The long, the short and the stalled: on the attributes of phytoplankton selected by physical mixing in lakes and rivers
The long, the short and the stalled: on the attributes of phytoplankton selected by physical mixing in lakes and rivers
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DOI：
10.1007/bf00007405
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发表时间：
1994-09
期刊：
影响因子：
2.6
通讯作者：
C. Reynolds
中科院分区：
文献类型：
--
作者：
C. Reynolds
矛盾的是，虽然湍流是湖泊、河流和海洋中浮游生物的开放水域环境的特征，但大多数浮游植物物种的体积都小于耗散能量的最小涡流的大小，因此必须在固有粘性的直接介质中发挥作用。然而，高度混合的系统，如风搅动的浅湖、河流和河口，不断调整悬浮藻类的垂直位置，通常还有其他无生命的吸光颗粒，其结果是藻类所处的光场不稳定，白天接收到的光剂量总体上被抑制：细胞需要相应地进行光适应。在河流环境中，应用了快速、水平、单向运输的附加约束，要求初级产物和细胞复制的快速处理属性。然而，所谓的“死区”的存在有利于大量的下游招募，这些死区保留了足够的水（和悬浮的浮游生物），以适应额外的细胞分裂。
Paradoxically, although turbulence characterises the open water environments of planktonic organisms in lakes, rivers and seas, most species of phytoplankton are smaller than the size of the smallest eddies dissipating the energy and, so, must function in an immediate medium which is inherently viscous. Intensively mixed systems, such as wind-stirred shallow lakes, rivers and estuaries, however, constantly readjust the vertical position of suspended algae and, often, other non-living, light-absorbing particles with the effect that the light field to which the algae are subject is erratic and the received day-time light dose is aggregately depressed: cells need to photoadapt accordingly. In fluvial environments the additional constraint of rapid, horizontal, supposedly unidirectional, transport is applied, requiring the attribute of rapid processing of primary products and cell replication. Significant downstream recruitment, however, is benefitted by the presence of so-called ‘dead-zones’ which retain water (and suspended plankton) sufficiently to accommodate additional cell divisions.