The biogeochemistry and ecology of Arctic aquatic ecosystems

北极水生生态系统的生物地球化学和生态学

• 批准号: 444873-2013
• 负责人: Tank, Suzanne
• 金额: $ 1.46万
• 依托单位: University of Alberta
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Northern Research Supplement
• 财政年份: 2018
• 资助国家: 加拿大
• 起止时间: 2018-01-01 至 2019-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=666521
• 关键词: biogeochemistry; ecology; Arctic; aquatic; ecosystems

Permafrost, which covers about half of Canada's landmass, is thawing throughout the Arctic. One of the results of this change to our northern landscapes is that the carbon (C), and other constituents currently 'locked away' (sequestered) in frozen ground are becoming available for reaction within and liberation from soils, and transport to aquatic environments. We are proposing to work in the western Canadian Arctic to investigate changes in the delivery of dissolved inorganic and dissolved organic C (DIC, DOC) from land to the aquatic environment with permafrost thaw, and the implications of this change. Both DIC and DOC are central components of the overall C cycle, but with contrasting effect. On the one hand, DIC typically represents an atmospheric CO2 sink: bicarbonate (HCO3-), generally the largest component of the aquatic DIC pool, is mainly produced by chemical weathering, whereby CO2 dissolved in water (carbonic acid) drives chemical reactions with rock or mineral soils, and causes the original CO2 to become 'fixed' as HCO3-. In contrast, the DOC that is mobilized from permafrost soils by the dissolution of soil organic C in water represents a future CO2 source, following DOC degradation to CO2 by sunlight or bacteria. These processes are significant: while weathering is one of the two primary CO2 sequestration mechanisms on land, about twice as much organic C is sequestered by permafrost as currently exists in the atmosphere as CO2. This research will quantify changes in chemical weathering with permafrost thaw, the susceptibility of permafrost DOC to capture by mineral soils and degradation by sunlight and bacteria, and how the C balance of DIC creation and DOC liberation offset each other. As such, it will aid in our understanding of the future trajectory of the northern aquatic C cycle, focusing specifically on a region (the western Canadian Arctic) where warming is intense and permafrost thaw is causing massive thaw slumps. This work will result in the training of numerous highly qualified personnel. It will also specifically integrate northern training and northern knowledge into the research endeavour, and facilitate outreach to northern communities to enable northern input to, and feedback on, this work.********

覆盖加拿大一半陆地的永久冻土层正在整个北极融化。我们北方景观的这种变化的结果之一是，目前“锁定”（封存）在冻土中的碳（C）和其他成分正在变得可以在土壤中反应和释放，并运输到水生环境。我们提议在加拿大西部北极地区开展工作，调查随着永久冻土解冻，溶解无机碳和溶解有机碳（DIC、DOC）从陆地向水生环境输送的变化，以及这种变化的影响。DIC和DOC都是整个C循环的中心成分，但作用不同。一方面，DIC通常代表大气CO2汇：碳酸氢盐（HCO 3-）通常是水生DIC池的最大成分，主要由化学风化产生，溶解在水中的CO2（碳酸）驱动与岩石或矿物土壤的化学反应，并导致原始CO2成为HCO 3-。与此相反，DOC动员从永冻层土壤中溶解的土壤有机碳在水中代表未来的CO2源，DOC降解为CO2的阳光或细菌。这些过程非常重要：虽然风化作用是陆地上两种主要的CO2隔离机制之一，但永久冻土隔离的有机C大约是目前大气中CO2的两倍。这项研究将量化的化学风化与永冻层融化，永冻层DOC的敏感性捕获矿质土壤和降解的阳光和细菌，以及如何碳平衡DIC创建和DOC释放相互抵消的变化。因此，它将有助于我们了解北方水生碳循环的未来轨迹，特别是在一个地区（加拿大北极西部），变暖是激烈的和永久冻土融化造成大规模的融化滑坡。这项工作将培养大量高素质人员。它还将具体地将北方培训和北方知识纳入研究工作，并促进与北方社区的联系，使北方能够对这项工作提供投入和反馈。