Senbayram, Mehmet

[["dc.bibliographiccitation.firstpage","2363"],["dc.bibliographiccitation.issue","21"],["dc.bibliographiccitation.journal","Rapid Communications in Mass Spectrometry"],["dc.bibliographiccitation.lastpage","2373"],["dc.bibliographiccitation.volume","27"],["dc.contributor.author","Koester, Jan Reent"],["dc.contributor.author","Well, Reinhard"],["dc.contributor.author","Dittert, Klaus"],["dc.contributor.author","Giesemann, Anette"],["dc.contributor.author","Lewicka-Szczebak, Dominika"],["dc.contributor.author","Muehling, Karl-Hermann"],["dc.contributor.author","Herrmann, Antje"],["dc.contributor.author","Lammel, Joachim"],["dc.contributor.author","Senbayram, Mehmet"],["dc.date.accessioned","2018-11-07T09:17:33Z"],["dc.date.available","2018-11-07T09:17:33Z"],["dc.date.issued","2013"],["dc.description.abstract","RATIONALEN(2)O isotopomer ratios may provide a useful tool for studying N2O source processes in soils and may also help estimating N2O reduction to N-2. However, remaining uncertainties about different processes and their characteristic isotope effects still hamper its application. We conducted two laboratory incubation experiments (i) to compare the denitrification potential and N2O/(N2O+N-2) product ratio of denitrification of various soil types from Northern Germany, and (ii) to investigate the effect of N2O reduction on the intramolecular N-15 distribution of emitted N2O. METHODSThree contrasting soils (clay, loamy, and sandy soil) were amended with nitrate solution and incubated under N-2-free He atmosphere in a fully automated incubation system over 9 or 28 days in two experiments. N2O, N-2, and CO2 release was quantified by online gas chromatography. In addition, the N2O isotopomer ratios were determined by isotope-ratio mass spectrometry (IRMS) and the net enrichment factors of the N-15 site preference (SP) of the N2O-to-N-2 reduction step ((SP)) were estimated using a Rayleigh model. RESULTSThe total denitrification rate was highest in clay soil and lowest in sandy soil. Surprisingly, the N2O/(N2O+N-2) product ratio in clay and loam soil was identical; however, it was significantly lower in sandy soil. The IRMS measurements revealed highest N2O SP values in clay soil and lowest SP values in sandy soil. The (SP) values of N2O reduction were between -8.2 and -6.1 , and a significant relationship between O-18 and SP values was found. CONCLUSIONSBoth experiments showed that the N2O/(N2O+N-2) product ratio of denitrification is not solely controlled by the available carbon content of the soil or by the denitrification rate. Differences in N2O SP values could not be explained by variations in N2O reduction between soils, but rather originate from other processes involved in denitrification. The linear O-18 vs SP relationship may be indicative for N2O reduction; however, it deviates significantly from the findings of previous studies. Copyright (c) 2013 John Wiley & Sons, Ltd."],["dc.description.sponsorship","German Federal Environmental Foundation (DBU)"],["dc.identifier.doi","10.1002/rcm.6699"],["dc.identifier.isi","000325254300009"],["dc.identifier.pmid","24097392"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/28198"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Wiley-blackwell"],["dc.relation.issn","1097-0231"],["dc.relation.issn","0951-4198"],["dc.title","Soil denitrification potential and its influence on N2O reduction and N2O isotopomer ratios"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","1671"],["dc.bibliographiccitation.issue","8"],["dc.bibliographiccitation.journal","Soil Biology and Biochemistry"],["dc.bibliographiccitation.lastpage","1677"],["dc.bibliographiccitation.volume","43"],["dc.contributor.author","Koester, Jan Reent"],["dc.contributor.author","Cardenas, Laura M."],["dc.contributor.author","Senbayram, Mehmet"],["dc.contributor.author","Bol, Roland"],["dc.contributor.author","Well, Reinhard"],["dc.contributor.author","Butler, Mark"],["dc.contributor.author","Muehling, Karl Hermann"],["dc.contributor.author","Dittert, Klaus"],["dc.date.accessioned","2018-11-07T08:53:50Z"],["dc.date.available","2018-11-07T08:53:50Z"],["dc.date.issued","2011"],["dc.description.abstract","Nitrous oxide (N(2)O) is one of the major greenhouse gases emitted from soils, where it is mainly produced by nitrification and denitrification. It is well known that rates of N(2)O release from soils are mainly determined by the availability of substrates and oxygen, but N(2)O source apportioning, highly needed to advance N(2)O mitigation strategies, still remains challenging. In this study, using an automated soil incubation system, the N(2)O site preference, i.e. the intramolecular 1514 distribution, was analyzed to evaluate the progression in N(2)O source processes following organic soil amendment. Biogas fermentation residue (BGR; originating from food waste fermentation) was applied to repacked grassland soil cores and compared to ammonium sulfate (AS) application, both at rates equivalent to 160 kg NH(4)(+)-N ha(-1), and to unamended soil (control). The soil cores were incubated in a helium-oxygen atmosphere with 20 kPa O(2) for 43 days at 80% water-filled pore space. 