scholarly journals Autonomous methane seep site monitoring offshore Western Svalbard: Hourly to seasonal variability and associated oceanographic parameters

2021 ◽  
Author(s):  
Knut Ola Dølven ◽  
Bénédicte Ferré ◽  
Anna Silyakova ◽  
Pär Jansson ◽  
Peter Linke ◽  
...  
Keyword(s):  
Negative Correlation ◽  
Bottom Water ◽  
Methane Concentration ◽  
Ocean Current ◽  
Polar Regions ◽  
Methane Seep ◽  
Atmospheric Methane ◽  
Rapid Variability ◽  
Methane Release ◽  
Methane Seepage

Abstract. Improved quantification techniques of natural sources is needed to explain variations in atmospheric methane. In polar regions, high uncertainties in current estimates of methane release from the seabed remain. We present two unique 10 and 3 months long time-series of bottom water measurements of physical and chemical parameters from two autonomous ocean observatories deployed at separate intense seabed methane seep sites (91 and 246 m depth) offshore Western Svalbard from 2015 to 2016. Results show high short term (100–1000 nmol L-1 within hours) and seasonal variation, as well as higher (2–7 times) methane concentrations compared to previous measurements. Rapid variability is explained by uneven distribution of seepage and changing ocean current directions. No overt influence of tidal hydrostatic pressure or water temperature variations on methane concentration was observed, but an observed negative correlation with temperature at the 246 site fits with hypothesized seasonal blocking of lateral methane pathways in the sediments. Negative correlation between bottom water methane concentration/variability and wind forcing, concomitant with signs of weaker water column stratification, indicates increased potential for methane release to the atmosphere in fall/winter. We highlight uncertainties in methane inventory estimates based on discrete water sampling and present new information about short- and long-term methane variability which can help constrain future estimates of seabed methane seepage.

Seasonal variability of natural methane seepage offshore Western Svalbard

2021 ◽  
Author(s):  
Manuel Moser ◽  
Knut Ola Dølven ◽  
Bénédicte Ferré
Keyword(s):  
Gas Hydrate ◽  
Bottom Water ◽  
Methane Flux ◽  
Mixing Rate ◽  
Bottom Water Temperature ◽  
Acoustic Data ◽  
Methane Seepage ◽  
Continental Shelves ◽  
Water Conditions ◽  
Methane Fluxes

<p>Natural methane seepage from the seafloor to the water column occurs worldwide in marine environments, from continental shelves to deep-sea basins. Depending on water depth, methane fluxes, and mixing rate of the seawater, methane may partially reach the atmosphere, where it could contribute to the global greenhouse effect. Estimates of annual marine methane fluxes are commonly calculated from hydro-acoustic data collected during single research surveys. These snapshot estimates neglect short (i.e., tide) and long (seasonal) variations.</p><p>Here we compare the seepage activity along the upper limit of the gas hydrate stability zone offshore Western Svalbard in August 2017 (bottom water temperature (BT) ~3.46°C), June 2020 (BT ~1.75°C), and November 2020 (BT ~3.96°C) using high-resolution vessel-based multibeam data. Our results complete annual methane flux estimates by Ferré et al. (2020) and confirm a significantly reduced seepage activity during the cold bottom-water conditions. We investigate short-term variation by comparing a 7.5 km long multibeam section at three phases of the lunar semidiurnal (M2) tide. We will discuss how these processes affect annual methane fluxes estimates offshore Svalbard and further Arctic methane fluxes estimates.</p><p>The research is part of the Centre for Arctic Gas Hydrate, Environment and Climate (CAGE) and is supported by the Research Council of Norway through its Centres of Excellence funding scheme grant No. 223259 and UiT.</p><p> </p><p>Ferré, B., Jansson, P. G., Moser, M., Serov, P., Portnov, A., Graves, C. A., et al. (2020). Reduced methane seepage from Arctic sediments during cold bottom-water conditions. Nat. Geosci. 13, 144–148. DOI: 10.1038/s41561-019-0515-3</p>

Atmospheric Methane Concentration Allows Estimating Natural Gas Leaks in Heating Systems in Tandil, Argentina

