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The microbial nitrogen cycle

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Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889194124 Year: Pages: 174 DOI: 10.3389/978-2-88919-412-4 Language: English
Publisher: Frontiers Media SA
Subject: Microbiology --- Science (General)
Added to DOAB on : 2015-12-10 11:59:06
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Nitrogen is an essential element in biological systems, and one that often limits production in both aquatic and terrestrial systems. Due to its requirement in biological macromolecules, its acquisition and cycling have the potential to structure microbial communities, as well as to control productivity on the ecosystem scale. In addition, its versatile redox chemistry is the basis of complex biogeochemical transformations that control the inventory of fixed nitrogen, both in local environments and over geological time. Although many of the pathways in the microbial nitrogen cycle were described more than a century ago, additional fundamental pathways have been discovered only recently. These findings imply that we still have much to learn about the microbial nitrogen cycle, the organisms responsible for it, and their interactions in natural and human environments. Progress in nitrogen cycle research has been facilitated by recent rapid technological advances, especially in genomics and isotopic approaches. In this Research Topic, we reviewed the leading edge of nitrogen cycle research based on these approaches, as well as by exploring microbial processes in modern ecosystems.

Linking Ecosystem Function to Microbial Diversity

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Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889199853 Year: Pages: 159 DOI: 10.3389/978-2-88919-985-3 Language: English
Publisher: Frontiers Media SA
Subject: Science (General) --- Oceanography --- Microbiology
Added to DOAB on : 2016-01-19 14:05:46
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Understanding the link between microbial diversity and ecosystem processes is a fundamental goal of microbial ecologists, yet we still have a rudimentary knowledge of how changes in diversity affect nutrient cycling and energy transfer in ecosystems. Due to the complexity of the problem, many published studies on this topic have been conducted in artificial or manipulated systems. Although researchers have begun to expose some possible mechanisms using these approaches, most have not yet been able to produce conclusive results that relate directly to natural systems. The few studies that have explored the link between diversity and activity in natural systems have typically focused on specific nutrient cycles or processes, such as nitrification, denitrification, and organic carbon degradation pathways, and the microbes that mediate them. What we have learned from these studies is that there are often strong associations between the physical and chemical features of the environment, the composition of the microbial communities, and their activities, but the rules that govern these associations have not been fully elucidated. These earlier studies of microbial diversity and processes in natural systems provide a framework for additional studies to broaden our understanding of the role of microbial diversity in ecosystem function. The problem is complex, but with recent advances in sequencing technology, -omics, and in-situ measurements of ecosystem processes and their applications to microbial communities, making direct connections between ecosystem function and microbial diversity seems more tractable than ever.

Nitrification in Fixed Bed Reactors Treating Saline Wastewater

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Book Series: Karlsruher Berichte zur Ingenieurbiologie / Institut für Ingenieurbiologie und Biotechnologie des Abwassers, Karlsruher Institut für Technologie ISSN: 01728709 ISBN: 9783866446915 Year: Volume: 47 Pages: XXIV, 173 p. DOI: 10.5445/KSP/1000023321 Language: ENGLISH
Publisher: KIT Scientific Publishing
Subject: Astronomy (General)
Added to DOAB on : 2019-07-30 20:01:58
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Two fixed bed reactors for nitrification with either polyethylene/clay sinter lamellas (FBR A) or porous ceramic rings (FBR B) were continously run for treating synthetic saline wastewater. Seawater from Hafen Büsum was used as an inoculums. The performance of the system was evaluated under different operating conditions. A better overall nitrification without nitrite accumulation was observed in FBR B during continuous incubation. However, in term of ammonia (AOR) and nitrite oxidation rates (NOR) that were determined in batch incubations, FBR A revealed a higher AOR and NOR of 6 and 7 mg N L-1 h-1, compared to the AOR and NOR of 5 and 5.9 mg N L-1 h-1 in FBR B, respectively. For studies of the effect of fluctuating salinity on the nitrification, polyethylene/clay sinter lamellas or porous ceramic rings from FBR A and B, respectively, were used as a source of immobilized nitrifiers. Salt concentrations were decreased from 3.5% to 0.03% via 2, 1 and 0.5% and increased from 3.5% to 5, 7 and 9%. A similar result for AOR and NOR during batch incubation was obtained for both substrata in FBR A and FBR B. The salinity changes influenced more the nitrite oxidizing bacteria (NOB) than the ammonia oxidizing bacteria (AOB). Measurement of oxidation rates during changing conditions show that the NORs were always higher than the AORs in all reactors, especially in initial phase. However, NORs were more sensitive to the salinity fluctuation than AORs, especially at lower salinity. The AORs remained constant for 0.5-3.5% NaCl and dropped to 70% and 68.5% after the salt concentration was brought to 0.034 or 5%, respectively. The NORs decreased significantly to 62% and 87.5% of initial rates after the salt concentration was changed to 2 and 5%, respectively.Non-halotolerant nitrifiers reactors with fresh polyethylene/clay as supporting material were inoculated with water samples taken from a ""Brackwasser""-location at the North Sea and were continuously run. The salt content in medium was 0% at the start and was then increased up to 10.5%. Increases of the salt concentration in a non-salt-adapted FBR suppressed more to NOR than AOR. When salinity was increased from 0.03% to 0.5, 1 and 2%, AORs remained constant. The AORs were approx. 90% of initial rates after the salt concentrations were increased stepwise to 3.5%, whereas the NORs decreased to 85, 52 and 36% of initial rate after salinity was increased to 1, 2 and 3.5%, respectively.

