From ice to ocean: Understanding the impacts of melting glaciers on marine biogeochemical cycles

从冰到海洋：了解冰川融化对海洋生物地球化学循环的影响

• 批准号: RGPIN-2020-05975
• 负责人: Bhatia, Maya
• 金额: $ 2.19万
• 依托单位: University of Alberta
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=750893
• 关键词: ice; ocean; Understanding; impacts; melting

Climate change is the defining challenge of our times, fundamentally reorganizing our planet's ecosystems and the human societies they support. Nowhere is this more evident than in Canada's Arctic, where melting glaciers define the landscape. While the contributions of these shrinking ice masses to sea level rise are undisputed, their role in broader biogeochemical cycling is just beginning to be revealed. When glaciers melt, they contribute large quantities of water, ice, sediments, and dissolved chemicals to the ocean. Recent work around Greenland and Antarctica shows that glacially-associated nutrients and carbon have the potential to stimulate production at the base of marine food webs with associated impacts up the food chain (e.g., enhanced local fish harvests) and on the broader carbon cycle via a more active marine biological pump. Yet, knowledge gaps remain about what life-essential elements are exported from glacial systems, what happens to this discharge in the ocean, and what the impacts are on marine microbial communities. Nowhere are these gaps in knowledge more prominent than in the Canadian Arctic Archipelago (CAA) - a region where the role of glacial meltwater in marine biogeochemical cycles is largely unexplored - despite the fact that the CAA is a hotspot for glacial retreat and meltwater runoff to the ocean. Over the next 5 years, my group and I will work to quantify contemporary export of nutrients and carbon from glacial systems, and the associated impact of this export on marine processes and ecosystems. Specifically we will ask: 1) What is the source of biogeochemical constituents (nutrients, carbon) leaving the ice system? 2)What is the fate of glacial meltwater and its associated constituents in the coastal ocean? and 3) How does glacial meltwater impact marine microbial community production, structure, and function? To answer these questions we will conduct novel ice-to-ocean studies, combining field measurements of chemical species with molecular biological assays and laboratory experiments. This approach will address the impact of meltwater interactions close to the glacier termini and at broader regional scales, and target unanswered mechanistic questions. My program will be achieved by HQP using interdisciplinary techniques, bridging oceanography, geochemistry and microbial ecology. Together we will do this work in Jones Sound in the CAA, a region surrounded by glaciers and home to Inuit hamlet of Grise Fiord. The termini of tidewater glaciers here are highly productive waters, serving as hunting grounds for the hamlet. Understanding the drivers of marine production at the base of the food web, and the susceptibility of these drivers to climate change, is important to the long-term health of this northern community, and to coastal Arctic ocean functioning. Collectively, this research is a critical step towards revealing the role of melting glaciers on the marine carbon cycle in the past, present, and future.

气候变化是我们这个时代的决定性挑战，它从根本上重组了我们星球的生态系统及其所支持的人类社会。这一点在加拿大北极地区最为明显，那里的地貌由融化的冰川决定。虽然这些萎缩的冰块对海平面上升的贡献是无可争议的，但它们在更广泛的生物地球化学循环中的作用才刚刚开始被揭示。当冰川融化时，它们会向海洋贡献大量的水、冰、沉积物和溶解的化学物质。最近围绕格陵兰岛和南极洲开展的工作表明，与冰川相关的营养物和碳有可能刺激海洋食物网基础的生产，并对食物链上游产生相关影响（例如，增加当地鱼类收成），并通过以下方式影响更广泛的碳循环：更活跃的海洋生物泵。然而，对于从冰川系统输出哪些生命必需元素、这些排放物在海洋中发生了什么以及对海洋微生物群落的影响，仍然存在知识差距。这些知识差距在加拿大北极群岛 (CAA) 最为突出，该地区的冰川融水在海洋生物地球化学循环中的作用基本上尚未被探索，尽管 CAA 是冰川退缩和融水径流的热点地区。海洋。 在接下来的五年中，我和我的团队将致力于量化当代冰川系统的营养物和碳的输出，以及这种输出对海洋过程和生态系统的相关影响。具体来说，我们会问：1）离开冰系统的生物地球化学成分（营养物、碳）的来源是什么？ 2）沿海海洋中冰川融水及其相关成分的命运如何？ 3）冰川融水如何影响海洋微生物群落的生产、结构和功能？为了回答这些问题，我们将进行新颖的冰到海洋研究，将化学物质的现场测量与分子生物学测定和实验室实验相结合。这种方法将解决靠近冰川终点和更广泛区域尺度的融水相互作用的影响，并针对尚未解答的机械问题。我的项目将由 HQP 使用跨学科技术、桥梁海洋学、地球化学和微生物生态学来实现。我们将一起在 CAA 的琼斯湾开展这项工作，该地区被冰川包围，也是格里斯峡湾因纽特人村庄的所在地。这里的潮水冰川的终点是高产水域，是这个小村庄的狩猎场。了解食物网基础上海洋生产的驱动因素，以及这些驱动因素对气候变化的敏感性，对于这个北部社区的长期健康以及北冰洋沿海的功能非常重要。总的来说，这项研究是揭示冰川融化对过去、现在和未来海洋碳循环作用的关键一步。