High performance liquid chromatography (HPLC) analysis of photosynthetic pigments in samples from Western Xiamen Bay and the Jiulong River Estuary showed that their major carotenoids were fucoxanthin, peridinin, zeaxa...High performance liquid chromatography (HPLC) analysis of photosynthetic pigments in samples from Western Xiamen Bay and the Jiulong River Estuary showed that their major carotenoids were fucoxanthin, peridinin, zeaxanthin, violaxanthin, and diadinoxanthin. Diatoms dominated in the spring bloom, dinoflagellates in summer. Violaxanthin and chlorophyll b indicated the appearance of chrysophytes and green algae, most of which were freshwater species. The high phytoplankton biomass region was located at the inner part of the bay. Diatoms and dinoflagellates dominated phytoplankton communities, contributing to over 50% of total biomass. All the main diagnostic carotenoids were significantly (P<0.01) correlated negatively to dissolved inorganic phosphorus, suggesting that they were limited by phosphorus. The high negative linear relationship (P<0.0001) between dissolved inorganic phosphorus and peridinin (dinoflagellates indicator) implied the potential of dissolved inorganic phosphorus for triggering red tide events in this region.展开更多
Observations indicate an abnormal characteristic of saltwater intrusion in the upper Modaomen Waterway of the Pearl River Estuary,i.e.,the maximum salinity occurs during the neap tide or the coming moderate tide inste...Observations indicate an abnormal characteristic of saltwater intrusion in the upper Modaomen Waterway of the Pearl River Estuary,i.e.,the maximum salinity occurs during the neap tide or the coming moderate tide instead of during the spring tide.To explore the associated dynamic mechanisms,a high resolution three-dimensional numerical model was set up based on the Finite Volume Coastal Ocean Model(FVCOM),which covered the entire river network,the Pearl River Estuary,and the adjacent sea.Numerical experiments illustrated that the upper Modaomen Waterway is significantly influenced by the saltwater intrusion from the Hongwan Waterway,a narrow and shallow channel connecting the Modaomen Waterway to the sea.Specific topography,spring-neap tidal variation,local wind stress,and their interaction drive an up-estuary residual current in the Hongwan Waterway,which is much stronger during the neap tide than during the spring tide.As a result,more saltwater in the Hongwan Waterway is spilled over into the Modaomen Waterway during the neap tide or the coming moderate tide.This is the inherent dynamic mechanism why the saltwater intrusion in the upper Modaomen Waterway reaches its maximum during the neap tide or the coming moderate tide.Besides,we also found that the winter prevailing wind can pronouncedly enhance the saltwater intrusion in the Modaomen Waterway.展开更多
文摘High performance liquid chromatography (HPLC) analysis of photosynthetic pigments in samples from Western Xiamen Bay and the Jiulong River Estuary showed that their major carotenoids were fucoxanthin, peridinin, zeaxanthin, violaxanthin, and diadinoxanthin. Diatoms dominated in the spring bloom, dinoflagellates in summer. Violaxanthin and chlorophyll b indicated the appearance of chrysophytes and green algae, most of which were freshwater species. The high phytoplankton biomass region was located at the inner part of the bay. Diatoms and dinoflagellates dominated phytoplankton communities, contributing to over 50% of total biomass. All the main diagnostic carotenoids were significantly (P<0.01) correlated negatively to dissolved inorganic phosphorus, suggesting that they were limited by phosphorus. The high negative linear relationship (P<0.0001) between dissolved inorganic phosphorus and peridinin (dinoflagellates indicator) implied the potential of dissolved inorganic phosphorus for triggering red tide events in this region.
基金supported by the "Creative Research Group" of National Natural Science Foundation of China (Grant No. 41021064)the National Basic Scientific Research Program of Global Change (Grant No.2010CB951201)Marine Special Program for Scientific Research on Public Causes (Grant No. 200705019)
文摘Observations indicate an abnormal characteristic of saltwater intrusion in the upper Modaomen Waterway of the Pearl River Estuary,i.e.,the maximum salinity occurs during the neap tide or the coming moderate tide instead of during the spring tide.To explore the associated dynamic mechanisms,a high resolution three-dimensional numerical model was set up based on the Finite Volume Coastal Ocean Model(FVCOM),which covered the entire river network,the Pearl River Estuary,and the adjacent sea.Numerical experiments illustrated that the upper Modaomen Waterway is significantly influenced by the saltwater intrusion from the Hongwan Waterway,a narrow and shallow channel connecting the Modaomen Waterway to the sea.Specific topography,spring-neap tidal variation,local wind stress,and their interaction drive an up-estuary residual current in the Hongwan Waterway,which is much stronger during the neap tide than during the spring tide.As a result,more saltwater in the Hongwan Waterway is spilled over into the Modaomen Waterway during the neap tide or the coming moderate tide.This is the inherent dynamic mechanism why the saltwater intrusion in the upper Modaomen Waterway reaches its maximum during the neap tide or the coming moderate tide.Besides,we also found that the winter prevailing wind can pronouncedly enhance the saltwater intrusion in the Modaomen Waterway.
