Methane oxidation potential of the arctic wetland soils of a taiga-tundra ecotone in northeastern Siberia

2020 ◽  
Vol 66 (4) ◽  
pp. 645-652
Author(s):  
Jun Murase ◽  
Atsuko Sugimoto ◽  
Ryo Shingubara ◽  
Maochang Liang ◽  
Tomoki Morozumi ◽  
...  
Keyword(s):  
Methane Oxidation ◽  
Oxidation Potential ◽  
The Arctic ◽  
Wetland Soils ◽  
Northeastern Siberia

scholarly journals Methane oxidation potential of the arctic wetland soils of a taiga-tundra ecotone in northeastern Siberia

2019 ◽  
Author(s):  
Jun Murase ◽  
Atsuko Sugimoto ◽  
Ryo Shingubara ◽  
Tomoki Morozumi ◽  
Shinya Takano ◽  
...  
Keyword(s):  
Methane Oxidation ◽  
Oxidation Rate ◽  
Time Lag ◽  
Soil Samples ◽  
The Arctic ◽  
Wetland Soils ◽  
Oxidation Rates ◽  
Northeastern Siberia ◽  
Water Saturated ◽  
Methane Oxidation Rate

Abstract. Arctic wetlands are significant sources of atmospheric methane and the observed accelerated climate changes in the arctic could cause the change in methane dynamics, where methane oxidation would be the key process to control methane emission from wetlands. In this study we determined the potential methane oxidation rate of the wetland soils of a taiga-tundra transition zone in northeastern Siberia. Peat soil samples were collected in summer from depressions covered with tussocks of sedges and Sphagnum spp. and from mounds vegetated with moss and larch trees. A bottle incubation experiment demonstrated that the soil samples collected from depressions in the moss- and sedge-dominated zones exhibited active methane oxidation with no time lag. The potential methane oxidation rates at 15 °C ranged from 94 to 496 nmol h−1 g−1 dw. Methane oxidation was observed over the depths studied (0–40 cm) including the water-saturated anoxic layers. The maximum methane oxidation rate was recorded in the layer above the water-saturated layer: the surface (0–2 cm) layer in the sedge-dominated zone and in the middle (4–6 cm) layer in the moss-dominated zone. The methane oxidation rate was temperature-dependent, and the threshold temperature of methane oxidation was estimated to be −4 to −11 °C, which suggested methane oxidation at subzero temperatures. Soil samples collected from the frozen layer of Sphagnum peat also showed immediate methane consumption when incubated at 15 °C. The present results suggest that the methane oxidizing bacteria in the wetland soils keep their potential activities even under anoxic and frozen conditions and immediately utilize methane when the conditions become favorable. On the other hand, the inhibitor of methane oxidation did not affect the methane flux from the sedge and moss zones in situ, which indicated the minor role of plant-associated methane oxidation.

scholarly journals Different methanotrophic potentials in stratified polar fjord waters (Storfjorden, Spitsbergen) identified by using a combination of methane oxidation techniques

2013 ◽  
Vol 10 (4) ◽  
pp. 6461-6491 ◽  
Author(s):  
S. Mau ◽  
J. Blees ◽  
E. Helmke ◽  
H. Niemann ◽  
E. Damm
Keyword(s):  
Water Column ◽  
Methane Oxidation ◽  
Deep Water ◽  
Oxidation Potential ◽  
Water Masses ◽  
Spatiotemporal Variability ◽  
The Arctic ◽  
Type I ◽  
Turnover Rates ◽  
Arctic Water

