Assessing The Fine Root And Mycorrhizal Components Of Net Primary Production Across A Tropical Rain Forest Landscape

Smithsonian Institution, Washington DC

Investigators

Abstract

Assessing the fine root and mycorrhizal components of net primary production across a tropical rain forest landscape Allocation to fine root production has been estimated to be the largest fraction of C allocation by plants and thus may represent the largest carbon input to soils. Yet for tropical evergreen forests there is very little information on fine root production, and there have been no studies of the fungal component of belowground NPP. In this one-year project the investigators will develop a methodology for estimating the mycorrhizal component of belowground production by assays for the fungal glycoprotein glomalin, a protein that is produced exclusively by symbiotic arbuscular mycorrhizal fungi. The PIs will use forest plots along a soil fertility gradient in old-growth lowland rain forest in Costa Rica. The results will determine whether glomalin can be used as an indicator for carbon allocation to symbiotic fungi, and will contribute to a more comprehensive process-level understanding of the carbon cycle than has been attained to date for any tropical forest. The study will have wide applicability for analyses of regional variations in tropical forest productivity, for managing human-influenced tropical ecosystems, and for predicting the responses and global role of tropical forests under changed global climate and atmospheric conditions.