December 09, 2021
What is the Fate of Wood-Carbon Ingested by Subterranean Termites?
A laboratory study utilizing FACE wood examines how termites influence soil biogeochemistry.
Termites are considered an important agent for decomposing wood; however, little is known about their rate of wood consumption and the fate of wood-carbon (C) that they consume. Yet, this information is fundamental to modeling wood decomposition and understanding how termites may influence soil biogeochemistry (Myer and Forschler 2019). This study investigated the subterranean termite (Reticulitermes flavipes) to determine the fate of wood-C. This study was made feasible through the use of loblolly pine (Pinus taeda) grown on the Duke Free Air CO2 Enrichment (FACE) site, as wood from this site has a distinct isotopic signature that enables tracking of consumed wood.
This study is the first to document the fate of wood-C ingested and processed by a subterranean termite species, thereby providing new insights into the metabolic pathways and providing needed data for modeling. This work showed that a significant proportion of the consumed dead wood (~40%) was transferred to other pools where it could be processed by other organisms or become part of the soil carbon pool. Also, a significant proportion of the dead wood was returned to the atmosphere, primarily as carbon dioxide, with very little as methane.
Subterranean termites are ecosystem engineers that consume dead wood, effectively transferring the wood-carbon into soil and atmosphere; however, little is known about the breakdown of those products, which are largely unaccounted for in carbon cycling models. The fate of C from wood utilized by Reticulitermes flavipes (Kollar) was determined in a laboratory study using δ13C labeled wood as a tracer. The percentage of wood-based carbon in respiratory gases, tissues, and organic deposits (frass and construction materials) was measured to determine wood-C mass distributed into metabolic and behavioral pathways. Termites emitted 42% of the C from wood as gas (largely as carbon dioxide), returned 40% to the environment as organic deposits (frass and construction materials), and retained 18% in their tissues (whole alimentary tracts and degutted bodies). These findings affirm that termites are a source of greenhouse gases but are also ecosystem engineers that return approximately half the C from dead wood as organic deposits into their surrounding environment.
University of Georgia
University of Georgia
U.S. Department of Energy, Biological and Environmental Research (SC-33)
Environmental System Science
Funding was provided by the U.S. Department of Energy Terrestrial Ecosystem Science program (Agmt. # DE-SC0016235) to the USDA Forest Service and University of Georgia.
Myer, A., et al. "Evidence for the Role of Subterranean Termites (Reticulitermes spp.) in Temperate Forest Soil Nutrient Cycling." Ecosystems 22 602–618 (2019). https://doi.org/10.1007/s10021-018-0291-8.
Myer, A., et al. "The Fate of Carbon Utilized by the Subterranean Termite Reticulitermes flavipes." Ecosphere 12 (12), e03872 (2021). https://doi.org/10.1002/ecs2.3872.