The challenges of quantifying the carbon stored in Arctic marine gas hydrate
The challenges of quantifying the carbon stored in Arctic marine gas hydrate
The quantification of the carbon stored in gas hydrate (GH) bearing marine sediments still remains a challenge. Despite recent efforts to develop approaches to better estimate the GH inventory globally, these estimates are still highly unconstrained due to insufficient field data and poor understanding of the mechanisms fuelling the GH stability zone (GHSZ). Here we use geophysically-derived GH saturations to constraint estimates of model-derived Arctic marine GH inventory at present. We also estimate the potential carbon released from GH dissociation under a seabed warming of 2 °C over 100 yr. We estimate an inventory ranging between 0.28 and 541 Gt of carbon, which upper bound results in average GH saturations of 0.25%. Our upper bound is mainly controlled by our imposed upwards carbon-rich fluid flow of 0.01 cm yr?1 and it is five times greater than the most recent estimate that only considers in-situ degradation of particulate organic carbon (POC). To obtain the seismically-inferred GH saturations of 5–10% offshore west of Svalbard and in the Beaufort Sea, an upwards advection of carbon-rich fluids equivalent to 0.02–0.04 cm yr?1 is required. This mechanism may be the most important source of carbon reaching the GHSZ in Arctic marine sediments. A 2 °C seabed temperature increase over 100 yr may reduce the GH inventory by about 88.44% (0.7 Gt C) if POC is the only source, and by about 5.4% (29.7 Gt C) if the main source of carbon is the upwards advection of carbon-rich fluids.
Gas hydrate inventory, Uncertainty, Carbon-rich fluids, Ocean warming, Arctic
76-82
Marin-Moreno, Héctor
e466cafd-bd5c-47a1-8522-e6938e7086a4
Giustiniani, Michela
ec0161c0-0df5-4c3c-ab8b-38b7c5a3556e
Tinivella, Umberta
5e53ed76-7821-4ad9-9afb-96b4f728f787
Piñero, Elena
863b41f9-eae5-4a2d-a987-dd89dc24bb52
March 2016
Marin-Moreno, Héctor
e466cafd-bd5c-47a1-8522-e6938e7086a4
Giustiniani, Michela
ec0161c0-0df5-4c3c-ab8b-38b7c5a3556e
Tinivella, Umberta
5e53ed76-7821-4ad9-9afb-96b4f728f787
Piñero, Elena
863b41f9-eae5-4a2d-a987-dd89dc24bb52
Marin-Moreno, Héctor, Giustiniani, Michela, Tinivella, Umberta and Piñero, Elena
(2016)
The challenges of quantifying the carbon stored in Arctic marine gas hydrate.
Marine and Petroleum Geology, 71, .
(doi:10.1016/j.marpetgeo.2015.11.014).
Abstract
The quantification of the carbon stored in gas hydrate (GH) bearing marine sediments still remains a challenge. Despite recent efforts to develop approaches to better estimate the GH inventory globally, these estimates are still highly unconstrained due to insufficient field data and poor understanding of the mechanisms fuelling the GH stability zone (GHSZ). Here we use geophysically-derived GH saturations to constraint estimates of model-derived Arctic marine GH inventory at present. We also estimate the potential carbon released from GH dissociation under a seabed warming of 2 °C over 100 yr. We estimate an inventory ranging between 0.28 and 541 Gt of carbon, which upper bound results in average GH saturations of 0.25%. Our upper bound is mainly controlled by our imposed upwards carbon-rich fluid flow of 0.01 cm yr?1 and it is five times greater than the most recent estimate that only considers in-situ degradation of particulate organic carbon (POC). To obtain the seismically-inferred GH saturations of 5–10% offshore west of Svalbard and in the Beaufort Sea, an upwards advection of carbon-rich fluids equivalent to 0.02–0.04 cm yr?1 is required. This mechanism may be the most important source of carbon reaching the GHSZ in Arctic marine sediments. A 2 °C seabed temperature increase over 100 yr may reduce the GH inventory by about 88.44% (0.7 Gt C) if POC is the only source, and by about 5.4% (29.7 Gt C) if the main source of carbon is the upwards advection of carbon-rich fluids.
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Marin-Moreno_etal_2015.pdf
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Published date: March 2016
Keywords:
Gas hydrate inventory, Uncertainty, Carbon-rich fluids, Ocean warming, Arctic
Organisations:
Marine Geoscience
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Local EPrints ID: 387236
URI: http://eprints.soton.ac.uk/id/eprint/387236
ISSN: 0264-8172
PURE UUID: 272a56f4-c11d-4634-ac9f-5824981a4b25
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Date deposited: 11 Feb 2016 14:03
Last modified: 15 Mar 2024 05:24
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Contributors
Author:
Héctor Marin-Moreno
Author:
Michela Giustiniani
Author:
Umberta Tinivella
Author:
Elena Piñero
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