Methane efflux from marine sediments in passive and active margins: Estimations from bioenergetic reaction–transport simulations |
| |
| Authors: | AW Dale P Van Cappellen DR Aguilera P Regnier |
| |
| Institution: | 1. GEOMAR Helmholtz Centre for Ocean Research Kiel, Wischhofstrasse 1–3, 24148 Kiel, Germany;2. NIOZ Royal Netherlands Institute for Sea Research, P.O. Box 59, 1790 AB Den Burg, Texel, The Netherlands;1. MARUM Center for Marine Environmental Sciences, University of Bremen, 28359 Bremen, Germany;2. Department of Marine Sciences, University of Georgia, 30602 Athens, GA, USA;3. Department of Marine Sciences, University of North Carolina at Chapel Hill, Chapel Hill, 27599 NC, USA;1. CAS Key Laboratory of Ocean and Marginal Sea Geology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, China;2. Laboratory for Marine Geology, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266061, China;3. Department of Biology, Hong Kong Baptist University, Hong Kong, China;4. Shanghai Engineering Research Center of Hadal Science and Technology, College of Marine Sciences, Shanghai Ocean University, Shanghai 201306, China;5. Institute for Geology, Center for Earth System Research and Sustainability, Universität Hamburg, 20146 Hamburg, Germany;6. Key Laboratory of Gas Hydrate, Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences, Guangzhou 510640, China;7. Japan Agency for Marine-Earth Science & Technology (JAMSTEC), 2-15 Natsushima-cho, Yokosuka, Kanagawa 237-0061, Japan;8. Key Laboratory of Gas Hydrate, Ministry of Land and Resources, Qingdao Institute of Marine Geology, Qingdao 266071, China;1. Deep Sea Science Division, Institute of Deep Sea Science and Engineering, Chinese Academy of Sciences, Sanya 572000, China;2. University of Chinese Academy of Sciences, Beijing 100049, China;3. Qingdao Institute of Marine Geology, Ministry of Land and Resources, Qingdao 266071, China;4. Key Laboratory of Earth and Planetary Physics, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China;5. Shanghai Institute of Applied Physics, Shanghai Synchrotron Radiation Facility, Chinese Academy of Sciences, Shanghai 219250, China;1. Center for Geomicrobiology, Department of Biological Sciences, Aarhus University, Ny Munkegade, Bld. 1535, 8000 Aarhus C, Denmark;2. Department of Earth Sciences, University of Cambridge, Cambridge CB2 3EQ, UK;3. The Interuniversity Institute for Marine Sciences of Eilat, PO Box 469, Eilat 88103, Israel;4. Department of Geological and Environmental Sciences, Ben-Gurion University of the Negev, P. O. Box 653, Beer-Sheva 84105, Israel;1. GEOMAR Helmholtz Centre for Ocean Research Kiel, Department of Marine Biogeochemistry, Wischhofstr. 1-3, 24148 Kiel, Germany;2. US Naval Research Laboratory, Marine Biogeochemistry Section, 4555 Overlook Ave. SW, Washington, DC 20375, USA |
| |
| Abstract: | A simplified version of a kinetic–bioenergetic reaction model for anaerobic oxidation of methane (AOM) in marine sediments Dale, A.W., Regnier, P., Van Cappellen, P., 2006. Bioenergetic controls on anaerobic oxidation of methane (AOM) in coastal marine sediments: a theoretical analysis. Am. J. Sci. 306, 246–294.] is used to assess the impact of transport processes on biomass distributions, AOM rates and methane release fluxes from the sea floor. The model explicitly represents the functional microbial groups and the kinetic and bioenergetic limitations of the microbial metabolic pathways involved in AOM. Model simulations illustrate the dominant control exerted by the transport regime on the activity and abundance of AOM communities. Upward fluid flow at active seep systems restricts AOM to a narrow subsurface reaction zone and sustains high rates of methane oxidation. In contrast, pore-water transport dominated by molecular diffusion leads to deeper and broader zones of AOM, characterized by much lower rates and biomasses. Under steady-state conditions, less than 1% of the upward dissolved methane flux reaches the water column, irrespective of the transport regime. However, a sudden increase in the advective flux of dissolved methane, for example as a result of the destabilization of methane hydrates, causes a transient efflux of methane from the sediment. The benthic efflux of dissolved methane is due to the slow growth kinetics of the AOM community and lasts on the order of 60 years. This time window is likely too short to allow for a significant escape of pore-water methane following a large scale gas hydrate dissolution event such as the one that may have accompanied the Paleocene/Eocene Thermal Maximum (PETM). |
| |
| Keywords: | |
| 本文献已被 ScienceDirect 等数据库收录！ |
|
