Hot spots of N2O emission move with the seasonally mobile oxic-anoxic interface in drained organic soils

Lee, Alexander; Winther, Malte; Priemé, Anders; Blunier, Thomas; Christensen, Søren

doi:10.1016/j.soilbio.2017.08.025

Cited by 17 publications

(11 citation statements)

References 34 publications

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“…OP-2011 included hot spots which contributed 86% of annual emissions. Hot spots have been observed in drained organic soils in the tropics (Oktarita et al, 2017), temperate (Lee et al, 2017) and Arctic zones (Repo et al, 2009;Marushchak et al, 2011). As in the study by Oktarita et al (2017) hot spots were located far from TABLE 5 | Peat CO 2 budget calculated as the difference of mean annual C outputs from heterotrophic soil respiration (SRh) and dissolved organic carbon (DOC) and mean annual C inputs from litterfall and root mortality in forest and oil palm (OP).…”

Section: Spatio-temporal Variability and Controls Of N 2 O Fluxmentioning

confidence: 82%

Spatio-Temporal Variability of Peat CH4 and N2O Fluxes and Their Contribution to Peat GHG Budgets in Indonesian Forests and Oil Palm Plantations

Swails

Hergoualc’h

Verchot

et al. 2021

Front. Environ. Sci.

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Land-use change in tropical peatlands substantially impacts peat emissions of methane (CH4) and nitrous oxide (N2O) in addition to emissions of carbon dioxide (CO2). However, assessments of full peat greenhouse gas (GHG) budgets are scarce and CH4 and N2O contributions remain highly uncertain. The objective of our research was to assess changes in peat GHG flux and budget associated with peat swamp forest disturbance and conversion to oil palm plantation and to evaluate drivers of variation in trace gas fluxes. Over a period of one and a half year, we monitored monthly CH4 and N2O fluxes together with environmental variables in three undrained peat swamp forests and three oil palm plantations on peat in Central Kalimantan. The forests included two primary forests and one 30-year-old secondary forest. We calculated the peat GHG budget in both ecosystems using soil respiration and litterfall rates measured concurrently with CH4 and N2O fluxes, site-specific soil respiration partitioning ratios, and literature-based values of root inputs and dissolved organic carbon export. Peat CH4 fluxes (kg CH4 ha−1 year−1) were insignificant in oil palm (0.3 ± 0.4) while emissions in forest were high (14.0 ± 2.8), and larger in wet than in dry months. N2O emissions (kg N2O ha−1 year−1) were highly variable spatially and temporally and similar across land-uses (5.0 ± 3.9 and 5.2 ± 3.7 in oil palm and forest). Temporal variation of CH4 was controlled by water table level and soil water-filled pore space in forest and oil palm, respectively. Monthly fluctuations of N2O were linked to water table level in forest. The peat GHG budget (Mg CO2 equivalent ha−1 year−1) in oil palm (31.7 ± 8.6) was nearly eight times the budget in forest (4.0 ± 4.8) owing mainly to decreased peat C inputs and increased peat C outputs. The GHG budget was also ten times higher in the secondary forest (10.2 ± 4.5) than in the primary forests (0.9 ± 3.9) on the account of a larger peat C budget and N2O emission rate. In oil palm 96% of emissions were released as CO2 whereas in forest CH4 and N2O together contributed 65% to the budget. Our study highlights the disastrous atmospheric impact associated with forest degradation and conversion to oil palm in tropical peatlands and stresses the need to investigate GHG fluxes in disturbed undrained lands.

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Section: Spatio-temporal Variability and Controls Of N 2 O Fluxmentioning

confidence: 82%

Spatio-Temporal Variability of Peat CH4 and N2O Fluxes and Their Contribution to Peat GHG Budgets in Indonesian Forests and Oil Palm Plantations

Swails

Hergoualc’h

Verchot

et al. 2021

Front. Environ. Sci.

