The role of endophytic methane oxidizing bacteria in submerged &lt;i&gt;Sphagnum&lt;/i&gt; in determining methane emissions of Northeastern Siberian tundra

Abstract. The behavior of tundra ecosystems is critical in the global carbon cycle due to their wet soils and large stores of carbon. Recently, cooperation was observed between methanotrophic bacteria and submerged Sphagnum, which reduces methane emissions in this type of vegetation and supplies CO2 for photosynthesis to the plant. Although proven in the lab, the differences that exist in methane emissions from inundated vegetation types with or without Sphagnum have not been linked to these bacteria before. To further investigate the importance of these bacteria, chamber flux measurements, microbial analysis and flux modeling were used to show that methane emissions in a submerged Sphagnum/sedge vegetation type were 50% lower compared to an inundated sedge vegetation without Sphagnum. From examining the results of the measurements, incubation experiments and flux modeling, it was found that it is likely that this difference is due to, for a large part, oxidation of methane below the water table by these endophytic bacteria. This result is important when upscaled spatially since oxidation by these bacteria plays a large role in 15% of the net methane emissions, while at the same time they promote photosynthesis of Sphagnum, and thus carbon storage. Future changes in the spread of submerged Sphagnum, in combination with the response of these bacteria to a warmer climate, could be an important factor in predicting future greenhouse gas exchange from tundra.

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The role of endophytic methane-oxidizing bacteria in submerged <I>Sphagnum</I> in determining methane emissions of Northeastern Siberian tundra

Biogeosciences ◽

10.5194/bg-8-1267-2011 ◽

2011 ◽

Vol 8 (5) ◽

pp. 1267-1278 ◽

Cited By ~ 34

Author(s):

F. J. W. Parmentier ◽

J. van Huissteden ◽

N. Kip ◽

H. J. M. Op den Camp ◽

M. S. M. Jetten ◽

...

Keyword(s):

Process Model ◽

Vegetation Type ◽

Relative Difference ◽

Methane Emissions ◽

Methane Cycling ◽

Methane Oxidizing Bacteria ◽

Incubation Study ◽

Flux Measurements ◽

Tundra Ecosystems

Abstract. The role of the microbial processes governing methane emissions from tundra ecosystems is receiving increasing attention. Recently, cooperation between methanotrophic bacteria and submerged Sphagnum was shown to reduce methane emissions but also to supply CO2 for photosynthesis for the plant. Although this process was shown to be important in the laboratory, the differences that exist in methane emissions from inundated vegetation types with or without Sphagnum in the field have not been linked to these bacteria before. In this study, chamber flux measurements, an incubation study and a process model were used to investigate the drivers and controls on the relative difference in methane emissions between a submerged Sphagnum/sedge vegetation type and an inundated sedge vegetation type without Sphagnum. It was found that methane emissions in the Sphagnum-dominated vegetation type were 50 % lower than in the vegetation type without Sphagnum. A model sensitivity analysis showed that these differences could not sufficiently be explained by differences in methane production and plant transport. The model, combined with an incubation study, indicated that methane oxidation by endophytic bacteria, living in cooperation with submerged Sphagnum, plays a significant role in methane cycling at this site. This result is important for spatial upscaling as oxidation by these bacteria is likely involved in 15 % of the net methane emissions at this tundra site. Our findings support the notion that methane-oxidizing bacteria are an important factor in understanding the processes behind methane emissions in tundra.

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The role of watershed characteristics, permafrost thaw, and wildfire on dissolved organic carbon biodegradability and water chemistry in Arctic headwater streams

Biogeosciences Discussions ◽

10.5194/bgd-12-4021-2015 ◽

2015 ◽

Vol 12 (5) ◽

pp. 4021-4056 ◽

Cited By ~ 5

Author(s):

J. R. Larouche ◽

B. W. Abbott ◽

W. B. Bowden ◽

J. B. Jones

Keyword(s):

Organic Carbon ◽

Dissolved Organic Carbon ◽

Aquatic Ecosystems ◽

Vegetation Type ◽

Watershed Scale ◽

Ecosystem Recovery ◽

Watershed Characteristics ◽

Stream Geomorphology ◽

Tundra Ecosystems

Abstract. In the Alaskan Arctic, rapid climate change is increasing the frequency of disturbance including wildfire and permafrost collapse. These pulse disturbances may influence the delivery of dissolved organic carbon (DOC) to aquatic ecosystems, however the magnitude of these effects compared to the natural background variability of DOC at the watershed scale is not well known. We measured DOC quantity, composition, and biodegradability from 14 river and stream reaches (watershed sizes ranging from 1.5–167 km2) some of which were impacted by permafrost collapse (thermokarst) and fire. We found that region had a significant impact on quantity and biodegradability of DOC, likely driven by landscape and watershed characteristics such as lithology, soil and vegetation type, elevation, and glacial age. However, contrary to our hypothesis, we found that streams disturbed by thermokarst and fire did not contain significantly altered labile DOC fractions compared to adjacent reference waters, potentially due to rapid ecosystem recovery after fire and thermokarst as well as the limited spatial extent of thermokarst. Overall, biodegradable DOC ranged from 4 to 46% and contrary to patterns of DOC biodegradability in large Arctic rivers, seasonal variation in DOC biodegradability showed no clear pattern between sites, potentially related to stream geomorphology and position along the river network. While thermokarst and fire can alter DOC quantity and biodegradability at the scale of the feature, we conclude that tundra ecosystems are resilient to these types of disturbance.

