Whole ecosystem carbon dynamics in lakes: accumulation, processing and degassing at different temporal and spatial scales

湖泊整个生态系统碳动态：不同时空尺度的积累、处理和脱气

• 批准号: 42418-2011
• 负责人: Prairie, Yves
• 金额: $ 2.77万
• 依托单位: Université du Québec à Montréal
• 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=521651
• 关键词: Whole; ecosystem; carbon; dynamics; lakes

At the global scale, lakes and rivers occupy a very small fraction of the landscape. Yet, our research has shown that they emit surprisingly large quantities of greenhouse gases (mostly carbon dioxide) to the atmosphere, nearly as much as the oceans currently absorb annually. Similarly, lakes also accumulate and store organic carbon in their sediments. Because of the high preservation observed in freshwater environments, lake sediments often contain as much carbon as the soils of their entire watersheds. Globally, this carbon sink is much larger than that of the oceans. In this proposal, we wish to increase our understanding of the factors determining 1) the rate at which carbon is emitted to the atmosphere and 2) the rates at which it accumulates in sediments. More specifically, we propose to develop multi-lake and multi-regional models predicting carbon accumulation in lakes at three different time scales (annual, multi-decadal, and millennial scales). We also propose to examine the factors influencing gas exchange, an important variable that determines how fast carbon dioxide and methane can be exchanged with the atmosphere. In addition, we will further test our earlier discovery that a significant part of methane escapes lake surface through evasion of methane microbubbles and test whether their importance can be better quantified and predicted.

在全球范围内，湖泊和河流只占景观的一小部分。然而，我们的研究表明，它们向大气中排放了令人惊讶的大量温室气体(主要是二氧化碳)，几乎相当于目前海洋每年吸收的量。同样，湖泊也会在沉积物中积累和储存有机碳。由于在淡水环境中观察到的高度保存性，湖泊沉积物通常含有与其整个流域的土壤一样多的碳。在全球范围内，这个碳汇比海洋的碳汇要大得多。在这项提案中，我们希望增加我们对决定1)碳排放到大气的速率和2)碳在沉积物中积累的速率的因素的理解。更具体地说，我们建议开发多湖泊和多区域模型，在三个不同的时间尺度(年、多十年和千年尺度)预测湖泊中的碳积累。我们还建议研究影响气体交换的因素，这是一个重要的变量，决定了二氧化碳和甲烷与大气交换的速度。此外，我们将进一步检验我们早先的发现，即很大一部分甲烷是通过逃避甲烷微气泡而逃出湖面的，并测试是否可以更好地量化和预测它们的重要性。