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Mechanistic understanding of the role of diatoms in the success of the Arctic Calanus complex and implications for a warmer Arctic

对硅藻在北极卡拉努斯复合体成功中的作用的机制理解以及对北极变暖的影响

基本信息

批准号：
NE/P006353/2
负责人：
Daniel Mayor
金额：
$ 20.36万
依托单位：
NATIONAL OCEANOGRAPHY CENTRE
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2019
资助国家：
英国
起止时间：
2019 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=NE%2FP006353%2F2
关键词：
Mechanistic understanding role diatoms success

项目摘要

Copepod species of the genus Calanus (Calanus hereafter) are rice grain-sized crustaceans, distant relatives of crabs and lobsters, that occur throughout the Arctic Ocean consuming enormous quantities of microscopic algae (phytoplankton). These tiny animals represent the primary food source for many Arctic fish, seabirds and whales. During early spring they gorge on extensive seasonal blooms of diatoms, fat-rich phytoplankton that proliferate both beneath the sea ice and in the open ocean. This allows Calanus to rapidly obtain sufficient fat to survive during the many months of food scarcity during the Arctic winter. Diatoms also produce one of the main marine omega-3 polyunsaturated fatty acids that Calanus require to successfully survive and reproduce in the frozen Arctic waters. Calanus seasonally migrate into deeper waters to save energy and reduce their losses to predation in an overwintering process called diapause that is fuelled entirely by carbon-rich fat (lipids). This vertical 'lipid pump' transfers vast quantities of carbon into the ocean's interior and ultimately represents the draw-down of atmospheric carbon dioxide (CO2), an important process within the global carbon cycle. Continued global warming throughout the 21st century is expected to exert a strong influence on the timing, magnitude and spatial distribution of diatom productivity in the Arctic Ocean. Little is known about how Calanus will respond to these changes, making it difficult to understand how the wider Arctic ecosystem and its biogeochemistry will be affected by climate change. The overarching goal of this proposal is to develop a predictive understanding of how Calanus in the Arctic will be affected by future climate change. We will achieve this goal through five main areas of research:We will synthesise past datasets of Calanus in the Arctic alongside satellite-derived data on primary production. This undertaking will examine whether smaller, more temperate species have been increasingly colonising of Arctic. Furthermore, it will consider how the timing of life-cycle events may have changed over past decades and between different Arctic regions. The resulting data will be used to validate modelling efforts.We will conduct field based experiments to examine how climate-driven changes in the quantity and omega-3 content of phytoplankton will affect crucial features of the Calanus life-cycle, including reproduction and lipid storage for diapause. Cutting-edge techniques will investigate how and why Calanus use stored fats to reproduce in the absence of food. The new understanding gained will be used to produce numerical models of Calanus' life cycle for future forecasting.The research programme will develop life-cycle models of Calanus and simulate present day distribution patterns, the timing of life-cycle events, and the quantities of stored lipid (body condition), over large areas of the Arctic. These projections will be compared to historical data.We will investigate how the omega-3 fatty acid content of Calanus is affected by the food environment and in turn dictates patterns of their diapause- and reproductive success. Reproductive strategies differ between the different species of Calanus and this approach provides a powerful means by which to predict how each species will be impacted, allowing us to identify the winners and losers under various scenarios of future environmental changes. The project synthesis will draw upon previous all elements of the proposal to generate new numerical models of Calanus and how the food environment influences their reproductive strategy and hence capacity for survival in a changing Arctic Ocean. This will allow us to explore how the productivity and biogeochemistry of the Arctic Ocean will change in the future. These models will be interfaced with the UK's Earth System Model that directly feeds into international efforts to understand global feedbacks to climate change.

Calanus 属的桡足类物种（以下简称 Calanus）是米粒大小的甲壳类动物，是螃蟹和龙虾的远亲，遍布北冰洋，消耗大量的微观藻类（浮游植物）。这些微小动物是许多北极鱼类、海鸟和鲸鱼的主要食物来源。在早春期间，它们会吃大量季节性开花的硅藻，这是一种富含脂肪的浮游植物，在海冰下和公海中繁殖。这使得哲水牛能够快速获得足够的脂肪，以便在北极冬季数月的食物短缺中生存。硅藻还产生一种主要的海洋 omega-3 多不饱和脂肪酸，这是哲水藻在冰冻的北极水域中成功生存和繁殖所必需的。哲水蚤会季节性地迁移到更深的水域，以节省能量并减少在称为滞育的越冬过程中因被捕食而造成的损失，该过冬过程完全由富含碳的脂肪（脂质）提供能量。这种垂直的“脂质泵”将大量碳转移到海洋内部，最终代表大气中二氧化碳（CO2）的减少，这是全球碳循环中的一个重要过程。整个21世纪持续的全球变暖预计将对北冰洋硅藻生产力的时间、幅度和空间分布产生重大影响。人们对卡拉努斯将如何应对这些变化知之甚少，因此很难理解更广泛的北极生态系统及其生物地球化学将如何受到气候变化的影响。该提案的总体目标是对北极的卡拉努斯将如何受到未来气候变化的影响进行预测。我们将通过五个主要研究领域来实现这一目标：我们将综合过去的北极卡拉努斯数据集以及卫星衍生的初级生产数据。这项工作将研究更小、更温带的物种是否越来越多地在北极定居。此外，它将考虑生命周期事件的时间在过去几十年中以及不同北极地区之间可能发生的变化。所得数据将用于验证建模工作。我们将进行实地实验，以研究气候驱动的浮游植物数量和 omega-3 含量变化将如何影响哲水蚤生命周期的关键特征，包括繁殖和滞育的脂质储存。尖端技术将研究哲水藻在没有食物的情况下如何以及为何利用储存的脂肪进行繁殖。获得的新认识将用于生成哲水蚤生命周期的数值模型，以供未来预测。该研究计划将开发哲水蚤生命周期模型，并模拟北极大片地区目前的分布模式、生命周期事件的时间以及储存的脂质（身体状况）的数量。这些预测将与历史数据进行比较。我们将研究 Calanus 的 omega-3 脂肪酸含量如何受到食物环境的影响，进而决定其滞育和繁殖成功的模式。不同种类的哲水龟的繁殖策略有所不同，这种方法提供了一种强大的方法来预测每个物种将受到的影响，使我们能够在未来环境变化的各种情况下确定赢家和输家。该项目综合将借鉴之前提案的所有要素，以生成新的哲水藻数值模型，以及食物环境如何影响其繁殖策略，从而影响其在不断变化的北冰洋中的生存能力。这将使我们能够探索北冰洋的生产力和生物地球化学未来将如何变化。这些模型将与英国的地球系统模型相结合，该模型直接参与国际社会了解全球对气候变化的反馈的努力。