu.2000.278.3.r545.

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Effects of hypoxia, anoxia, and endogenous ethanol (EtOH) on selected temperature (Tsel) and activity in goldfish were evaluated. Blood and brain EtOH concentrations ([EtOH]) and brain oxygen partial pressure ([Formula: see text]) were quantified at crucial ambient oxygen pressures. Below a threshold value near 31 Torr, Tsel decreased as a function of environmental[Formula: see text]. Tsel of 15°C-acclimated fish was ∼10°C at the onset of anoxia and changed little over 2 h. Activity showed a similar response pattern. Brain [EtOH] was significantly elevated above control levels after 1 h anoxia. In normoxic water, Tsel remained different in previously anoxic and normoxic control fish for ∼20 min. Blood [EtOH] of previously anoxic fish remained significantly elevated ([EtOH] >4.0 μmol/g blood), and activity was significantly depressed at 20 min. Brain[Formula: see text] reached normal levels in <3 min. We conclude that [EtOH] (brain or blood) and brain[Formula: see text] are not proximal causes of either behavioral anapyrexia (hypothermia) or inactivity in goldfish exposed to oxygen-depleted environments.
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Dissertations / Theses on the topic "Anoxic environments"

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Gupta, A. "Metagenomes and metatranscriptomes of cellulolytic communities in anoxic environments." Thesis, University of Liverpool, 2017. http://livrepository.liverpool.ac.uk/3022648/.

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Sun, Wenjie. "Microbial Oxidation of Arsenite in Anoxic Environments: Impacts on Arsenic Mobility." Diss., The University of Arizona, 2008. http://hdl.handle.net/10150/194899.

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AbstractArsenic (As) contamination of groundwater and surface water is a worldwide problem. Exposure to arsenic in drinking water is an important current public health issue. Arsenic is well known for its carcinogenic and teratogenic effects. The U.S. Environmental Protection Agency (USEPA) has recently enacted a stricter drinking water standard for arsenic that lowers the maximum contaminant level (MCL) from 50 to 10 ug l-1.Localized elevated As concentrations in groundwater or surface water have been attributed to the natural release of As from the weathering of As bearing minerals. Microbial reduction of arsenate (As(V)) to arsenite (As(III)) and ferric (hydr)oxides to Fe(II) is hypothesized to be the dominant mechanisms of As mobilization in subsurface environments. If oxidizing conditions can be restored, As can be immobilized by the formation of As(V) and ferric (hydr)oxides. As(V) is more strongly adsorbed than As(III) at circumneutral conditions by common non-iron metal oxides in sediments such as those of aluminum. Ferric (hydr)oxides have strong affinity for both As(III) and As(V) in circumneutral environments. Oxygen can be introduced into the anaerobic zone by injection of gaseous O2 to promote oxidation reactions of As(III) and Fe(II), but O2 is poorly soluble and chemically reactive and thus difficult to distribute in the subsurface. Nitrate or chlorate can be considered as alternative oxidants with advantages over elemental oxygen due to their high aqueous solubility and lower chemical reactivity which together enable them to be better dispersed in the saturated subsurface.The objective of this study is to evaluate the importance of anoxic oxidation of As(III) to As(V) by anaerobic microorganisms such as chemolithotrophic denitrifying bacteria and chlorate respiring bacteria in the biogeochemical cycle of arsenic. This study also investigated a arsenic potential bioremediation strategy based on injecting nitrate or chlorate into contaminated groundwater and surface water under anaerobic conditions.In this study, denitrification or chlorate reduction linked to the oxidation of As(III) to As(V) was shown to be a widespread microbial activity in anaerobic sludge and sediment samples that were not previously exposed to arsenic contamination. The biological oxidation of As(III) utilizing nitrate or chlorate as sole electron acceptor was feasible and stable over prolonged periods of operation in continuous-flow anaerobic bioreactors. Evidence for the complete denitrification was demonstrated by direct measurement of N2 formation dependent on As(III) addition. Also complete chlorate reduction to chloride was attributable to the oxidation of As(III). A 16S rRNA gene clone library characterization of enrichment cultures indicated that the predominant phylotypes responsible for As(III) oxidation linked to denitrification were from the genus Azoarcus and the family Comamonadaceae. A bioremediation strategy was explored that is based on injecting nitrate to support the microbial oxidation of Fe(II) and As(III) in the subsurface as a means to immobilize arsenic. Two models were utilized to illustrate the mechanisms of As removal.1) Sediment columns packed with activated alumina were utilized to demonstrate the role of nitrate in supporting microbial As(III) oxidation and arsenic mobility in anoxic sediments containing mostly non-iron oxides;2) Sand-packed columns were used to simulate natural anaerobic groundwater and sediment systems with co-occurring As(III) and Fe(II) in the presence or absence of nitrate. Microbial oxidation by denitrifying microorganisms lead to the formation of ferric (hydroxides) which adsorbed As(V) formed from As(III)-oxidation.The studies presented here demonstrate that anoxic microbial oxidation of As(III) and Fe(II) linked to denitrification significantly enhance the immobilization of As in the anaerobic subsurface environments.
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Ficken, Katherine J. "Lipid and sulphur geochemistry of recent sediments from oxic and anoxic environments." Thesis, University of Newcastle Upon Tyne, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.384952.

