Frontiers of instability in marine ecosystems and carbon export (Marine Frontiers)

海洋前沿是一个创新项目，将推动海洋生态系统功能稳定性极限的知识前沿。它将首次在全球模型中引入导致广泛死亡的三种诱因：病毒、早期生命周期和微塑料污染，并测试未来世纪可能出现的极端条件的影响。海洋生态系统使大气中二氧化碳的浓度保持在百万分之200 （ppm）左右，低于其他情况下的浓度。在过去的地质时期，海洋生态系统并不稳定。它们促成并可能引发了大规模的海洋缺氧事件。研究表明，用于气候研究的全球海洋生态系统模式低估了一系列变量的变异性，包括多个时间和空间尺度上碳和氧通量的变异性，以及浮游生物生物量的变异性。当前这一代海洋碳模型无法重现观测到的变率，这意味着海洋生态系统的不稳定性和相关的碳通量从未得到充分探索。在海洋中，死亡过程是至关重要的，因为生物量的更替非常快。然而，到目前为止，死亡率过程几乎没有受到关注。观测技术（特别是基因组学和自动成像）和知识方面的最新进展突出了可能从根本上改变海洋死亡过程的过程。为了探索海洋生态系统在不断变化的环境中的稳定性，“海洋前沿”项目将首次尝试对三种最重要的死亡诱因进行建模。《海洋前沿》将利用理论、观测和新的计算方法，扩展nemo -浮游生物模型中的死亡率过程。通过粒子功能类型（PtclFTs）的表示，提出了一个新的海洋生态系统表示框架，包括浮游植物、浮游动物和细菌等活粒子，以及病毒、微塑料和不同大小的有机聚集体等死粒子。病毒将作为一种新的惰性PtclFT引入。病毒将根据最近海洋观测得出的见解，用繁殖率和衰减率进行参数化。将介绍甲壳类动物、水母和翼足类动物的早期生命周期，最初通过卵、幼虫和成虫阶段的明确表示，但在第二阶段优化模型资源。微塑料将作为一种具有惰性特性的新型PtclFT引入，使用基于观察的海洋流入和根据观察到的分布优化的衰减率。微塑料会通过浮游动物偶然的掠食进入食物链，造成物理损害和化学中毒。将利用生态系统功能的涌现特性，如chla的南北比、春季开花的最大强度、斑块和营养金字塔，开发一种先进的方法来验证该模型。这是标准验证生物地球化学领域（营养物、碳、生物量）的补充。食物网的涌现特性和理论分析也将有助于建立不稳定的前兆指标。然后，该模型将用于探索海洋生态系统的敏感性，以及由此产生的碳出口对气候变化、海洋酸化、微塑料污染、渔业和综合压力因素日益增长的外部压力的影响。这个雄心勃勃的项目建立在由项目首席研究员（PI）领导的9个“绿海”研讨会上，并与了解和观察海洋生态系统的前沿专家进行国际合作。PI是在引领前沿研究方面拥有丰富经验的世界领导者。她是英国皇家学会会员，2018年和2019年被高度引用的研究员，并因其工作获得了七项奖项和奖章。

Marine Frontiers is an innovative project that will push the frontiers of knowledge on the limits to stability in marine ecosystem functioning. It will introduce, for the first time in a global model, three triggers of widespread mortality: viruses, early life cycles, and microplastic pollution, and test the impact of extreme conditions that are plausible for the coming Century. Marine ecosystems keep the concentration of atmospheric CO2 about 200 parts per million (ppm) lower than it would be otherwise. Marine ecosystems were not stable in the geological past. They contributed and possibly triggered massive Ocean Anoxic Events. Global marine ecosystem models used for climate study have been shown to underestimate variability in a range of variables, including variability in carbon and oxygen fluxes over multiple time and space scales, and variability in plankton biomass. The incapacity of the current generation of ocean carbon models to reproduce observed variability means instabilities in marine ecosystems and associated carbon fluxes have never been adequately explored.Mortality processes are critical in the ocean because the biomass turns over very quickly. Yet mortality processes have received little attention so far. Recent advances in observation technology (particularly genomics and automated imaging) and in knowledge have highlighted processes that could radically alter mortality processes in the ocean. Marine Frontiers will attempt, for the first time, to model three of the most important triggers of mortality, in order to explore the stability of marine ecosystems in a changing environment. Marine Frontiers will expand mortality processes in the NEMO-PlankTOM model using theory, observations, and new computing methods. A new framework for representing marine ecosystems is proposed through the representation of Particle Functional Types (PtclFTs) that include living particles such as phytoplankton, zooplankton, and bacteria, as well as dead particles such as virus, microplastics, and organic aggregates of different size.Viruses will be introduced as a new PtclFT of inert properties. Viruses will be parameterised with a reproduction and decay rates based on recent insights from ocean observations. Early life cycles will be introduced for crustaceans, jellyfish, and pteropods, initially through the explicit representation of the eggs, the larvae and the adult stages, but with optimisation of model resources in a second stage. Microplastics will be introduced as a new PtclFT of inert properties, using an ocean influx based on observations and a decay rate optimised to the observed distribution. Microplastics will penetrate the food chain through incidental grazing by zooplankton, causing physical damages and chemical poisoning.An advanced approach to validate the model will be developed using emergent properties of the ecosystem functioning such as the North/South ratio in chla, the maximum intensity of the Spring bloom, patchiness, and trophic pyramids. This is in addition to standard validation biogeochemical fields (nutrients, carbon, biomass). Emergent properties and theoretical analysis of the strengths of food webs will also serve to establish precursor indicators for instabilities. The model will then be used to explore the sensitivity of marine ecosystems and resulting carbon export to growing external pressures from climate change, ocean acidification, microplastic pollution, fisheries, and combined stressors. This highly ambitious project builds on nine "Greenocean" Workshops led by the project Principal Investigator (PI), and international collaborations with experts at the forefront of understanding and observing marine ecosystems. The PI is a world leader who has demonstrated experience in leading cutting-edge research. She is a Fellow of the Royal Society, a highly cited researcher for 2018 & 2019, and has won seven Prizes and Medals for her work.