胶州湾表层沉积物中甲藻孢囊的分布

DISTRIBUTION OF DINOFLAGELLATE RESTING CYSTS IN SURFACE SEDIMENT OF JIAOZHOU BAY, CHINA

为了解胶州湾表层沉积物中甲藻孢囊的分布特征,于2015年7月采集胶州湾12个站位的表层沉积物进行甲藻孢囊分析,共鉴定甲藻孢囊37种(分属5个类群)和2种未定种,包括自养型20种和异养型17种,优势种为膝沟藻。其Shannon-Wiener多样性指数[H′(log2)]介于2.84—3.91,平均值为3.42;均匀度指数介于0.75—0.98,平均值为0.88,总体值较高。胶州湾海域各站位的甲藻孢囊丰度介于96—969cyst/g DW(干重),平均丰度为401cyst/g DW,呈现出临近湾口处丰度较高,而湾内较低的空间分布差异特征。尤其值得注意的是,有两种产虾夷扇贝毒素(Yessotoxin,YTX)甲藻[具刺膝沟藻(Gonyaulax spinifera)和多边舌甲藻(Lingulodinium polyedrum)]的孢囊和3种产麻痹性贝类毒素(PSP)甲藻[塔玛/链状亚历山大藻(Alexandrium catenella/tamarense)、微小/相似亚历山大藻(A.minutum/affine)和链状裸甲藻(Gymnodinium catenatum)]的孢囊在胶州湾海域大多数站位均有分布,尽管其数量不高,但其广泛的分布范围仍需引起我们的重视。

Distribution of dinoflagellate resting cysts in surface sediment of Jiaozhou Bay was investigated in July, 2015. In total, about 37 species representing 5 groups and 2 uncertain taxa were identified from 12 sediment samples, including 20 autotrophic and 17 heterotrophic species. The dominant taxa were Gonyaulax spp. The cyst species diversity（Shannon-Wiener index） ranged from 2.84 to 3.91 at each station, in mean of 3.42 across the bay. In addition, Pielou＇s evenness index ranged from 0.75 to 0.98, and the average was 0.88, indicating a relatively stable phytoplankton community. However, cyst abundance showed a relative spatial variation from 96 to 969cyst/g DW, in average of 401cyst/g DW across the whole study area. It was generally high around the mouth of the bay and low in inner bay. Besides the dominant species Gonyaulax sp., the resting cysts of several toxic groups were also recognized, including G. spinifera and Lingulodinium polyedrum, Alexandrium catenella/tamarense, A. minutum/affine and Gymnodinium catenatum. Although in relative low abundance, these toxic species could be observed at most stations, indicating a wide distribution in Jiaozhou Bay.