43-day cumulative N(2)O emissions were highest with BGR treated soil accounting for about 1.68 kg N(2)O-N ha(-1) while application of AS caused much lower fluxes of c. 0.23 kg N(2)O-N ha(-1). Also, after BGR application, carbon dioxide (CO(2)) fluxes showed a pronounced initial peak with steep decline until day 21 whereas with ammonium addition they remained at the background level. N(2)O dual isotope and isotopomer analysis of gas samples collected from BGR treated soil indicated bacterial denitrification to be the main N(2)O generating process during the first three weeks when high CO(2) fluxes signified high carbon availability. In contrast, in the second half after all added labile carbon substrates had been consumed, nitrification, i.e. the generation of N(2)O via oxidation of hydroxylamine, gained in importance reaching roughly the same N(2)O production rate compared to bacterial denitrification as indicated by N(2)O SP. Overall in this study, bacterial denitrification seemed to be the main N(2)O forming process after application of biogas residues and fluxes were mainly driven by available organic carbon. (C) 2011 Elsevier Ltd. All rights reserved."],["dc.description.sponsorship","Biotechnology and Biological Sciences Research Council (BBSRC)"],["dc.identifier.doi","10.1016/j.soilbio.2011.04.004"],["dc.identifier.isi","000292995300007"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/22523"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Pergamon-elsevier Science Ltd"],["dc.relation.issn","0038-0717"],["dc.title","Rapid shift from denitrification to nitrification in soil after biogas residue application as indicated by nitrous oxide isotopomers"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","55"],["dc.bibliographiccitation.journal","Geochimica et Cosmochimica Acta"],["dc.bibliographiccitation.lastpage","73"],["dc.bibliographiccitation.volume","134"],["dc.contributor.author","Lewicka-Szczebak, Dominika"],["dc.contributor.author","Well, Reinhard"],["dc.contributor.author","Koester, Jan Reent"],["dc.contributor.author","Fuss, Roland"],["dc.contributor.author","Senbayram, Mehmet"],["dc.contributor.author","Dittert, Klaus"],["dc.contributor.author","Flessa, Heiner"],["dc.date.accessioned","2018-11-07T09:39:53Z"],["dc.date.available","2018-11-07T09:39:53Z"],["dc.date.issued","2014"],["dc.description.abstract","Quantifying denitrification in arable soils is crucial in predicting nitrogen fertiliser losses and N2O emissions. Stable isotopologue analyses of emitted N2O (delta N-15, delta O-18 and SP = N-15 site preference within the linear N2O molecule) may help to distinguish production pathways and to quantify N2O reduction to N-2. However, such interpretations are often ambiguous due to insufficient knowledge on isotopic fractionation mechanisms. Here we present a complex experimental approach to determine the net fractionation factors (eta) associated with denitrification. This determination is based on three laboratory experiments differing in their experimental set-up and soil properties. Static and dynamic incubation techniques were compared. All available methods for independent determination of N2O reduction contribution were used, namely, N-2-free atmosphere incubation, acetylene inhibition technique and N-15 gas-flux method. For N2O production: (i) the determined difference in delta O-18 between soil water and produced N2O vary from +18 parts per thousand to +42 parts per thousand and show very strict negative correlation with soil water saturation; (ii) the determined eta N-15 of N2O production vary from -55 parts per thousand to -38 parts per thousand and the fractionation decreases with decreasing substrate availability; (iii) the determined SP of produced N2O vary from -3 parts per thousand to +9 parts per thousand. For N2O reduction: (i) the determined eta O-18 and eta N-15 of N2O reduction vary in very wide ranges from -18 parts per thousand to +4 parts per thousand and from -11 parts per thousand to +12 parts per thousand, respectively, and depend largely on the differences in experimental setups; whereas (ii) the determined eta SP of N2O reduction shows a very consistent value with all previous studies and varies in a rather narrow range from -2 parts per thousand to -8 parts per thousand. It can be concluded that eta values of N2O production determined during laboratory incubations yield only roughly estimates for respective values