Trait-related feedback dynamics in natural plankton communities

生物多样性的丧失往往伴随着与资源利用和生长有关的性状的丧失，这些性状对食物网动态和营养转移效率非常重要。在DYNATLOSS II项目中，我们特别关注通过浮游动物多样性介导的变化，从减少浮游植物性状多样性到浮游植物动力学的反馈回路。我们将通过对天然浮游生物群落的实地实验来解决这一总体目标，以估计总反馈效应的方向和强度。此外，我们将分析复杂和多因子反馈效应集的各个组成部分（主要通过实验室实验）。我们的工作计划将集中于以下主要研究问题：由于浮游植物多样性的变化而改变的放牧是否会导致多重（部分相互依赖的）反馈效应？我们将用一系列可测试的假设来解决这个研究问题。实地试验可以分析自然条件下的总反馈效应。为了理清个体反馈机制，如与放牧依赖的大小分布和养分有效性有关，将进行额外的、高度控制的实验室实验。这些反馈机制都可能影响食草浮游动物的群落。这可能潜在地补偿与浮游植物相关的浮游动物组成变化的短期影响。除了实验室和实地的实验方法外，我们还将利用浮游植物-浮游动物系统中已建立的营养动力学模型的扩展来模拟所提出的反馈效应。

Biodiversity loss is often accompanied by a loss of traits related to resource use and growth which are important for food web dynamics and trophic transfer efficiencies. In the DYNATLOSS II project, we specially focus on the feedback loop from reduced phytoplankton trait diversity to phytoplankton dynamics via diversity-mediated shifts in zooplankton. We will address this general objective with field experiments with natural plankton communities to estimate the direction and strength of total feedback effects. Additionally, we will analyse the individual components of the complex and multifactorial set of feedback effects (mainly by laboratory experiments). Our work programme will focus on the following main research question: Can altered grazing, due to shifts in phytoplankton diversity result in multiple (and partially interdependent) feedback effects? We will address this research question with a chain of testable hypotheses. Field experiments allow analysing total feedback effects under natural conditions. To disentangle individual feedback mechanisms such as linked to grazing dependent size distribution and nutrient availability, additional, highly controlled laboratory experiments will be performed.These feedback mechanisms may all affect the community of herbivorous zooplankton. This could potentially compensate short term effects of phytoplankton related shifts in zooplankton composition. In addition to the experimental approaches in laboratory and in the field, we will also model the proposed feedback effect using an extension of established nutrient dynamics models in phytoplankton – zooplankton systems.