湛江港湾潜在赤潮生物的时空分布及其影响因素

Spatiotemporal distribution and related affecting factors of red tide latent organisms in Zhanjiang Bay,Guangdong Province of South China

2009年2月(冬)、5月(春)、8月(夏)和11月(秋)分别对湛江港湾的浮游植物和环境因子进行了调查,并对该海域潜在赤潮生物的时空分布及其影响因素进行了分析。结果表明,湛江港湾海域潜在赤潮生物共有126种,其中硅藻门26属85种,占潜在赤潮生物种类数的67.5%,甲藻门14属36种,占潜在赤潮生物种类数的28.6%,蓝藻门1属2种,占潜在赤潮生物种类数的1.6%,金藻门2属2种,占潜在赤潮生物种类数的1.6%,针胞藻纲1属1种,占潜在赤潮生物种类数的0.8%。种类数以春季最多,达89种,秋季次之,为71种,夏季61种,冬季最少,仅有58种。细胞丰度在12.36×104～43.55×104cells·L-1,春季最高,夏季次之,冬季最低,从各主要优势种的细胞丰度和细胞大小判断,该海域潜在赤潮生物的丰度均未达到赤潮发生的阈值。4季均出现的种类共有31种,季节相似性指数在0.43～0.50。优势种共有19种,全为硅藻,没有观测到甲藻。优势度最大的种类主要有浮动弯角藻(Eucampia zoodiacus)、旋链角毛藻(Chaetoceros curvisetus)和中肋骨条藻(Skeletonema costatum),没有全年优势种。中肋骨条藻、旋链角毛藻和冰河拟星杆藻(Asteri-onellopsis glacialis)为3季优势种。分析表明,潜在赤潮生物细胞丰度与叶绿素a、水温、盐度和pH值存在着极显著的正相关,与DIN和SiO32-存在着极显著的负相关,与PO43-不存在显著相关关系。

An investigation was conducted on the phytoplankton community and environmental factors in the Zhanjiang Bay of Guangdong in February（winter）,May（spring）,August（summer）,and November（autumn） 2009 to analyze the spatiotemporal distribution and related affecting factors of red tide latent organisms in this sea area.A total of 126 red tide latent species were recorded,among which,85 species of 26 genera belonged to Bacillariophyta,accounting for 67.5% of all species,36 species of 14 genera were of Pyrrophyta,accounting for 28.6%,2 species of 1 genus were of Cyanophyta,accounting for 1.6%,2 species of 2 genera were of Chrysophyta,accounting for 1.6%,and 1 species of 1 genus was of Raphidophyceae,accounting for 0.8%.Eighty nine species occurred in spring,61 species in summer,71 species in autumn,and 58 species in winter.The average cell abundances of the red tide latent organisms ranged from 12.36×104 cells·L-1 to 43.55×104 cells·L-1,with the maximum in spring,the second in summer,and the minimum in winter.The abundances of the red tide latent species did not reach the threshold value of the outbreak of red tide,according to the cell abundances and cell sizes of the majority of the dominant species in this sea area.There were 31 red tide latent species which occurred in all seasons.The seasonal Jaccard similarity index ranged from 0.43 to 0.50,implying no obvious seasonal succession.A total of 19 dominant species were observed,all of which belonged to Bacillariophyta,and no Pyrrophyta.The species with maximum dominance were Eucampia zoodiacus,Chaetoceros curvisetus,and Skeletonema costatum.No dominant species occurred all year round.S.costatum,C.curvisetus,and Asterionellopsis glacialis were dominated in three seasons.The abundance of the red tide latent organisms were significantly positively correlated to the water body’s chlorophyll a,temperature,salinity,and pH,significantly negatively correlated to the DIN and silicate,but had no significant correlation to the phosphate content.