Temperature responses of leaf dark respiration and their implications for tropical forest carbon balance

据估计，植物的暗呼吸（即新陈代谢的能量消耗）消耗了森林生态系统中每日光合作用碳吸收率的30-80%，并预计会随着变暖而增加。该项目将利用巴拿马史密森尼热带研究所管理的树冠起重机，研究气候变暖如何影响热带森林上层树冠的暗呼吸和光合作用碳吸收。该项目的最终目标是推进基于过程的森林碳动态模型及其对气候变化的响应。研究人员将利用自然环境变化和实验室温度控制条件下的原位测量，对具有不同生态特征的常绿乔木、落叶乔木和木本藤本等不同物种的暗呼吸与温度的关系进行表征。对冠层叶片和幼苗的长期温度制度的实验操作将用于测试它们是否能够适应或改善温度升高对其碳平衡和生长速度的负面影响。因此，该项目的结果将填补热带森林植物暗呼吸特征经验知识的关键空白，热带森林负责全球光合作用碳吸收的三分之一以上。研究人员将把这些经验数据应用到一个复杂的气候-植被反馈计算机模拟模型中，并评估热带森林的物种多样性和相关功能多样性如何响应气候变化和大气二氧化碳浓度。该项目将大大促进正在进行的开发应对气候变化和可持续发展的综合学术项目的努力。该项目将为本科生和研究生提供研究和参与式学习的机会。课程将通过生态系统建模练习来加强，说明气候-植被的反馈，以及在线活动，学生将了解正在进行的项目和实验，并参与基于博客的讨论。

Dark respiration by plants (i.e., energy consumption for metabolism) is estimated to consume 30-80% of daily photosynthetic carbon uptake in forest ecosystems and is predicted to increase with warming. This project will study how climate warming affects dark respiration and photosynthetic carbon uptake by leaves in the upper tropical forest canopy, using a canopy crane managed by the Smithsonian Tropical Research Institute in Panama. The ultimate goal of this project is to advance a process-based model of forest carbon dynamics and its response to climate changes. The investigators will characterize the relationship between dark respiration and temperature for various species with different ecological characteristics, such as evergreen trees, deciduous trees and woody vines, using in-situ measurements under natural environmental variation as well as measurements under controlled temperature settings in the lab. Experimental manipulation of long-term temperature regimes for canopy leaves and seedlings will be used to test whether they can acclimate or ameliorate the negative impact of warmer temperature on their carbon balance and growth rates. Thus, the results of this project will fill a critical gap in empirical knowledge of dark respiration characteristics of plants in tropical forests, which are responsible for more than one third of the global photosynthetic carbon uptake. The researchers will apply the empirical data to a sophisticated computer-simulation model of climate-vegetation feedbacks, and evaluate how species diversity and associated functional diversity in the tropical forests respond to changing climate and atmospheric carbon dioxide concentration. The project will add significantly to ongoing efforts to develop comprehensive academic programs that address climate change and sustainability. The project will provide research and participatory learning opportunities to undergraduate and graduate students. Courses will be enhanced through ecosystem modeling exercises that illustrate climate-vegetation feedbacks, as well as online activities in which students will learn about the ongoing projects and experiments and engage in blog-based discussions.