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Houghton, James. "Molecular diversity and functional composition of cellulose degrading communities in anoxic environments." Thesis, University of Liverpool, 2013. http://livrepository.liverpool.ac.uk/14933/.

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The major fraction of microbial communities cannot be cultivated by artificial means in the laboratory. In order to access the full diversity of microbial life in the open environment it is necessary to employ culture independent methods. Molecular biology and now metagenomics have enabled the phylogenetic and functional investigation of microbial communities without isolation and cultivation of organisms and has led to a new appreciation of the breadth of diversity of microbes on Earth and to the discovery and characterisation of new enzymes. Here, molecular biological techniques have been applied to the study of microbial communities specifically in anaerobic environments and with an emphasis on those involved in the primary degradation of plant cellulosic biomass. Quantitative PCR was used to assess the presence of cellulolytic bacteria both in landfill leachate and specifically in association with cotton cellulose “baits” maintained in leachate microcosms. Lineages of clostridia previously associated with cellulose degrading strains were detected in all five of the landfill leachate samples, and Fibrobacter spp. were detected at low abundance (2.3% of total bacteria) in one sample. Clostridia Group III and Fibrobacter spp. were enriched on the surface of a bait (17% and 29% of total bacteria, respectively) that was rapidly degraded by the colonising community and were present in low abundance (< 1%) and absent, respectively, on another colonised by a community which did not exhibit any degradation of the cellulose. The observed correlation between high levels of cellulose degradation and presence Fibrobacter spp. demonstrates a cellulolytic role outside of the gut environment for these organisms the first time. A metatranscriptome was prepared from a set of cotton cellulose baits maintained in a lake sediment for 2-8 weeks, and Illumina sequencing was used to generated ca. 7 million paired-end reads. Just under one million putative protein coding sequences were identified and of these, MEGAN analysis determined that 40% had no blast hit to the NCBI NR database suggesting that a large number of unknown sequences were present. Analysis of this metatranscriptome and a metagenome produced from the same site revealed that bacteria accounted for 75% of the protein coding sequences and 97% of the metagenome. Genes with matches to cellulolytic lineages of clostridia were found to be present and Fibrobacter sequences were also detected in both of these datasets further demonstrating their presence in the wider environment as probable cellulose degraders ORF prediction and HMM searching were used to search for expressed cellulases in the metatranscriptome and identified 503 sequences with high similarity to glycoside hydrolase protein families, representing carbohydrate active enzymes with possible cellulolytic activity. Of these 112 were also found to have representatives in the metagenome with 100% sequence similarity. All of these sequences had a low level of identity to entries in the NCBI NR database indicating the discovery of previously unknown genes. A fosmid library was produced from the same DNA used to generate the metatranscriptome and it is possible that full-length copies of the expressed genes identified in silico will have been captured. This fosmid library can be interrogated accordingly using probe and PCR primer sequences designed using the curated metatranscriptome dataset. In this way, potentially novel cellulases can be discovered for biochemical characterisation, genetic manipulation and biotechnological exploitation.
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Sandberg, Scott Alan. "The biodegradation of valeric, butyric, propionic and acetic acids in anoxic, subsurface, soil environments." Thesis, Virginia Polytechnic Institute and State University, 1988. http://hdl.handle.net/10919/52069.

