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Song X.,CAS South China Sea Institute of Oceanography | Song X.,State Key Laboratory of Oceanography in the Tropics | Lai Z.,Sun Yat Sen University | Lai Z.,University of Massachusetts Dartmouth | And 10 more authors.
Continental Shelf Research | Year: 2012

The Northwest South China Sea (NWSCS) ecosystem is controlled by multiple physical processes in summer including the monsoon wind induced coastal upwelling, the cyclonic eddy off the eastern Leizhou Peninsular (ELP), and the Yuexi Coastal Current (YCC). Based on the high-resolution . in situ and remote sensing data, this study examined in details the spatial patterns of phytoplankton biomass and primary production in the coast of NWSCS in summer and discussed the underline physical processes involved. The results suggested that the southwesterly monsoon wind induced coastal upwelling is the major mechanism for the relatively high phytoplankton biomass and primary production found in the coastal area. However, the waters off the ELP have relatively higher phytoplankton biomass than that off the eastern Hainan Island (EHI). This is probably due to the topography- and eddy-driven enhancement of nutrient supply and light availability along the ELP. A small but distinguishably high biomass/productivity area was found at the east side of the Qiongzhou Strait. This eddy-shaped feature appears to be separated from the larger high productivity area near the Qiongzhou Strait, and is likely caused by the interaction of multiple dynamical processes including coastal upwelling, topographically-induced double eddy circulation, the YCC and associated large-scale cold eddy, and possibly the tidal mixing in this area. The YCC tends to inhibit phytoplankton growth and thus depresses the surface phytoplankton biomass in the near-shore waters of the ELP, mainly through the stratification-induced nutrient limitation (primarily phosphorous limitation). Overall, the interaction of physical processes between wind-induced upwelling, coastal current and tidal-shoaling mixing as well as eddy upwelling are key drivers regulating the horizontal and vertical distribution of phytoplankton biomass and productivity in the NWSCS. © 2012 Elsevier Ltd.

Song X.,CAS South China Sea Institute of Oceanography | Song X.,State Key Laboratory of Oceanography in the Tropics | Huang L.,CAS South China Sea Institute of Oceanography | Huang L.,State Key Laboratory of Oceanography in the Tropics | And 10 more authors.
Acta Oceanologica Sinica | Year: 2011

Chemometric approach based on principal component analysis (PCA) was utilized to examine the spatial variances of environmental and ecological characteristics in the Zhujiang River (Pearl River) Estuary and adjacent waters (ZREAW) in the South China Sea. The PCA result shows that the ZREAW can be divided into different zones according to the principal components and geographical locations of the study stations, and indicates that there are distinct regional variances on environmental features and the corresponding phytoplankton biomass and community structures among different areas. The spatial distribution of ecological features was implied to be influenced by various degrees of the different water resources, such as the Pearl River discharges, the coastal current and the oceanic water from the South China Sea. The variation of the biomass maximum zone and the complex impacts on the spatial distributions of phytoplankton biomass and production were also evaluated. © The Chinese Society of Oceanography and Springer-Verlag Berlin Heidelberg 2011.

Liu H.,CAS South China Sea Institute of Oceanology | Liu H.,Graduate University of China Academy of Science | Huang L.,CAS South China Sea Institute of Oceanology | Song X.,CAS South China Sea Institute of Oceanology | And 4 more authors.
Water and Environment Journal | Year: 2012

Seasonal measurements of phytoplankton biomass [chlorophyll a (chl a)], primary production (PP) and nutrient were conducted to understand the trophic status of Daya Bay in 2008-2009. Both nitrate and phosphate concentrations in winter were higher than those in summer. Maximum chl a and PP records appeared in the summer, when a harmful algae bloom (HAB) occurred in the north-western part of the bay. Microplankton dominated the phytoplankton community in nearshore waters, while pico- or nanophytoplankton was predominant in other area of the bay. High chl a and PP could often be found in the inner bay, such as the Dapeng'ao Cove and Aotou Cove. High PP values (>20mgC/m3/h) often appeared in waters with frequent outburst of HABs. The results suggested that PP was a suitable index of coastal eutrophication in Daya Bay. © 2011 The Authors. Water and Environment Journal © 2011 CIWEM.

Gao S.,Ocean University of China | Gao S.,State Oceanic Administration | Wang H.,State Oceanic Administration | Liu G.,State Oceanic Administration | And 4 more authors.
Acta Oceanologica Sinica | Year: 2012

The response of chlorophyll a (Chl a) concentration to wind stress is analyzed in the South China Sea (SCS), using in-situ data of Chl a and remote sensing data (QuikScat-sea surface wind (SSW), AVHRR-sea surface temperature (SST), AVISO merged-sea level anomalies (SLA), SeaWiFSderived Chl a and MODIS Terra-derived Chl a) in August/September/October 2004, 2006 and 2009. The variability of SSW, SST and SLA 7 d before in-situ Chl a sampling (including the work day of in-situ Chl a sampling) with the same latitude and longitude of the study area are investigated, and the correlation coefficients are calculated between these hydrographic factors and in-situ Chl a concentration. The results show that the Chl a-SSW correlation coefficients at upper layers (such as 0 m and 25 m) are more significant than those at deeper layers (such as 50, 75 and 100 m) 1-3 d before, which indicates that there is a time lag of strong surface winds stimulating phytoplankton bloom. By analyzing the relationship among the daily remote sensing derived (RSderived) SSW, SST, SLA and 3 d averaged SeaWiFS/MODIS-derived Chl a concentration in the northern SCS in September 2004 and 2009 respectively, it shows that the intensity and speed of surface winds could have great influence on extend of Chl a increase. If surface winds reach 4-5 m/s over, Chl a concentration would increase 1-3 d after the process of strong surface winds in open sea area of the northern SCS mainly during September. © The Chinese Society of Oceanography and Springer-verlag Berlin Heidelberg 2012.

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