DISTRIBUTION OF BENTHIC FORAMINIFERA IN SURFACE SEDIMENTS IN THE JUNCTION OF BOHAI SEA AND YELLOW SEA AND ENVIRONMENTAL CONSTRAINTS

144 surficial samples acquired from the northwestern Yellow Sea and the eastern Bohai Sea in 2008 and 2009 were selected to study the distribution pattern of benthic foraminifera and its relationships with modern marine environment. The benthic foraminiferal fauna are mainly composed of the species with high tolerances to low temperature and low salinity. Moreover, 78 species/genera with relatively higher abundance were chosen to carry out a Q-mode factor analysis, and 5 varimax factors corresponding to 5 foraminiferal assemblages were obtained. Correlations between the assemblages and environmental parameters suggest that:1. Protelphidium turberculatum (d'Orbigny) assemblage be constrained by the water temperature and the grain size of sediment; 2. Buccella frigida (Cushman)-Buccella tunicata (Ho,Hu et Wang)-Elphidium advenum (Cushman) assemblage be constrained by the cold water masses; 3.Cribrononion subincertum (Asano)-Cribrononion porisuturalis (Zheng) -Elphidium advenum (Cushman) assemblage be constrained by water depth and salinity; 4. Eggerella advena (Cushman)-Proteonina atlantica (Cushman)-Haplophragmoides canariensis (d'Orbigny) assemblage be constrained by the grain size of sediment; 5. Elphidium advenum (Cushman)-Ammonia becarii (Linné) -Ammonia compressiuscula (Brady) assemblage be constrained by temperature, salinity and grain size of sediment. In general, water depth shows no distinct influence on the distribution pattern of foraminifera. However, the topography of the sea floor has great influences on the distribution of benthic foraminifera.