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The biodegradation potential of two subsurface soils was characterized by monitoring the biodegradation of short-chain fatty acids in anaerobic soil microcosms. Valerate, butyrate, propionate, and acetate concentrations were monitored independently using separate microcosms. The effect of sulfate on the microbial communities was also investigated. One soil, from Newport News, Virginia, consisted of a sandy loam collected beneath a low lying, grassy field. The microcosms containing the soil were characterized by: a neutral pH, the utilization of sulfate with concomitant precipitation of iron sulfide , an increase in the degradation rate as a result of sulfate addition, and a production of bicarbonate directly related to acid mineralization. Another soil, from Blacksburg, Virginia, consisted of a silty-clay collected beneath a wooded hilltop. Microcosms containing the soil were characterized by : a pH between 4 and 5, little sulfate utilization with no visible iron sulfide precipitation, an increase in degradation rates upon the addition of sulfate, and little or no accumulation of bicarbonate. These results indicate that short-chain fatty acids are readily degraded in subsurface anaerobic soil systems and that these rates are dependent on the availability of electron acceptors and the diversity of the indigenous population.<br>Master of Science
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Tobler, Nicole Béatrice. "Iron-mediated coupling of microbial oxidation and abiotic reduction of organic contaminants in anoxic environments /." Zürich : ETH, 2007. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=17155.

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Rubelmann, Haydn III. "A Functional Approach to Resolving the Biogeocomplexity of Two Extreme Environments." Scholar Commons, 2014. https://scholarcommons.usf.edu/etd/5432.

