Modelling spatial distributions of Ceratium hirundnella and Microcystis. in a small productive British lake
Modelling spatial distributions of Ceratium hirundnella and Microcystis. in a small productive British lake
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DOI：
10.1007/s10750-004-2349-1
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发表时间：
2004-10
期刊：
影响因子：
2.6
通讯作者：
R. Hedger;N. Olsen;D. George;T. Malthus;P. Atkinson
中科院分区：
文献类型：
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作者：
R. Hedger;N. Olsen;D. George;T. Malthus;P. Atkinson
利用水动力模型研究了英国英格兰湖区富营养化小湖泊Esthwaite Water浮游植物的空间分布与环境条件之间的短期关系。模拟了两种情况下浮游植物的空间分布，第一种情况下浮游植物的种群以甲藻为主，第二种情况下浮游植物的种群以蓝藻为主，估计了甲藻Ceratium hirundinellaa和蓝藻Microcystis sspm.的垂直运动性和浮力作为光照的函数。通过在有限体积非结构非正交网格上求解三维Navier-Stokes方程来估计水流速度场。模拟的水体和浮游植物的环流模式与现场观测得到的环流模式相似。近地表漂流是由风应力引起的，然后沿着季节性温跃层产生返回流。在温跃层附近存在的基元陶瓷集合体被深部返回流推上风，并聚集在上升区。相反，近地表的微囊藻聚集物被表面洋流推向下风，并聚集在下流区。浮游植物的水平和垂直分布是浮游植物垂直运动(取决于光环境)和浮游植物聚集深度的速度矢量(取决于风应力和形态测量)之间相互作用的结果。模拟结果表明，浮游植物的运动性和浮力对浮游植物的空间分布有很大影响。
The short-term relationships between the spatial distributions of phytoplankton and the environmental conditions of Esthwaite Water, a small eutrophic lake in the English Lake District, UK, were examined using a hydrodynamic model. Spatial distributions of phytoplankton were simulated on two occasions the first, when the population was dominated by dinoflagellates; and the second, when the population was dominated by cyanobacteria.Vertical motility of the dinoflagellateCeratium hirundinellaand buoyancy of the cyanobacteriaMicrocystis ssprm.were estimated as functions of irradiance. Water velocity fields were estimated through solving the 3-D Navier–Stokes equations on a finite-volume, unstructured non-orthogonal grid. Simulated circulation patterns of water and phytoplankton were similar to those obtained through field observations. Near-surface drift currents were initiated by wind stress, which then generated return currents along the seasonal thermocline. Aggregations of motileCeratiumthat existed near the thermocline were pushed upwind by the deep return currents and accumulated at upwelling areas. In contrast, near-surface aggregations ofMicrocystiswere pushed downwind by the surface currents and accumulated at downwelling areas. Horizontal and vertical phytoplankton distributions resulted from the interaction between the vertical motility of the phytoplankton (dependent upon the light environment) and the velocity vectors at the depths at which the phytoplankton accumulated (dependent upon wind stress and morphometry). Modelling showed that phytoplankton motility and buoyancy greatly affect phytoplankton spatial distributions.