2019 ◽  
Vol 48 (3) ◽  
pp. 762-769
Author(s):  
Victoria S. Fusé ◽  
José I. Gere ◽  
Daiana Urteaga ◽  
M. Paula Juliarena ◽  
Sergio A. Guzmán ◽  
...  
Keyword(s):  
Natural Gas ◽  
Methane Concentration ◽  
Atmospheric Methane ◽  
Heating Systems ◽  
Gas Leaks

scholarly journals Changes Of Atmospheric Methane Concentration Parallel To Climatic Changes

1990 ◽  
Vol 14 ◽  
pp. 359-359
Author(s):  
B. Stauffer ◽  
H. Oeschger ◽  
J. Schwander
Keyword(s):  
Climatic Change ◽  
Methane Concentration ◽  
Ice Core ◽  
Younger Dryas ◽  
Climatic Changes ◽  
Atmospheric Methane ◽  
Sources And Sinks ◽  
Core Samples ◽  
Climatic Optimum ◽  
Present Understanding

Measurements on ice-core samples showed that atmospheric methane concentration changed with the large climatic cycles during the last two glaciations (Stauffer and others, 1988; Raynaud and others, 1988). The methane concentration is lower in cold periods and higher in warm periods. In this paper we discuss the results of CH4 measurements of samples from periods of minor climatic change, like the climatic optimum 8000 years B.P. and the Younger Dryas period about 10 000 to 11 000 years B.P.. The data are interpreted in terms of the present understanding of methane sources and sinks.

scholarly journals Changes Of Atmospheric Methane Concentration Parallel To Climatic Changes

1990 ◽  
Vol 14 ◽  
pp. 359
Author(s):  
B. Stauffer ◽  
H. Oeschger ◽  
J. Schwander
Keyword(s):  
Climatic Change ◽  
Methane Concentration ◽  
Ice Core ◽  
Younger Dryas ◽  
Climatic Changes ◽  
Atmospheric Methane ◽  
Sources And Sinks ◽  
Core Samples ◽  
Climatic Optimum ◽  
Present Understanding

Measurements on ice-core samples showed that atmospheric methane concentration changed with the large climatic cycles during the last two glaciations (Stauffer and others, 1988; Raynaud and others, 1988). The methane concentration is lower in cold periods and higher in warm periods. In this paper we discuss the results of CH4 measurements of samples from periods of minor climatic change, like the climatic optimum 8000 years B.P. and the Younger Dryas period about 10 000 to 11 000 years B.P.. The data are interpreted in terms of the present understanding of methane sources and sinks.

scholarly journals Postglacial response of Arctic Ocean gas hydrates to climatic amelioration

2017 ◽  
Vol 114 (24) ◽  
pp. 6215-6220 ◽  
Author(s):  
Pavel Serov ◽  
Sunil Vadakkepuliyambatta ◽  
Jürgen Mienert ◽  
Henry Patton ◽  
Alexey Portnov ◽  
...  
Keyword(s):  
Arctic Ocean ◽  
Gas Hydrates ◽  
Gas Hydrate ◽  
Bottom Water ◽  
Environmental Changes ◽  
Thermal Dissociation ◽  
Ice Sheet ◽  
The Arctic ◽  
Ocean Bottom ◽  
Methane Release

Seafloor methane release due to the thermal dissociation of gas hydrates is pervasive across the continental margins of the Arctic Ocean. Furthermore, there is increasing awareness that shallow hydrate-related methane seeps have appeared due to enhanced warming of Arctic Ocean bottom water during the last century. Although it has been argued that a gas hydrate gun could trigger abrupt climate change, the processes and rates of subsurface/atmospheric natural gas exchange remain uncertain. Here we investigate the dynamics between gas hydrate stability and environmental changes from the height of the last glaciation through to the present day. Using geophysical observations from offshore Svalbard to constrain a coupled ice sheet/gas hydrate model, we identify distinct phases of subglacial methane sequestration and subsequent release on ice sheet retreat that led to the formation of a suite of seafloor domes. Reconstructing the evolution of this dome field, we find that incursions of warm Atlantic bottom water forced rapid gas hydrate dissociation and enhanced methane emissions during the penultimate Heinrich event, the Bølling and Allerød interstadials, and the Holocene optimum. Our results highlight the complex interplay between the cryosphere, geosphere, and atmosphere over the last 30,000 y that led to extensive changes in subseafloor carbon storage that forced distinct episodes of methane release due to natural climate variability well before recent anthropogenic warming.

