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ARS Home » Southeast Area » Oxford, Mississippi » National Sedimentation Laboratory » Water Quality and Ecology Research » Research » Publications at this Location » Publication #428789
Research Project: Enhancing Long-Term Agroecosystem Sustainability of Water and Soil Resources Through Science and Technology

Location: Water Quality and Ecology Research

Title: Legacy phosphorus storage and release dynamics in an oxbow lake within the Mississippi Alluvial Plain

Author
item Witthaus, Lindsey
item Taylor, Jason
item Locke, Martin
item WEBSTER, BENJAMIN - Oak Ridge Institute For Science And Education (ORISE)
item Lizotte Jr, Richard
item MARTIN, HARPER - University Of Arkansas
item STEVENS, ERIC - Lawrence Berkeley National Laboratory

Submitted to: Journal of Environmental Quality
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/17/2026
Publication Date: 3/26/2026
Citation: Witthaus, L.M., Taylor, J.M., Locke, M.A., Webster, B., Lizotte Jr, R.E., Martin, H., Stevens, E. 2026. Legacy phosphorus storage and release dynamics in an oxbow lake within the Mississippi Alluvial Plain. Journal of Environmental Quality. 55:e70164. https://doi.org/10.1002/jeq2.70164.
DOI: https://doi.org/10.1002/jeq2.70164

Interpretive Summary: Lakes are common features in agricultural areas of the Mississippi Delta. Erosion around these areas can cause nutrients and soils to wash into lakes causing water quality problems. High concentrations of phosphorus from soils and lake sediments in shallow oxbows can be a major concern. We looked at shallow and deep sediments from Beasley Lake, Mississippi, to better understand these connections and how phosphorus can be both stored and released in these types of sediments. We found the sediment in Beasley Lake could store a large amount of phosphorus, but it could also be available for algae to use which could impact the quality of the lake water.

Technical Abstract: Oxbow lakes are common features within the agricultural landscape of the Mississippi Alluvial Plain (MAP), USA. Erosive soils provide high external nutrient and sediment loads that contribute to eutrophication of lakes. Internal nutrient loading of stored phosphorus (P) from sediments may perpetuate or enhance eutrophic conditions in shallow oxbow lakes. Eight years of depth-integrated water column monitoring in Beasley Lake suggests periods of high benthic PO4-P during dry months corresponded with periods of lower benthic DO, but there is uncertainty in the magnitude of internal contributions and drivers. To address this knowledge gap, we collected sediments from deep and shallow habitats within Beasley Lake. We characterized sediment properties with sequential P fractions, P sorption curves, and measured nutrient and metal concentrations. We quantified P fluxes from intact sediment cores under anaerobic and aerobic conditions over 14 days. Sediment total P ranged from 660 – 980 mg-P kg-1 with sorption capacity for an additional 2000 mg-P kg-1. Less-labile fractions associated with Fe or Al dominated sediment P. Anaerobically-treated cores had higher P release rates (30.9-102.4 mg m-2 day-1) than aerobic cores (2.4-3.7 mg m-2 day-1). Deep cores had higher P release of shorter duration compared to shallow cores under anaerobic conditions. Our findings demonstrate high capacity for legacy P storage in MAP lake sediments, which can become available for water column productivity under temporally explicit conditions, potentially impacting management and assessment of nutrients in shallow lakes.