Abstract. The bacterially mediated aerobic methane oxidation (MOx) is a key mechanism in controlling methane (CH4) emissions from the world's oceans to the atmosphere. In this study, we investigated MOx in the Arctic fjord Storfjorden (Spitsbergen) by applying a combination of radio-tracer based incubation assays (3H-CH4 and 14H-CH4), stable C-CH4 isotope measurements, and molecular tools (16S rRNA DGGE-fingerprinting, pmoA- and mxaF gene analyses). Strofjorden is stratified in the summertime with melt water (MW) in the upper 60 m of the water column, Arctic water (ArW) between 60–100 m and brine-enriched shelf water (BSW) down to 140 m. CH4 concentrations were supersaturated with respect to the atmospheric equilibrium (∼3 nM) throughout the water column, increasing from ∼20 nM at the surface to a maximum of 72 nM at 60 m and decreasing below. MOx rate measurements at near in situ CH4 concentrations (here measured with 3H-CH4 raising the ambient CH4 pool by <2 nM) showed a similar trend: low rates at the sea surface increasing to a maximum of ∼2.3 nM d−1 at 60 m followed by a decrease in the deeper ArW/BSW. In contrast, rate measurements with 14H-CH4 at elevated CH4 concentrations (incubations were spiked with ∼450 nM of 14H-CH4, providing an estimate of the CH4 oxidation potential) showed comparably low turnover rates (<1 nMd−1) at 60 m, but peaked in ArW/BSW at ∼100 m water depth, concomitant with increasing 14C-values in the residual CH4 pool. Our results indicate that the MOx community in the surface MW is adapted to relatively low CH4 concentrations. In contrast, the activity of the deep water MOx community is relatively low at the ambient, summertime CH4 concentrations but has the potential to increase rapidly in response to CH4 availability. A similar distinction between surface and deep water MOx is also suggested by our molecular analyses. Although, we found pmoA and maxF gene sequences throughout the water column attesting the ubiquitous presence of MOx communities in Storfjorden, deep water amplicons of pmoA and maxF were unusually long. Also a DGGE band related to the known Type I MOx Mehtylosphera was observed in deep BWS, but absent in surface MW. Apparently, different MOx communities have developed in the stratified water masses in Storfjorden, which is possibly related to the spatiotemporal variability in CH4 supply to the distinct water masses.

The role of atmospheric dynamics in extreme wildfire activity in northeastern Siberia

2021 ◽  
Author(s):  
Rebecca Scholten ◽  
Coumou Dim ◽  
Luo Fei ◽  
Sander Veraverbeke
Keyword(s):  
Large Scale ◽  
Meridional Wind ◽  
Atmospheric Dynamics ◽  
The Arctic ◽  
Burned Area ◽  
Fast Fourier Transformation ◽  
Arctic Circle ◽  
Wave Dynamics ◽  
Northeastern Siberia ◽  
Fire Activity

&lt;p&gt;In the summer of 2020, extreme fires have raged in northeastern Siberia, many of them within the Arctic Circle burning in ecotonal larch forest and tundra ecosystems. This unprecedented increase in fire activity within the Arctic Circle has been linked to record-high temperatures measured in the region, as well as to high lightning activity.&lt;/p&gt;&lt;p&gt;In mid-latitudes, the pronounced and long-lasting heatwaves of the last decade have been linked to amplified Rossby waves connected with weak atmospheric circulation. These amplified waves tend to phase-lock in preferred positions and thereby lead to more persistent summer weather. Linkages between atmospheric teleconnections and boreal wildfires exist for some regions, yet the influence of wave dynamics on arctic-boreal wildfires is unknown. We explored relationships between wave dynamics, heatwaves, and the unprecedented fire activity in Siberia in 2020 to assess whether the recent surge in arctic-boreal fires in Siberia is driven by large-scale atmospheric dynamics.&lt;/p&gt;&lt;p&gt;We determined wave amplitudes as phase positions by applying fast Fourier transformation on weekly averaged mid- to high-latitudinal mean meridional wind velocities at the 250 mb level from ERA5 reanalysis data. Gridded percentage area burned between 2001 and 2020 was derived from the Moderate Resolution Imaging Spectrometer (MODIS) Burned Area product (MCD64A1). We then quantified the importance of Rossby wave patterns on fire activity clustered by latitude in eastern Siberia.&lt;/p&gt;

scholarly journals Role of Landfill Cover in Reducing Methane Emission

2013 ◽  
Vol 39 (3) ◽  
pp. 115-126 ◽  
Author(s):  
Yucheng Cao ◽  
Ewelina Staszewska
Keyword(s):  
Climate Change ◽  
Carbon Dioxide ◽  
Global Warming ◽  
Methane Oxidation ◽  
Landfill Gas ◽  
Oxidation Potential ◽  
Landfill Cover ◽  
High Fraction ◽  
Engineered Landfill

