A review of oceanographic applications of water column data from multibeam echosounders

Colbo, Keir; Ross, Tetjana; Brown, Craig J.; Weber, Thomas C.

doi:10.1016/j.ecss.2014.04.002

Cited by 129 publications

(94 citation statements)

References 103 publications

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“…Undirected hydrostatic pressures decrease during bubble ascent resulting in gas exsolution and bubble expansion and fragmentation, which in turn results in increased buoyancy, possible expansion of the bubble plume, and changes in the interfacial tension of hydrate-shelled bubbles. Vortex tube generation could explain the consistent relatively slender morphologies associated with plumes seen in multibeam data (Solomon et al, 2009;Colbo et al, 2014;Skarke et al, 2014;Smith et al, 2014;Tudino et al, 2014;Weber et al, 2014;Garcia-Pineda et al, 2015;Wilson et al, 2015) and recent observations indicate that vertical rise of buoyant plumes may be augmented by spiral flow geometries (von Deimling et al, 2015). Because the reflection and scattering from a bubble plume is a bulk effect, rotation has not been observed in seismic reflection data.…”

Section: Axialized Plumes In Vortex Tubesmentioning

confidence: 94%

Submarine vortices derived from natural gas hydrate conversion: a mechanism for ocean mixing

Barnard

Max

Gualdesi³

2017

Medit. Mar. Sci.

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We propose that the source water for some abyssal undular vortices cored by cool, low-salinity water identified at depths in excess of 2,500 m in the deepwater region of the Eastern Mediterranean Basin may be related to conversion of natural gas hydrate (NGH) in abyssal marine sediments. The conditions for extensive formation of NGH in the gas hydrate stability zones (GHSZ) of the upper seafloor sediments existed in this region during previous glacial episodes when colder water supported a thicker GHSZ. Seafloor warming during the most recent interglacial caused thinning of the GHSZ at its base and has driven endothermic NGH dissociation that would have released large volumes of low-salinity water and gas that would tend to pond below the base GHSZ. Periodically, trapped low-salinity water and gas would be released into the sea through the overlying sediments. Buoyant low-salinity water masses, supersaturated with gas and locally containing free gas would ascend and introduce a dynamic element into an otherwise generally static environment. As a result of the interaction of the rise of this buoyant plume and Coriolis acceleration the ascending mass would begin to rotate and form a vortex tube in midwater. NGH conversion within the seafloor introduces large coherent masses of low-salinity, lower-temperature water containing a buoyant free gas fraction from near-surface reservoirs into the abyssal depths even where there may only be a weak natural gas petroleum system.

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Section: Axialized Plumes In Vortex Tubesmentioning

confidence: 94%

Submarine vortices derived from natural gas hydrate conversion: a mechanism for ocean mixing

Barnard

Max

Gualdesi³

2017

Medit. Mar. Sci.

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“…For example, Aquadopp models (Nortek 1 ) working at 2000 kHz allow a maximum depth resolution of 6 km with an accuracy of 0.5 cm/s. Multibeam Echo Sounders (MBES), based on the emission of multiple ultrasonic frequencies, are commonly used for the characterization of the seabed (Lo Iacono et al, 2008;Lurton, 2010;Lecours et al 2016), the analysis of the water column-seabed interface, and the identification of gas plumes (Colbo et al, 2014;Innangi et al, 2016;Zhao et al 2017). When the MBES are combined with navigation data of a moving platform (see next section), a complete characterization of Enceladus' rocky nucleus surface could be obtained (e.g., Wynn et al, 2014).…”

Section: Sonarsmentioning

confidence: 99%

Exo-Ocean Exploration with Deep-Sea Sensor and Platform Technologies

et al. 2020

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“…Near vertical acoustic anomalies in the water column, associated with gas rising from the seafloor, termed acoustic ЉflaresЉ, are commonly identified in images of processed sonar data (Colbo et al 2014, and references therein). Integration of bathymetry, backscatter, and water column acoustic data by modern multibeam processing software, essential for holistic interpretation, gives geologic context to water column flares.…”

Section: Multibeam Echo Soundingsmentioning

confidence: 99%

A New Look at Seafloor Venting: Natural Gas Hydrate Derivatives

Barnard

Sager

Snow

et al. 2016

Day 3 Wed, May 04, 2016

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Natural leaks of multiphase hydrocarbons from the seafloor are widespread. Characterizing the temporal and spatial variability of these emissions provides baselines for comparison to the magnitude of anthropogenic leaks. Determining leakage rates will be important to our understanding the sustainable implementation of subsea infrastructure and the relative contribution of natural sources to global budgets. Multibeam echo soundings from cruise AT21-02 were used to define a region with several~600 to 900 m tall gas plumes in the water column directly above cratered hummocky regions of the sea floor with high backscatter in water depths of~1500 m over the Barbados Accretionary Complex. The relationship of seafloor morphologic features such as faults, craters, and mud volcanoes with vent-gas plumes in the water column is indicative of substantial emissions from this region. Disappearance of the acoustic plumes at~600 m is coincident with the top of CH 4 gas hydrate stability in the water column. In the plumes, natural gas hydrate shells that form at the gas-water interface and armor the gas from dissolution during ascent likely encapsulate bubbles. Ascent-driven pressure change in the bubbles causes shattering of shells forming gas hydrate shards that rise with the ascending plume and add to its acoustic reflection strength. The multiphase fluid consisting of gas, shelled bubbles, shards, and water changes character at the top of gas hydrate stability where the hydrate dissociates and dissolves. Differentiating sources and further characterizing emissions will provide baselines and also contribute to understanding the relative importance of the different emissions sources.

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A review of oceanographic applications of water column data from multibeam echosounders

Cited by 129 publications

References 103 publications

Submarine vortices derived from natural gas hydrate conversion: a mechanism for ocean mixing

Submarine vortices derived from natural gas hydrate conversion: a mechanism for ocean mixing

Exo-Ocean Exploration with Deep-Sea Sensor and Platform Technologies

A New Look at Seafloor Venting: Natural Gas Hydrate Derivatives

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