Spatial and temporal variability of nitrogen cycling in forests

森林氮循环的时空变化

• 批准号: RGPIN-2016-05242
• 负责人: Casson, Nora
• 金额: $ 1.82万
• 依托单位: University of Winnipeg
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=754772
• 关键词: Spatial; temporal; variability; nitrogen; cycling

The water quality of streams and lakes located in Canada's boreal forests depend in large part on the cycling of water and nutrients [e.g. nitrogen (N)] on the landscape. These water and N cycling processes are extremely variable in both space and time, which makes it hard to predict how these cycles will respond to environmental changes, such as changes in the frequency or intensity of precipitation events. These events change the way water flows through forests and alter soil properties such as temperature and moisture. These environmental conditions determine the rates of N transformation processes in forests which ultimately determine the chemistry of lakes and streams that drain these forests. There are gaps in our scientific understanding of the controls on N processes in forests, and this limits our ability to make predictions about forest water quality into the future.The major objective of this proposal is to investigate hydrological and landscape controls on spatial and temporal variability in N cycling processes in forests, with a particular focus on the impact of increasing frequency and intensity of hydroclimatic events. We will investigate controls on N cycling in soils near the edge of streams which are particularly vulnerable to droughts and freezing. We will assess how flowpaths of water and N vary during events of different magnitudes and frequencies. We will examine where and when N2O, a potent but elusive greenhouse gas, in produced in forest soils. Ultimately, this work will provide critical insights into N cycling in forests, and help refine models of water quality responses to climate change.

位于加拿大北方森林的溪流和湖泊的水质在很大程度上取决于水和养分[例如氮（N）]在景观中的循环。这些水和氮循环过程在空间和时间上都是非常可变的，这使得很难预测这些循环将如何响应环境变化，例如降水事件的频率或强度的变化。这些事件改变了水流过森林的方式，并改变了土壤的性质，如温度和湿度。这些环境条件决定了森林中氮转化过程的速率，最终决定了这些森林中湖泊和溪流的化学性质。 有差距，我们的科学认识的控制在森林中的N过程，这限制了我们的能力，使森林水质预测到future.The主要目标的建议是调查水文和景观控制的空间和时间变异性在森林中的N循环过程，特别注重的影响日益增加的频率和强度的水文气候事件。我们将调查控制氮循环的河流，特别是容易受到干旱和冻结的边缘附近的土壤。我们将评估水和N的流动路径如何在不同量级和频率的事件中变化。我们将研究何时何地N2O，一个强大的，但难以捉摸的温室气体，在森林土壤中产生。最终，这项工作将为森林中的氮循环提供重要的见解，并帮助完善水质对气候变化的响应模型。