February 24, 2017

An Ecosystem-Scale, Experimental System to Study Whole-Ecosystem Warming

Protocols developed for continuous warming and elevated CO₂ experimental manipulations of tall-stature peatland forests.

The Science

Scientists at Oak Ridge National Laboratory (ORNL) have documented an experimental system that combines aboveground and deep-soil heating approaches to provide researchers with a plausible method with which to glimpse future environmental conditions for intact peatland ecosystems.

The Impact

This experimental system allows researchers to study a broad range of organisms (microbes, moss, shrubs, trees, and insects) and ecosystem processes (carbon cycle and water use) under realistic field environments for a broad range of alternative environments that may occur in the future.

Summary

This study describes methods to achieve and measure both deep-soil heating (0 m to 3 m) and whole-ecosystem warming (WEW) appropriate to the scale of tall-stature, boreal forest peatlands. The methods were developed to provide scientists with a plausible set of ecosystem-warming scenarios within which immediate and longer-term (1-decade) responses of organisms (microbes to trees) and ecosystem functions (carbon, water, and nutrient cycles) could be measured. Elevated carbon dioxide (CO₂) was also incorporated to test for interactions with temperature. The WEW approach was successful in sustaining a wide range of aboveground and belowground temperature treatments (as much as +9°C) in large 115-m², open-topped enclosures. The system is functional year round, including warm summer and cold winter periods. The study contrasts its WEW method with prior closely related field-warming approaches and includes a full discussion of factors that must be considered in interpreting experimental results. The WEW method enables observations of future temperature conditions not available in the current observational record, thereby providing a plausible glimpse of future environmental conditions.

Principal Investigator

Paul Hanson
Oak Ridge National Laboratory
hansonpj@ornl.gov

Program Manager

Daniel Stover
U.S. Department of Energy, Biological and Environmental Research (SC-33)
Environmental System Science
daniel.stover@science.doe.gov

Funding

This material is based on work supported by the Office of Biological and Environmental Research, within the U.S. Department of Energy (DOE) Office of Science, and the DOE Graduate Fellowship Program (DE-AC05-06OR23100 to A. L. G.). Oak Ridge National Laboratory is managed by UT-Battelle, LLC, for the DOE under Contract No. DE-AC05- 00OR22725.

References

Hanson, P. J., J. S. Riggs, W. R. Nettles, and J .R. Phillips, et al. "Attaining whole-ecosystem warming using air and deep-soil heating methods with an elevated CO2 atmosphere." Biogeosciences 14 861–883 (2017). https://doi.org/10.5194/bg-14-861-2017.