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| Main Authors: | , , |
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| Format: | Dataset Open Access |
| Language: | en |
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PANGAEA
2017
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| Online Access: | https://doi.org/10.1594/PANGAEA.883200 |
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| _version_ | 1867171371749998592 |
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| author | Krämer, Knut Herbst, Gabriel Winter, Christian |
| author_facet | Krämer, Knut Herbst, Gabriel Winter, Christian |
| collection | Datos científicos de ciencias marinas y ambientales |
| contents | A series of multibeam bathymetry surveys revealed the emergence of a large pockmark field in the southeastern North Sea. Covering an area of around 915 km^2, up to 1,200 pockmarks per square kilometer have been identified. The time of emergence can be confined to 3 months in autumn 2015, suggesting a very dynamic genesis. The gas source and the trigger for the simultaneous outbreak remain speculative. Subseafloor structures and high methane concentrations of up to 30 µmol/l in sediment pore water samples suggest a source of shallow biogenic methane from the decomposition of postglacial deposits in a paleo river valley. Storm waves are suggested as the final trigger for the eruption of the gas. Due to the shallow water depths and energetic conditions at the presumed time of eruption, a large fraction of the released gas must have been emitted to the atmosphere. Conservative estimates amount to 5 kt of methane, equivalent to 67% of the annual release from the entire North Sea. These observations most probably describe a reoccurring phenomenon in shallow shelf seas, which may have been overlooked before because of the transient nature of shallow water bedforms and technology limitations of high resolution bathymetric mapping. |
| format | Dataset Open Access |
| id | pangaea_https___doi_org_10_1594_PANGAEA_883200 |
| institution | PANGAEA |
| language | en |
| publishDate | 2017 |
| publisher | PANGAEA |
| record_format | pangaea |
| spellingShingle | Hydroacoustic data showing the emergence of a methane-related pockmark field in the Helgoland Reef area in the German Bight Krämer, Knut Herbst, Gabriel Winter, Christian Center for Marine Environmental Sciences; MARUM; NOAH; North Sea Observation and Assessment of Habitats A series of multibeam bathymetry surveys revealed the emergence of a large pockmark field in the southeastern North Sea. Covering an area of around 915 km^2, up to 1,200 pockmarks per square kilometer have been identified. The time of emergence can be confined to 3 months in autumn 2015, suggesting a very dynamic genesis. The gas source and the trigger for the simultaneous outbreak remain speculative. Subseafloor structures and high methane concentrations of up to 30 µmol/l in sediment pore water samples suggest a source of shallow biogenic methane from the decomposition of postglacial deposits in a paleo river valley. Storm waves are suggested as the final trigger for the eruption of the gas. Due to the shallow water depths and energetic conditions at the presumed time of eruption, a large fraction of the released gas must have been emitted to the atmosphere. Conservative estimates amount to 5 kt of methane, equivalent to 67% of the annual release from the entire North Sea. These observations most probably describe a reoccurring phenomenon in shallow shelf seas, which may have been overlooked before because of the transient nature of shallow water bedforms and technology limitations of high resolution bathymetric mapping. |
| title | Hydroacoustic data showing the emergence of a methane-related pockmark field in the Helgoland Reef area in the German Bight |
| topic | Center for Marine Environmental Sciences; MARUM; NOAH; North Sea Observation and Assessment of Habitats |
| url | https://doi.org/10.1594/PANGAEA.883200 |