U.S. Department of Energy Office of Biological and Environmental Research

BER Research Highlights


Aquatic Plants Accelerate Arctic Methane Emissions
Published: September 14, 2016
Posted: November 07, 2016

Climate change has caused a boom in aquatic plant biomass on the Arctic tundra in recent decades. Those plants, in turn, are releasing increasing amounts of methane into the atmosphere.

The Science
Researchers measured methane (CH4) fluxes of aquatic vegetation in 2010-2013 at sites characterized in the 1970s at the International Biological Program (IBP) research site near Barrow, Alaska. They then developed statistical models to determine the major environmental factors associated with CH4 emissions such as plant biomass and active-layer depth. They used the IBP historic datasets to model changes in CH4 fluxes between the 1970s and 2010s. Next, using high-resolution imagery, the researchers mapped aquatic vegetation and applied their model to estimate regional changes in CH4 emissions.

The Impact
The regionally observed increases in plant biomass and active-layer thickening over the past 40 years not only have major implications for energy and water balance, but also have significantly altered land-atmosphere CH4 emissions for this region, potentially acting as a positive feedback to climate warming.

Summary
Plant-mediated CH4 flux is an important pathway for land-atmosphere CH4 emissions, but the magnitude, timing, and environmental controls, spanning scales of space and time, remain poorly understood in arctic tundra wetlands, particularly under the long-term effects of climate change. CH4 fluxes were measured in situ during the peak growing season for the dominant aquatic emergent plants in the Alaskan arctic coastal plain, Carex aquatilis and Arctophila fulva, to assess the magnitude and species-specific controls on CH4 flux. Plant biomass was a strong predictor of A. fulva CH4, flux while water depth and thaw depth were copredictors for C. aquatilis CH4 flux. The researchers used plant and environmental data from 1971 to 1972 from the historic IBP research site near Barrow, Alaska, which they resampled in 2010-2013, to quantify changes in plant biomass and thaw depth. They used these data to estimate species-specific decadal-scale changes in CH4 fluxes. A ~60% increase in CH4 flux was estimated from the observed plant biomass and thaw-depth increases in tundra ponds over the past 40 years. Despite covering only ~5% of the landscape, the researchers estimate that aquatic C. aquatilis and A. fulva account for two-thirds of the total regional CH4 flux of the Barrow Peninsula. The regionally observed increases in plant biomass and active-layer thickening over the past 40 years not only have major implications for energy and water balance, but also have significantly altered land- atmosphere CH4 emissions for this region, potentially acting as a positive feedback to climate warming.

Contacts (BER PM)
Daniel Stover and Jared DeForest
SC-23.1
Daniel.Stover@science.doe.gov 301-903-0289 and Jared.DeForest@science.doe.gov 301-903-1678

(PI Contact)
Christian G. Andresen
Los Alamos National Laboratory, Los Alamos, NM
candresen@lanl.gov 505-665-7661

Funding
This research is supported by the U.S. Department of Energy, Office of Science, Office of Biological and Environmental Research, Next-Generation Ecosystem Experiments-Arctic project; and by the National Science Foundation Graduate Research Fellowship Program (NSF-1110312).

Publications
Andresen, C. G., M. J. Lara, C. T. Tweedie, and V. L. Lougheed. 2016. “Rising Plant-Mediated Methane Emissions from Arctic Wetlands,” Global Change Biology, DOI: 10.1111/gcb.13469. (Reference link)

Related Links
EOS article

Topic Areas:

  • Research Area: Terrestrial Ecosystem Science
  • Research Area: Carbon Cycle, Nutrient Cycling

Division: SC-23.1 Climate and Environmental Sciences Division, BER

 

BER supports basic research and scientific user facilities to advance DOE missions in energy and environment. More about BER

Recent Highlights

May 10, 2019
Quantifying Decision Uncertainty in Water Management via a Coupled Agent-Based Model
Considering risk perception can improve the representation of human decision-making processes in age [more...]

May 09, 2019
Projecting Global Urban Area Growth Through 2100 Based on Historical Time Series Data and Future Scenarios
Study provides country-specific urban area growth models and the first dataset on country-level urba [more...]

May 05, 2019
Calibrating Building Energy Demand Models to Refine Long-Term Energy Planning
A new, flexible calibration approach improved model accuracy in capturing year-to-year changes in bu [more...]

May 03, 2019
Calibration and Uncertainty Analysis of Demeter for Better Downscaling of Global Land Use and Land Cover Projections
Researchers improved the Demeter model’s performance by calibrating key parameters and establi [more...]

Apr 22, 2019
Representation of U.S. Warm Temperature Extremes in Global Climate Model Ensembles
Representation of warm temperature events varies considerably among global climate models, which has [more...]

List all highlights (possible long download time)