Observations of Rising Methane Bubbles in Trondheimsfjord and Its Implications to Gas Dissolution

Olsen, Jan Erik; Krause, Daniel; Davies, Emlyn John; Skjetne, Paal

doi:10.1029/2018jc013978

Cited by 12 publications

(6 citation statements)

References 22 publications

(63 reference statements)

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“…Wüest et al. (1992) and others have extended the theory to rising bubbles to establish the commonly used expression for a bubble’s mass loss as a function of rise height, z (cm), as implemented by numerous studies (Leifer & Patro, 2002; McGinnis et al., 2006; Olsen et al., 2017, 2019; Rehder et al., 2009):

\frac{d M}{d z} = \frac{- (4 π r^{2}) \cdot K \cdot (C_{S} - C_{0})}{v} .

…”

Section: Discussionmentioning

confidence: 99%

Hydrate Formation on Marine Seep Bubbles and the Implications for Water Column Methane Dissolution

Waite

Ruppel

2021

JGR Oceans

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Methane released from seafloor seeps contributes to a number of benthic, water column, and atmospheric processes. At seafloor seeps within the methane hydrate stability zone, crystalline gas hydrate shells can form on methane bubbles while the bubbles are still in contact with the seafloor or as the bubbles begin ascending through the water column. These shells reduce methane dissolution rates, allowing hydrate‐coated bubbles to deliver methane to shallower depths in the water column than hydrate‐free bubbles. Here, we analyze seafloor videos from six deepwater seep sites associated with a diverse range of bubble‐release processes involving hydrate formation. Bubbles that grow rapidly are often hydrate‐free when released from the seafloor. As bubble growth slows and seafloor residence time increases, a hydrate coating can form on the bubble's gas‐water interface, fully coating most bubbles within ∼10 s of the onset of hydrate formation at the seafloor. This finding agrees with water‐column observations that most bubbles become hydrate‐coated after their initial ∼150 cm of rise, which takes about 10 s. Whether a bubble is coated or not at the seafloor affects how much methane a bubble contains and how quickly that methane dissolves during the bubble's rise through the water column. A simplified model shows that, after rising 150 cm above the seafloor, a bubble that grew a hydrate shell before releasing from the seafloor will have ∼5% more methane than a bubble of initial equal volume that did not grow a hydrate shell after it traveled to the same height.

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\frac{d M}{d z} = \frac{- (4 π r^{2}) \cdot K \cdot (C_{S} - C_{0})}{v} .

…”

Section: Discussionmentioning

confidence: 99%

Hydrate Formation on Marine Seep Bubbles and the Implications for Water Column Methane Dissolution

Waite

Ruppel

2021

JGR Oceans

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“…Observers included representatives of the oil companies involved, the Norwegian Pollution Control Authority, an ornithologist from the Norwegian Institute of Nature Research (NINA), and external observers. Recently, a series of field releases of natural gas took place in the Trondheim Fjord and on the Norwegian Shelf, (e.g., Olsen et al [222]). A key motivator for experimental oil releases is that Norway requires all oil spill response measures to be field-tested.…”

Section: More Data: Controlled Oil Release Experimentsmentioning

confidence: 99%

Progress in Operational Modeling in Support of Oil Spill Response

Barker

Kourafalou

Beegle-Krause

et al. 2020

JMSE

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Following the 2010 Deepwater Horizon accident of a massive blow-out in the Gulf of Mexico, scientists from government, industry, and academia collaborated to advance oil spill modeling and share best practices in model algorithms, parameterizations, and application protocols. This synergy was greatly enhanced by research funded under the Gulf of Mexico Research Initiative (GoMRI), a 10-year enterprise that allowed unprecedented collection of observations and data products, novel experiments, and international collaborations that focused on the Gulf of Mexico, but resulted in the generation of scientific findings and tools of broader value. Operational oil spill modeling greatly benefited from research during the GoMRI decade. This paper provides a comprehensive synthesis of the related scientific advances, remaining challenges, and future outlook. Two main modeling components are discussed: Ocean circulation and oil spill models, to provide details on all attributes that contribute to the success and limitations of the integrated oil spill forecasts. These forecasts are discussed in tandem with uncertainty factors and methods to mitigate them. The paper focuses on operational aspects of oil spill modeling and forecasting, including examples of international operational center practices, observational needs, communication protocols, and promising new methodologies.

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“…The discovery of widespread and persistent methane emissions at shallow water depths along the edge of the Aquitaine Shelf (140-220 m water depth) also questions the fate of methane in the water through dissolution (Olsen et al, 2019), aerobic oxidation via microbial processes (Kelley, 2003), and transfer to the atmosphere (Römer et al, 2017) with potential contribution to the global atmospheric methane budget.…”

Section: Discussionmentioning

confidence: 99%

The Aquitaine Shelf Edge (Bay of Biscay): A Primary Outlet for Microbial Methane Release

Dupré

Loubrieu

Cartigny

et al. 2020

Geophysical Research Letters

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A few thousand (2,612) seeps are releasing microbial methane bubbles from the seafloor at the Aquitaine Shelf edge (Bay of Biscay) at shallow water depths (140-220 m). This methane contributes to the formation of meter-scale subcircular carbonate structures, which are (sub)outcropping over 375 km 2 . Based on in situ flow rate measurements and acoustic data, and assuming steady and continuous fluxes over time, the methane entering the water column is estimated at 144 Mg/yr. Microbial methane circulation has been ongoing for at least a few thousand years. This discovery highlights the importance of microbial methane generation, disconnected from deep thermogenic sources and gas hydrates, at continental shelves. The shelf edge may be viewed as a focus area for methane circulation and release and related diagenesis, all having an impact on the shaping of continental shelves and potentially on the oceanic and atmospheric carbon budget. Plain Language Summary At the Aquitaine Shelf of the Bay of Biscay (Northeast AtlanticOcean), the recent acoustic, chemical, and visual investigations of microbial methane release at the seafloor have led to the discovery of a vast fluid system. This methane escapes as bubbles from the seafloor into the seawater at 2,612 sites, all located at shallow water depths (140-220 m) along the edge of the continental shelf. Methane-derived authigenic carbonates that are by-products of gas seepage cover the (sub) seafloor over a large area of 375 km 2 . These carbonates form subcircular meter-scale pavements and mounds, less than 2 m in height above the surrounding seafloor. Based on the growth rate of authigenic carbonates, it can be inferred that methane circulation has occurred for at least a few thousand years. The amount of methane released from the Aquitaine Shelf seafloor into the water column, estimated at 144 t/yr, questions the fate of the methane in the ocean and its possible passage to the atmosphere with therefore consequent potential contribution to the oceanic and atmospheric carbon budget over time.

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Observations of Rising Methane Bubbles in Trondheimsfjord and Its Implications to Gas Dissolution

Cited by 12 publications

References 22 publications

Hydrate Formation on Marine Seep Bubbles and the Implications for Water Column Methane Dissolution

Hydrate Formation on Marine Seep Bubbles and the Implications for Water Column Methane Dissolution

Progress in Operational Modeling in Support of Oil Spill Response

The Aquitaine Shelf Edge (Bay of Biscay): A Primary Outlet for Microbial Methane Release

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