Distribution of Microbial Populations and Their Relationship with Environmental Variables in the North Yellow Sea,China

In order to understand the large-scale spatial distribution characteristics of picoplankton,nanophytoplankton and virio-plankton and their relationship with environmental variables in coastal and offshore waters,flow cytometry(FCM) was used to ana-lyze microbial abundance of samples collected in summer from four depths at 36 stations in the North Yellow Sea(NYS).The data revealed spatial heterogeneity in microbial populations in the offshore and near-shore waters of the NYS during the summer.For the surface layer,picoeukaryotes were abundant in the near-shore waters,Synechococcus was abundant in the offshore areas,and bacte-rial and viral abundances were high in the near-shore waters around the Liaodong peninsula.In the near-shore waters,no significant vertical variation of picophytoplankton(0.2-2μm) abundance was found.However,the nanophytoplankton abundance was higher in the upper layers(from the surface to 10 m depth) than in the bottom layer.For the offshore waters,both pico-and nanophytoplankton(2-20μm) abundance decreased sharply with depth in the North Yellow Sea Cold Water Mass(NYSCWM).But,for the vertical dis-tribution of virus and bacteria abundance,no significant variation was observed in both near-shore and offshore waters.Autotrophic microbes were more sensitive to environmental change than heterotrophic microbes and viruses.Viruses showed a positive correla-tion with bacterial abundance,suggesting that the bacteriophage might be prominent for virioplankton(about 0.45μm) in summer in the NYS and that viral abundance might play an important role in microbial loop functions.

Hydrocarbon Potential of Pre-cenozoic Strata in the North Yellow Sea Basin

The North Yellow Sea Basin ( NYSB ), which was developed on the basement of North China (Huabei) continental block, is a typical continental Mesozoic-Cenozoic sedimentary basin in the sea area. Its Mesozoic basin is a residual basin, below which there is probably a larger Paleozoic sedimentary basin. The North Yellow Sea Basin comprises four sags and three uplifts. Of them, the eastern sag is a Mesozoic-Cenozoic sedimentary sag in NYSB and has the biggest sediment thickness; the current Korean drilling wells are concentrated in the eastern sag. This sag is comparatively rich in oil and gas resources and thus has a relatively good petroleum prospect in the sea. The central sag has also accommodated thick Mesozoic-Cenozoic sediments. The latest research results show that there are three series of hydrocarbon source rocks in the North Yellow Sea Basin, namely, black shales of the Paleogene, Jurassic and Cretaceous. The principal hydrocarbon source rocks in NYSB are the Mesozoic black shale. According to the drilling data of Korea, the black shales of the Paleogene, Jurassic and Cretaceous have all come up to the standards of good and mature source rocks. The NYSB owns an intact system of oil generation, reservoir and capping rocks that can help hydrocarbon to form in the basin and thus it has the great potential of oil and gas. The vertical distribution of the hydrocarbon resources is mainly considered to be in the Cretaceous and then in the Jurassic.

Evolution of Surface Cold Patches in the North Yellow Sea Based on Satellite SST Data

Ten years （from 2005 to 2014） of satellite sea surface temperature （SST） data from the Advanced Very High Resolution Radiometer （AVHRR） are analyzed to reveal the monthly changes in surface cold patches （SCPs） in the main areas of the Northern Yellow Sea （NYS）. The Canny edge detection algorithm is used to identify the edges of the patches. The monthly changes are de- scribed in terms of location, temperature and area. The inter-annual variations, including changes in the location and area of the SCPs from 2010 to 2014, are briefly discussed. The formation mechanisms of the SCPs in different periods are systematically analyzed using both in situ data and numerical simulation. The results show that from May to October, the location and area of the SCPs re- main stable, with a north-south orientation. The SCPs altogether cover about I° of longitude （124°E-125°E） in width and 2° of lati- tude （37.5°N-39.5°N） in length. In November, the SCP separates from the Jangsan Cape and forms a closed, isolated, and approxi- mately circular cold patch in the central NYS. From May to October, the upweUing that leads to the formation of the SCP is mainly triggered by the headland residual current, wind field, climbing movement of the current and secondary circulation at the tide front. In November, cyclonic circulation in the NYS is primarily responsible for generating the upwelling that leads to the formation of the closed and isolated SCE

Weathered and Volcanic Provenance-Sedimentary System and Its Influence on Reservoir Quality in the East of the Eastern Depression, the North Yellow Sea Basin

Seismic stratigraphy, core logging and the data from cores are used to identify the development and evolution of the east provenance-sedimentary system and to analyze its influence on the quality of reservoirs in the eastern depression of the North Yellow Sea Basin. The eastern provenance-sedimentary system is a fan delta （delta） and subaqueous fan sedimentary system with volcanic provenance. Its evolution is closely related to internal uplift and coeval volcanic activity. During faulting and volcanic activity, an internal uplift gradually formed and the eastern provenance-sedimentary system began to develop. Clastic materials from the weathered uplift and volcanic activity were the main sources of sediment and were deposited in the Middle Jurassic to the Early Cretaceous. A subaqueous fan sedimentary system developed in the Middle Jurassic, a deltaic to subaqueous fan sedimentary system developed in the Late Jurassic, and a fan delta to subaqueous fan sedimentary system developed in the Early Cretaceous. The volcaniclastic detritus was mainly composed of acidic materials with a small amount of intermediate materials. The reservoir in the eastern sedimentary system is a type of tight sandstone with ultra-low porosity and very low permeability due to the influence of volcanism and diagenesis. The reservoir quality is worse than those of the northern and the western sedimentary systems. However, the high volume of volcanic materials and deep-marine sedimentary conditions resulted in good-quality hydrocarbon source rocks that ensures the exploration potential in the eastern sedimentary system reservoir.

Paleo-Fluvial Systems during Marine Isotope Stages 6, 4 and 2 in the North Yellow Sea

Objective During the sea-level lowstands of the Late Quatemary, paleo-channels resulting from large-scale glacial regressions were extensively developed on continental shelves worldwide. Great attention has been paid to the mechanisms and ages of these successions of fluvial incisions, which provide insight into the sedimentary evolution and processes of shelves.