The adaptive capacity of multitrophic plankton communities in a changing ocean

科学界的广泛共识是，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正在积累。例如，在水生领域，这样的后果包括浮游植物和浮游动物物候的转变，以及浮游植物群落组成的重组，转向细胞尺寸较小的物种。在不断变化的环境中，生态群落需要调整它们的表型分布，以便平均适应度增加，群落能够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(例如，微进化)或通过不同形式的表型可塑性来发挥作用。目前尚不清楚这种机制是否会在真实的海洋中发挥作用，例如通过使浮游植物群落(因此海洋食物网)对不断变化的环境条件更具弹性。我们在此提出一个项目，旨在将各种实验室数据和现场观测数据，包括在DyaTrait内获得的数据，整合到一个新的基于特征的建模框架中。该模型框架基于浮游植物细胞大小的适应动态，关键是基于浮游植物细胞大小与1)浮游植物营养吸收、2)浮游动物觅食和3)浮游植物下沉之间的关系而产生的权衡。浮游植物群落的适应能力被与繁殖相关的特征变异机制捕捉到，因此当特征在后代物种中传播时，特征变异保持不变。利用这一工具，我们计划调查在一系列环境冲击、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地区(温带和热带)的食物网动态。归根结底，我们的项目代表着一个机会，可以将在DyaTrait方案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.