1300-m-high rising bubbles from mud volcanoes at 2080m in the Black Sea: Hydroacoustic characteristics and temporal variability

Greinert, Jens; Artemov, Yu. G.; Егоров, В. Н.; Batist, Marc De; Mcginnis, Daniel Frank

doi:10.1016/j.epsl.2006.02.011

Cited by 226 publications

(205 citation statements)

References 49 publications

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“…The rapidity of this process strongly depends on the bubble size, the rising velocity, as well as the composition and conditions of the surrounding medium and the presence of upwelling flows 59 . Several studies have demonstrated that methane escapes the 320 bubbles well before final bubble dissolution 11,56,60,61 . Our suggestion that most of the methane discharged from the South Georgia northern shelf does not reach the upper water column is additionally strengthened by the relatively low concentrations of dissolved methane (about 5 nmol/l) in the intermediate to uppermost water masses at two hydrocast stations, deliberately acquired close to recorded flares in the Cumberland Bay area (Figs.…”

Section: Discussionmentioning

confidence: 99%

First evidence of widespread active methane seepage in the Southern Ocean, off the sub-Antarctic island of South Georgia

Römer

Torres

Kasten

et al. 2014

Earth and Planetary Science Letters

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25A new extensive submarine cold-seep area was discovered on the northern shelf of South Georgia during R/V Polarstern cruise ANT-XXIX/4 in spring 2013. Hydroacoustic surveys and video-based sea floor observations documented the presence of 133 individual gas bubble emissions, which were restricted to glacially-formed fjords and troughs. Effective methane transport from these emissions into the hydrosphere was proven by relative enrichments of dissolved methane in near-bottom 30 waters. Stable carbon isotopic signatures of the methane pointed to a predominant microbial origin.Although known from many continental margins in the world's oceans, this is the first report of an active area of methane seepage in the Southern Ocean. Our finding of substantial methane emission related to a trough and fjord system, a topographical setting that exists commonly in glaciallyaffected areas, opens up the possibility that methane seepage is a more widespread phenomenon in 35 polar and sub-polar regions than previously thought.

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Section: Discussionmentioning

confidence: 99%

First evidence of widespread active methane seepage in the Southern Ocean, off the sub-Antarctic island of South Georgia

Römer

Torres

Kasten

et al. 2014

Earth and Planetary Science Letters

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“…Volumetric estimates-Spatial heterogeneities of gas ebullition in areas of hydrocarbon seeps were studied using sonar techniques (Vagle and Farmer 1992;Jackson et al 1998;Quigley et al 1999;Greinert et al 2006), assuming the direct relationship between backscattering strength and the amount of bubbles in the water column. In fact, our data (Eq.…”

Section: Discussionmentioning

confidence: 99%

“…Bubble-size distribution in nature is a subject of great interest because many parameters required for the assessment of gas transport through the water column (e.g., rise velocity, gas exchange between bubble and water) are sizedependant (Wüest et al 1992;Leifer and Patro 2002;McGinnis et al 2004). To date, only a few attempts have been made to study spatial and temporal variability of gas emission with echosounders in the ocean (e.g., Greinert et al 2003;Artemov 2006;Greinert et al 2006); furthermore, there are almost no data reported from reservoirs and lakes (Ostrovsky 2003).…”

Section: Introductionmentioning

confidence: 99%

Quantifying gas ebullition with echosounder: the role of methane transport by bubbles in a medium‐sized lake

Ostrovsky

Mcginnis

Lapidus

et al. 2008

Limnology & Ocean Methods

152

165

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In lakes and reservoirs with variable water level, gas ebullition can play a substantial role in methane transport in the water column and to the atmosphere. However, measuring methane ebullition from sediment is difficult as releases are highly heterogeneous and intermittent on macro- and micro-scales. In contrast to conventional gas traps and optical methods, hydroacoustic technology allows rapid scanning over large volumes of the water column synoptically to quantify gas bubble abundance. A 120-kHz dual beam downward-looking echosounder was used to measure the size distributions of bubbles that do not resonate at the sonar frequency. Data obtained with this sonar permit accurate calculation and evaluation of ebullition flux from the bottom. A robust relationship was established between gas volumes and backscattering cross-section of individual bubbles in experimental conditions, and rise velocities of bubbles were precisely measured. The volume backscattering coefficient was shown to be a good gauge of the total volume of bubbles per cubic meter of water, allowing the use of a single-beam sonar for measuring volumetric bubble concentrations. Data obtained from hydroacoustic surveys on Lake Kinneret, where gaseous methane is emitted from randomly dispersed sediment sources, indicated that ~90% of bubbles escaping from soft sediments ranged from 1.3 mm to 4.5 mm and ~50% ranged from 2.0 mm to 3.2 mm in equivalent radius. In summer-fall 2001, the gaseous methane fluxes from hypolimnetic sediments was ~10 mmol m-2 d-1, accounting for one-third of the observed methane accumulation in the hypolimnion. This relatively high ebullition rate could be attributed to the gradual decreasing of the mean water level in preceding years

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“…The basic limitation of this last approach is that it is feasible when strictly localized emission occurs, without any other dry seepage. A different approach to the problem of counting of bubbles rising from submerged vents is based on acoustic emissions induced by active hydroacoustic echosounding (Greinert and Nützel, 2004;Greinert et al, 2006;Nikolowska and Schanze, 2007;Nikolowska et al, 2008). Natural acoustic emissions (Leighton, 1994) from bubbles at depth can be also considered for monitoring inland structures with the hypothesis that they provide seismic signal that can be detected at the surface, as in the case of hot volcanoes.…”

Section: Albarello Et Al: Monitoring Methane Emission Of Mud Volcmentioning

confidence: 99%

Monitoring methane emission of mud volcanoes by seismic tremor measurements: a pilot study

Albarello

Palo

Martinelli

2012

Nat. Hazards Earth Syst. Sci.

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Abstract.A new approach for estimating methane emission at mud volcanoes is here proposed based on measurements of the seismic tremor on their surface. Data obtained at the Dashgil mud volcano in Azerbaijan reveal the presence of energy bursts characterized by well-determined features (i.e. waveforms, spectra and polarization properties) that can be associated with bubbling at depth. Counting such events provides a possible tool for monitoring gas production in the reservoir, thus minimizing logistic troubles and representing a cheap and effective alternative to more complex approaches. Specifically, we model the energy bursts as the effect of resonant gas bubbles at depth. This modelling allows to estimate the dimension of the bubbles and, consequently, the gas outflow from the main conduit in the assumption that all emissions from depth occur by bubble uprising. The application of this model to seismic events detected at the Dashgil mud volcano during three sessions of measurements carried out in 2006 and 2007 provides gas flux estimates that are in line with those provided by independent measurements at the same structure. This encouraging result suggests that the one here proposed could be considered a new promising, cheap and easy to apply tool for gas flux measurements in bubbling gas seepage areas.

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1300-m-high rising bubbles from mud volcanoes at 2080m in the Black Sea: Hydroacoustic characteristics and temporal variability

Cited by 226 publications

References 49 publications

First evidence of widespread active methane seepage in the Southern Ocean, off the sub-Antarctic island of South Georgia

First evidence of widespread active methane seepage in the Southern Ocean, off the sub-Antarctic island of South Georgia

Quantifying gas ebullition with echosounder: the role of methane transport by bubbles in a medium‐sized lake

Monitoring methane emission of mud volcanoes by seismic tremor measurements: a pilot study

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