Phytoplankton abundance was found to be positively correlated with seasonal changes of seawater temperature in Port Shelter and Lamma Channel, Hong Kong in 1998. Rising water temperature from around 20℃ to 25℃ coinc...Phytoplankton abundance was found to be positively correlated with seasonal changes of seawater temperature in Port Shelter and Lamma Channel, Hong Kong in 1998. Rising water temperature from around 20℃ to 25℃ coincided with an increase in phytoplankton abundance at both locations. Heavy rains from June to September reduced salinity from 30 to 20, but the decrease in salinity was not correlated with a decline in phytoplankton abundance. In spring 1998, over 0.6×10^6 cells dm^-3 and 0.1× 10^6 cells dm^-3 of the dinoflagellate, Gymnodinium mikimotoi Miyake et Kominami ex Oda occurred in the coastal waters of Port Shelter and Lamina Channel, respectively. High abundance of the dinoflagellate Ceratium furca （Ehr.） Claparede et Lachmann （〉1×10^6 cells dm^-3） produced long-lasting blooms in the waters of Port Shelter from September to October in 1998. The abundances of both diatoms and dinoflagellates were significantly lower in the waters of Lamina Channel than those in Port Shelter due to the less frequent blooms in 1998. Hydrographic conditions such as stable water masses and water column stratification were the main reasons for the differences in the algal abundance and bloom frequency found between the two locations since neither of the two areas appeared to be nutrient-limited. This type water condition for the formation of algal bloom in Port Shelter has not been reported previously and it is not a general case for many bays along China＇s coast where algal bloom occurs as well.展开更多
基金Supported by the Project for Coastal Sea Investigation and Assessment in China (No. 908-02-03-09, 908-01-ST06and FJ908-01-01-HS)the Natural Science Foundation of China (No.10705019)
文摘Phytoplankton abundance was found to be positively correlated with seasonal changes of seawater temperature in Port Shelter and Lamma Channel, Hong Kong in 1998. Rising water temperature from around 20℃ to 25℃ coincided with an increase in phytoplankton abundance at both locations. Heavy rains from June to September reduced salinity from 30 to 20, but the decrease in salinity was not correlated with a decline in phytoplankton abundance. In spring 1998, over 0.6×10^6 cells dm^-3 and 0.1× 10^6 cells dm^-3 of the dinoflagellate, Gymnodinium mikimotoi Miyake et Kominami ex Oda occurred in the coastal waters of Port Shelter and Lamina Channel, respectively. High abundance of the dinoflagellate Ceratium furca （Ehr.） Claparede et Lachmann （〉1×10^6 cells dm^-3） produced long-lasting blooms in the waters of Port Shelter from September to October in 1998. The abundances of both diatoms and dinoflagellates were significantly lower in the waters of Lamina Channel than those in Port Shelter due to the less frequent blooms in 1998. Hydrographic conditions such as stable water masses and water column stratification were the main reasons for the differences in the algal abundance and bloom frequency found between the two locations since neither of the two areas appeared to be nutrient-limited. This type water condition for the formation of algal bloom in Port Shelter has not been reported previously and it is not a general case for many bays along China＇s coast where algal bloom occurs as well.