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The role of watershed characteristics, permafrost thaw, and wildfire on dissolved organic carbon biodegradability and water chemistry in Arctic headwater streams

Biogeosciences ◽

10.5194/bg-12-4221-2015 ◽

2015 ◽

Vol 12 (14) ◽

pp. 4221-4233 ◽

Cited By ~ 45

Author(s):

J. R. Larouche ◽

B. W. Abbott ◽

W. B. Bowden ◽

J. B. Jones

Keyword(s):

Organic Carbon ◽

Dissolved Organic Carbon ◽

Aquatic Ecosystems ◽

Vegetation Type ◽

Watershed Scale ◽

Ecosystem Recovery ◽

Watershed Characteristics ◽

Stream Geomorphology ◽

Tundra Ecosystems

Abstract. In the Alaskan Arctic, rapid climate change is increasing the frequency of disturbance including wildfire and permafrost collapse. These pulse disturbances may influence the delivery of dissolved organic carbon (DOC) to aquatic ecosystems, however the magnitude of these effects compared to the natural background variability of DOC at the watershed scale is not well known. We measured DOC quantity, composition, and biodegradability from 14 river and stream reaches (watershed sizes ranging from 1.5–167 km2) some of which were impacted by permafrost collapse (thermokarst) and fire. We found that region had a significant impact on quantity and biodegradability of DOC, likely driven by landscape and watershed characteristics such as lithology, soil and vegetation type, elevation, and glacial age. However, contrary to our hypothesis, we found that streams disturbed by thermokarst and fire did not contain significantly altered labile DOC fractions compared to adjacent reference waters, potentially due to rapid ecosystem recovery after fire and thermokarst as well as the limited spatial extent of thermokarst. Overall, biodegradable DOC ranged from 4 to 46 % and contrary to patterns of DOC biodegradability in large Arctic rivers, seasonal variation in DOC biodegradability showed no clear pattern between sites, potentially related to stream geomorphology and position along the river network. While thermokarst and fire can alter DOC quantity and biodegradability at the scale of the feature, we conclude that tundra ecosystems are resilient to these types of disturbance.

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The stability of Pd/TS-1 and Pd/silicalite-1 for catalytic oxidation of methane – understanding the role of titanium

Catalysis Science & Technology ◽

10.1039/c9cy01579e ◽

2020 ◽

Vol 10 (4) ◽

pp. 1193-1204 ◽

Cited By ~ 4

Author(s):

Hadi Hosseiniamoli ◽

Adi Setiawan ◽

Adesoji A. Adesina ◽

Eric M. Kennedy ◽

Michael Stockenhuber

Keyword(s):

Relative Humidity ◽

Catalytic Oxidation ◽

Catalytic Combustion ◽

Methane Emissions ◽

Oxidation Of Methane ◽

The Stability

The stability of Pd/TS-1 and Pd/silicalite-1 catalysts was assessed at 400 °C and an approximate relative humidity (RH) of 80% for catalytic combustion of fugitive methane emissions, aiming to understand the role of titanium in the stability of the catalysts.

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The importance of small artificial water bodies as sources of methane emissions in Queensland, Australia

10.5194/hess-2018-294 ◽

2018 ◽

Cited By ~ 1

Author(s):

Alistair Grinham ◽

Simon Albert ◽

Nathaniel Deering ◽

Matthew Dunbabin ◽

David Bastviken ◽

...

Keyword(s):

Greenhouse Gas ◽

Surface Area ◽

Total Surface Area ◽

Methane Emissions ◽

Water Bodies ◽

Emission Rates ◽

Flux Measurements ◽

Artificial Water Bodies ◽

Artificial Water

Abstract. Emissions from flooded land represent a direct source of anthropogenic greenhouse gas emissions. Methane emissions from large, artificial water bodies have previously been considered, with numerous studies assessing emission rates and relatively simple procedures available to determine their surface area and generate upscaled emissions estimates. In contrast, the role of small artificial water bodies (ponds) is very poorly quantified, and estimation of emissions is constrained both by a lack of data on their spatial extent, and a scarcity of direct flux measurements. In this study, we quantified the total surface area of water bodies

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Comparative surface and ultrastructural views of methylotrophic bacteria by TEM, STEM, SE, and freeze-etch electron microscopy.

