Parvin, Shahnaj

[["dc.bibliographiccitation.firstpage","142"],["dc.bibliographiccitation.journal","The Science of The Total Environment"],["dc.bibliographiccitation.lastpage","151"],["dc.bibliographiccitation.volume","586"],["dc.contributor.author","Krohn, Johannes"],["dc.contributor.author","Lozanovska, Ivana"],["dc.contributor.author","Kuzyakov, Yakov"],["dc.contributor.author","Parvin, Shahnaj"],["dc.contributor.author","Dorodnikov, Maxim"],["dc.date.accessioned","2018-11-07T10:23:50Z"],["dc.date.available","2018-11-07T10:23:50Z"],["dc.date.issued","2017"],["dc.description.abstract","Two peatland micro-relief forms (microforms) - hummocks and hollows - differ by their hydrological characteristics (water table level, i.e. oxic-anoxic conditions) and vegetation communities. We studied the CH4 and CO2 production potential and the localization of methanogenic pathways in both hummocks and hollows at depths of 15, 50, 100, 150 and 200 cm in a laboratory incubation experiment. For this purpose, we measured CH4 and CO2 production rates, peat elemental composition, as well as delta C-13 values of gases and solids; the specific inhibitor of methanogenesis BES (2-bromo-ethane sulfonate, 1 mM) was aimed to preferentially block the acetoclastic pathway. The cumulative CH4 production of all depths was almost one fold higher in hollows than in hummocks, with no differences in CO2. With depth, CO2 and CH4 production decreased, and the relative contribution of the hydrogenotrophic pathway of methanogenesis increased. The highest methanogenic activity among all depths and both microforms was measured at 15 cm of hollows (91%) at which the highest relative contribution of acetoclastic vs. hydrogenotrophic pathway (92 and 8%, respectively) was detected. For hummocks, the CH4 production was the highest at 50 cm (82%), where relative contribution of acetoclastic methanogenesis comprised 89%. The addition of 1 mM BES was not selective and inhibited both methanogenic pathways in the soil. Thus, BES was less efficient in partitioning the pathways compared with the delta C-13 signature. We conclude that the peat microforms - dry hummocks and wet hollows - play an important role for CH4 but not for CO2 production when the effects of living vegetation are excluded. (C) 2017 Elsevier B.V. All rights reserved."],["dc.identifier.doi","10.1016/j.scitotenv.2017.01.192"],["dc.identifier.isi","000398758800014"],["dc.identifier.pmid","28169027"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/42538"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","PUB_WoS_Import"],["dc.publisher","Elsevier Science Bv"],["dc.relation.issn","1879-1026"],["dc.relation.issn","0048-9697"],["dc.title","CH4 and CO2 production below two contrasting peatland micro-relief forms: An inhibitor and delta C-13 study"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","67"],["dc.bibliographiccitation.journal","Geoderma"],["dc.bibliographiccitation.lastpage","76"],["dc.bibliographiccitation.volume","324"],["dc.contributor.author","Parvin, Shahnaj"],["dc.contributor.author","Blagodatskaya, Evgenia"],["dc.contributor.author","Becker, Joscha Nico"],["dc.contributor.author","Kuzyakov, Yakov"],["dc.contributor.author","Uddin, Shihab"],["dc.contributor.author","Dorodnikov, Maxim"],["dc.date.accessioned","2018-04-23T11:35:19Z"],["dc.date.available","2018-04-23T11:35:19Z"],["dc.date.issued","2018"],["dc.description.abstract","The formation of microrelief forms in peatlands - elevated and dry hummocks, depressed wet hollows and intermediate lawns - is controlled by the interaction of water table, nutrient availability and dominant plant communities. This affects the composition and activity of various functional groups of microorganisms. With depth, the change in peat quality from less to more highly processed organic material additionally regulates microbial activity. We hypothesized that microbial biomass and enzyme activities are driven by aeration and by peat quality and therefore (i) they increase from hollows (water saturated/anaerobic) through lawns (intermediate) to hummocks (aerobic) in the top peat and ii) they decrease with depth due to increasing distance from fresh plant-derived inputs and lower oxygen availability. These hypotheses were tested for enzymes catalysing the decomposition of C-, N-, P- and S-containing organic compounds in peat of the three microform types at three depths (15, 50 and 200 cm). Microbial biomass and peat chemical characteristics were compared with enzyme kinetic parameters, i.e. maximal potential activity (Vmax) and the Michaelis constant (Km). Microbial biomass carbon (MBC) and Vmax of β-glucosidase and N-acetyl glucosaminidase increased by 30–70% from