长江中下游浅水湖泊依沙矛丝藻的分布

DISTRIBUTION OF CUSPIDOTHRIX ISSATSCHENKOI IN THE SHALLOW LAKES IN MIDDLE AND LOWER REACHES OF THE YANGTZE RIVER

利用长江中下游87个浅水湖泊的调查数据,研究了依沙矛丝藻(Cuspidothrix issatschenkoi)在长江中下游湖泊中的分布现状以及生态适应性特征。结果表明,依沙矛丝藻在长江中下游湖泊中分布广泛,在调查区域内超过一半的湖泊被检测到,生物量为0.001—3.019 mg/L;依沙矛丝藻的生物量与总磷呈现负相关关系,与总氮呈现正相关关系,表明依沙矛丝藻在低磷的条件下具有更好的适应性和竞争力,水体中充足的氮源将增加依沙矛丝藻水华的风险。此外,依沙矛丝藻已被报道是中国水体中产生鱼腥藻毒素的主要类群之一,可能会对淡水生态安全造成巨大威胁。研究结果可为今后开展有害藻类的生态学研究和风险管控提供基础资料。

Cuspidothrix issatschenkoi formerly Aphanizomenon issatschenkoi,is the potentially toxic cyanobacterium.Nowadays,this species has been discovered on all continents except the Antarctica.The cyanobacterial blooms and toxins caused by C.issatschenkoi from different countries have caused many aquatic environmental problems,however,there are few studies researched on its geographical distribution and ecological characteristics in China.The present study initiated based on the field survey data derived from 87 shallow lakes in the middle and lower reaches of the Yangtze River from June to August 2013,we found C.issatschenkoi occurred in more than half of the freshwater lakes in the investigated area,and its biomass fluctuating from 0.001 to 3.019 mg/L.The correlation analysis between C.issatschenkoi and environmental factors showed that the biomass of C.issatschenkoi is negative with the total phosphorus in freshwater ecosystem,indicated that C.issatschenkoi had better adaptability and competitiveness under the condition of low phosphorus.And there is a positive correlation between its biomass and total nitrogen,thus sufficient nitrogen source in the water may increase the potential risk of forming water blooms by C.issatschenkoi.Since C.issatschenkoi has been reported to be the main cyanobacterial species to synthesis anatoxins in Chinese freshwater bodies,indicating that severe threat in freshwater security may posed by this species.Our results revealed the geographical and ecological characteristics of C.issatschenkoi,which can provide data foundation for the ecological research and management of harmful algae in the future.