Net ecosystem exchange of carbon greenhouse gases in high arctic ecoregions

北极高生态区碳温室气体的净生态系统交换

• 批准号: 203236-2009
• 负责人: StLouis, Vincent
• 金额: $ 3.21万
• 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: 2013
• 资助国家: 加拿大
• 起止时间: 2013-01-01 至 2014-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=523403
• 关键词: Net; ecosystem; exchange; carbon; greenhouse

Human activities have elevated global atmospheric concentrations of the greenhouse gases (GHGs) carbon dioxide (CO2) and methane (CH4) to levels that have resulted in an unequivocal and unprecedented warming of the Earth's climate system. This is especially true in the high Arctic, where in the past century average annual temperatures have increased at almost twice the global rate. Current climate models predict that in certain regions of the Canadian Arctic, by 2100, autumn/winter temperatures will increase by up to 9 C, while annual precipitation will likely rise by 35%. Such warming and wetting is anticipated to result in permafrost degradation and glacial melt, increased surface runoff, pond formation and/or drying, and increased vegetation growth (i.e., primary productivity) on landscapes. In polar desert regions of the high Arctic, large amounts of CO2 could be sequestered from the atmosphere through primary production if tundra vegetation colonizes the desert ecosystem in response to increased warming and wetting. In contrast, in regions with large stores of organic carbon in soil, the increased soil activity that will result from permafrost degradation may cause increased decomposition and release of CO2 and CH4 into the atmosphere, positively feeding back on global climate warming. We are proposing to quantify the impacts of climate change on the net exchange of CO2 and CH4 from both terrestrial and aquatic landscapes in Quttinirpaaq National Park, Ellesmere Island. Such new and comprehensive measurements, at the most northerly landscape ever studied, are essential to determine if this region is currently in a phase of net primary productivity or net decomposition, whether future warming will result in positive or negative feedbacks of GHGs to the atmosphere, and what role Arctic ecosystems will play in future trajectories of climate change. From a socio-economic perspective, primary productivity provides energy for herbivorous animals like caribou, muskox, and numerous aquatic organisms including fish. Thus, understanding the net exchange of CO2 in high Arctic landscapes is important for predicting how abundances of certain organisms used as Inuit traditional foods may be altered due to climate change.

人类活动已将全球大气中温室气体 (GHG)、二氧化碳 (CO2) 和甲烷 (CH4) 的浓度提高到一定水平，导致地球气候系统明显且前所未有的变暖。在北极地区尤其如此，在过去的一个世纪里，这里的年平均气温几乎以全球速度的两倍上升。目前的气候模型预测，到2100年，加拿大北极某些地区的秋冬气温将上升高达9摄氏度，而年降水量可能会增加35%。预计这种变暖和湿润将导致永久冻土退化和冰川融化、地表径流增加、池塘形成和/或干燥以及景观上植被生长（即初级生产力）增加。在北极高纬度的极地沙漠地区，如果苔原植被因气候变暖和湿润的加剧而在沙漠生态系统中定居，那么大量的二氧化碳可能会通过初级生产从大气中被封存。相比之下，在土壤中储存大量有机碳的地区，永久冻土退化导致的土壤活动增加可能会导致二氧化碳和甲烷分解增加并释放到大气中，从而对全球气候变暖产生积极的影响。我们提议量化气候变化对埃尔斯米尔岛库蒂尼尔帕克国家公园陆地和水生景观中二氧化碳和甲烷净交换的影响。在有史以来研究过的最北地貌上进行的这种新的、全面的测量对于确定该地区目前是否处于净初级生产力或净分解阶段、未来变暖是否会导致温室气体对大气的正反馈或负反馈，以及北极生态系统在未来气候变化轨迹中将发挥什么作用至关重要。从社会经济角度来看，初级生产力为驯鹿、麝牛等草食动物和包括鱼类在内的众多水生生物提供能量。因此，了解北极高地景观中二氧化碳的净交换对于预测因纽特人传统食物中某些生物体的丰度可能因气候变化而发生的变化非常重要。