Arctic Marine Biogeochemistry

北冰洋作为大气中二氧化碳的汇在全球气候系统中扮演着重要的角色。然而，由于全球气候变化，北极海洋系统正在发生迅速而不可预测的变化，对其二氧化碳吸收潜力及其对海洋酸化的敏感性产生了潜在影响。在过去的几十年里，观测到的海冰、河流流量和沿海永久冻土的变化已经改变了北极淡水系统和海洋碳循环。不幸的是，我们对这些变化的影响的理解在某些部门仍然有限，包括加拿大北极群岛，阻碍了我们评估它们对沿海生态系统当前和未来影响的能力。总的来说，了解北极变暖对淡水和海洋碳循环的影响对于预测海洋酸化对沿海生态系统动态的影响以及北冰洋作为重要二氧化碳汇能力的长期变化至关重要。拟议的研究将调查淡水来源（海冰融化、河流）、地点（区域变异）和时间（季节和年际变异）对加拿大北极群岛海岸线碳循环过程的影响。特别是，本研究的目标是：(i)表征跨河海混合带的碳和营养交换，并确定沿这一梯度改变碳的关键过程；（ii）确定不同淡水来源（海冰融化、河流径流）在确定沿海海洋二氧化碳汇源状况和海洋酸化敏感性方面的季节性作用；（三）考察本地碳循环过程如何在规模上级联影响区域碳动态。为了实现这些目标，将在整个南加拿大北极群岛的战略地点沿着陆海混合梯度跟踪淡水，并将与北部社区密切合作。将北部社区成员作为这项研究的核心组成部分，将为整合当地土著知识创造机会，为沿海生态系统变化的长期驱动因素提供独特的理解。通过这些合作产生的见解将支持生态系统模型的开发和应用，这些模型将用于预测未来的海洋酸化状态和北极沿海海域二氧化碳汇源状态的变化。

The Arctic Ocean plays an important role in the global climate system as a sink for atmospheric CO2. However, the Arctic marine system is changing rapidly and unpredictably in response to global climate change, with potential consequences for its CO2 uptake potential, and its sensitivity to ocean acidification. Over the past few decades, observed changes in sea ice, river discharge, and coastal permafrost have altered both the Arctic freshwater system and the marine carbon cycle. Unfortunately, our understanding of the influences of these changes is still limited in certain sectors, including the Canadian Arctic Archipelago, hindering our ability to assess their present and future impacts on the coastal ecosystem. Overall, understanding the influences of Arctic warming on freshwater and the marine carbon cycle will be crucial to predicting the impacts of ocean acidification on coastal ecosystem dynamics and the long-term changes in the Arctic Ocean's ability to act as an important CO2 sink. The proposed research will investigate the influences of freshwater source (sea ice melt, rivers), location (regional variability), and timing (seasonal and inter-annual variability) on carbon cycle processes along the Canadian Arctic Archipelago coastline. In particular, the objectives of this research are to: (i) characterize carbon and nutrient exchanges across the river-ocean mixing zone and identify the key processes that modify carbon along this gradient; (ii) determine the seasonal roles of different sources of freshwater (sea ice melt, river runoff) in setting the CO2 sink-source status of the coastal ocean and sensitivity to ocean acidification; and (iii) examine how local carbon-cycle processes cascade in scale to affect regional carbon-dynamics. These objectives will be achieved by tracking freshwater along the land-to-sea mixing gradient at strategic locations throughout the southern Canadian Arctic Archipelago and will be carried out in close collaboration with northern communities. Engaging northern community members as a core component of this research will generate opportunities to integrate local Indigenous Knowledge, providing a unique understanding of the long-term drivers of coastal ecosystem change. Insights generated through these collaborations will support the development and application of ecosystem models that will be used to predict future ocean acidification states and changes to the CO2 sink-source status of Arctic coastal seas.