Coupling hydrodynamics and buoyancy regulation in Microcystis aeruginosa for its vertical distribution in lakes
Coupling hydrodynamics and buoyancy regulation in Microcystis aeruginosa for its vertical distribution in lakes
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DOI：
10.1016/j.ecolmodel.2012.08.029
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发表时间：
2013-01-10
影响因子：
3.1
通讯作者：
Clercx, H. J. H.
中科院分区：
文献类型：
--
作者：
Medrano, E. Aparicio;Uittenbogaard, R. E.;Clercx, H. J. H.
在这项研究中，我们引入了耦合柱模型来模拟天然湖泊中铜绿微囊藻的垂直迁移。铜绿假单胞菌是一种形成菌落的单细胞蓝细菌。它们产生毒素，因此对水质和人类健康构成潜在威胁。了解该物种在空间和时间上的分布对于改进水管理策略非常重要。我们提出的模型包括流体动力学和生理反应，包括微囊藻细胞中明确的浮力调节。我们的模型应用 Langevin-Fokker-Planck 方法来模拟沿水柱的总菌落数浓度。这种方法可以描述不同大小和成分的菌落在湍流混合下的下沉和上升速度。该模型于 2009 年夏季首次应用于荷兰 30 m 深的弗利特兰湖。今年夏季，该湖出现微囊藻大量繁殖，最终导致岸边形成浮渣。模拟显示了铜绿假单胞菌通过水柱的优先分布及其对菌落大小的强烈依赖性。在每日周期中，小菌落（50-200μm）不会停留在表面附近，而是高度集中在表层中部，而大菌落（>=800μm）能够迁移到更深处，并且仅暂时集中在表面附近。为了将我们的计算机模型与微囊藻浓度分布的现有测量结果进行比较，我们将其应用于艾瑟尔湖和芬克芬湖。结果表明与浮力状态日变化的观测结果非常吻合。 (C) 2012 Elsevier B.V. 保留所有权利。
In this research we introduce a coupled column model to simulate the vertical migration of Microcystis aeruginosa in natural lakes. M. aeruginosa is a unicellular cyanobacteria that form colonies. They produce toxins and therefore become a potential threat to water quality and human health. Understanding the distribution of this species in space and time is important for improving water management strategies. The model we propose includes both hydrodynamics and physiological responses including explicitly buoyancy regulation in Microcystis cells. Our model applies the Langevin-Fokker-Planck approach to simulate the total colony number concentration along the water column. This approach allows the description of sinking and rising velocities of colonies of different sizes and compositions subjected to turbulent mixing. The model is first applied to the 30 m deep Lake Vlietland in the Netherlands for the summer of 2009. During this summer, the lake showed high blooms of Microcystis which eventually led to scum formation along the shore. The simulations show the preferential distribution of M. aeruginosa through the water column and their strong dependency on colony size. On a daily cycle, small colonies (50-200 mu m) do not remain near the surface but are highly concentrated in the middle of the epilimnion, whereas large colonies (>= 800 mu m) are able to migrate to greater depths and concentrate only temporarily near the surface. For comparing our computer model with available measurements of Microcystis concentration distributions we applied it to lakes Ijsselmeer and Vinkeveen. The results show a good agreement with the observations of diurnal changes in buoyancy status. (C) 2012 Elsevier B.V. All rights reserved.