Taihu Lake Laboratory Ecosystem Station, State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, 73 East Beijing Road, Nanjing 210008, PR China; University of Chinese Academy of Sciences, Beijing 100049, PR China.
Taihu Lake Laboratory Ecosystem Station, State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, 73 East Beijing Road, Nanjing 210008, PR China.
Harmful Algae. 2016 May;55:213-220. doi: 10.1016/j.hal.2016.03.016. Epub 2016 Mar 31.
Toxic cyanobacterial harmful algal blooms (CyanoHABs) have posed serious water use and public health threats because of the toxins they produce, such as the microcystins (MCs). The direct physical effects of turbulence on MCs, however, have not yet been addressed and is still poorly elucidated. In this study, a 6-day mesocosm experiment was carried out to evaluate the effects of wind wave turbulence on the competition of toxic Microcystis and MCs production in highly eutrophicated and turbulent Lake Taihu, China. Under turbulent conditions, MCs concentrations (both total and extracellular) significantly increased and reached a maximum level 3.4 times higher than in calm water. Specifically, short term (∼3 days) turbulence favored the growth of toxic Microcystis species, allowing for the accumulation of biomass which also triggered the increase in MCs toxicity. Moreover, intense turbulence raises the shear stress and could cause cell mechanical damage or cellular lysis resulting in cell breakage and leakage of intracellular materials including the toxins. The results indicate that short term (∼3 days) turbulence is beneficial for MCs production and release, which increase the potential exposure of aquatic organisms and humans. This study suggests that the importance of water turbulence in the competition of toxic Microcystis and MCs production, and provides new perspectives for control of toxin in CyanoHABs-infested lakes.
有毒蓝藻水华（CyanoHABs）产生的毒素，如微囊藻毒素（MCs），对水的利用和公共健康构成了严重威胁。然而，水的紊流对 MCs 的直接物理影响尚未得到解决，其机制仍不清楚。本研究通过为期 6 天的中尺度实验，评估风浪紊流对中国富营养化、紊流太湖中有毒微囊藻竞争和 MCs 产生的影响。在紊流条件下，MCs 浓度（总浓度和胞外浓度）显著增加，最高水平达到静水条件下的 3.4 倍。具体来说，短期（约 3 天）紊流有利于有毒微囊藻的生长，使其生物量积累，从而导致 MCs 毒性增加。此外，强烈的紊流会增加切应力，可能导致细胞机械损伤或细胞裂解，从而导致细胞破裂和细胞内物质（包括毒素）泄漏。研究结果表明，短期（约 3 天）紊流有利于 MCs 的产生和释放，增加了水生生物和人类暴露于 MCs 的潜在风险。本研究表明了水的紊流在有毒微囊藻和 MCs 产生的竞争中的重要性，为富营养化湖泊中 CyanoHABs 水华的防控提供了新的视角。
