Institute of Ecosystem Studies

2008 BES Annual Meeting Presentation and Poster Abstracts

A novel approach for studying atmospheric CO2 consequences in Baltimore metropolitan forests
Loecke, Terry
Co-Authors: Dr. Peter M. Groffman
Abstract: Global atmospheric CO2 concentrations are increasing at historically unprecedented but ecologically gradual rates while air temperatures are warming. We do not know in detail how terrestrial ecosystems will respond to these perturbations. For example, soils may sequester more C into soil organic matter, providing a negative feedback on global warming. Alternatively, soils may be C saturated or C sequestration may be limited by other soil nutrients or moisture, or warming may accelerate decomposition and deplete soil C. To date, atmospheric CO2 enrichment studies have relied on abrupt elevation of atmospheric CO2 to study ecosystem under future climate scenarios. Ecosystem responses may differ when CO2 increases are gradual, although such responses have not yet been tested in situ. This research uses a novel 14C isotopic approach to document the atmospheric CO2 chronosequences (spanning 40 to 80 years) of forest patches exposed to gradually increasing atmospheric CO2 along a spatial gradient that ranges in CO2 concentration from ambient to ~125% of ambient. Specifically, this study takes advantage of a rural-urban transect of ten remnant forest patches across the Baltimore metropolitan area. Structural equation and hierarchical Bayesian modeling approaches will being used to disentangle multiple biotic and abiotic factors potentially driving soil and biomass C sequestration rates and soil microbial processes across this transect.