hummocks and lawns to hollows in the top 15 cm, contradicting the hypothesis. Similarly, Km and the catalytic efficiency of enzymes (Ka = Vmax/Km) were best related to MBC distribution and not to the aeration gradient. With depth, Vmax of β-glucosidase, xylosidase and leucine aminopeptidase followed the hypothesized pattern in hollows. In contrast, MBC was 1.3–4 times higher at 50 cm, followed by successively lower contents at 15 and 200 cm in all microforms. The same depth pattern characterized the Vmax distribution of 6 out of 8 enzymes. Phosphatase activity decreased from drier hummock to wetter hollows and the higher activity throughout the peat profile suggested a high microbial demand for P. Enzyme activities and catalytic efficiency in peat were closely linked to the distribution of microbial biomass with depth, which in turn was best explained by P content. From the ecological perspective, these results clearly show that peat decomposition will be accelerated when microbial activity is stimulated e.g. by increased P availability."],["dc.identifier.doi","10.1016/j.geoderma.2018.03.006"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/13274"],["dc.language.iso","en"],["dc.notes.status","final"],["dc.title","Depth rather than microrelief controls microbial biomass and kinetics of C-, N-, P- and S-cycle enzymes in peatland"],["dc.type","journal_article"],["dc.type.internalPublication","unknown"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","182"],["dc.bibliographiccitation.journal","Soil Biology and Biochemistry"],["dc.bibliographiccitation.lastpage","191"],["dc.bibliographiccitation.volume","100"],["dc.contributor.author","Lozanovska, Ivana"],["dc.contributor.author","Kuzyakov, Yakov"],["dc.contributor.author","Krohn, Johannes"],["dc.contributor.author","Parvin, Shahnaj"],["dc.contributor.author","Dorodnikov, Maxim"],["dc.date.accessioned","2018-11-07T10:09:57Z"],["dc.date.available","2018-11-07T10:09:57Z"],["dc.date.issued","2016"],["dc.description.abstract","Increasing natural and anthropogenic deposition of nitrate (NO3-) and sulfate (Sail to peatlands may modify CH4 oxidation, CO2 and N2O production, thereby affecting the balance of greenhouse gases (GHG) globally. Among environmental factors controlling these biogeochemical processes, effects of peatland microrelief are poorly understood. Fluxes of CO2, CH4 and N2O were measured before and after incubation with NO3- and Sair-for peat samples collected from various microrelief positions,of a boreal oligotrophic mire in Eastern Finland. Soil was spiked with (CH4)-C-13 to understand the processes of CH4 oxidation, its microbial utilization and incorporation into soil organic matter (SOM). We hypothesized that the addition of NO3- and SO42- would 1) stimulate CO2 and N2O production (nutritional effect), but 2) decrease CH4 oxidation due to acceleration of other more energetically favorable processes (e.g., denitrification), and 3) these patterns should follow the naturally established aerobic zone of a microform type and decrease with depth. Microbial biomass (MB) at 50 cm below all microforms was 9-15 folds higher than in the topsoil. MB controlled the GHG dynamics and was related to specific depth-dependent environmental conditions, rather than oxygen availability. Indeed, production of CO2 and N2O, and oxidation potentials of CH4 revealed no clear linkage with the naturally established aeration zone of the peatland's microforms. Following NO3- and SO42- addition, production of CO2 decreased by 20-65% compared to the control, with the greatest reduction in CO2 emission occurring in the topsoil of hollows. In turn, CH4 oxidation was suppressed by 20-94% with NO3- addition at 50 cm in lawns and with both NO3- and SO42- at 50 cm in hollows. The N2O production was increased up to 180-240 times under NO3- treatment at 50 cm in hollows and lawns. In conclusion, human-induced deposition of NO3- and SO4- may suppress CO2 emissions from and CH4 oxidation by boreal oligotrophic mires especially under the conditions of deposition increase. Finally, the deposition of inorganic compounds is strongly important to be considered in the estimation of ecosystem C and N balances. (C) 2016 Elsevier Ltd. All rights reserved."],["dc.identifier.doi","10.1016/j.soilbio.2016.06.018"],["dc.identifier.isi","000380600100021"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/39755"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Pergamon-elsevier Science Ltd"],["dc.relation.issn","0038-0717"],["dc.title","Effects of nitrate and sulfate on greenhouse gas emission potentials from microform-derived peats of a boreal peatland: A C-13 tracer study"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]