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Harvard Forest REU Symposium Abstract 2013
- Title: Respiration and isotopic composition of soil cores and their components in relation to tree dominance
- Author: Monica M Allende Quiros (University of Puerto Rico - Rio Piedras Campus)
- Abstract:
Soil respiration fluxes and belowground carbon pools represent a major component of ecosystem carbon cycling. Climate change impacts and is impacted by ecosystem carbon cycling, and understanding how belowground carbon processes work is necessary for predicting the future of the climate and the ecosystem. The two main objectives for this research project are 1) to determine how belowground respiration and its carbon isotopic composition vary according to tree dominance and 2) to determine the relative contribution of various belowground components to the total soil CO2 efflux using their isotopic signatures. Soil cores were collected near the Environmental Measurement Site (EMS) from two plots with different dominant tree species: a mixed maple and oak plot and a hemlock plot. Using a quantum cascade laser spectrometer located at the EMS, CO2 fluxes of the whole core and its components (litter, root free organic and mineral horizons, and roots) were measured, and Keeling plots were used to determine the isotopic compositions of these fluxes. While the magnitude of the CO2 fluxes from the samples diminished over time after excavation, their isotopic signatures remained stable. The signature for root-free soil was close to -29‰, while the signature for root respiration was close to -27‰, both of these regardless of dominance. Although much is still unknown about belowground carbon pools, these isotopic signatures for roots and root-free soil may allow determining each component’s contribution to the total soil CO2 efflux.
- Research Category: Forest-Atmosphere Exchange
- Figures: monicaAbstractPic.jpg
