Turbulent mixing and phytoplankton spring bloom development in a deep lake
Turbulent mixing and phytoplankton spring bloom development in a deep lake
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DOI：
10.4319/lo.2007.52.1.0286
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发表时间：
2007-01-01
影响因子：
4.5
通讯作者：
Ollinger, Dieter
中科院分区：
文献类型：
--
作者：
Peeters, Frank;Straile, Dietmar;Ollinger, Dieter
应用一维浮游植物力学模型结合一维水动力学模型模拟了冬春季博登湖上游浮游植物的生长。模拟的叶绿素a浓度同意以及从8年的时间段考虑的数据。特别是，浮游植物生长的时间的年际变化是充分模拟的模式。博登湖上游浮游植物水华的发生对光合有效辐射、藻类下沉速度或水温对生物过程速率的影响的变化不敏感，但主要由湍流扩散（即，从冬季和早春的强混合过渡到弱混合）。混合条件的过渡，因此也开始浮游植物种群增长与建立的第一个轻微的温度分层。在不考虑浮游植物损失的情况下进行的模拟，由于放牧高估了藻类生物量后不久，藻类生长的开始。包括浮游动物放牧大大提高了模型和数据之间的协议，并建议纤毛虫放牧，特别是导致浮游植物丰度在春季开始后的藻华显着减少。
A one-dimensional (1-D) mechanistic phytoplankton model combined with a 1-D hydrodynamic model was applied to simulate phytoplankton growth during winter and spring in deep monomictic Upper Lake Constance. Modeled chlorophyll a concentrations agree well with data from the 8-y time period considered. In particular, the interannual variation in the timing of phytoplankton growth is adequately simulated by the model. The onset of phytoplankton blooms in Upper Lake Constance is not sensitive to variations in the photosynthetically active radiation, the sinking velocity of the algae, or the effect of water temperature on biological process rates, but is primarily determined by turbulent diffusion (i.e., by the transition from strong mixing in winter and early spring to weak mixing). The transition in mixing conditions and thus also the beginning of phytoplankton population growth correlates with the build up of the first slight temperature stratification. Simulations performed without consideration of phytoplankton loss due to grazing overestimate algal biomass soon after the onset of algal growth. Including grazing by zooplankton substantially improves the agreement between model and data and suggests that ciliate grazing in particular leads to a significant reduction of phytoplankton abundance in spring after the start of the algal bloom.