| 171 water samples were collected from 56 stations in typical regions where Harmful Alage blooms frequently occurred in the East China Sea during April to May, 2004. Prorocentrum donghaiense cell density ranged from 2.5×103 to 6.0×l07cells·L-1 at surface water layer, with an average of 4.87×106cells·L-1. The highest P. donghaiense cell density was observed at the station rbl2A located at 122.94°E and 30°N. P.donghaiense cell density ranged from 1.0×103 to 5.32×106 cells·L-1 at middle water layer, with an average of 6.17×l05cells·L-1. The highest P. donghaiense cell density was found at the station rf40 located at 122.53°E and 29.3335°N. Alexandrium catenella cell density ranged from 1.0×103to 4.25 × 105cells ? L-1 at surface water layer, with average of 7.52 × 104cells·L-1. The highest A catenella cell density was found at the station rc20 located at 122.87°E and 29.46°N.Effects of initial cell density on growth of two causative HABs species,P. donghaiense and A. catenella, were invesgated in laboratory conditions. When cultured seperatly, the best initial cell density for P. donghaiense and A. catenella were 2.0×106 cells·L-1 and 0.4×106 cells·L-1, respectively. Different initial cell density and inoculation proportions had notable effects on the species interaction between the two species when co-cultures were carried on. The results showed that A. catenella would have more advantage in the co-cultures with the promoting of initial cell density and inoculation proportions. The effects of initial cell density and inoculation proportion on the species interaction between two causative species was a very important factor in HABs occurrence. Not only the consumption of nutrients but also the species interaction could notably affected the interspecific competition. Effect of P. donghaiense on inhibition of A. catenella was larger than the inhibitory effect of P. donghaiense exerted on A. catenella.
|
PDF Full Text Request