Testing the Microbial-ENzyme Decomposition (MEND) model of soil carbon and nitrogen cycling at Serra do Mar, São Paulo

• Grant number: 12/51582-7
• Support Opportunities: Regular Research Grants
• Start date: May 01, 2013
• End date: October 31, 2015
• Field of knowledge: Biological Sciences - Botany - Pant Physiology
• Agreement: UT - Battelle
• Principal Investigator: Marcos Pereira Marinho Aidar
• Grantee: Marcos Pereira Marinho Aidar
• Host Institution: Instituto de Botânica. Secretaria de Meio Ambiente, Infraestrutura e Logística (São Paulo - Estado). São Paulo , SP, Brazil

Abstract

Contemporary models of soil organic carbon, simulate C dynamics by determining pool sizes and turnover rates. Microbial activities are not explicitly considered, and this is a major gap in the ability to accurately predict the response of terrestrial ecosystems to a variety of climate forcings. The key issue is one of acclimation - how and if the microbial community acclimates to changes in climate will determine the extent of feedbacks from soils, which constitute the largest terrestrial reservoir of C. If microbial communities acclimate to higher temperatures with increased efficiency, for instance, then the fluxes of CO2 from soils will be much less than if the communities do not acclimate. Therefore, it is important to determine the extent of acclimation to increased temperatures by the microbial community to accurately predict our climate's future. Under a recent ORNL program, we developed the Microbial-Enzyme Decomposition (MEND) Model. We now testing our model, incorporate N, and eventually link it into the global Community Land Model. We are currently choosing field sites including tropical, temperate, and arctic ecosystems for lab-scale experiments and model testing and validation at the field scale. The Brazilian Atlantic Forest is a important tropical ecosystem and sites are established over an elevational gradient in São Paulo State, with existing data on above and below ground biomass, soil characteristics (C and N contents) and greenhouse gas fluxes. Thus, by exploiting a well- studied environment over an elevational gradient, this proposal will investigate the topic "Tropical Forest Ecosystems Response to Environmental Changes" as specified in Section 4(a) of the FAPESP-ORNL Call for Proposals. (AU)