Scientific Implications and Preliminary Surveying Results of Geological and Physical Oceanography Environment in the Shenhu Area of the Northern South China Sea

A multi-disciplinary synthetic survey about marine geological, physical oceanography and biological environment was conducted in the Shenhu area bearing with the active gas hydrate in the northern South China Sea. Ten box corer and gravity-piston corer sites were located with the water depth of 1 000 to 4 000 m in the continental slope and deep basin area. It is the key area with the active oil and gas hydrate and is also the region of trial production of the gas hydrate in the northern South China Sea. The 10 sites coring designed by the cruise was conducted onboard with the surface box corer and gravity-piston corer sediment sampling. By deploying a "Haiyan" underwater glider, the underway measurement time-series profiles of the physical oceanography environment were obtained on the area of trial production of the gas hydrate in the Shenhu area. By using deployment and recovery of the two ocean bottom seismometers on two sites, time-series data of seafloor seismicity and microseisms and short duration events were obtained. Layering water sample from the CTD's bottles and sediment samples from the box corers and gravity-piston corers are conducted by the microbiological experiment testing. The preliminary results of the cruise indicate that the sediment type is mainly clay and soft mud in the surveying area. The temperature and salinity parameter variations of the whole seawater from the CTD measurements and from the underwater glider are clearly shown. The seismicity activity and micro tremor possibly related to the gas hydrate is observed by the ocean bottom seismometers. The microbiological experiment shows the characteristic of the bacterial community abundance in the sediment.