RV Sonne Cruise Report SO196: SUMSUN 2008, Suva – Guam – Okinawa Trough – Manila, February 19 - March 26, 2008

• Other Authors: Rehder, Gregor, Schneider von Deimling, Jens
• Format: Report
• Language: English
• Published: 2008
• Subjects: Ocean acidification
• Online Access: https://oceanrep.geomar.de/id/eprint/20848/; https://oceanrep.geomar.de/id/eprint/20848/1/SO196.pdf

1.1 SUMSUN Objective In the frame of the agreement of Kyoto and beyond, the directives of emission trading promoted by the EU, as well as the research of deposition/dumping of CO2 especially supported by the U.S.A and Japan, the discharge of CO2 into the ocean is considered as a possibility to reduce CO2 emission into the atmosphere. The injection of liquid CO2 in midwater or at the seafloor, which are the major scenarios discussed in the IPCC 2005 special report on CCS for marine carbon storage, became less likely due to the increasing awareness of ocean acidification. At the same time, it has been promoted that storage in deep marine sediments might be the safest option for carbon storage, as density gradients favour migration into the sediment and the potential to form CO2 hydrates acts as an additional barrier for re-entering of the CO2 into the ocean/atmosphere system. The expedition 196 of RV SONNE is the central field campaign of the Project SUMSUN (“StUdien zur Marinen CO2-Sequestrierung durch Untersuchung natürlicher hydrothermaler CO2-Austritte im Nördlichen Westpazifik”. The project aims to investigate some of the few known hydrothermal locations where liquid CO2 is stored in the upper sediment or is escaping from the seafloor in forms of droplets with CO2 as the main component. Though the geological and hydrothermal framework resulting in the separation of a CO2-dominated volatile phase is an interesting topic on its own, this is not in the main focus of the project. SUMSUN aims to investigate the interaction of liquid CO2 with the seafloor and the water column and potential impact on seafloor geochemistry and biology. The rationale is to characterize a natural analogue for proposed scenarios of CO2 deposition in the ocean. Three of the four locations known today where liquid CO2 generated by hydrothermal activity interacts with the seafloor and/or emanates into the water column, are located in the Okinawa Trough. The processes in the vicinity of CO2 injection in case of direct injection or leakage ...