COLLABORATIVE RESEARCH: Nitrogen Retention and Ecosystem Succession: Theory Meets Data

合作研究：氮保留和生态系统演替：理论与数据的结合

• 批准号: 1257808
• 负责人: Christine Goodale
• 金额: $ 26.6万
• 依托单位: Cornell University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-09-01 至 2018-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1257808&HistoricalAwards=false
• 关键词: COLLABORATIVE; RESEARCH; Nitrogen; Retention; Ecosystem

Nitrogen is a critical nutrient for forests, and scarcity of nitrogen often limits forest growth. Theoretical considerations in ecology indicate that as a forest ages and its growth slows, its uptake of nitrogen from the soil should also slow, leading to increased loss of nitrogen in drainage water. Long-term measurements of nitrogen in streams draining the Hubbard Brook Experimental Forest in New Hampshire contradict this expected pattern. This project seeks to understand the discrepancy between the theory and the data by testing the hypothesis that young forests extract nitrogen from deep soils, but as the forest ages, re-accumulation of the nitrogen in the soil delays the loss of nitrogen in drainage water. The hypothesis will be tested by a field experiment to determine the propensity for nitrogen accumulation in soil beneath forest stands of different ages, and careful accounting of the amount of nitrogen in a sequence of forests ranging from 15 to over 200 years old. In addition, a computer simulation model of forest ecosystems will be revised to incorporate these new observations. This work is important for management of forests to minimize loss of nitrogen, a key plant nutrient. Air pollution adds excess nitrogen to the forest, and if it is lost in drainage water, it can pollute streams and lakes. The project will involve training of two graduate students and two postdoctoral associates, and a teacher training module will help two high school science teachers develop a unit for teaching about forest ecology in their classrooms.

氮是森林的重要养分，氮的缺乏往往限制了森林的生长。 生态学的理论考虑表明，随着森林年龄的增长和生长的减缓，它从土壤中吸收氮的速度也会减慢，导致排水中氮的损失增加。 对新罕布什尔州哈伯德布鲁克实验森林的溪流中氮的长期测量与这种预期的模式相矛盾。该项目试图通过测试以下假设来理解理论与数据之间的差异：幼林从深层土壤中提取氮，但随着森林年龄的增长，土壤中氮的重新积累延迟了排水中氮的损失。 这一假设将通过一项实地实验来检验，以确定不同年龄的森林下土壤中氮积累的倾向，并仔细计算从15岁到200岁以上的森林序列中的氮含量。 此外，还将修订森林生态系统的计算机模拟模型，以纳入这些新的观察结果。这项工作对于森林管理非常重要，可以最大限度地减少氮的损失，氮是一种关键的植物营养素。空气污染给森林增加了过量的氮，如果氮在排水中流失，就会污染河流和湖泊。该项目将涉及培训两名研究生和两名博士后助理，教师培训单元将帮助两名高中科学教师开发一个在课堂上讲授森林生态学的单元。