The adaptive capacity of multitrophic plankton communities in a changing ocean

科学界有一个广泛的共识，即世界气候正在以前所未有的速度变化。关于气候变化的生态后果的证据越来越多。例如，在水生领域，这种后果涉及浮游植物和浮游动物物候的变化，以及浮游植物群落组成向细胞尺寸较小的物种的重组。在不断变化的环境中，生态群落需要适应其表型分布，以提高平均适应度，使群落在新的环境条件下茁壮成长。适应可以通过基因组成的改变（如微进化）或不同形式的表型可塑性来实现。这种机制是否会在真实的海洋中发挥作用，例如，使浮游植物群落（以及海洋食物网）对不断变化的环境条件更具弹性，目前尚不清楚。我们在这里提出了一个项目，旨在将各种实验室数据和现场观测数据（包括在DynaTrait中获得的数据）整合到一个新的基于特征的建模框架中。这个建模框架是基于浮游植物细胞大小的自适应动态，更重要的是，基于浮游植物细胞大小与1)浮游植物营养吸收、2)浮游动物放牧和3)浮游植物下沉之间关系的权衡。浮游植物群落的适应能力是通过与繁殖相关的性状变异机制来捕获的，因此性状变异在物种的后代中得以维持。利用这个工具，我们计划研究在一系列环境冲击、干扰和未来情景下，浮游植物群落组成和表型多样性的变化如何影响大西洋两个不同区域（温带和热带）的食物网动态。最终，我们的项目提供了一个机会，将在DynaTrait项目中获得的知识转化为真实的海洋环境。

There is broad consensus in the scientific community that the worlds climate is changing at an unprecedented rate. Evidence is accumulating on the ecological consequences of the changing climate. In the aquatic realm, for example, such consequences have involved shifts in the phenology of phytoplankton and zooplankton and reorganizations of phytoplankton community compositions towards species with smaller cell sizes. In a changing environment, ecological communities need to adapt their distribution of phenotypes so that the average fitness increases and the community can thrive under the new environmental conditions. Adaptation can work through a change in the genetic composition (e.g. microevolution) or through different forms of phenotypic plasticity. Whether such mechanisms will play a role in the real ocean, for example by making phytoplankton communities (and therefore the marine foodweb) more resilient to changing environmental conditions, is currently unclear. We propose here a project aiming at integrating a variety of laboratory data and field observations, including those acquired within DynaTrait, into a novel trait-based modelling framework. This modelling framework is based on the adaptive dynamics of phytoplankton cell-size and, critically, on a trade-off emerging from relationships between phytoplankton cell size and 1) phytoplankton nutrient uptake, 2) zooplankton grazing, and 3) phytoplankton sinking. The adaptive capacity of the phytoplankton community is captured by a mechanism of trait variation associated to reproduction so that trait variance is maintained as traits are diffused through subsequent generations of species. With this tool we plan to investigate how shifts in phytoplankton community composition and phenotypic diversity impact the foodweb dynamics of two contrasting regions (temperate and tropical) of the Atlantic Ocean under a number of environmental shocks, disturbances, and future scenarios. Ultimately, our project represents an opportunity to translate the knowledge aquired within the DynaTrait programme into the context of a real ocean environment.