Sulfur Geochemistry Destabilizes Population Oscillations of Wild Rice (Zizania palustris)

Sophia LaFond-Hudson, Nathan W. Johnson, John Pastor, Brad Dewey

Research output: Contribution to journalArticlepeer-review

2 Scopus citations


Elevated inputs of sulfate to freshwater systems can increase sulfide concentrations in anoxic soils and subsequently destabilize aquatic plant populations, but the interactions between sulfate, other geochemical cycles, and interannual plant population cycles are poorly understood. Increased sulfate loading increases mineralization of nitrogen from litter, but the sulfide produced during this process can limit nitrogen uptake by plants. In some cases, iron may mitigate sulfide's impacts on plants by precipitating iron sulfide. We examined the interannual effects of sulfate loading on mesocosm populations of wild rice, an emergent aquatic plant that undergoes population oscillations and is sensitive to sulfide. Using experimental mesocosms with self-perpetuating populations, we investigated how population dynamics respond to manipulations of surface water sulfate (10 mg L−1 or 300 mg L−1), sediment iron (4.3 mg g−1 or 10.9 mg g−1 dry weight), and shoot litter (present or removed). Populations exposed to constant 10 mg L−1 sulfate concentrations had stable biomass oscillations of approximately 3-year periods, consistent with previous studies that demonstrated litter-driven oscillations in nitrogen availability. Populations exposed to 300 mg L−1 sulfate concentrations produced fewer and smaller seeds and declined to extinction in 6 years or less. We did not find a strong effect of iron loading or litter removal on wild rice biomass or seed production. Our observations show the potential of elevated surface water sulfate to rapidly destabilize wild rice populations under varying iron and organic carbon concentrations.

Original languageEnglish (US)
Article numbere2022JG006809
JournalJournal of Geophysical Research: Biogeosciences
Issue number8
StatePublished - Aug 2022

Bibliographical note

Funding Information:
This work was prepared by S. LaFond-Hudson, N. Johnson, J. Pastor, and B. Dewey using federal funds under award NA15OAR4170080 from Minnesota Sea Grant, National Sea Grant College Program, National Oceanic and Atmospheric Administration, U.S. Department of Commerce. The statements, findings, conclusions, and recommendations are those of the author(s) and do not necessarily reflect the views of NOAA, the Sea Grant College Program, or the U.S. Department of Commerce. The authors would like to thank the Fond du Lac Band of Lake Superior Chippewa for providing sediment. This manuscript has been authored by UT-Battelle, LLC under Contract No. DE-AC05-00OR22725 with the U.S. Department of Energy. The United States Government retains and the publisher, by accepting the article for publication, acknowledges that the United States Government retains a nonexclusive, paid-up, irrevocable, world-wide license to publish or reproduce the published form of this manuscript, or allow others to do so, for United States Government purposes. The Department of Energy will provide public access to these results of federally sponsored research in accordance with the DOE Public Access Plan (

Funding Information:
This work was supported by a research grant from Seoul Women's University (2022‐0114).

Publisher Copyright:
© 2022 Oak Ridge National Laboratory, managed by UT-Battelle, LLC and The Authors.


  • cycles
  • interannual
  • iron
  • litter
  • mesocosms
  • nitrogen


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