NSF Award Abstract - #0223312

AWSFL008-DS3

CaRTE Workshop: Carbon Respiration from Terrestrial Ecosystems - Reducing
Uncertainties in the role played by respiration in the global carbon cycle

Abstract

ABSTRACT

This is a proposal to conduct a workshop that will synthesize and advance understanding of terrestrial ecosystem respiration. Carbon enters ecosystems through a single process, photosynthesis, and nearly all is returned to the atmosphere through respiration. Respiration spans the activity of many organisms, from the plants that fixed the carbon to soil fauna decomposing plant tissue residues, and the time carbon spends in an ecosystem can vary from minutes to millennia. While the major processes affecting plant metabolic (autotrophic) respiration and decomposition rates (heterotrophic respiration) are known, our ability to predict the variation in soil respiration in space and time is limited. - a major uncertainty in the current and future carbon cycle. To reduce this uncertainty this workshop will bring up to 50 ecosystem, soil, and carbon cycle scientists together to 1) identify the current disparities and limitations in various measurement methods, 2) identify the key processes controlling autotrophic and heterotrophic that should be incorporated in models, 3) plan new observational, experimental, and modeling activities based on the new questions that emerge from a synthesis of our current understanding. This workshop will produce a group of synthesis papers that will constitute a journal special feature on trends and uncertainties in understanding and predicting ecosystem respiration. Recent advances in methodology and modeling have focused research in terrestrial ecosystem respiration on a few key topics, which are the ones this workshop will address: What factors control how total ecosystem respiration partitioned into (a) aboveground and belowground components and (b) autotrophic versus heterotrophic sources in a range of space and time scales? How do the different fractions of organic matter that contribute to heterotrophic respiration change with factors like temperature and moisture and how will these potentially provide feedbacks to climate change? What is the role of time lags and site history in determining the magnitude and variability of fluxes on seasonal, interannual and decadal timescales? Intellectual Merit. Terrestrial ecosystem respiration remains one of the key elements of the global carbon cycle that limits our ability to predict future CO2 concentrations. This workshop will provide a plan for the community to resolve current areas of controversy, such as the potential for increased heterotrophic respiration to act as a feedback to global warming. Broader Impact. By producing a series of papers on this topic in a peer-reviewed journal special issue, the workshop will have broad impact and influence future research planned in this area. The workshop will provide a venue for international exchange of ideas, and student participation in the workshop will be encouraged.