Rapid Variations in Atmospheric Methane Concentration During the Past 110,000 Years

Science ◽  
1996 ◽  
Vol 273 (5278) ◽  
pp. 1087-1091 ◽  
Author(s):  
E. J. Brook ◽  
T. Sowers ◽  
J. Orchardo
Keyword(s):  
Methane Concentration ◽  
Atmospheric Methane ◽  
The Past

Airborne measurement of atmospheric methane concentration using pulsed lidar

2012 ◽  
Author(s):  
Anand Ramanathan ◽  
Kenji Numata ◽  
Stewart T. Wu ◽  
Steven X. Li ◽  
Martha W. Dawsey ◽  
...  
Keyword(s):  
Methane Concentration ◽  
Atmospheric Methane ◽  
Airborne Measurement

scholarly journals Stable isotopes provide revised global limits of aerobic methane emissions from plants

2007 ◽  
Vol 7 (1) ◽  
pp. 237-241 ◽  
Author(s):  
D. F. Ferretti ◽  
J. B. Miller ◽  
J. W. C. White ◽  
K. R. Lassey ◽  
D. C. Lowe ◽  
...  
Keyword(s):  
Methane Concentration ◽  
Ice Core ◽  
Stable Carbon Isotope ◽  
Atmospheric Methane ◽  
Stable Carbon ◽  
Terrestrial Plants ◽  
Unknown Mechanism ◽  
Stable Carbon Isotope Ratios ◽  
Annual Total ◽  
Plant Emissions

Abstract. Recently Keppler et al. (2006) discovered a surprising new source of methane – terrestrial plants under aerobic conditions, with an estimated global production of 62–236 Tg yr−1 by an unknown mechanism. This is ~10–40% of the annual total of methane entering the modern atmosphere and ~30–100% of annual methane entering the pre-industrial (0 to 1700 AD) atmosphere. Here we test this reported global production of methane from plants against ice core records of atmospheric methane concentration (CH4) and stable carbon isotope ratios (δ13CH4) over the last 2000 years. Our top-down approach determines that global plant emissions must be much lower than proposed by Keppler et al. (2006) during the last 2000 years and are likely to lie in the range 0–46 Tg yr−1 and 0–176 Tg yr−1 during the pre-industrial and modern eras, respectively.

scholarly journals Measurements of the background methane concentration with a remote lidar on kilometer routes in the Moscow region.

2021 ◽  
Vol 2021 (9) ◽  
Author(s):  
V.I. Grigorievsky ◽  
◽  
V.P. Sadovnikov ◽  
A.V. Elbakidze ◽  
◽  
...  
Keyword(s):  
Natural Gas ◽  
Solid Waste ◽  
Methane Concentration ◽  
Radiation Power ◽  
Heavy Traffic ◽  
Moscow Region ◽  
Background Concentration ◽  
Atmospheric Methane ◽  
Waste Landfill ◽  
Livestock Farm

Local path measurements of the background methane concentration in the northeast of the Moscow Region were carried out using a remote active lidar based on a powerful Raman amplifier of optical radiation in the wavelength range of ~ 1650 nm. The radiation power in the pulse was about 3 W. The trasses were selected taking into account possible anomalous deviations of the background of atmospheric methane and included forests, gasified buildings with natural gas, a peat lake, a road with heavy traffic, a livestock farm and a solid waste landfill. The length of the distances ranged from ~ 0.6 km to ~ 3.15 km. The highest background concentration of methane was observed over a livestock farm, over a highway and a solid waste landfill, which confirms the fact of an increase in gas emissions over these facilities. Also higher methane levels were observed above of the gasified homes and the heavy traffic road, indicating a possible increase in the number of vehicles using methane as fuel and a possible leak of natural gas from pipelines supplying buildings with natural gas.

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