Dynamics of phytoplankton size-structure as explained by bio-physical principles and ecological history: a trait based adaptive dynamics modeling approach

全球生物多样性丧失的速度不断加快，这是一个紧迫的问题，但对多样性动态进行定量预测的能力有限。这一总主题下的一个特殊问题是了解社区对自然界经常发生的多种压力源的反应。多个压力源的组合和顺序都会影响多样性动态，从而降低了性状和生态系统动态的整体可预测性。在拟议的项目中，我们的目标将是建立一个新的定量模型框架，非常适合整合生理，生物物理和基于最优性的描述。我们采用了一种基于特征的适应性动力学模型（ATBM）方法，该方法以前由申请人之一开发用于浮游生物群落[维尔茨2013：海洋生物学，160：2319-2335]。该模型解决了平均浮游植物细胞大小的基本特征，调节许多过程相关的健身（即生长和死亡率）。利用这一框架，我们的目标是研究多重压力在不同组织水平的单细胞自养生物的影响，特别关注性状多样性的变化。该模型的机械基础将使我们的分析扩展到遗传变化，由于进化适应。由于重点将是浮游植物作为一种模式生物，具有较短的世代时间，我们的项目将直接与乌尔里希·索默教授（GEOMAR，基尔）提出的围隔实验相互作用。在这里，该模型随后将进一步改进和分析选择性放牧和营养限制对浮游植物群落的大小结构的影响，目的是后投观察到的自然浮游植物群落的响应，以个人和顺序应用放牧和营养限制为主要压力。进一步的模型应用模型，外地人口的设想，并有望完善我们的机械理解多尺度多样性的变化性质。

Ever-increasing rates of global biodiversity loss is a pressing concern, yet only limited capacity exists for a quantitative prediction of diversity dynamics. A particular issue under this general theme is understanding the response of communities to multiple stressors as often occur in nature. Both the combination and sequence of multiple stressors affect diversity dynamics, which reduces the overall predictability of trait and ecosystem dynamics. In the proposed project, our aim will be to establish a novel quantitative model framework that is ideally suitable for the integration of physiological, biophysical and optimality-based descriptions. We adopt a trait-based adaptive dynamics model (ATBM) approach developed previously for plankton communities by one of the applicants [Wirtz 2013: Marine Biology, 160:2319-2335]. The model resolves mean phytoplankton cell size as the fundamental trait that regulates many processes related to fitness (i.e. growth and mortality). Using this framework, we aim to study the effects of multiple stressors at different organizational level of unicellular autotrophs, with a particular focus on the changes in trait diversity. The mechanistic basis of the model will enable extension of our analysis to genetic shifts due to evolutionary adaptation. As the focus will be on phytoplankton as a model organism with short generation times, our project will directly interact with the mesocosm experiments proposed by Prof. Ulrich Sommer (GEOMAR, Kiel). Here, the model will be subsequently improved and analyzed further with respect to the effects of selective grazing and nutrient limitation on the size-structure of the phytoplankton community, with the aim to hind-cast the observed response of natural phytoplankton communities to individual and sequential application of grazing and nutrient limitation as major stressors. Further model applications of the model to field populations is envisaged and is expected to refine our mechanistic understanding of multi-scale diversity changes in nature.