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The biodiversity of two distinct marine environments was observed to describe the biogeocomplexity of these extreme ecological systems. A shallow-water hydrothermal vent in Papua New Guinea served as a study of a thermophilic ecosystem influenced by arsenic rich vent fluids while a 60 m deep offshore primarily anoxic karst sink served as a study of an anaerobic sulfur-influenced habitat. Both environments support unique biological communities that are influenced by the physical and chemical pressures imposed on them by the harsh conditions of these systems. In Tutum Bay, Ambitle Isle, Papua New Guinea, a transect was created from a shallow hydrothermal vent that extended 120 m away from the vent. Previous studies have shown that the geochemistry of the system is heavily influenced by arsenic which is toxic to most organisms. In this study, macro- and meiofauna were collected and scored and combined with bacterial sequence data collected along the length of the transect. It was found that near vent sites harbored biological communities more similar than sites further from the vent. Many species were found only at sites near the hydrothermal vent. Near-vent communities were less diverse than those away from the vent, and biodiversity generally increased as distance from the vent increased. Distinct correlations between thermophilic organisms and temperature were observed. The metabolic repertoire of the microbial communities suggests that many strategies are used to obtain energy and carbon. The relative abundance of bacteria containing genes to reduce arsenic was comparable to those able to reduce sulfur compounds. Primary production appeared to be a mix of chemo- and phototrophy. Food webs and association analysis suggest a complex interplay between macrofaunal, meiofaunal and bacterial communities. While the system is heavily influenced by arsenic, no specific correlation between the relative abundance of arsenic metabolizing organisms and the amount of arsenic in the system could be drawn. This is likely due to the fact that most of the arsenic produced by the system is readily adsorbed onto iron oxyhydroxides, reducing the arsenic's bioavailability. The anoxic conditions at Jewfish sink provide a different hurdle than the hot arsenic conditions found in Papua New Guinea. The anoxic conditions are shared by other pit features found in karst geography, but the metabolic processes between Jewfish sink and these other karst habitats are different. The blue holes and black holes of the Bahamas are some of the most well-studied of these karstic pits. In these features, which are large circular pits with diameters of over 300 m, light and sulfur are used as a means of energy acquisition. Jewfish sink, having an opening only 6 m in diameter, is light restricted compared to these systems. As a result, the strategy of organisms dwelling in the anoxic conditions of the sink is different than those found at the well-studied holes in the Bahamas. Geochemical measurements were recorded over two time periods spanning a combined total of 6 years. The anoxic bottom waters of Jewfish sink remain stable and contained high levels of sulfide throughout most of the seasons studies. Sequence analysis of prokaryotes within the sink showed that sulfur reducers had the highest relative abundance compared to other functional guilds. To monitor the changes of the microbial communities within the sink, bacterial communities were examined at 4 depths within the sink at 9 different intervals over a period of 685 days. Denaturing Gradient Gel Electrophoresis (DGGE) was used to fingerprint 16s rRNA bacterial communities and dissimilatory sulfite reducing communities by targeting the 16s rRNA bacterial gene and the dsr gene associated with dissimilatory sulfite reducing bacteria and archaea. The lowest depth studied within the sink (40 m) remained stable chemically and biologically until a turnover event occurred within the second winter of the study. This turnover event disrupted the biological communities at 40 m and led to a reestablished community comprised of different species that those found prior to the event. Upper waters within the sink show that clines establish themselves seasonally and partition zones that confine bacterial communities that are more similar to each other within these zones while excluding bacterial communities that are outside of these zones. Oxygenated water was shown to not contain prokaryotes containing the dsr gene. As the oxycline changed seasonally, dissimilatory sulfite reducing prokaryotes containing the dsr gene remained in the anoxic zone and required time to reestablish themselves whenever oxygenated water displaced them.
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Scott, Brian T. "VARIATION IN C/P RATIOS IN DEVONIAN-MISSISSIPPIAN MARINE SHALES: TESTING THE PRODUCTIVITY-ANOXIA FEEDBACK MODEL." Lexington, Ky. : [University of Kentucky Libraries], 2009. http://hdl.handle.net/10225/1076.

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Thesis (M.S.)--University of Kentucky, 2009.<br>Title from document title page (viewed on October 28, 2009). Document formatted into pages; contains: viii, 82 p. : ill. (some col.), maps (some col.). Includes abstract and vita. Includes bibliographical references (p. 77-81).
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Hemmingsson, Tryggve. "Exhaled nitric oxide in extreme environments." Stockholm : Karolinska institutet, 2009. http://diss.kib.ki.se/2009/978-91-7409-609-5/.

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Carmo, Janine Araujo do. "Estratigrafia magnética e magnetismo ambiental do sítio DSDP-511 (Platô das Falklands) durante o limite Barremiano-Aptiano." Universidade de São Paulo, 2017. http://www.teses.usp.br/teses/disponiveis/14/14132/tde-04062018-105352/.

