The Lake Hazen watershed as a sentinel of Arctic environmental change

哈森湖流域是北极环境变化的哨兵

• 批准号: RGPIN-2014-04365
• 负责人: StLouis, Vincent
• 金额: $ 2.62万
• 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: 2017
• 资助国家: 加拿大
• 起止时间: 2017-01-01 至 2018-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=631882
• 关键词: Lake; Hazen; watershed; sentinel; Arctic

Current climate change models predict that in the Canadian high Arctic, temperatures will rise 3-5°C over most land areas by 2100, but up to 9°C in the very northern Canadian Arctic Archipelago. At the same time, mean annual precipitation is predicted to increase ~12% for the Arctic, but up to 35% in regions with the highest warming. Such warming and wetting is anticipated to greatly alter the energy balance of Arctic landscapes, resulting in melting of glaciers, permafrost thaw, longer growing seasons and increased plant production on landscapes and in freshwaters. In fact, not only are these changes anticipated, but most are already occurring in Quttinirpaaq National Park (QNP; northern Ellesmere Island, Nunavut), Canada’s most northerly National Park. Situated in the middle of QNP is Lake Hazen, the world’s largest lake by volume north of the Arctic Circle. It supports one of the largest stocks of landlocked Arctic char, which has been historically harvested by Inuit, Thule and Paleo-Eskimo peoples. Lake Hazen is 540 km2 in surface area and 265 m deep, and has a 8400 km2 watershed that is half glaciated. Satellite observations of the watershed have revealed 2006-2012 summer glacier surface temperatures up to 1.3°C warmer than during 2000-2005, and a decline in ice cover duration on Lake Hazen. This has resulted in recent 10-fold increases in glacial meltwater and sediment inputs into Lake Hazen. Despite these recent and significant changes in the watershed, we know very little about how they are impacting water quality and metabolism in Lake Hazen itself, a freshwater jewel of Canada’s high Arctic. Will these landscape changes lead to a cascade of effects that will not only impact the normal metabolic functioning of Lake Hazen (e.g., algal production, sediment microbial respiration), but also degrade ecosystem services of socio-economic significance? I am proposing an integrated whole-ecosystem approach to quantifying impacts of climate change on high Arctic watersheds, using the Lake Hazen watershed as a sentinel system. There are three overarching objectives to my proposed research. My first objective is to quantify how the net energy balance of the Lake Hazen watershed is changing and how that is impacting both physical (e.g., the extent of permafrost thaw) and biological (e.g., plant production) processes occurring there. The second objective of my research program is to quantify inputs of organic carbon, nutrients and other chemical parameters including legacy contaminants (e.g., mercury, perfluorinated acids) to Lake Hazen from snowmelt, glacial melt and permafrost thaw. Finally, I am proposing to quantify how these inputs of organic carbon, nutrients and other chemical parameters are impacting metabolic processes like algal production and sediment microbial respiration, as well as basic water quality, in Lake Hazen. From a scientific basis, my team’s research will: 1) provide much-needed baseline data in Canada’s most understudied yet most changing ecoregion, from which all future data can be benchmarked; 2) assist modelers in predicting broader changes across the high Arctic; and 3) provide ground-truthing for remote sensors and satellite imagery. From the more applied and socio-economic perspective, increasing our ability to predict impacts of warming northern ecosystems on watershed productivity and water quality is vital for securing food, clean drinking water and traditional lifestyles for Northern peoples, as well as for sustainable resource development. All funding will go directly towards the training of highly qualified personnel, including northern training, consultation and outreach.

目前的气候变化模型预测，到2100年，在加拿大北极高地，大多数陆地地区的气温将上升3-5°C，但在加拿大北极群岛的北方，气温将上升9°C。与此同时，预计北极的年平均降水量将增加约12%，但在变暖最严重的地区，年平均降水量将增加35%。预计这种变暖和变湿将大大改变北极景观的能量平衡，导致冰川融化、永久冻土融化、生长季节延长以及景观和淡水中植物产量增加。事实上，这些变化不仅在预期之中，而且大多数已经发生在加拿大最北端的国家公园--库蒂尼帕克国家公园（QNP;埃尔斯米尔岛北方，努纳武特）。哈岑湖位于昆士兰州北部，是北极圈以北世界上体积最大的湖泊。它支持内陆北极炭的最大库存之一，历史上由因纽特人，图勒人和古爱斯基摩人收获。哈岑湖面积540平方公里，深265米，有一个8400平方公里的半冰川流域。对该流域的卫星观测显示，2006-2012年夏季冰川表面温度比2000-2005年高1.3°C，哈岑湖的冰盖持续时间减少。这导致最近进入哈岑湖的冰川融水和沉积物增加了10倍。尽管流域最近发生了这些重大变化，但我们对它们如何影响哈岑湖本身的水质和新陈代谢知之甚少，哈森湖是加拿大北极地区的淡水宝石。这些景观变化是否会导致级联效应，不仅会影响哈岑湖的正常代谢功能（例如，藻类生产、沉积物微生物呼吸），但也会降低具有社会经济意义的生态系统服务？我建议采用一种综合的全生态系统方法，以哈岑湖流域为哨兵系统，量化气候变化对北极高流域的影响。我提出的研究有三个总体目标。我的第一个目标是量化哈岑湖流域的净能量平衡是如何变化的，以及这是如何影响两个物理（例如，永久冻土融化的程度）和生物（例如，生产过程中发生的。我的研究计划的第二个目标是量化有机碳，营养素和其他化学参数的输入，包括遗留污染物（例如，汞，全氟酸）到哈岑湖从融雪，冰川融化和永久冻土融化。最后，我建议量化这些有机碳，营养物质和其他化学参数的输入是如何影响代谢过程，如藻类生产和沉积物微生物呼吸，以及基本的水质，在哈岑湖。从科学的角度来看，我的团队的研究将：1）在加拿大研究最不足但变化最大的生态区提供急需的基线数据，所有未来的数据都可以以此为基准; 2）协助建模人员预测整个北极地区更广泛的变化; 3）为遥感器和卫星图像提供地面实况。从更实用和社会经济的角度来看，提高我们预测北方生态系统变暖对流域生产力和水质的影响的能力，对于确保北方人民的粮食、清洁饮用水和传统生活方式以及可持续资源开发至关重要。所有资金将直接用于培训高素质人员，包括北方培训、咨询和外联。