Recent Advances in Water Management: Saving, Treatment and Reuse

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ISBN: 9783038970316 / 9783038970323 Year: Pages: 208 DOI: 10.3390/books978-3-03897-032-3 Language: eng
Publisher: MDPI - Multidisciplinary Digital Publishing Institute
Subject: Science (General) --- Environmental Sciences
Added to DOAB on : 2019-08-28 11:21:28
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Abstract

This book is a printed edition of the Special Issue Recent Advances in Water Management: Saving, Treatment and Reuse that was published in Water

Keywords

guidelines --- contaminated sites --- risk assessment --- China --- ferrous iron --- ferrous sulfide --- hydrogen sulfide --- odor control --- pumping mains --- sewerage --- pharmaceuticals --- micropollutant removal --- tezontle --- filter media --- active sites --- trickling filter --- anaerobic digester --- swine wastewater --- organic matter --- COD --- decomposition analysis --- global patent data --- research and development strategy --- water treatment technology --- anammox bacteria --- wastewater treatment --- nitrification --- denitrification --- zeolite --- combined sewer --- wastewater treatment --- microbiological quality --- surface water --- river --- lignin --- delignification --- pulp-and-paper-mill c --- wastewater --- white rot fungi --- B. adusta --- P. crysosporium --- foreign countries --- agricultural occupations --- water --- environmental education --- surveys --- sustainability --- milk production --- water --- footprint --- water recycling --- conservation --- partitioning --- efficiency --- forest waste --- palm mulch --- constructed wetlands --- vertical flow --- water treatment --- passive treatment systems --- anaerobic processes --- constructed wetlands --- ornamental plants --- treated wastewater reuse --- advanced oxidation processes (AOPs) --- activated carbon adsorption --- carbamazepine toxicity --- conventional treatment processes --- membrane technology --- occurrence --- food industry --- anticorrosive agent --- benzotriazole --- emerging contaminant --- oxygen injection --- Pb(II) --- nano illite/smectite clay --- adsorption kinetics --- adsorption thermodynamic

Carbon, Nitrogen and Phosphorus Cycling in Forest Soils

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ISBN: 9783038976820 / 9783038976837 Year: Pages: 238 DOI: 10.3390/books978-3-03897-683-7 Language: eng
Publisher: MDPI - Multidisciplinary Digital Publishing Institute
Subject: Science (General) --- Biology --- Forestry
Added to DOAB on : 2019-06-26 08:44:06
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Abstract

The majority of carbon stored in the soils of the world is stored in forests. The refractory nature of some portions of forest soil organic matter also provides the slow, gradual release of organic nitrogen and phosphorus to sustain long term forest productivity. Contemporary and future disturbances, such as climatic warming, deforestation, short rotation sylviculture, the invasion of exotic species, and fire, all place strains on the integrity of this homeostatic system of C, N, and P cycling. On the other hand, the CO2 fertilization effect may partially offset losses of soil organic matter, but many have questioned the ability of N and P stocks to sustain the CO2 fertilization effect.

Keywords

carbon distribution index --- moisture gradient --- soil organic matter fraction --- soil degradation --- soil available nitrogen --- soil available phosphorus --- temperature --- stand density --- charcoal --- forest soil --- carbon mineralization --- microbial activity --- nitrification --- polyphenols --- temperature --- soil microbial communities --- PLFA --- seasons --- nitrogen dynamics --- gross nitrogen transformations --- Daxing’an Mountains --- climatic factors --- soil nutrients --- forest types --- principal component analyses --- soil structure --- soil pH --- Oxisol --- variable-charge soils --- aluminum accumulator --- seasonal trends --- beech forests --- soil enzymes --- organic matter --- multilevel models --- near natural forest management --- Pinus massoniana plantation --- Cunninghamia lanceolata plantation --- soil greenhouse gas flux --- biolability --- tree-DOM --- dissolved organic matter (DOM) --- carbon --- dissolved organic carbon (DOC) --- stemflow --- throughfall --- alpine forest --- ammonia-oxidizing bacteria --- ammonia-oxidizing archaea --- ammonium --- nitrate --- revegetation --- microbial biomass --- chloroform fumigation extraction --- enzyme activities --- stoichiometric homeostasis --- the Three Gorges Reservoir --- Eucalyptus sp. --- wood volume --- second production cycle --- annual increment average --- soil fertility --- nutrient cycling --- Chamaecyparis forest --- humic substances --- 31P nuclear magnetic resonance spectroscopy (31P NMR) --- P species --- topography --- net primary productivity --- climate zone --- climate --- soil N --- litter N --- climate change --- manuring --- manure pelleting --- northern temperate --- pyrolysis --- information review --- leaf N:P ratio --- P resorption efficiency --- soil P fractions --- P stock --- stand age

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