expectable under field study conditions. eta O-18 and eta N-15 associated with N2O reduction may vary largely, probably depending on spatial and temporal coincidence of N2O production and reduction, and are hence not yet predictable for natural conditions. However, the eta SP of N2O reduction appeared to be relatively robust and a most probable value of about -5 parts per thousand can be used to constrain N2O reduction based on SP of soil emitted N2O. (C) 2014 Elsevier Ltd. All rights reserved."],["dc.description.sponsorship","German Research Foundation [DFG We/1904-4]"],["dc.identifier.doi","10.1016/j.gca.2014.03.010"],["dc.identifier.isi","000335136400004"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/33393"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Pergamon-elsevier Science Ltd"],["dc.relation.issn","1872-9533"],["dc.relation.issn","0016-7037"],["dc.title","Experimental determinations of isotopic fractionation factors associated with N2O production and reduction during denitrification in soils"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","197"],["dc.bibliographiccitation.journal","Soil Biology and Biochemistry"],["dc.bibliographiccitation.lastpage","207"],["dc.bibliographiccitation.volume","104"],["dc.contributor.author","Wu, D. I."],["dc.contributor.author","Senbayram, Mehmet"],["dc.contributor.author","Well, Reinhard"],["dc.contributor.author","Brueggemann, Nicolas"],["dc.contributor.author","Pfeiffer, Birgit"],["dc.contributor.author","Loick, Nadine"],["dc.contributor.author","Stempfhuber, Barbara"],["dc.contributor.author","Dittert, Klaus"],["dc.contributor.author","Bol, Roland"],["dc.date.accessioned","2018-11-07T10:29:36Z"],["dc.date.available","2018-11-07T10:29:36Z"],["dc.date.issued","2017"],["dc.description.abstract","The application of reactive nitrogen (N) in the form of synthetic/organic fertilizers plays a central role in supporting a larger human population, but also contributes to global warming through the emission of nitrous oxide (N2O). The use of nitrification inhibitors (Nls) has repeatedly been shown to minimize N2O emissions; however, their effectiveness in reducing N2O emissions varies greatly under different environmental conditions. A better understanding of how and to what extent NIs can mitigate fertilizer related soil-borne N2O emissions under a range of different conditions is required. In the present study, we carried out a soil incubation experiment in a fully automated continuous-flow incubation system under conditions favoring either nitrification- or denitrification-derived N2O emissions. Additionally, the abundance of AOB amoA, and AOA amoA genes was quantified and N2O isotopic signatures were analyzed. We mixed a common NI (PIADIN (R)) with mineral fertilizer (ammonium sulfate) and examined the N2O mitigation potential of the NI in a fertilized sandy soil (low denitrification potential) and a sandy soil mixed with wheat straw (high denitrification potential) at 70% water holding capacity (WHC). In non-NI treatments, the addition of straw led to a drastic increase of CO2 and N2O emissions compared to the non-straw-amended soils, suggesting stimulated microbial activity and higher denitrification rate. The NI reduced N2O emissions in the straw-amended treatment by 41%, whereas in the treatment without straw this was only 17%. With the combination of N2O isotopic signatures and functional gene abundances, fungal denitrification was considered to be the major process contributing to the higher N2O fluxes specifically in straw-amended soils. Overall, our study indicated that NI can be used as an effective method for mitigating N2O emissions in cropland specifically when the denitrification potential is high, e.g. in moist N-fertilized and straw-amended soils. (C) 2016 Elsevier Ltd. All rights reserved."],["dc.identifier.doi","10.1016/j.soilbio.2016.10.022"],["dc.identifier.isi","000389555900019"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/43673"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","PUB_WoS_Import"],["dc.publisher","Pergamon-elsevier Science Ltd"],["dc.relation.issn","0038-0717"],["dc.title","Nitrification inhibitors mitigate N2O emissions more effectively under straw-induced conditions favoring denitrification"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","65"],["dc.bibliographiccitation.journal","Soil Biology and Biochemistry"],["dc.bibliographiccitation.lastpage","74"],["dc.bibliographiccitation.volume","84"],["dc.contributor.author","Koester, Jan Reent"],["dc.contributor.author","Cardenas, Laura M."],["dc.contributor.author","Bol, Roland"],["dc.contributor.author","Lewicka-Szczebak, Dominika"],["dc.contributor.author","Senbayram, Mehmet"],["dc.contributor.author","Well, Reinhard"],["dc.contributor.author","Giesemann, Anette"],["dc.contributor.author","Dittert, Klaus"],["dc.date.accessioned","2018-11-07T09:58:01Z"],["dc.date.available","2018-11-07T09:58:01Z"],["dc.date.issued","2015"],["dc.description.abstract","Assessing