湛江湾角毛藻群落的时空分布及其影响因素

Spatiotemporal distribution pattern of Chaetoceros community in Zhanjinag Bay and affecting factors

2009年2—11月以水采、网采和显微鉴定的方法分别对湛江湾的浮游植物进行了周年的季节调查,分析了湛江湾角毛藻(Chaetoceros)群落的时空分布和影响因素。结果表明:湛江湾角毛藻共有32种,其中有17种为赤潮种,优势种有旋链角毛藻(C.curvisetus)、假弯角毛藻(C.pseudocurvisetus)和牟氏角毛藻(C.muelleri)3种;种类丰富度和细胞丰度在季节分布上表现为春夏季高于秋冬季,而在空间分布上总体表现为湾口高,向内湾逐渐降低。相关分析表明:角毛藻细胞丰度与水温、盐度、pH、叶绿素a浓度及浮游植物细胞丰度呈极显著的正相关,与DIN、SiO32-呈极显著的负相关,与PO43-相关性不显著;角毛藻细胞丰度的季节变化主要取决于水温,由季节更替而产生的种间竞争和浮游动物的摄食压力也是重要的影响因素,而空间变化则受到光照、盐度、pH和高丰度养殖贝类滤食压力的影响。

By the methods of water sampling, net sampling, and microscope identification, a seasonal investigation was conducted on the phytoplankton community in Zhanjiang Bay of Cuangdong, China in February-November 2009, with the spatiotemporal distribution of Chatoceros community in the Bay and affecting factors analyzed. A total of 32 Chatoceros species were collected, including 17 red tide causative species. The dominant species in the Chatoceros community were C. curvisetus, C. pseudocurvisetus, and C. muelleri. Temporally, the species richness and cell abundance of Chaetoceros were characterized by a typical seasonal pattern, with the high- est in spring and summer and the lowest in autumn and winter. Spatially, the species richness and cell abundance decreased from outer bay to inner bay. The cell abundance of Chaetoceros was significantly positively con-elated with water temperature, salinity, pH, chlorophyll a, and cell abundance of pbytoplankton, and significantly negatively correlated with water DIN and silicate, but had no significant correlation with water phosphate. The seasonal variation of Chaetoceros cell abundance was mainly controlled by water temperature, and also, affected by the interspecific competition and the feeding pressure from zooplankton produced by seasonal ahernation; while the spatial distribution of Chaetoceros cell abundance was affected by illumination, water salinity, pH, and the feeding pressure from high-density cultured shellfish.