Abstract Uncontrolled emissions of landfill gas may contribute significantly to climate change, since its composition represents a high fraction of methane, a greenhouse gas with 100- year global warming potential 25 times that of carbon dioxide. Landfill cover could create favourable conditions for methanotrophy (microbial methane oxidation), an activity of using bacteria to oxidize methane to carbon dioxide. This paper presents a brief review of methanotrophic activities in landfill cover. Emphasis is given to the effects of cover materials, environmental conditions and landfill vegetation on the methane oxidation potential, and to their underlying effect mechanisms. Methanotrophs communities and methane oxidation kinetics are also discussed. Results from the overview suggest that well-engineered landfill cover can substantially increase its potential for reducing emissions of methane produced in landfill to the atmosphere.

scholarly journals Accurate measurements of atmospheric carbon dioxide and methane mole fractions at the Siberian coastal site Ambarchik

2018 ◽  
Author(s):  
Friedemann Reum ◽  
Mathias Göckede ◽  
Jost V. Lavric ◽  
Olaf Kolle ◽  
Sergey Zimov ◽  
...  
Keyword(s):  
Arctic Ocean ◽  
Atmospheric Carbon Dioxide ◽  
Monitoring Network ◽  
The Arctic ◽  
Data Quality Control ◽  
In Situ Data ◽  
Northeastern Siberia ◽  
East Siberian Sea ◽  
The Arctic Ocean ◽  
Atmospheric Carbon

Abstract. Sparse data coverage in the Arctic hampers our understanding of its carbon cycle dynamics and our predictions of the fate of its vast carbon reservoirs in a changing climate. In this paper, we present accurate measurements of atmospheric CO2 and CH4 dry air mole fractions at the new atmospheric carbon observation station Ambarchik, which closes a large gap in the atmospheric trace gas monitoring network in northeastern Siberia. The site, operational since August 2014, is located near the delta of the Kolyma River at the coast of the Arctic Ocean. Data quality control of CO2 and CH4 measurements includes frequent calibrations traced to WMO scales, employment of a novel water vapor correction, an algorithm to detect influence of local polluters, and meteorological measurements that enable data selection. The available CO2 and CH4 record was characterized in comparison with in situ data from Barrow, Alaska. A footprint analysis reveals that the station is sensitive to signals from the East Siberian Sea, as well as northeast Siberian tundra and taiga regions. This makes data from Ambarchik highly valuable for inverse modeling studies aimed at constraining carbon budgets within the pan-Arctic domain, as well as for regional studies focusing on Siberia and the adjacent shelf areas of the Arctic Ocean.

scholarly journals Stable Water Isotope Assessment of Tundra Wetland Hydrology as a Potential Source of Arctic Riverine Dissolved Organic Carbon in the Indigirka River Lowland, Northeastern Siberia

2021 ◽  
Vol 9 ◽  
Author(s):  
Shinya Takano ◽  
Youhei Yamashita ◽  
Shunsuke Tei ◽  
Maochang Liang ◽  
Ryo Shingubara ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Late Summer ◽  
Wetland Hydrology ◽  
Temporal Variations ◽  
The Arctic ◽  
Stable Water Isotopes ◽  
River Level ◽  
Northeastern Siberia ◽  
Doc Concentration

Arctic tundra wetlands may be an important source of dissolved organic carbon (DOC) in Arctic rivers and the Arctic Ocean under global warming. We investigated stable water isotopes and DOC concentration in wetlands, tributaries, and the mainstream at the lower reaches of the Indigirka River in northeastern Siberia during the summers of 2010–2014 to assess the complex hydrology and role of wetlands as sources of riverine DOC. The wetlands had higher values of δ18O and DOC concentration than the tributaries and mainstream of the Indigirka River. A relationship between the two parameters was observed in the wetlands, tributaries, and mainstream, suggesting the wetlands can be a source of DOC for the mainstream through the tributaries. The combined temporal variations in riverine δ18O and DOC concentration indicate the mainstream water flowed into the tributaries during relatively high river-level periods in summer, whereas high DOC water in the downstream wetlands could be discharged to the mainstream through the tributaries during the low river-level periods. A minor fraction (7–13%) of riverine and wetland DOC was degraded during 40 days of dark incubation. Overall, the downstream wetlands potentially provide relatively less biodegradable DOC to the Arctic river and costal ecosystem during the low river-level periods—from late summer to autumn.

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