Resumen
We present a comprehensive study showing new results from a shallow gas seep area in ∼40 m water depth located in the North Sea, Netherlands sector B13 that we call “Dutch Dogger Bank seep area.” It has been postulated that methane presumably originating from a gas reservoir in ∼600 m depth below the seafloor is naturally leaking to the seafloor. Our ship-based subbottom echosounder data indicate that the migrating gas is trapped in numerous gas pockets in the shallow sediments. The gas pockets are located at the boundary between the top of the Late Pliocene section and overlying fine-grained sediments, which were deposited during the early Holocene marine transgression after the last glaciation. We mapped gas emissions during three R/V Heincke cruises in 2014, 2015, and 2016 and repeatedly observed up to 850 flares in the study area. Most of them (∼80%) were concentrated at five flare clusters. Our repeated analysis revealed spatial similarities of seep clusters, but also heterogeneities in emission intensities. A first calculation of the methane released from these clusters into the water column revealed a flow rate of 277 L/min (SD = 140), with two clusters emitting 132 and 142 L/min representing the most significant seepage sites. Above these two flare clusters, elevated methane concentrations were recorded in atmospheric measurements. Our results illustrate the effective transport of methane via gas bubbles through a ∼40 m water column, and furthermore provide an estimate of the emission rate needed to allow for a contribution to the atmospheric methane concentration.
| Idioma original | English |
|---|---|
| Páginas (desde-hasta) | 2617-2633 |
| Número de páginas | 17 |
| Publicación | Geochemistry, Geophysics, Geosystems |
| Volumen | 18 |
| N.º | 7 |
| DOI | |
| Estado | Published - 1 ene 2017 |
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ASJC Scopus subject areas
- Geophysics
- Geochemistry and Petrology
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Assessing marine gas emission activity and contribution to the atmospheric methane inventory : A multidisciplinary approach from the Dutch Dogger Bank seep area (North Sea). / Römer, M.; Wenau, S.; Mau, S.; Veloso, M.; Greinert, J.; Schlüter, M.; Bohrmann, G.
En: Geochemistry, Geophysics, Geosystems, Vol. 18, N.º 7, 01.01.2017, p. 2617-2633.Resultado de la investigación: Article
TY - JOUR
T1 - Assessing marine gas emission activity and contribution to the atmospheric methane inventory
T2 - A multidisciplinary approach from the Dutch Dogger Bank seep area (North Sea)
AU - Römer, M.
AU - Wenau, S.
AU - Mau, S.
AU - Veloso, M.
AU - Greinert, J.
AU - Schlüter, M.
AU - Bohrmann, G.
PY - 2017/1/1
Y1 - 2017/1/1
N2 - We present a comprehensive study showing new results from a shallow gas seep area in ∼40 m water depth located in the North Sea, Netherlands sector B13 that we call “Dutch Dogger Bank seep area.” It has been postulated that methane presumably originating from a gas reservoir in ∼600 m depth below the seafloor is naturally leaking to the seafloor. Our ship-based subbottom echosounder data indicate that the migrating gas is trapped in numerous gas pockets in the shallow sediments. The gas pockets are located at the boundary between the top of the Late Pliocene section and overlying fine-grained sediments, which were deposited during the early Holocene marine transgression after the last glaciation. We mapped gas emissions during three R/V Heincke cruises in 2014, 2015, and 2016 and repeatedly observed up to 850 flares in the study area. Most of them (∼80%) were concentrated at five flare clusters. Our repeated analysis revealed spatial similarities of seep clusters, but also heterogeneities in emission intensities. A first calculation of the methane released from these clusters into the water column revealed a flow rate of 277 L/min (SD = 140), with two clusters emitting 132 and 142 L/min representing the most significant seepage sites. Above these two flare clusters, elevated methane concentrations were recorded in atmospheric measurements. Our results illustrate the effective transport of methane via gas bubbles through a ∼40 m water column, and furthermore provide an estimate of the emission rate needed to allow for a contribution to the atmospheric methane concentration.
AB - We present a comprehensive study showing new results from a shallow gas seep area in ∼40 m water depth located in the North Sea, Netherlands sector B13 that we call “Dutch Dogger Bank seep area.” It has been postulated that methane presumably originating from a gas reservoir in ∼600 m depth below the seafloor is naturally leaking to the seafloor. Our ship-based subbottom echosounder data indicate that the migrating gas is trapped in numerous gas pockets in the shallow sediments. The gas pockets are located at the boundary between the top of the Late Pliocene section and overlying fine-grained sediments, which were deposited during the early Holocene marine transgression after the last glaciation. We mapped gas emissions during three R/V Heincke cruises in 2014, 2015, and 2016 and repeatedly observed up to 850 flares in the study area. Most of them (∼80%) were concentrated at five flare clusters. Our repeated analysis revealed spatial similarities of seep clusters, but also heterogeneities in emission intensities. A first calculation of the methane released from these clusters into the water column revealed a flow rate of 277 L/min (SD = 140), with two clusters emitting 132 and 142 L/min representing the most significant seepage sites. Above these two flare clusters, elevated methane concentrations were recorded in atmospheric measurements. Our results illustrate the effective transport of methane via gas bubbles through a ∼40 m water column, and furthermore provide an estimate of the emission rate needed to allow for a contribution to the atmospheric methane concentration.
KW - atmospheric CH input
KW - Dogger Bank
KW - flare cluster
KW - methane bubble emission
KW - subseafloor gas accumulation
UR - http://www.scopus.com/inward/record.url?scp=85030232054&partnerID=8YFLogxK
U2 - 10.1002/2017GC006995
DO - 10.1002/2017GC006995
M3 - Article
AN - SCOPUS:85030232054
VL - 18
SP - 2617
EP - 2633
JO - Geochemistry, Geophysics, Geosystems
JF - Geochemistry, Geophysics, Geosystems
SN - 1525-2027
IS - 7
ER -