Understanding the links between pelagic microbial ecosystems and organic matter cycling in the changing Arctic (Micro-ARC)

北冰洋在调节全球气候方面的关键作用对气候变化高度敏感。在最近一段时间里，北极气温的上升幅度超过了全球平均水平，导致多年海冰消失，生态系统结构和功能发生根本性变化。北极初级生产力和生物地球化学循环预计将发生变化。更长的无冰期和更薄的海冰增加了光的可获得性，增加了浮游植物的产量，这也可能受到二氧化碳增加的进一步刺激。我们已经组建了一个多学科的英国/德国团队来应对NERC/BMBF北极呼吁，他们在海洋远洋生态系统的结构和功能方面拥有著名的开创性研究记录，包括在北极的广泛研究。该项目的主要目的是提高我们对北冰洋物理环境的短期(如季节性)和长期(如气候驱动)变化如何影响远洋微生物生态系统，以及这些变化如何影响当前和未来的有机质(OM)生物地球化学的理解。我们活动的重点主要是应对NERC/BMBF北极呼吁挑战1“发展对北极生态系统结构和功能的量化了解”。我们的多学科团队拥有海洋微生物生态学、OM生物地球化学、极地浮游生物生态学和生态系统建模方面的专业知识，将全面描述与OM循环有关的远洋北极食物网的微生物基础(古生菌、细菌、原生生物，包括浮游植物和真菌)。通过一个全面的多地点和多季节邮轮方案，我们将解决北极微生物生态系统结构和功能之间在广泛的海冰环境中的联系方面的主要知识差距。我们的采样策略，包括很少采样的冬季和早春，将使我们能够量化北极季节性对与OM循环相关的微生物生态系统结构和功能的影响，使我们能够跟踪自养和异养生产的主要变化。结合观察和建模，我们将分析在季节尺度上影响微生物动态和随后的OM循环的潜在机制。模式的建立将整合强迫数据和Nemo-Medusa模拟的结果。数据模型合成将使我们能够解决和约束仍未解决的过程或假定在Medusa中不变的过程。因此，我们的模型结果将指明未来使用NEMO-Medusa和英国地球系统模型(UKESM)对北极进行预测时可能考虑的不确定范围。

The Arctic Ocean's key role in regulating the global climate is highly sensitive to climate change. Arctic temperatures have increased more strongly than the global average during the recent past, causing a loss of multiyear sea-ice and fundamental changes in ecosystem structure and function. Arctic primary production and biogeochemical cycling are projected to change. Longer ice-free periods and thinner sea-ice increase light availability, enhancing phytoplankton production, which may also be further stimulated by increased carbon dioxide. We have assembled a multidisciplinary UK/German team to address this NERC/BMBF Arctic call with a renowned track record of pioneering research concerning the structure and function of marine pelagic ecosystems, including extensive research in the Arctic. This project has the overarching aim to improve our understanding of how short-term (e.g. seasonal-scale) and long-term (e.g. climate-driven) changes in the physical environment of the Arctic Ocean are impacting pelagic microbial ecosystems and how these affect current and future organic matter (OM) biogeochemistry. The focus of our activities principally addresses the NERC/BMBF Arctic call Challenge 1 "To develop quantified understanding of the structure and functioning of Arctic ecosystems". Our multidisciplinary team with expertise in marine microbial ecology, OM biogeochemistry, polar plankton ecology, and ecosystem modelling will fully characterise the microbial base (archaea, bacteria, protists including phytoplankton and fungi) of the pelagic Arctic food web in relation to OM cycling. Through a comprehensive multi-location and multi-seasonal cruise programme, we will address major knowledge gaps in the links between Arctic microbial ecosystem structure and function across a broad range of sea-ice environments. Our sampling strategy, including the rarely sampled winter and early spring, will allow us to quantify impacts of Arctic seasonality on the structure and functioning of microbial ecosystems in relation to OM cycling, allowing us to track major changes in autotrophic and heterotrophic production. Combining observation and modelling, we will analyse the underlying mechanisms that impact microbial dynamics and subsequent OM cycling on seasonal scales. The model setup will integrate forcing data and results of NEMO-MEDUSA simulations. Data-model synthesis will enable us to resolve and constrain processes that remain either unresolved or are assumed constant in MEDUSA. Our model results will thus specify uncertainty ranges that may be accounted for in future projections of the Arctic with NEMO-MEDUSA and the UK Earth System Model (UKESM).