The objective of this research project is to test whether leaf- decomposing fungi short-circuit phosphorus mineralization in a phosphorus-depauperate tropical rainforest. A microcosm experiment is planned to determine if fungi can export 32P from partially decomposed leaves into fresh litter. Fungal transport from old litter could explain previously observed increased in P above 100% of the initial amount during early stages of leaf decomposition. If mineralization of phosphorus from litter is bypassed because of internal recycling by decomposer fungi the availability of P to plant roots may be restricted. In some phosphorus and nitrogen depauperate ecosystems, nutrients sequestered in fungal biomass may become available to higher plants when fungal populations crash. Future objectives will include the determination of timing of nutrient mineralization from fungal biomass as it may be controlled by wetting and drying cycles and fungivorous microarthropods. Results of this research should have implications for the management of tropical forest ecosystems as well as for the fundamental ecological understanding of those systems. The principal investigator is well motivated and supported by knowledgeable colleagues. Institutional facilities and accommodation are adequate to the research.
