Mechanisms of phytoplankton coexistence

在本项目中，我们从实验和理论上研究了浮游植物共存的机制。(1)培养实验：利用连续培养的植物营养物种，我们研究了共存和竞争下的不同浓度的营养物质和流速的培养基。绿色栅藻和蓝藻微囊藻的竞争和排斥作用取决于营养液浓度和流速。特别是，由于迄今为止还没有尝试过不同介质供应模式的实验，因此目前关于供应模式影响的结果是新的。(2)理论分析：考察了低流量连续培养中的竞争、浮游生物悖论和富集悖论。均匀环境中的优势种被认为是一个或几个。浮游植物物种多样性通常很高，但水环境似乎是同质的。这种高度的多样性被称为“ 关于我们 浮游生物的悖论“在较高的营养条件下，多样性被认为会增加。然而，在许多水体环境的实地观察中，情况并非如此。这种多样性沿着养分梯度的变化被称为“富集悖论”。“在低营养和低流量连续培养中，浮游植物物种不一定处于名义营养浓度下，但实际上处于较低的营养浓度下。这种关系是种特异性的，并解释了较低的多样性低，在较低的营养条件。在格子模型中，我们假设十个物种的生长略有差异。我们引入了“生态时间尺度”，即系统在生态上是长的，但在这个时间尺度内系统并不处于稳定状态。在这个理论框架中，我们研究了物种数量的变化。这种增长率取决于生态时间尺度上的养分浓度。浮游植物物种的生长比通常认为的要本地化。局部生长解释了“浮游生物悖论”。在更高的营养物质中，每个物种都在全球范围内生长，有些物种被排除在外。这就是“致富悖论”。“少

In this project, we studied mechanisms of phytoplankton coexistence, experimentally and theoretically.(1) Culture experiments: Using continuous cultures of phytoplanktonic species, we examined coexistence and competition under various concentration of nutrients and flow speed of culture medium. Competition and exclusion of the green alga Scenedesmus quadricauda and the cyanobacterium Microcystis novacekii depended on nutrient concentration and flow speed of supply culture medium. Since experiments with varying supply modes of the medium, especially, has not been tried to date, the present results on the effects of the supply mode were new.(2) Theoretical analysis: Competition in the low flow continuous culture, the paradox of plankton and the paradox of enrichment were examined. Dominant species in homogeneous environments is considered to be one or a few. Phytoplankton species diversity is usually high, though water environments seems homogeneous. This high diversity has been called " … More the paradox of plankton." In the higher nutrient conditions, diversity is considered to increase. However, diversity in the field observation of many water environments, this is not the case. This diversity change along nutrient gradient is called "the paradox of enrichment."In the low nutrient and low flow continuous cultures, phytoplankton species were not necessarily under nominative concentration of nutrients, but were in reality under lower nutrient concentrations. This relation was species-specific and explained the lower diversity low in lower nutrient conditions. In the lattice model, we assumed slight differences in growth of ten species. We introduced "ecological time scale" that means it is long ecologically, but in the time scales the system is not in stable conditions. In this theoretical framework, we examined changes in the number of species. This growth rate depended on nutrient concentrations in the ecological time scale. Phytoplankton species grew more locally than it is generally considered. The local growth explained "the paradox of plankton". In higher nutrients, each species grew more globally, and some species became excluded. This means "the paradox of enrichment." Less