DISTRIBUTION AND DIVERSITY OF DINOFLAGELLATE CYSTS IN SURFACE SEDIMENTS IN MEISHAN BAY,ZHEJIANG
Dinoflagellate cysts can serve as seed banks for algal blooms and be also used to indicate water eutrophication.Previous studies on the distribution of dinoflagellate cysts have predominantly focused on open waters and natural bays,with fewer investigations conducted in semi-enclosed artificial bays.Meishan Bay was once an open bay and accessible from the north and south,and underwent a transformation into a semi-enclosed artificial bay following the construction of dams from 2012 to 2017.In this study,six surface sediment samples were collected from the inner and outer waters of the bay.A total of 37 species of dinoflagellate cysts were identified in abundance ranging from 237 to 1 054 cysts/g.The average cyst abundance was higher in the inner water than in the outer water due to the decreases in suspended matter content,hydrodynamics,and sedimentation rate,and the increases in water transparency and the water eutrophication inside the bay.The Shannon-Wiener diversity index(H')ranged between 1.63～2.47,and Pielou's evenness index(J')ranged between 0.58～0.82.Both indices were significantly higher outside than inside of the bay,reflecting lower ecosystem stability and a higher possibility of red tides inside the bay.A total of 16 species capable of causing red tides and 8 toxic species of dinoflagellate cysts were identified in this study.Both the percentage of abundance and species number of toxic and red tide dinoflagellate cysts were higher inside the bay than outside.Dominant species included Protoperidinium sp.,Protoperidinium americanum,Diplopsalis lenticula,Alexandrium minutum,Gymnodinium catenatum,and Scrippsiella trochoidea.The construction of dams not only exacerbated the disparity in dinoflagellate cysts in surface sediments between inner and outer regions of the bay but also increased the risk of toxic and harmful red tides within the bay.Therefore,monitoring toxic and harmful dinoflagellate within the bay shall be strengthened in the future.
harmful algal bloomsthe effect of construction of damsemi-enclosed artificial baydinoflagellate cyst
万方数据
维普
