南非科技与工业研究会（CSIR）的湖泊学家保罗·奥博郝斯特博士研究出一种可以预测有毒的蓝绿藻在淡水环境（如江河湖泊）中暴发的方法，这种早期预警方法对于监测淡水环境，帮助水源管理部门采取恰当的水排放策略来减少下游污染和健康风险具有重要应用意义。
蓝绿藻又称蓝藻或蓝菌，是一种生长于水中的浮游生物，当水中的营养物质过剩时，原本稀少的蓝绿藻会在短时间内迅速繁殖，在河流、湖泊或水库的水面上形成庞大而浓密的藻垫，这就是蓝藻暴发。蓝藻暴发打乱了湖泊水库正常的生态系统和功能，造成水中严重缺氧，致使大量鱼类和其他水生物死亡；同时会产生有腥臭味的“水华”现象，令饮用水源受到威胁，而蓝藻中含有的毒素更是严重影响人类健康。
奥博郝斯特的研究小组考察了位于南非自由州的克鲁格斯德瑞福特湖，对其近岸水域的物理和化学特性以及生物相互作用进行了研究，特别是对在靠近该湖水坝区域暴发的有毒蓝藻进行了重点研究。通过比较参考点和有毒蓝藻污染区域物种构成的变化，他们成功地利用大型无脊椎动物的多样性指数对有毒蓝藻暴发的可能性进行了评估。他们采用水蛭作为生物指示物，因为与某些大型无脊椎动物相反，水蛭可以在被蓝藻释放的有毒物质污染的水中生存，它们的存在往往是水质差的证明。如果水蛭出现在比较稠密的蓝藻周围，说明这种蓝藻极有可能是有毒的。
但水蛭不能说明水体中的毒性水平到底有多高。为此，他们同时采用基因技术来检测可以合成蓝绿细菌毒素的蓝绿细菌基因的存在。这种灵敏的酶联免疫吸收分析方法利用一种抗体可以识别出能产生毒性的基因片段，并测出其含量，由此可以确定毒性高低。
奥博郝斯特表示，这是首次将这两种方法结合起来对湖泊水库的有毒蓝藻暴发进行早期预警评估。有关结果发表在近期出版的《生态毒理学》杂志上(生物谷Bioon.com)。
生物谷推荐原始出处：
Ecotoxicology 2009年1月 :DOI:10.1007/s10646-008-0254-5
The influence of a toxic cyanobacterial bloom and water hydrology on algal populations and macroinvertebrate abundance in the upper littoral zone of Lake Krugersdrift, South Africa
Paul J. Oberholster1 , Anna-Maria Botha2 and Peter J. Ashton1
The biological interactions and the physical and chemical properties of the littoral zone of Lake Krugersdrift were studied for a 4-month period when a dense, toxic cyanobacterial bloom dominated by Microcystis aeruginosa was present in the main lake basin. The presence of a toxic strain of M. aeruginosa was confirmed through the use of ELISA and molecular markers that detect the presence of the mcyB and mcyD genes of the mcy gene cluster that synthesizes microcystin. An increase in Microcystis toxicity at sites dominated by the cyanobacterial scum was accompanied by an increase in total abundance of the macroinvertebrate families Hirudinae, Chironomidae, and Tubificidae. Sites located away from the cyanobacterial scum had a lower abundance but a higher diversity of macroinvertebrates. The water quality under the Microcystis scum was characterized by low pH values, low concentrations of dissolved oxygen, and lower total alkalinity values. The periphytic alga Ulothrix zonata was absent in areas dominated by the cyanobacterial scum, possibly as a result of overshadowing by the scum or direct toxic allelopathic effects on growth and photosynthesis. The diatom Diatoma vulgare dominated the benthic algal flora beneath the cyanobacterial scum.
(1) CSIR Natural Resources and the Environment, PO Box 395, Pretoria, ZA0001, South Africa
(2) Department of Genetics, University of Pretoria, Hillcrest, Pretoria, ZA002, South Africa