effects of organic fertilizer applications on N2O emissions is of great interest because they can cause higher N2O emissions compared to inorganic fertilizers for a given amount of added nitrogen (N). But there are also reports about enhanced N2O reduction to climate-neutral elemental Ny after application of organic manures to soils. Factors controlling the N2O/(N2O + N-2) product ratio of denitrification are interrelated, and also the ratio is difficult to study because of limitations in N-2 flux measurements. In this study, we investigated N2O and N-2 emissions from soil treated with organic fertilizers with different C/N ratios. An N2O isotopomer approach combined with conventional N2O and Ny flux measurements was employed to study underlying microbial pathways. A grassland soil was amended with anaerobic digestate (AD) from food waste digestion (low C/N ratio) or cattle slurry (CS; high C/N ratio), respectively, adjusted to 90% WFPS, and incubated for 52 days under helium-oxygen atmosphere (10% O-2) using a soil incubation system capable of automated N2O, N-2, and CO2 measurements. N2O isotopomer signatures, i.e. the delta O-18 and SP values (site preference between N-15 at the central and the peripheral position in the N2O molecule), were determined by Isotope Ratio Mass Spectrometry and used to model and subsequently estimate the contribution of bacterial denitrification and autotrophic nitrification to N2O production. For this approach the direct determination of emitted N-2 is essential to take isotope effects during N2O reduction to N-2 into account by correcting the measured isotope signatures for isotope effects during N2O reduction using previously determined fractionation factor ranges. The addition of both organic fertilizers to soil drastically increased the rate of gaseous N emissions (N2O + N-2), probably due to the effects of concurrent presence of nitrate and labile C on the denitrification rate. In the initial phase of the experiment (day 1 to similar to 15), gaseous N emissions were dominated by N-2 fluxes in soils amended with organic manures; meanwhile, N2O emissions were lower compared to untreated Control soils, but increased after 15-20 days relative to the initial fluxes, especially with CS. Extremely low N2O, but high Ny emissions in the initial phase suggest that reduction of N2O to Ny via denitrification was triggered when the soil was amended with organic fertilizers. In contrast in the untreated Control, N2O release was highest during the initial phase. Total N2O release from AD treated soil was similar to Control, while N2O from CS treated soil was considerably higher, indicating that denitrification was triggered more by the high labile carbon content in CS, while the cumulative N2O/ (N2O + N-2) product ratio and thus N2O reduction were similar with both organic fertilizers. The results of the N2O source partitioning based on the isotopomer data suggest that about 8-25% (AD) and 33-43% (CS) of the cumulated N2O emission was due to nitrification in organically amended soil, while in the untreated Control nitrification accounted for about 5-16%. The remaining N2O production was attributed mainly to denitrification, while the poor model fit for other source pathways like fungal denitrification suggested their contribution to be of minor importance. The observed rather distinct phases with predominance first of denitrification and later of nitrification may help developing mitigation measures by addressing N2O source processes individually with appropriate management options. The observation of relatively large shares of nitrification-derived N2O is surprising, but may possibly be related to the low soil pH and will require further investigation. The determination of N-2 production is essential for this isotopomer-based source partitioning approach, but so far only applicable under laboratory conditions. The results of this study indicate that the combination of N2O delta O-18 and SP values is very useful in obtaining more robust source estimates as compared to using SP values alone. (C) 2015 Elsevier Ltd. All rights reserved."],["dc.identifier.doi","10.1016/j.soilbio.2015.01.021"],["dc.identifier.isi","000353087600007"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/37287"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Pergamon-elsevier Science Ltd"],["dc.relation.issn","0038-0717"],["dc.title","Anaerobic digestates lower N2O emissions compared to cattle slurry by affecting rate and product stoichiometry of denitrification - An N2O isotopomer case study"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]