title: Enhanced methane emissions from oil and gas exploration areas to the atmosphere--the central Bohai Sea.
abstract: The distributions of dissolved methane in the central Bohai Sea were investigated in November 2011, May 2012, July 2012, and August 2012. Methane concentration in surface seawater, determined using an underway measurement system combined with wavelength-scanned cavity ring-down spectroscopy, showed marked spatiotemporal variations with saturation ratio from 107% to 1193%. The central Bohai Sea was thus a source of atmospheric methane during the survey periods. Several episodic oil and gas spill events increased surface methane concentration by up to 4.7 times and raised the local methane outgassing rate by up to 14.6 times. This study demonstrated a method to detect seafloor CH4 leakages at the sea surface, which may have applicability in many shallow sea areas with oil and gas exploration activities around the world.
authors.affiliation: Key Laboratory for Ecological Environment in Coastal Areas (State Oceanic Administration), National Marine Environmental Monitoring Center, Dalian 116023, China; Key Laboratory of Coastal Zone Environmental Processes and Ecological Remediation, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai 264003, China.
authors.forename: Yong
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Key Laboratory for Ecological Environment in Coastal Areas (State Oceanic Administration), National Marine Environmental Monitoring Center, Dalian 116023, China.
authors.forename: Hua-de
authors.initials: HD
authors.lastname: Zhao
authors.affiliation: Key Laboratory for Ecological Environment in Coastal Areas (State Oceanic Administration), National Marine Environmental Monitoring Center, Dalian 116023, China. Electronic address: wdzhai@126.com.
authors.forename: Wei-dong
authors.initials: WD
authors.lastname: Zhai
authors.affiliation: Key Laboratory for Ecological Environment in Coastal Areas (State Oceanic Administration), National Marine Environmental Monitoring Center, Dalian 116023, China.
authors.forename: Kun-peng
authors.initials: KP
authors.lastname: Zang
authors.affiliation: Key Laboratory for Ecological Environment in Coastal Areas (State Oceanic Administration), National Marine Environmental Monitoring Center, Dalian 116023, China.
authors.forename: Ju-ying
authors.initials: JY
authors.lastname: Wang
mesh_terms: D000393:Air Pollutants / Q000737:chemistry*; D001272:Atmosphere / Q000737:chemistry*; D019652:Extraction and Processing Industry; D008697:Methane / Q000737:chemistry*; D009792:Oceans and Seas; D012623:Seawater; D013995:Time
chemical_list: D000393:Air Pollutants; D008697:Methane
keywords: Bohai Sea; Methane; Oil spill; Sea–air flux; Underway measurement