LiT: Microbial control on soil C and N cycling during forest recovery: Linking ecosystem processes with microbial function

University Of Wisconsin-Madison, Madison WI

Investigators

Abstract

Microorganisms in soils regulate important terrestrial ecosystem processes, such as plant productivity, nutrient availability, soil carbon sequestration, and greenhouse gas production. Much research has focused on global change impacts on plant diversity and nutrient cycling, with less attention on the bacteria and fungi that drive many ecological and biogeochemical processes. Linking soil microbial community composition with function, and understanding their response to changes in land use and land cover is important for sustaining ecosystem productivity and for predicting the impact of future disturbances. This research will combine novel genomic technologies, biomarker analyses, and measurements of microbial activity to identify relationships between soil microbial functional diversity and activity and soil organic matter cycling. The investigators will conduct this research in a well-replicated series of secondary forest sites of different ages growing on former pastures in Puerto Rico. Changes in soil carbon, forest structure, biomass, and tree species composition have already been described. This research will focus on the role of soil microbial communities in carbon cycling and their response to ecosystem recovery. Advances in genomics are increasing our knowledge about the vast diversity of microorganisms in soils at a very fast pace, but more work is needed to link microorganism identity with ecological processes. The emergence of carbon trading markets and payments for ecosystem services has focused global attention on forest carbon sequestration. However, the soil carbon pool is still unable to be predicted. This pool, which can be twice as large as that in aboveground plant biomass, will respond to changes in vegetation. A better understanding of how microbial functional diversity changes during forest recovery, and how this affects organic matter retention or loss from soils, can improve efforts to maintain ecosystem productivity and restore soil fertility to degraded sites. Findings from this research will be incorporated into existing courses on biogeography, biogeochemistry, and microbial ecology. The investigators are actively engaged in education and mentoring activities at the University of Wisconsin, and in external programs for increasing the participation of underrepresented minorities, including women, in the environmental sciences. Presentations in English and Spanish will be developed on tropical ecology, microbiology, and global change for local schools with diverse student bodies in Wisconsin and in Puerto Rico.