Poster Presentation Society for Freshwater Science 2025 Annual Meeting

Vegetation Decomposition and Leaching in H2Ohio Wetlands (117190)

Jihae Dick 1 , Laura Johnson 2 , Jakob Boehler 3 , Austin Nainiger 3 , Emily Clark 3 , Deandra Jones 3
  1. Biology & Toxicology, Ashland University, Ashland, Ohio, United States
  2. Michigan Department of Agriculture and Rural Development, Office of Agricultural Science and Research, Lansing, Michigan, United States
  3. National Center for Water Quality Research, Tiffin, Ohio, United States

The state of Ohio’s H2Ohio program aims to create and restore wetlands to improve regional water quality around Lake Erie. Wetlands provide crucial ecosystem services such as absorbing floodwaters, capturing pollutants, and removing nutrients. (Zhou et al. 2023). Since nutrient retention is dependent on vegetation decay, studying decomposition rates and nutrient release is key in evaluating the nutrient-capturing potential of the project’s new wetlands (Tank et al. 2010). We explored how rates of vegetation decomposition varied across different plant species that are prevalent across four wetlands. The H2Ohio site-ID codes were FRUW, REDB, UPPB, and BRIC. Across each site, we deployed a series of pre-weighed bags containing one of three plant species. Two were chosen to accurately represent the community composition while the third was a cattail control of Typha angustifolia (Benfield et al. 2017). Total decomposition time was quantified as 1/k (days). Cattails had the slowest decay rates across all wetlands (58.6-72.5 days) and the lowest rate constants (0.0138-0.0171). Cattails also served as the control to compare decay between wetlands. After comparing site-specific decay rates, they were ranked from slowest to fastest as follows: BRIC, REDB, FRUW, and UPPB. Furthermore, decomposition rates also differed between species. For instance, REDB pondweed had the highest rate constant (0.0853), followed by FRUW pondweed (0.0526) and UPPB milfoil (0.0502). It was determined that these plants would subsequently decompose in 11.7, 19.0, and 19.9 days, respectively. Additionally, nutrient leaching was assessed by testing the leachate from dried plant material for phosphorus, nitrate, and organic carbon. Submerged plants, like Potamogeton natans (broad-leaved pondweed) and Myriophyllum sp. (water-milfoil), leached higher concentrations of P than other species. Overall, decomposition rates and leachate nutrient content varied widely between both species and wetlands. The results illustrated that abiotic or biotic features were circumstantial contributors to nutrient retention. Future research should explore how the composition of detritivore communities affects decomposition.

  1. Zhou, X., Dong, K., Tang, Y., Huang, H., Peng, G., Wang, D., 2023. Research Progress on the Decomposition Process of Plant Litter in Wetlands: A Review. Water. 15: 3246-3261.
  2. Tank, J. L., E. J. Rosi-Marshall, N. A. Griffiths, S. A. Entrekin, and M. L. Stephen. 2010. A Review of Allochthonous Organic Matter Dynamics and Metabolism in Streams. Journal of the North American Benthological Society 29:118–146.
  3. Benfield, E. F., K. M. Fritz, and S. D. Tiegs. 2017. Chapter 27: Leaf-Litter Breakdown. Pages 71–82 Methods in Stream Ecology, Volume 2: Ecosystem Function 3rd. essay, Academic Press, London.