Phytoplankton seed populations of the cape peninsula upwelling plume, with particular reference to resting spores of Chaetoceros (bacillariophyceae) and their role in seeding upwelling waters
Phytoplankton seed populations of the cape peninsula upwelling plume, with particular reference to resting spores of Chaetoceros (bacillariophyceae) and their role in seeding upwelling waters
复制标题
开普半岛上升流羽流的浮游植物种子种群，特别是角毛藻（硅藻纲）的休眠孢子及其在上升流水域播种中的作用
DOI：
10.1016/0272-7714(90)90105-z
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发表时间：
1990
影响因子：
2.8
通讯作者：
G. Pitcher
中科院分区：
文献类型：
--
作者：
G. Pitcher
研究了本格拉南部开普半岛上升流系统收集的新上升流水体的浮游植物种子种群。沿着整个羽流底部的浮游植物的相似组成表明，在每个单独的上升流事件中都有一个共同的水源。不同上升流事件下浮游植物组成和丰度的较大差异归因于不同的近海浮游植物发育过程、不同物种播种策略的成功以及环流模式的变化。这种变异被发现有助于确定物种组成和开花发育所需的时间。完整的硅藻休眠孢子，特别是毛藻属的孢子，在新上升流的水体中普遍存在，这表明孢子能够利用混合和电流模式来为上升流系统提供种子。较高的下沉率似乎是孢子形成的关键优势，在养分耗尽后迅速将种群从不适宜生存的环境中移除，从而防止离岸平流并使种群保持在上升流中心附近。在新上升水的孵育下，硅藻休眠孢子的萌发为上升水系统中休眠孢子引发硅藻华提供了令人信服的证据。因此，这些休息阶段在播种上升流系统中具有选择性优势，增加了一个物种在有利生长条件下被代表的机会。因此，形成孢子的硅藻物种已被发现是本格拉南部最丰富和持久的浮游植物物种之一。
Phytoplankton seed populations of newly upwelled water collected off the Cape Peninsula in the southern Benguela upwelling system were examined. The similar composition of the phytoplankton along the entire base of the plume implies a common source of water during each individual upwelling event. Greater variability in the composition and abundance of phytoplankton of different upwelling events was attributed to varying offshore phytoplankton developmental processes, the success of the seeding strategies of various species and variation in circulation patterns. Such variability was found to be instrumental in determining the species composition and the time required for bloom development. The prevalence of intact diatom resting spores, especially of the genusChaetoceros, in newly upwelled waters demonstrated the ability of spores to utilize the mixing and current patterns in order to seed upwelling systems. Higher sinking rates would appear to be the key advantage to spore formation, rapidly removing the population from an inhospitable environment following nutrient depletion, thus preventing offshore advection and maintaining the population close to the centre of upwelling. The germination of diatom resting spores following incubation of newly upwelled water provided convincing evidence of the initiation of diatom blooms by resting spores in upwelling systems. These resting stages are therefore of selective advantage in seeding upwelling systems, increasing the chances of a species being represented when conditions are favourable for growth. Thus spore-forming diatom species have been found to be among the most abundant and persistent phytoplankton species in the southern Benguela.