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“…To the best of our knowledge, the work presented in Lee et al (2017) and Ji and Grundle (2019) discusses the only published uses of G5131-i models. A prior model (the G5101-i), which employs a different spectral region and does not offer the capability for δ 18 O, was used by Peng et al (2014), Erler et al (2015), Li et al (2015), Lebegue et al (2016) and Winther et al (2018).…”

Section: Crds (Picarro Inc)mentioning

confidence: 99%

“…The term δ 15 N bulk is used to express the average δ 15 N value and is equivalent to δ 15 N bulk = (δ 15 N α + δ 15 N β )/2. Extensive evidence has shown that SP, δ 15 N bulk and δ 18 O can be used to differentiate N 2 O source processes and biogeochemical cycling (Decock and Six, 2013;Denk et al, 2017;Heil et al, 2014;Lewicka-Szczebak et al, 2014Ostrom et al, 2007;Sutka et al, 2003Sutka et al, , 2006Toyoda et al, 2005Toyoda et al, , 2017Wei et al, 2017). Isotopocule abundances have been measured in a wide range of environments, including the troposphere (Harris et al, 2014;Röckmann and Levin, 2005;Toyoda et al, 2013), agricultural soils (Buchen et al, 2018;Ibraim et al, 2019;Köster et al, 2011;Mohn et al, 2012;Ostrom et al, 2007;Park et al, 2011;Pérez et al, 2001Pérez et al, , 2006Toyoda et al, 2011;Verhoeven et al, 2018Verhoeven et al, , 2019Well et al, 2008;Well and Flessa, 2009;Wolf et al, 2015), mixed urban-agricultural environments (Harris et al, 2017), coal and waste combustion (Harris et al, 2015b;Ogawa and Yoshida, 2005), fossil fuel combustion (Toyoda et al, 2008), wastewater treatment (Harris et al, 2015a, b;Wunderlin et al, 2012Wunderlin et al, , 2013, groundwater (Koba et al, 2009;Minamikawa et al, 2011;…”

Section: Introductionmentioning

confidence: 99%

N<sub>2</sub>O isotopocule measurements using laser spectroscopy: analyzer characterization and intercomparison

et al. 2020

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Abstract. For the past two decades, the measurement of nitrous oxide (N2O) isotopocules – isotopically substituted molecules 14N15N16O, 15N14N16O and 14N14N18O of the main isotopic species 14N14N16O – has been a promising technique for understanding N2O production and consumption pathways. The coupling of non-cryogenic and tuneable light sources with different detection schemes, such as direct absorption quantum cascade laser absorption spectroscopy (QCLAS), cavity ring-down spectroscopy (CRDS) and off-axis integrated cavity output spectroscopy (OA-ICOS), has enabled the production of commercially available and field-deployable N2O isotopic analyzers. In contrast to traditional isotope-ratio mass spectrometry (IRMS), these instruments are inherently selective for position-specific 15N substitution and provide real-time data, with minimal or no sample pretreatment, which is highly attractive for process studies. Here, we compared the performance of N2O isotope laser spectrometers with the three most common detection schemes: OA-ICOS (N2OIA-30e-EP, ABB – Los Gatos Research Inc.), CRDS (G5131-i, Picarro Inc.) and QCLAS (dual QCLAS and preconcentration, trace gas extractor (TREX)-mini QCLAS, Aerodyne Research Inc.). For each instrument, the precision, drift and repeatability of N2O mole fraction [N2O] and isotope data were tested. The analyzers were then characterized for their dependence on [N2O], gas matrix composition (O2, Ar) and spectral interferences caused by H2O, CO2, CH4 and CO to develop analyzer-specific correction functions. Subsequently, a simulated two-end-member mixing experiment was used to compare the accuracy and repeatability of corrected and calibrated isotope measurements that could be acquired using the different laser spectrometers. Our results show that N2O isotope laser spectrometer performance is governed by an interplay between instrumental precision, drift, matrix effects and spectral interferences. To retrieve compatible and accurate results, it is necessary to include appropriate reference materials following the identical treatment (IT) principle during every measurement. Remaining differences between sample and reference gas compositions have to be corrected by applying analyzer-specific correction algorithms. These matrix and trace gas correction equations vary considerably according to N2O mole fraction, complicating the procedure further. Thus, researchers should strive to minimize differences in composition between sample and reference gases. In closing, we provide a calibration workflow to guide researchers in the operation of N2O isotope laser spectrometers in order to acquire accurate N2O isotope analyses. We anticipate that this workflow will assist in applications where matrix and trace gas compositions vary considerably (e.g., laboratory incubations, N2O liberated from wastewater or groundwater), as well as extend to future analyzer models and instruments focusing on isotopic species of other molecules.

