KLSG,;
Second;
Institute;
of;
Oceanography;
of;
the;
State;
Oceanic;
Administration,;
Hangzhou;
310012,;
China;
KLSG,;
Second;
Institute;
of;
Oceanography;
of;
the;
State;
Oceanic;
Administration,;
Hangzhou;
310012,;
China;
Qingdao;
Institute;
of;
Marine;
Geology;
of;
China;
Geology;
Survey,;
Qingdao;
266071,;
China;
KLSG,;
Second;
Institute;
of;
Oceanography;
of;
the;
State;
Oceanic;
Administration,;
Hangzhou;
310012,;
China;
KLSG,;
Second;
Institute;
of;
Oceanography;
of;
the;
State;
Oceanic;
Administration,;
Hangzhou;
310012,;
China;
Petroleum;
and;
Marine;
Resources;
Research;
Division,;
Korea;
Institute;
of;
Geoscience;
and;
Mineral;
Resources,;
Daejon;
305-350,;
South;
Korea;
KLSG,;
Second;
Institute;
of;
Oceanography;
of;
the;
State;
Oceanic;
Administration,;
Hangzhou;
310012,;
China;
KLSG,;
Second;
Institute;
of;
Oceanography;
of;
the;
State;
Oceanic;
Administration,;
Hangzhou;
310012,;
China;
gas; hydrate,; carbon; isotopes,; nitrogen; isotopes,; C/N; ratio,; nitrogen; fixation.;