SGER: Measuring and Interpreting Nitrogen in Tree Rings

SGER：测量和解释树木年轮中的氮

• 批准号: 0087007
• 负责人: Paul Sheppard
• 金额: $ 6万
• 依托单位: University of Arizona
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-08-01 至 2004-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0087007&HistoricalAwards=false
• 关键词: SGER; Measuring; Interpreting; Nitrogen; Tree

Abstract 00-87007 Sheppard SGER: Measuring and interpreting nitrogen in tree rings Presently, scientists cannot unequivocally interpret nitrogen concentrations in tree rings. The ability to do this would greatly improve understanding of N cycling, including the effects of recent large anthropogenic increases in N deposition. One difficulty in interpreting N concentration in tree rings is that N is notoriously mobile across plant tissues, rendering questionable its simple interpretability in tree rings as indicators of environmental availability at the time of ring formation. Another difficulty that has confounded simple interpretations of tree-ring N concentration is that its response to changes in N availability and uptake is still uncertain. This exploratory research has two objectives: to refine techniques for accurately measuring N in tree rings and accounting for possible translocation of N across rings, and to calibrate the response of N concentration in tree rings to known changes in N availability.

Sheppard SGER：测量和解释树木年轮中的氮目前，科学家们还不能明确地解释树木年轮中的氮浓度。这样做的能力将大大提高对氮循环的理解，包括最近大量人为增加的氮沉降的影响。解释树木年轮中N浓度的一个困难是，众所周知，N在植物组织中是可移动的，这使得其在树木年轮中作为年轮形成时环境可用性指标的简单解释受到质疑。另一个使树轮氮浓度的简单解释变得混乱的困难是，它对氮有效性和吸收变化的反应仍然不确定。本探索性研究有两个目的：完善准确测量树木年轮中N的技术，并计算N在年轮之间可能的转运，以及校准树木年轮中N浓度对已知N有效性变化的响应。