To sink or to be lysed? Contrasting fate of two large phytoplankton species in Lake Biwa
To sink or to be lysed? Contrasting fate of two large phytoplankton species in Lake Biwa
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DOI：
10.4319/lo.2006.51.6.2775
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发表时间：
2006-11-01
影响因子：
4.5
通讯作者：
Urabe, Jotaro
中科院分区：
文献类型：
--
作者：
Kagami, Maiko;Gurung, Tek Bahadur;Urabe, Jotaro
我们估计了沉积物和细胞裂解对琵琶湖两个大型浮游植物物种(Fragilaria crotonensis和Staurstrum dorsidentiferum)损失的贡献。主要的损失过程因物种不同而不同，大型浮游植物不一定起到营养体汇的作用。由于营养物质的枯竭和随后沉积速率的增加，巴豆的春季水华被终止。虽然这一物种偶尔会被浮游动物捕食，但沉积作用消除了表面的营养物质。相反，夏季开花主要是由于表面混合层内真菌感染引起的细胞溶解所致，占该物种死亡率的75%以上。苏云金杆菌的细胞裂解可能导致表层混合层内的营养物质，支持细菌和浮游动物的生产。这两个物种的不同损失过程表明，浮游植物在物质流动中的功能不能仅用细胞大小来评估。真菌寄生可以导致不同的命运，这可能在湖泊的物质循环中发挥重要作用。
We estimated the contributions of sedimentation and cell lysis to the loss of two large phytoplankton species (Fragilaria crotonensis and Staurastrum dorsidentiferum) in Lake Biwa. Major loss process differed between species, and large phytoplankton did not necessarily function as a nutrient sink. The spring bloom of F crotonensis was terminated by nutrient depletion and a subsequent increase in sedimentation rate. Although this species could be occasionally grazed by zooplankton, sedimentation eliminated nutrients from the surface. In contrast, the summer bloom of Staurastrum dorsidentiferum crashed mainly as a result of cell lysis caused by fungal infection within the surface mixing layer, which accounted for more than 75% of the mortality rate of this species. Cell lysis of S. dorsidentiferum may lead to nutrients within the surface mixing layer, supporting the production of bacteria and zooplankton. The different loss process of these two species implies that the function of phytoplankton in material flows cannot be assessed by cell size alone. Fungal parasitism can result in a different fate, which may play an important role in material cycling in lakes.