Arctic Marine Biogeochemistry

北冰洋作为大气二氧化碳的汇，在全球气候系统中扮演着重要的角色。然而，北极海洋系统正在迅速和不可预测地变化，以应对全球气候变化，这可能会对其二氧化碳吸收潜力和对海洋酸化的敏感性产生影响。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了解仍然局限于某些部门，包括加拿大北极群岛，这妨碍了我们评估其目前和未来对沿海生态系统的影响的能力。总体而言，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的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)、位置(区域变异性)和时间(季节性和年际变异性)对加拿大北极群岛海岸线碳循环过程的影响。特别是，这项研究的目标是：(I)描述河流-海洋混合区的碳和营养交换的特征，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)在决定沿海海洋的二氧化碳汇-源地位和对海洋酸化的敏感性方面的季节性作用；(Iii)研究当地碳循环过程如何在规模上串连影响区域碳动态。这些目标将通过在整个加拿大北极群岛南部的战略地点沿海陆混合梯度追踪淡水来实现，并将与北部社区密切合作执行。将北方社区成员作为这项研究的核心组成部分，将产生整合当地土著知识的机会，提供对沿海生态系统变化的长期驱动因素的独特了解。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.