Stan D. Wullschleger
27 September 2017
Quantification of codynamics between permafrost, soil, and vegetation properties.
A novel monitoring strategy was developed to quantify complex Arctic ecosystem responses to the seasonal freeze-thaw growing season conditions. The spatially and temporally dense monitoring data sets revealed several insights about tundra system behavior at a site located near Barrow, Alaska.
Coincident monitoring of the spatiotemporal distribution of and interactions between land, soil, and permafrost properties is important for advancing the predictive understanding of ecosystem dynamics. Demonstration of this first aboveground and belowground geophysical monitoring approach within an Arctic ecosystem illustrates its significant potential to remotely “visualize” permafrost, soil, and vegetation ecosystem codynamics in high resolution over field-relevant scales.
The novel strategy exploited autonomous measurements obtained through electrical resistivity tomography to monitor soil properties; pole-mounted optical cameras to monitor vegetation dynamics; point probes to measure soil temperature; and periodic measurements of thaw layer thickness, snow thickness, and soil dielectric permittivity. Among other results, the soil electrical conductivity (a proxy for soil water content) in the active layer indicated an increasing positive correlation with the green chromatic coordinate (a proxy for vegetation vigor) over the growing season, with the strongest correlation (R = 0.89) near the typical peak of the growing season. Soil conductivity and green chromatic coordinate also showed significant positive correlations with thaw depth, which is influenced by soil and surface properties. These correlations have been then confirmed at larger spatial scale using an unmanned aerial system (UAS) platform.
BER Program Manager
Terrestrial Ecosystem Science, SC-23.1
Stan D. Wullschleger
Oak Ridge National Laboratory
Oak Ridge, TN 37831
LBNL Contact: Susan Hubbard
Lawrence Berkeley National Laboratory (LBNL)
Berkeley, CA 94720
The Next-Generation Ecosystem Experiments (NGEE)–Arctic project is supported by the Office of Biological and Environmental Research within the U.S. Department of Energy Office of Science. This NGEE-Arctic research is supported through Contract No. DE-AC02-05CH11231 to Lawrence Berkeley National Laboratory.
Dafflon, B., Oktem, R., Peterson, J., Ulrich, C., Tran, A.P., Romanovsky, V., and Hubbard, S.S. "Coincident aboveground and belowground autonomous monitoring to quantify covariability in permafrost, soil, and vegetation properties in Arctic tundra." Journal of Geophysical Research: Biogeosciences, 122(6), 1321–1342 (2017). [DOI:10.1002/2016JG003724].