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“…Oxic-anoxic interfaces and the vadose zones with fluctuating water content would provide settings in organic-and nitrogen-rich soils, where co-occurrence of obligately aerobic methanotrophy and obligately anaerobic denitrification is possible (31,32). Whether such an N 2 O-production mechanism is truly relevant in the field, however is not yet known, as neither methanobactin production nor its influence on denitrifiers has been observed in complex microbiomes such as agriculture soils.…”

Section: Introductionmentioning

confidence: 99%

Enhancement of nitrous oxide emissions in soil microbial consortia via copper competition between proteobacterial methanotrophs and denitrifiers

Chang

Kim²,

Semrau

et al. 2020

Preprint

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Unique means of copper scavenging have been identified in proteobacterial methanotrophs, particularly the use of methanobactin, a novel ribosomally synthesized post-translationally modified polypeptide that binds copper with very high affinity. The possibility that copper sequestration strategies of methanotrophs may interfere with copper uptake of denitrifiers in situ and thereby enhance N2O emissions was examined using a suite of laboratory experiments performed with rice paddy microbial consortia. Addition of purified methanobactin from Methylosinus trichosporium OB3b to denitrifying rice paddy soil microbial consortia resulted in substantially increased N2O production, with more pronounced responses observed for soils with lower copper content. The N2O emission-enhancing effect of the soil's native mbnA-expressing Methylocystaceae methanotrophs on the native denitrifiers was then experimentally verified with a Methylocystaceae-dominant chemostat culture prepared from a rice paddy microbial consortium as the inoculum. Lastly, with microcosms amended with varying cell numbers of methanobactin-producing Methylosinus trichosporium OB3b before CH4 enrichment, microbiomes with different ratios of methanobactin-producing Methylocystaceae to gammaproteobacterial methanotrophs incapable of methanobactin production were simulated. Significant enhancement of N2O production from denitrification was evident in both Methylocystaceae-dominant and Methylococcaceae-dominant enrichments, albeit to a greater extent in the former, signifying the comparative potency of methanobactin-mediated copper sequestration while implying the presence of alternative copper abstraction mechanisms for Methylococcaceae. These observations support that copper-mediated methanotrophic enhancement of N2O production from denitrification is plausible where methanotrophs and denitrifiers cohabit.

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Hot spots of N2O emission move with the seasonally mobile oxic-anoxic interface in drained organic soils

Cited by 17 publications

References 34 publications

Spatio-Temporal Variability of Peat CH4 and N2O Fluxes and Their Contribution to Peat GHG Budgets in Indonesian Forests and Oil Palm Plantations

Spatio-Temporal Variability of Peat CH4 and N2O Fluxes and Their Contribution to Peat GHG Budgets in Indonesian Forests and Oil Palm Plantations

N<sub>2</sub>O isotopocule measurements using laser spectroscopy: analyzer characterization and intercomparison

Enhancement of nitrous oxide emissions in soil microbial consortia via copper competition between proteobacterial methanotrophs and denitrifiers

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Hot spots of N2O emission move with the seasonally mobile oxic-anoxic interface in drained organic soils

Cited by 17 publications

References 34 publications

Spatio-Temporal Variability of Peat CH4 and N2O Fluxes and Their Contribution to Peat GHG Budgets in Indonesian Forests and Oil Palm Plantations

Spatio-Temporal Variability of Peat CH4 and N2O Fluxes and Their Contribution to Peat GHG Budgets in Indonesian Forests and Oil Palm Plantations

N&lt;sub&gt;2&lt;/sub&gt;O isotopocule measurements using laser spectroscopy: analyzer characterization and intercomparison

Enhancement of nitrous oxide emissions in soil microbial consortia via copper competition between proteobacterial methanotrophs and denitrifiers

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N<sub>2</sub>O isotopocule measurements using laser spectroscopy: analyzer characterization and intercomparison