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Circulation, biogeochemistry and carbon cycling in ocean margins
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Phytoplankton community response to coastal upwelling events during the different stages in the northeastern South China Sea
P-M1-23-S
Yanping Zhong* , College of Environment and Ecology, Xiamen University
Xin Liu, College of Environment and Ecology, Xiamen University
Jun Hu, College of Environment and Ecology, Xiamen University
Bangqin Huang, College of Environment and Ecology, Xiamen University
Presenter Email: zhongyanping@stu.xmu.edu.cn |
| Coastal upwelling plays an important role in marine ecosystemthe primary production with nutrient-rich water. However, ecological responses associated with short-term pulsed upwelling events have not been well investigated in the field study especially in the complicate shelf ofex marginal sea. Ecological responses to periodic upwelling events, especially the changes of phytoplankton community structure, were investigated based on the combination of field surveys (mapping investigations and time-series observations) and satellite data during August 2004 and July 2005 in the northeastern South China Sea (NESCS). The upwelling event had a dramatic influence not only on the distribution patterns of temperature, salinity, and nutrients, but also on the plankton community. According to surface temperature, salinity, nitrate concentrations and chlorophyll-a (Chl-a) concentrations, three stages of upwelling (newly upwelled water, matured water and aged water) in the NESCS were defined. In the initial of upwelling phytoplankton growth rate reached a maximum for high nutrient concentrations and diatoms dominated the phytoplankton community in the first two stage, accounted for above 69% of the total Chl-a concentrations. In the third stage the contribution of Synechococcus increased and accounted for 37% of the total Chl-a concentrations as the increase of temperature and decrease of nutrient concentrations. Meanwhile the changes of mircozooplankton community and graze are also the important factors that induce the succession of phytoplankton species during the relaxation of upwelling. In the first stage of upwelling shellless ciliates and tintinnids dominates mircozooplankton communities together and then the biomass of shellless ciliates and heterotrophic flagellate increased in other two stages. Overall, our study revealed the dynamics of phyto plankton structurcommunitye during the difference stages of upwelling events and provide more insights into multiple driving factors such as temperature, nutrients, and microzooplankton graze. |
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