Planktonic events may cause polymictic-dimictic regime shifts in temperate lakes.
Planktonic events may cause polymictic-dimictic regime shifts in temperate lakes.
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DOI：
10.1038/srep24361
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发表时间：
2016-04-14
影响因子：
4.6
通讯作者：
Kirillin G
中科院分区：
文献类型：
--
作者：
Shatwell T;Adrian R;Kirillin G
水体透明度影响湖泊的热结构，在一定的湖泊深度范围内，它可以决定湖泊从春季到夏季是否有规律地混合（多态）或连续分层（多态）。浮游植物生物量可以影响透明度，但其季节性模式对分层的影响尚不清楚。因此，我们分析了两个深度、透明度和气候相似但一个多聚和一个二聚的湖泊的长期现场数据，并用水动力模型模拟了一个概念性湖泊。研究中湖泊的透明度在春季和夏季水华期间通常较低，而在清水期（CWP）期间透明度较高，这是由浮游动物吃春季水华时造成的。透明度的变化对热结构的影响在中间透明度处更强，并且在春季湖泊变暖速率最高的关键窗口期间更强。春季水华加强了春季的分层，而 CWP 则削弱了夏季的分层。 CWP 的存在或不存在会影响分层持续时间，并在某些条件下决定混合方式。因此，季节性浮游生物动态，包括抑制 CWP 的生物相互作用，可以影响湖泊温度、分层持续时间，并可能影响混合机制。
Water transparency affects the thermal structure of lakes, and within certain lake depth ranges, it can determine whether a lake mixes regularly (polymictic regime) or stratifies continuously (dimictic regime) from spring through summer. Phytoplankton biomass can influence transparency but the effect of its seasonal pattern on stratification is unknown. Therefore we analysed long term field data from two lakes of similar depth, transparency and climate but one polymictic and one dimictic, and simulated a conceptual lake with a hydrodynamic model. Transparency in the study lakes was typically low during spring and summer blooms and high in between during the clear water phase (CWP), caused when zooplankton graze the spring bloom. The effect of variability of transparency on thermal structure was stronger at intermediate transparency and stronger during a critical window in spring when the rate of lake warming is highest. Whereas the spring bloom strengthened stratification in spring, the CWP weakened it in summer. The presence or absence of the CWP influenced stratification duration and under some conditions determined the mixing regime. Therefore seasonal plankton dynamics, including biotic interactions that suppress the CWP, can influence lake temperatures, stratification duration, and potentially also the mixing regime.