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

PI-Submitted Research Highlights for
Terrestrial Ecosystem Science Program

Dynamic Vertical Profiles of Peat Porewater Chemistry in a Northern Peatland

Natalie Griffiths
Oak Ridge National Laboratory


[24] October 2016

The Science
We examined weekly to monthly variation in peat porewater chemistry (pH, cations, nutrients, total organic carbon [TOC]) depth profiles in the SPRUCE experimental bog and compared this temporal variation to spatial (among plot) variation in chemistry.

The Impact
These data provide baseline information on porewater chemistry in the SPRUCE experimental bog, and highlight the importance of collecting samples across both space and time.   Capturing temporal and spatial variability is needed especially for solute pool and flux calculations and for parameterizing process-based models.

We found strong gradients in chemistry depth profiles.   For example, ammonium increased and TOC decreased with depth, likely reflecting mineralization of deep peat or TOC.   These depth profiles were also temporally dynamic, with ammonium, soluble reactive phosphorus, and potassium concentrations more temporally variable in near-surface porewater than deeper porewater, and pH, and calcium and TOC concentrations more temporally variable at deeper depths.   When temporal variation in porewater chemistry at one location was compared to spatial variation in porewater chemistry across 17 locations (SPRUCE plots), we found that temporal variation in chemistry at one location was often greater than spatial variation in chemistry, especially in near surface porewater.   These results suggest that representative sampling of porewater requires measurements across both space and time.

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

(PI Contact)
Natalie Griffiths
Oak Ridge National Laboratory
griffithsna@ornl.gov / 865-576-3457

This research was part of the SPRUCE project and supported by the U.S. Department of Energy’s Office of Science, Biological and Environmental Research and the Northern Research Station of the USDA Forest Service.   Oak Ridge National Laboratory is managed by UT-Battelle, LLC, for the U.S. Department of Energy under contract DE-AC05-00OR22725.

N.A. Griffiths and S.D. Sebestyen, “Dynamic vertical profiles of peat porewater chemistry in a northern peatland.” Wetlands (2016) [DOI:10.1007/s13157-016-0829-5].

Related Links

ORNL TES SFA (SPRUCE) and the Northern Research Station of the USDA Forest Service.

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