Gashydrate in europäischen Meeresgebieten Größte Vorkommen im Schwarzen Meer und im europäischen Nordmeer 22.11.2019/Kiel. Erdgas, gespeichert in sogenannten Gashydraten, findet man weltweit an vielen Kontinentalrändern. Im Rahmen des von der Europäischen Kommission geförderten Projektes MIGRATE (Marine Gas Hydrates: An Indigenous Resource of Natural Gas for Europe) wurde nun erstmalig eine Bestandsaufnahme der Vorkommen in europäischen Meeresgebieten zusammengetragen. Teilergebnisse des vom GEOMAR Helmholtz-Zentrum für Ozeanforschung Kiel koordinierten Projektes wurden jetzt in der internationalen Fachzeitschrift Marine and Petroleum Geology veröffentlicht.

Abstract. Methane release from beneath lowland permafrost represents an important uncertainty in the Arctic greenhouse gas budget. Our current knowledge is arguably best developed in settings where permafrost is being inundated by rising sea level, which means much of the methane is oxidised in the water column before it reaches the atmosphere. Here we provide a different process perspective that is appropriate for Arctic fjord valleys where local deglaciation causes isostatic uplift to out pace rising sea level. We describe how the uplift induces permafrost aggradation in former marine sediments, whose pressurisation results in methane escape directly to the atmosphere via groundwater springs. In Adventdalen, central Spitsbergen, we show how the springs are historic features responsible for the formation of open-system pingos and capable of discharging brackish waters enriched with high concentrations of mostly biogenic methane (average 18 mg L−1). Thermodynamic calculations show that the methane concentrations sometimes marginally exceed the solubility limit for methane in water at 0 ∘C (41 mg L−1). Year-round emissions from the pingos are described. During winter, rapid methane loss to the atmosphere occurs following outburst events from beneath an ice blister. During summer, highly variable emissions occur due to complex surface processes at the seepage point and its inundation by surface runoff. In spite of this complexity, our observations confirm that sub-permafrost methane migration deserves more attention for the improved forecasting of Arctic greenhouse gas emissions.

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Histone N-lysine methylation is a widespread posttranslational modification that is specifically recognised by a diverse class of N-methyllysine binding reader proteins. Combined thermodynamic data, molecular dynamics simulations, and quantum chemical studies reveal that reader proteins efficiently bind trimethylornithine and trimethylhomolysine, the simplest N-trimethyllysine analogues that differ in the length of the side chain.

Abstract. Methane release from beneath lowland permafrost represents an important uncertainty in the Arctic greenhouse gas budget. Our current knowledge is arguably best-developed in settings where permafrost is being inundated by rising sea level, which means much of the methane is oxidised in the water column before it reaches the atmosphere. Here we provide a different process perspective that is appropriate for Arctic fjord valleys, where local deglaciation causes isostatic uplift to out-pace rising sea level. We show how the uplift induces permafrost aggradation in former marine sediments, whose pressurisation results in methane escape directly to the atmosphere via ground water springs. In Adventdalen, Central Spitsbergen, we show how the springs are historic features, responsible for the formation of open system pingos, and capable of discharging brackish waters enriched with high concentrations of mostly biogenic methane (average 18 mg L−1). Thermodynamic calculations show that the methane concentrations sometimes marginally exceed the solubility limit for methane in water at 0 °C (41 mg L−1). In our case study, emissions from just four pingo springs with a combined discharge of less than 2 L s−1 increase the land-atmosphere methane flux by 16 %. This confirms that sub-permafrost methane migration deserves more attention for improved forecasting of Arctic greenhouse gas emissions.