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Information - BG3.7 Methane fluxes in the sea: Approaches to observing, mapping and quantifying gas fluxes and associated processes
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Event Information |
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Methane plays an important role in atmospheric chemistry and climate change, but many questions remain as to the formation, flux and degradation of methane on earth. With regard to atmospheric fluxes of methane, the ocean appears to contribute little. However, in the global budget, marine methane production rates and sinks are significant, but remain poorly quantified. This session will look at processes of methane formation, transport, storage and consumption, and will provide a platform to discuss current approaches to the quantification of methane fluxes and associated processes in the ocean.
A main source for the microbial production of methane is the deposition of organic material at continental margins and its burial below the sulfate zone. The continuous methane formation in shelf and margin sediments may lead to accumulations of free gas and gas hydrates. Other source processes include the subsurface thermogenic formation of methane from buried organic materials at high temperatures, the abiotic production of methane through serpentinization reactions, and unknown reactions causing methane anomalies in oxic surface waters. Related to methane accumulation and leakage, complex subsurface and surface seafloor structures form such as gas chimneys, pockmarks, mud volcanoes and carbonate cements. If methane reaches the surface seafloor, it becomes the basis of spectacular chemosynthetic ecosystems. Enigmatic methane-oxidizing aerobic and anaerobic microorganisms are responsible for methane consumption in the seafloor and hydrosphere, and are efficiently controlling methane emission. Unfortunately, still little is known on their diversity, function and distribution – which is also true for the methanogens responsible for methane formation in the ocean in the seabed and potentially also the water column. From biogeochemical research on methane fluxes in past and present times, new facts and hypotheses have emerged on drivers and controls of methane fluxes in the ocean. Furthermore, combinations of new high resolution and in situ methods from a variety of disciplines allow a better insight on the role of methane in shaping ocean habitats and ecosystems.
This session will highlight the most recent approaches to quantify methane fluxes in the seafloor, hydrosphere and to the atmosphere, and look at the importance of physical, geological, chemical and (micro)biological factors in regulating methane fluxes. We would like to bring together experts from geophysics, geology, oceanography, geochemistry, numerical modelling, microbiology and ecology to discuss current knowledge on the assessment, drivers and controls of methane fluxes and associated ecosystems. We welcome contributions from EU 5th and 6th FPs, especially the IP HERMES, ESF EUROCORES EuroMargins. INTERRIDGE and other programs on vents and seamounts, IODP, and other recent and current projects with relevance to methane fluxes.
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Preliminary List of Solicited Speakers |
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Back to Session Programme
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