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O Cretáceo inferior é caracterizado por mudanças drásticas em todos os envelopes terrestres, envolvendo desde variações geodinâmicas a importantes mudanças paleoclimáticas. Entretanto, há poucos registros desses eventos no hemisfério sul, sendo o DSDP-511 o principal deles. Com objetivo de gerar melhores vínculos temporais para os registros do Cretáceo Inferior no hemisfério sul, foram realizados estudos paleomagnéticos e de magnetismo ambiental em alta resolução espacial em uma secção do sítio DSDP-511 (núcleos 58 e 59), a qual corresponde ao intervalo entre 508,77 a 523,94 mbsf (meters below sea floor) e abrange os estágios Barremiano e Aptiano. A compreensão dos eventos paleoclimáticos neste sítio não é trivial, uma vez que, além de ambiguidade nas idades inferidas pela bioestratigrafia, apenas parte do evento de anoxia oceânica OAE 1a está registrada devido a uma lacuna de amostragem. Foram identificados dois principais portadores magnéticos através da análise de curvas de aquisição e desmagnetização de magnetização remanente anisterética (ARM) e magnetização remanente isotérmica (IRM). O mineral de baixa corecividade é a magnetita, confirmada a partir da desmagnetização de IRM triaxial. Sua origem é provavelmente detrítica. O portador de alta coercividade foi interpretado como hematita. A contribuição relativa dos portadores magnéticos apresentou uma variação acentuada no intervalo entre 512 e 514 mbsf, sendo manifestada através de um pico em todos os parâmetros de magnetismo ambiental. Esta variação está associada também à maior concentração de minerais magnéticos neste intervalo e coincide com um marcado aumento na temperatura da superfície dos oceanos. Após desmagnetização progressiva e identificação da componente magnética característica foram definidas duas zonas de polaridade normal e uma zona de polaridade reversa (518,9 e 518,16 mbsf). Além disso, foi definida uma zona discreta de polaridade reversa em 509,20 mbsf. Os resultados encontrados apresentam diferenças significativas quando comparadas com estudos anteriores no mesmo testemunho. Uma datação Re-Os em folhelhos negros de 125,3 ± 2,2 Ma entre 519,01 e 519,40 mbsf foi obtida recentemente e forneceu um vínculo absoluto de idade para o intervalo estudado. O padrão de reversões encontrado foi compatível com a presença dos chrons M0r e ISEA. O modelo de idades proposto permite reposicionar o evento OAE 1a entre as profundidades 513,5 a 518 mbsf, incluindo a parte não recuperada do testemunho. Esta interpretação também compatível com dados de TOC e de 13C obtidos recentemente por outros autores.<br>The lower Cretaceous is characterized by drastic changes in the Earth, from geodynamic variations to important paleoclimatic changes. However, there are few records of these events in the southern hemisphere, the DSDP-511 being the most comprehensive one. In order to provide better temporal constraints for the lower Cretaceous records in the southern hemisphere, paleomagnetic and high-resolution environmental magnetism studies were performed in a section of the DSDP-511 site (cores 58 and 59), which corresponds to the interval between 508.77 to 523.94 mbsf (meters below sea floor) and covers the Barremian and Aptian stages. The correct assessment of paleoclimatic events at this site is not trivial because, in addition to the ambiguity at the ages inferred by biostratigraphy, only part of the OAE 1a (oceanic anoxic event) was recovered. Two main magnetic carriers were identified through the analysis of acquisition and demagnetization of anhysteretic remanent magnetization (ARM) and isothermal remanent magnetization (IRM) curves. The low coercivity mineral is magnetite, as attested by triaxial IRM demagnetization. Its origin is likely detrital. The high coercivity carrier was interpreted as hematite. The relative contribution of magnetic carriers has a strong variation in the interval between 512 and 514 mbsf, being manifested by a peak in all parameters of environmental magnetism. This variation is also associated with the higher concentration of magnetic minerals and coincides with a marked increase in the sea surface temperature in this interval. After stepwise demagnetization and identification of the characteristic magnetic component, two zones of normal polarity and a zone of reverse polarity (518.9 and 518.16 mbsf) were defined. In addition, a discrete zone of reverse polarity was defined at 509.20 mbsf. The results obtained present significant differences when compared with previous studies in the same core. A Re-Os dating on black shales of 125.3 ± 2.2 Ma between 519.01 and 519.40 mbsf was obtained recently and provided an absolute constraint onto which the polarity zones could be matched. The pattern of reversions found is compatible with the presence of chrons M0r and ISEA. The proposed age model allows repositioning the OAE 1a event between depths 513.5 to 518 mbsf in the core and overlap the unrecovered part. This interpretation is also compatible with TOC and 13C data recently obtained by other authors.
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Books on the topic "Anoxic environments"

1

Wilkin, Richard T. Mineralogical preservation of solid samples collected from anoxic subsurface environments. United States Environmental Protection Agency, National Risk Management Research Laboratory, 2006.

