广东省水库拟柱孢藻(Cylindrospermopsis raciborskii)的分布特征及影响因子分析

Distribution and Factors Affecting Cylindrospermopsis raciborskii in Guangdong Reservoirs

拟柱孢藻(Cylindrospermopsis raciborskii)是热带亚热带地区的特征性蓝藻,具潜在的产毒能力,近年来因其向全球温带地区扩展而备受关注.本研究以广东省20座不同营养类型水库的历史数据(2010年的春季、夏季和冬季)为基础,重点考察拟柱孢藻在广东省水库的发生和分布状况.调查期间共发现19座水库存在拟柱孢藻,其种群生物量在0. 000 1~39. 740mg·L^(-1)之间,占浮游植物的0. 02%~97. 07%.拟柱孢藻具明显的空间及季节分布特征,粤西地区的出现率(77. 78%)高于珠江三角洲地区(66. 67%)和粤北地区(33. 33%),冬季的检出率(85%)高于夏季(70%)和春季(40%),分析表明水温是决定拟柱孢藻空间及季节变化的关键因素.拟柱孢藻在不同营养状态的水库之间出现率差异明显,富营养型水库的检出率(81. 48%)显著高于中富营养型水库(66. 67%)和贫中营养型水库(33. 33%),冗余分析(RDA)结果表明拟柱孢藻生物量与总氮(TN)、营养状态指数(TSI)呈正相关,与可溶性无机氮(DIN)、可溶性活性磷(SRP)及透明度(SD)呈负相关,推测高氮、低磷、低透明度的环境条件有利于拟柱孢藻形成优势.

Cylindrospermopsis raciborskii originating from tropical and subtropical regions is potentially toxic and attracts much attention due to its extension to the global temperate zone in recent years. Based on historical data of 20 reservoirs with different trophic levels （dry season, wet season, and transitional season of 2010） , this study focuses on the analysis of the occurrence and distribution of C. raciborskii in the Guangdong Province. Based on the results, C. raciborskii was found in 19 of the 20 reservoirs and its biomass ranges from 0.000 1-39.740 mg·L^-l and accounts for 0.02%-97.07% of the total phytoplankton biomass. Both a notable spatial and seasonal distribution of C. raciborskii were observed. Its occurrence is higher in the western coastal area （77.78%） than in the Zhujiang Delta （66. 67% ） and northern coastal area （33.33%） and is relatively lower in the dry season （40%） compared with the rainy season （70%） and transition season （85%）. The trophic level has a significant effect on the presence of C. raciborskii, which is notably higher in eutrophic reservoirs （81.48%） than in mesotrophic reservoirs （66.67%） and oligotrophic reservoirs （33.33%）. The redundancy analysis shows that C. raciborskii biomass is positively correlated with total nitrogen （TN） and the trophic state index （TSI） and negatively correlated with dissolved inorganic nitrogen （DIN） , soluble reactive phosphorus （SRP） , and the secchi depth （SD）. Thus, C. raciborskii in Guangdong reservoirs may be promoted by environmental factors such as high nitrogen contents, low phosphorus concentration, and transparency.