2015—2016年长江口及其邻近海域甲藻群落与阿米巴藻感染的周年变化

THE 2015—2016 ANNUAL VARIATION OF DINOFLAGELLATE COMMUNITY AND AMOEBOPHRYA INFECTIONS IN THE CHANGJIANG(YANGTZE) RIVER ESTUARY AND ADJACENT WATERS

通过2015年2月—2016年1月间在长江口及其邻近海域开展的10个航次调查,研究了该海域浮游甲藻的群落特征和时空变化,分析了寄生性甲藻阿米巴藻宿主种类及其感染率的周年变化。研究结果表明:调查海域浮游甲藻群落结构相对稳定,共检出浮游甲藻类38种,膝沟藻目处于绝对优势,优势种全年既有交叉又有演替;各季节间浮游甲藻丰度差异不显著(P>0.05),但各月间浮游甲藻丰度差异显著(P<0.05);全年丰度在9.06×10~3—6.10×10~6cells/L之间,其中4月份甲藻丰度最高,2月的丰度最低,全年的平均丰度为6.62×10~5cells/L。调查海域阿米巴藻宿主甲藻种类繁多,14种浮游甲藻被寄生感染,感染率范围为0.006%—5.13%;该海域阿米巴藻宿主种类及感染率表现出明显的季节差异,夏、秋两季宿主种类较多,感染率也明显高于春、冬两季。

We conducted an annual survey on the dinoflagellate community and Amoebophrya infections in the Changjiang(Yangtze)River estuary and adjacent waters from February 2015 to January 2016.Results show that the planktonic dinoflagellate community structure was relatively stable,and totally 38 dinoflagellate taxa were identified.The dominant species were diversified and varied among seasons,of which Gonyaulacales ranked first in species richness.Dinoflagellate abundance showed no significant different among seasons but months(P<0.05).Dinoflagellate densities ranged from 9.06×103 to 6.10×106 cells/L,the highest in April and the lowest in February.The annual average abundance was 6.62×105 cells/L.In addition,14 free-living marine dinoflagellate species were found infected by the parasitic dinoflagellate Amoebophrya during the survey,the infection rates ranged from 0.006%to 5.13%.The host dinoflagellate species and the prevalence of Amoebophrya infection had an obvious seasonal variation,of which those of summer and fall were obviously higher than those in spring and winter.