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Tropical forest soils and climate change: A source or sink for atmospheric carbon?

Objective

The response of tropical forest ecosystems to global climate change and elevated atmospheric carbon dioxide levels remains poorly understood. Despite the important role of tropical forest soils in the global carbon cycle, estimates of the carbon sequestration potential of tropical forests are based primarily on estimates of aboveground production and biomass, because little is known about belowground carbon cycling and how it may be affected by climate change. Primary production in some tropical forests has increased during recent decades, prompting speculation that this will boost carbon sequestration.

However, this response is likely to be limited by nutrient availability. Importantly, greater inputs of readily degradable carbon in leaf litter may accelerate the decomposition of stable soil organic matter, which would greatly reduce the value of the soil as a carbon sink. Improved understanding of the belowground components of the carbon cycle and their interactions with aboveground processes is required to accurately assess the carbon sequestration potential of tropical forest ecosystems.

This project combines litter addition, litter removal, fertilization, and root exclusion treatments to quantify the relative contributions of roots, microbes, and leaf lit ter to soil carbon dioxide efflux. The fate of carbon inputs from decomposing leaf litter will be determined by adding litter that is naturally labelled with 13C and analysing microbial biomass, microbial functional types and soil leachate.

Changes in soil organic carbon composition will be assessed directly using state of the art nuclear magnetic resonance spectroscopy to detect functional groups representing stable and labile structures. The results will provide key information on the response of tropical forest soils to increased primary productivity. This is of high international importance, because such information is required urgently to calibrate models of future global climate change.

Call for proposal

FP6-2004-MOBILITY-6
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Coordinator

THE CHANCELLOR, MASTERS AND SCHOLARS OF THE UNIVERSITY OF CAMBRIDGE
Address
The Old Schools, Trinity Lane
Cambridge
United Kingdom

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Participants (1)

SMITHSONIAN TROPICAL RESEARCH INSTITUTE
Panama
Address
Apartado 2072, Balboa, Ancon
Panama

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