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Song, Yigang. Sediment-water interactions in anoxic freshwater sediments: Mobility of heavy metals and nutrients. Springer, 1999.

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Edwards, David Lawrence. Evaluation of chemical conversion material (protective coating) exposed to space environmental conditions CDDF: Final report (no. 90-07). National Aeronautics and Space Administration, George C. Marshall Space Flight Center, 1993.

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Devito, Kevin John. The importance of runoff and winter anoxia to P and N dynamics of a beaver pond. Queen's Printer for Ontario, 1992.

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Downen, Mark R. 1998 Lake Cassidy survey: The warmwater fish community competing under conditions of hypolimnetic anoxia and dense aquatic macrophytes. Washington Dept. of Fish and Wildlife, Fish Program, Fish Management Division, Warmwater Enhancement Program, 1999.

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Hay, K. James. Development of Venturi/Vortex Scrubber Technology for controlling chromium electroplating hazardous air emissions. US Army Corps of Engineers, Construction Engineering Research Laboratories, 1998.

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United States. Congress. Senate. Committee on Environment and Public Works. Water quality in Lake Erie: Field hearing before the Committee on Environment and Public Works, United States Senate, One Hundred Seventh Congress, second session, on anoxia in the central basin of Lake Erie, and the impact of "dead zones" on the ecology of the Great Lakes region, August 5, 2002, Cleveland, OH. U.S. G.P.O., 2004.

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Saints, scholars, and schizophrenics: Mental illness in rural Ireland. 2nd ed. University of California Press, 2001.

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Kirchman, David L. Processes in anoxic environments. Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780198789406.003.0011.

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During organic material degradation in oxic environments, electrons from organic material, the electron donor, are transferred to oxygen, the electron acceptor, during aerobic respiration. Other compounds, such as nitrate, iron, sulfate, and carbon dioxide, take the place of oxygen during anaerobic respiration in anoxic environments. The order in which these compounds are used by bacteria and archaea (only a few eukaryotes are capable of anaerobic respiration) is set by thermodynamics. However, concentrations and chemical state also determine the relative importance of electron acceptors in organic carbon oxidation. Oxygen is most important in the biosphere, while sulfate dominates in marine systems, and carbon dioxide in environments with low sulfate concentrations. Nitrate respiration is important in the nitrogen cycle but not in organic material degradation because of low nitrate concentrations. Organic material is degraded and oxidized by a complex consortium of organisms, the anaerobic food chain, in which the by-products from physiological types of organisms becomes the starting material of another. The consortium consists of biopolymer hydrolysis, fermentation, hydrogen gas production, and the reduction of either sulfate or carbon dioxide. The by-product of sulfate reduction, sulfide and other reduced sulfur compounds, is oxidized back eventually to sulfate by either non-phototrophic, chemolithotrophic organisms or by phototrophic microbes. The by-product of another main form of anaerobic respiration, carbon dioxide reduction, is methane, which is produced only by specific archaea. Methane is degraded aerobically by bacteria and anaerobically by some archaea, sometimes in a consortium with sulfate-reducing bacteria. Cultivation-independent approaches focusing on 16S rRNA genes and a methane-related gene (mcrA) have been instrumental in understanding these consortia because the microbes remain uncultivated to date. The chapter ends with some discussion about the few eukaryotes able to reproduce without oxygen. In addition to their ecological roles, anaerobic protists provide clues about the evolution of primitive eukaryotes.
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Geochemical and Microbial Controls on Dolomite Formation in Anoxic Environments - A Case Study from the Middle Triassic: Ticino, Switzerland (Contributions to Sedimentology,). Balogh Scientific Books, 1994.

