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: $ 0.07万
• 依托单位: York University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Northern Research Supplement
• 财政年份: 2014
• 资助国家: 加拿大
• 起止时间: 2014-01-01 至 2015-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=554081
• 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.

覆盖加拿大约一半陆地的永久冻土正在整个北极地区融化。我们北方景观的这种变化的结果之一是，碳（C）和目前“锁定”（隔离）在冻土中的其他成分正在变得可在土壤内发生反应并从土壤中释放出来，并运输到水生环境中。我们提议在加拿大西部北极地区开展工作，调查永久冻土融化时溶解性无机碳和溶解性有机碳（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 循环的核心组成部分，但效果却截然不同。一方面，DIC通常代表大气CO2汇：碳酸氢盐(HCO3-)，通常是水生DIC池的最大组成部分，主要是由化学风化产生的，其中溶解在水中的CO2(碳酸)驱动与岩石或矿质土壤的化学反应，并导致原始CO2被“固定”为HCO3-。相比之下，通过土壤有机碳溶解在水中而从永久冻土中释放的 DOC 代表了未来的 CO2 来源，随后 DOC 被阳光或细菌降解为 CO2。这些过程意义重大：虽然风化是陆地上两种主要的二氧化碳封存机制之一，但永久冻土封存的有机碳大约是目前大气中二氧化碳的两倍。这项研究将量化永久冻土融化导致的化学风化变化、永久冻土 DOC 被矿质土壤捕获以及阳光和细菌降解的敏感性，以及 DIC 产生和 DOC 释放的 C 平衡如何相互抵消。因此，它将有助于我们了解北部水生碳循环的未来轨迹，特别关注变暖剧烈且永久冻土融化导致大规模解冻衰退的地区（加拿大西部北极地区）。这项工作将培训大量高素质人才。它还将专门将北方培训和北方知识纳入研究工作，并促进对北方社区的宣传，以使北方能够对这项工作进行投入和反馈。