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Full text release has been delayed at the author's request until May 08, 2026

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Influences of Land Use and Environmental Stressors on Phytoplankton Community Dynamics in the Upper Ohio River Basin

Sanchez, Nayeli Kristel
http://orcid.org/0000-0003-0938-1279
http://rave.ohiolink.edu/etdc/view?acc_num=osu1682060747307701

Abstract Details

2023, Master of Science, Ohio State University, Environment and Natural Resources.
Phytoplankton respond to environmental conditions through specialized adaptations and may proliferate to cause harmful algal blooms (HABs). Nutrient enrichment, largely linked to land-use, has been studied extensively in lakes, but less in streams and rivers. I investigated the influence of nitrogen (N), phosphorus (P), and environmental variables on phytoplankton community dynamics in streams and reservoirs in seven catchments representing a gradient of agricultural, forested, and mixed land uses in the upper Ohio River Basin. The main objectives of this study were to (1) examine the spatiotemporal variability of phytoplankton biomass and relative abundance and (2) identify environmental drivers associated with phytoplankton community structure. In reservoirs, total phosphorus (TP) ranged from 0.001 to 1.50 mg/L and did not differ among catchments, whereas total nitrogen (TN) ranged from 0.084 to 1.91 mg/L and differed significantly among catchments. Total chlorophyll a ranged from 2.56 to 150 µg/L, with Indian Lake exhibiting the highest concentrations (150 chl a µg/L). Cyanobacterial chlorophyll a concentrations were highest in Indian Lake (143.2 chl a µg/L) and positively correlated with percentage agriculture and ammonium concentrations, and were negatively correlated with total phosphorus and TN:TP ratio. There were noticeable differences in the relative abundance of phytoplankton taxonomic groups across catchments and years. Percentage agriculture was identified as a strong predictor of total and cyanobacteria chlorophyll a concentrations. In streams, TP ranged from 0 to 1.32 mg/L, and TN ranged from 0.093 to 4.72 mg/L. Indian Lake exhibited the greatest total chlorophyll a concentrations, with the highest concentrations of both cyanobacterial (76.1 µg/L) and chlorophyte (30.8 µg/L) chlorophyll a. Non-metric multidimensional scaling (NMDS) and permutational multivariate analysis (PERMANOVA) showed differences in phytoplankton communities between years and among catchments, and in reservoirs, Barren River saw an increase in chlorophyte and cryptophyte abundance and Patoka’s community became more similar to that of Barren River. Phytoplankton communities in Taylorsville, Burr Oak, Monroe, and Patoka streams showed similarity between years, but there was a trend of increased dissimilarity in Patoka, while the Indian Lake community increased in size and had more overlap with all catchments in 2021. Environmental variables, including percentage forest land cover, DIN:DIP, ammonium, water temperature, and TP, were found to be predictors of total chlorophyll in streams. Overall, I found that stream and nutrient concentrations were significantly affected by land use, indicating the need for effective management strategies to reduce nutrient pollution. Although agricultural land use exhibited the strongest impact on phytoplankton abundance and community dynamics, urbanization also had a notable effect on nutrient enrichment, as evidenced by high nutrient levels and cyanobacteria concentrations in sites with the most urbanization. In addition to the influence of land use, my results suggest links between several environmental factors that act as drivers of phytoplankton community structure. Owing to the paucity of information relative to the distribution and drivers of phytoplankton in inland aquatic ecosystems – and in particular, streams and rivers – these findings will make important contributions to understanding the effects of nutrient enrichment and broader aspects of stream and watershed ecology.
Mazeika Sullivan (Advisor)
Lauren Pintor (Committee Member)
Kaiguang Zhao (Committee Member)
103 p.
Biology; Ecology; Freshwater Ecology; Limnology
phytoplankton; algae; cyanobacteria; nitrogen; phosphorus; streams; reservoirs

Recommended Citations

Citations

  • Sanchez, N. K. (2023). Influences of Land Use and Environmental Stressors on Phytoplankton Community Dynamics in the Upper Ohio River Basin [Master's thesis, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1682060747307701

    APA Style (7th edition)

  • Sanchez, Nayeli. Influences of Land Use and Environmental Stressors on Phytoplankton Community Dynamics in the Upper Ohio River Basin. 2023. Ohio State University, Master's thesis. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1682060747307701.

    MLA Style (8th edition)

  • Sanchez, Nayeli. "Influences of Land Use and Environmental Stressors on Phytoplankton Community Dynamics in the Upper Ohio River Basin." Master's thesis, Ohio State University, 2023. http://rave.ohiolink.edu/etdc/view?acc_num=osu1682060747307701

    Chicago Manual of Style (17th edition)

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© 2023, all rights reserved.
This open access ETD is published by The Ohio State University and OhioLINK.
Release 3.2.12