Krämer, Knut; Herbst, Gabriel; Winter, Christian (2017): Hydroacoustic data showing the emergence of a methane-related pockmark field in the Helgoland Reef area in the German Bight. PANGAEA, https://doi.org/10.1594/PANGAEA.883200, Supplement to: Krämer, Knut; Holler, Peter; Herbst, Gabriel; Bratek, Alexander; Ahmerkamp, Soeren; Neumann, Andreas; Bartholomä, Alexander; van Beusekom, Justus; Holtappels, Moritz; Winter, Christian (2017): Abrupt emergence of a large pockmark field in the German Bight, southeastern North Sea. Scientific Reports, 7(1), https://doi.org/10.1038/s41598-017-05536-1
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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.
Median Latitude: 53.557349 * Median Longitude: 8.559346 * South-bound Latitude: 53.523100 * West-bound Longitude: 8.548130 * North-bound Latitude: 53.567500 * East-bound Longitude: 8.580400
Date/Time Start: 2014-03-11T00:10:00 * Date/Time End: 2016-09-21T23:59:00
Datasets listed in this publication series
- Krämer, K; Herbst, G; Winter, C (2017): Gridded bathymetry data obtained by multibeam echosounder during HEINCKE cruises HE417, HE432, HE441, HE447, HE470 and HE471 between March 2014 and September 2016. https://doi.org/10.1594/PANGAEA.883197
- Krämer, K; Herbst, G; Winter, C (2017): Sub-bottom profiler transect across the pockmark field.during HEINCKE cruise HE471. https://doi.org/10.1594/PANGAEA.883199