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100128274 ◽

1987 ◽

Vol 45 ◽

pp. 792-793

Author(s):

T.A. Fassel ◽

M.J. Schaller ◽

M.E. Lidstrom ◽

C.C. Remsen

Keyword(s):

Cytoplasmic Membrane ◽

Structural Features ◽

Methylotrophic Bacteria ◽

Type I ◽

Type Ii ◽

Membrane Complex ◽

Oxidation Of Methane ◽

Methane Oxidizing Bacteria ◽

Wall Structures ◽

Methylomonas Albus

Methylotrophic bacteria play an Important role in the environment in the oxidation of methane and methanol. Extensive intracytoplasmic membranes (ICM) have been associated with the oxidation processes in methylotrophs and chemolithotrophic bacteria. Classification on the basis of ICM arrangement distinguishes 2 types of methylotrophs. Bundles or vesicular stacks of ICM located away from the cytoplasmic membrane and extending into the cytoplasm are present in Type I methylotrophs. In Type II methylotrophs, the ICM form pairs of peripheral membranes located parallel to the cytoplasmic membrane. Complex cell wall structures of tightly packed cup-shaped subunits have been described in strains of marine and freshwater phototrophic sulfur bacteria and several strains of methane oxidizing bacteria. We examined the ultrastructure of the methylotrophs with particular view of the ICM and surface structural features, between representatives of the Type I Methylomonas albus (BG8), and Type II Methylosinus trichosporium (OB-36).

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ANDROST-5-ENE-3β,17β-DIOL IN OVARY OF POST-MENOPAUSAL HYPEROESTROGENIC WOMEN

Acta Endocrinologica ◽

10.1530/acta.0.0580364 ◽

1968 ◽

Vol 58 (3) ◽

pp. 364-376 ◽

Cited By ~ 5

Author(s):

S. Pesonen ◽

M. Ikonen ◽

B-J. Procopé ◽

A. Saure

Keyword(s):

Ovarian Tissue ◽

Cortical Layer ◽

Vaginal Smears ◽

Incubation Experiments ◽

Cell Groups ◽

Post Menopause ◽

Reducing Activity ◽

Post Menopausal ◽

One Year

ABSTRACT The ovaries of ten patients, at least one year after the post-menopause, were incubated with two Δ5-C19-steroids and also studied histochemically. All these patients had post-menopausal uterine bleeding and increased oestrogen excretion of the urine. The urinary estimations of gonadotrophins, 17-KS, 17-OHCS and pregnanediol were carried out on all patients. Vaginal smears were read according to Papanicolaou, and the endometrium and ovaries were studied histologically. The incubation experiments indicate the presence of Δ5-3β-hydroxysteroid-dehydrogenase. When androst-5-ene-3β,17β-diol was used as precursor the formation of testosterone occurred without any concomitant production of DHA and/or androstenedione. This seems to indicate the possible role of the Δ5-pathway in the formation of testosterone by post-menopausal ovarian tissue. The histochemical reactions indicated a reducing activity on NADH, lactate and glucose-6-phosphate, in certain corpora albicantia, atretic follicles and in diffuse thecoma regions in the cortical layer of the ovary. Steroid-3β-ol-dehydrogenase and β-hydroxybutyrate-dehydrogenase were found only at the edges of certain corpora albicantia, in some individual stroma cell groups and in some atretic follicles. Our studies, both biochemical and histochemical, suggest that the observed increase in the urinary oestrogens of the patients studied might in part at least, be of ovarian origin. This opinion is also supported by the postoperative oestrogen values.

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The morphology of experimentally produced charcoal distinguishes fuel types in the Arctic tundra

The Holocene ◽

10.1177/0959683620908629 ◽

2020 ◽

Vol 30 (7) ◽

pp. 1091-1096 ◽

Cited By ~ 1

Author(s):

Eleanor MB Pereboom ◽

Richard S Vachula ◽

Yongsong Huang ◽

James Russell

Keyword(s):

Arctic Tundra ◽

Global Carbon Cycle ◽

Fire Frequency ◽

The Arctic ◽

Fuel Type ◽

The Past ◽

Primary Means ◽

Forested Ecosystems ◽

Global Carbon ◽

Tundra Ecosystems

Wildfires in the Arctic tundra have become increasingly frequent in recent years and have important implications for tundra ecosystems and for the global carbon cycle. Lake sediment–based records are the primary means of understanding the climatic influences on tundra fires. Sedimentary charcoal has been used to infer climate-driven changes in tundra fire frequency but thus far cannot differentiate characteristics of the vegetation burnt during fire events. In forested ecosystems, charcoal morphologies have been used to distinguish changes in fuel type consumed by wildfires of the past; however, no such approach has been developed for tundra ecosystems. We show experimentally that charcoal morphologies can be used to differentiate graminoid (mean = 6.77; standard deviation (SD) = 0.23) and shrub (mean = 2.42; SD = 1.86) biomass burnt in tundra fire records. This study is a first step needed to construct more nuanced tundra wildfire histories and to understand how wildfire will impact the region as vegetation and fire change in the future.

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