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Book chapters on the topic "Anoxic environments"

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Millero, F. J. "Redox Processes in Anoxic Waters." In Chemical Processes in Marine Environments. Springer Berlin Heidelberg, 2000. http://dx.doi.org/10.1007/978-3-662-04207-6_5.

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Pfeifer, Felicitas, Regina Frommherz, Karin Faist, Torsten Hechler, Katharina Teufel, and Larissa Marschaus. "Effect of Anoxic Conditions and Temperature on Gas Vesicle Formation in Halobacterium salinarum." In Halophiles and Hypersaline Environments. Springer Berlin Heidelberg, 2011. http://dx.doi.org/10.1007/978-3-662-45796-2_13.

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Edgcomb, Virginia P., Joan M. Bernhard, and Sunok Jeon. "Deep-Sea Microbial Eukaryotes in Anoxic, Microoxic, and Sulfidic Environments." In Cellular Origin, Life in Extreme Habitats and Astrobiology. Springer Netherlands, 2007. http://dx.doi.org/10.1007/978-1-4020-6112-7_39.

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Bazylinski, Dennis A., Christopher T. Lefèvre, and Richard B. Frankel. "Magnetotactic Protists at the Oxic–Anoxic Transition Zones of Coastal Aquatic Environments." In Cellular Origin, Life in Extreme Habitats and Astrobiology. Springer Netherlands, 2011. http://dx.doi.org/10.1007/978-94-007-1896-8_7.

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Struck, Ulrich. "On The Use of Stable Nitrogen Isotopes in Present and Past Anoxic Environments." In Cellular Origin, Life in Extreme Habitats and Astrobiology. Springer Netherlands, 2011. http://dx.doi.org/10.1007/978-94-007-1896-8_26.

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Shammas, Nazih K., and Lawrence K. Wang. "Aerobic and Anoxic Suspended-Growth Biotechnologies." In Environmental Biotechnology. Humana Press, 2010. http://dx.doi.org/10.1007/978-1-60327-140-0_13.

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Pagacova, Petra, Katarina Galbova, and Ivana Jonatova. "Anoxic Granulation of Activated Sludge." In NATO Science for Peace and Security Series C: Environmental Security. Springer Netherlands, 2009. http://dx.doi.org/10.1007/978-90-481-2365-0_25.

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Peter, L. M. "Photoelectrochemistry of Anodic Films on Metal Electrodes." In Photocatalysis and Environment. Springer Netherlands, 1988. http://dx.doi.org/10.1007/978-94-009-3015-5_9.

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Mapelli, Francesca, Sara Borin, and Daniele Daffonchio. "Microbial diversity in deep hypersaline anoxic basins." In Adaption of Microbial Life to Environmental Extremes. Springer Vienna, 2012. http://dx.doi.org/10.1007/978-3-211-99691-1_2.

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Ganiyu, Soliu O., and Carlos A. Martínez-Huitle. "Coupling of Anodic Oxidation and Soil Remediation Processes." In Environmental Pollution. Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-68140-1_9.

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Conference papers on the topic "Anoxic environments"

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Rahman, Aleksandra, Niko Finke, Kai Blumberg, et al. "NOVEL EPSILONPROTEOBACTERIA FROM SAANICH INLET COUPLES BIOGEOCHEMICAL CYCLES IN ANOXIC MARINE ENVIRONMENTS." In GSA Annual Meeting in Seattle, Washington, USA - 2017. Geological Society of America, 2017. http://dx.doi.org/10.1130/abs/2017am-307626.

