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

University Of Florida, Gainesville FL

Investigators

Abstract

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.