Date Approved
8-2-2024
Graduate Degree Type
Thesis
Degree Name
Biology (M.S.)
Degree Program
Biology
First Advisor
Alan Steinman
Second Advisor
Casey Godwin
Third Advisor
Don Uzarski
Academic Year
2023/2024
Abstract
Restoring wetlands can increase biodiversity and water quality in both the wetland and connecting ecosystems; however, failing to consider past land uses can result in negative water quality effects. Prior agricultural practices at a coastal wetland restoration site in West Michigan have caused high legacy phosphorus (P) concentrations in sediments, as well as high P levels in the water column. Sediment dredging is being considered as a restoration tool to control internal phosphorus loading (IPL). In addition, climate warming is resulting in increases in both mean temperature and temperature extremes, which may affect IPL. I examined the effects of both sediment dredging and climate warming on P dynamics in this wetland complex by incubating sediment cores in a controlled laboratory experiment. Both ponds exhibited hypereutrophic conditions, although mean water-column and sediment TP concentrations were ~2.5 and ~8 times higher, respectively, in the north pond compared to the south pond. Unexpectedly, sediment cores that had the top 10 cm removed by hand (dredged) had higher mean SRP release rates in both ponds (north ~22 mg m-2 d -1 , south ~1.9 mg m-2 d -1 ) compared to undredged cores (north ~18.6 mg m-2 d -1 , south ~1.5 mg m-2 d -1 ). Equilibrium P concentrations suggest sediments are a source of SRP to the overlying water column regardless of dredging treatment. Increases to average temperature and simulated heatwaves both increased P release and accumulation measures in core tubes, but only in the less enriched south pond. Our results emphasize the need for precursory research before implementing management actions and show that dredging alone might not be the ideal management technique for this restoration site. Successful management of internal and external P loading is crucial to reducing eutrophication worldwide, leading to healthier freshwater ecosystems and enhancing the beneficial ecosystem services they provide.
ScholarWorks Citation
Lucas, Katherine M., "Impact of Climate Change and Restoration on Phosphorus Loading in an Impaired Wetland" (2024). Masters Theses. 1126.
https://scholarworks.gvsu.edu/theses/1126