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Mascord, Catherine S. R., Liam G. Herringshaw, Krysia Mazik, Dan Parsons, and Duncan McIlroy. "WORMS ON FILM: UNDERSTANDING THE INFAUNAL COLONISATION OF ANOXIC, MATGROUND-DOMINATED EDIACARAN–CAMBRIAN SEDIMENTARY ENVIRONMENTS." In GSA 2020 Connects Online. Geological Society of America, 2020. http://dx.doi.org/10.1130/abs/2020am-357161.

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Cochran, Doug, and Paul A. Bizier. "Review of Anoxic/Oxic Digester Performance." In World Water and Environmental Resources Congress 2003. American Society of Civil Engineers, 2003. http://dx.doi.org/10.1061/40685(2003)73.

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Chen, Xiu-qin, and Xu-ping Chen. "Investigation on the electrochemical properties of TiO2 nanotubes prepared by anodic oxidation." In Environment (ICMREE). IEEE, 2011. http://dx.doi.org/10.1109/icmree.2011.5930595.

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Vega, Leticia M., Jacobs Sverdrup, and Dean Muirhead. "Fate of Dissolved and Particulate Carbon in an Anoxic Biological Water Processor." In International Conference On Environmental Systems. SAE International, 2005. http://dx.doi.org/10.4271/2005-01-3019.

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Wenjin, Tong, Sun Shuiyu, Li Chuhua, Zheng Li, Xu Yanbin, and Yao Weiting. "Ultrasonic Pretreatment for Anoxic-Aerobic Digestion of Activated Sludge." In 2012 International Conference on Computer Distributed Control and Intelligent Environmental Monitoring (CDCIEM). IEEE, 2012. http://dx.doi.org/10.1109/cdciem.2012.202.

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Yanjun Lu and Jifeng Guo. "Study on anoxic-oxic process treating for dioscorea zingiberensis wastewater." In 2011 International Symposium on Water Resource and Environmental Protection (ISWREP). IEEE, 2011. http://dx.doi.org/10.1109/iswrep.2011.5893288.

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Yang, Qiyong, Chunyuan Tao, Tao Yang, Zhongwei Wu, Yingxiang Wang, and Shuiyang Dong. "Anoxic-aerobic process biotreatment of polyester fabric alkali-peeling process wastewater." In International Conference on Civil, Transportation and Environmental Engineering (CTEE 12). WIT Press, 2013. http://dx.doi.org/10.2495/ctee120721.

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Pattarawan Chanakul and Suchat Leungprasert. "Nitrogen removal from shrimp farm wastewater by aerobic and anoxic recirculation systems." In 2010 International Conference on Environmental Engineering and Applications (ICEEA). IEEE, 2010. http://dx.doi.org/10.1109/iceea.2010.5596083.

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Liu, Zhiqiang, Qingqing Li, Chao Liu, and Xiaomei Zhang. "Pilot Study on Anoxic/Aerobic Membrane Bioreactor for Domestic Wastewater Treatment." In 2010 International Conference on Challenges in Environmental Science and Computer Engineering. IEEE, 2010. http://dx.doi.org/10.1109/cesce.2010.206.

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Reports on the topic "Anoxic environments"

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Barkay, Tamar. Microbial pathways for the mobilization of mercury as Hg(O) in anoxic subsurface environments. Office of Scientific and Technical Information (OSTI), 2005. http://dx.doi.org/10.2172/893449.

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Orphan, Victoria. Integrative molecular and microanalytical studies of syntrophic partnerships linking C, S, and N cycles in anoxic environments. Office of Scientific and Technical Information (OSTI), 2016. http://dx.doi.org/10.2172/1275739.

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Boteva, Nikoleta, Nils-Kåre Birkeland, and Margarita Kambourova. Metagenome-assembled Genomes Related to Ammoniaoxidizing Thaumarchaeota Recovered from Near-anoxic Environment. "Prof. Marin Drinov" Publishing House of Bulgarian Academy of Sciences, 2021. http://dx.doi.org/10.7546/crabs.2021.03.07.

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