The Relationship Between Plant Density and Microplastic Concentration in the Water in Lake Bemidji, MN

Authors

Arian Garcia

Document Type

Article

Abstract

Microplastics, plastic particles smaller than 5 mm, are an increasing environmental threat, particularly due to their widespread distribution and toxicity. While much research has focused on larger freshwater and marine ecosystems, the presence and impacts of microplastics in smaller inland lakes remain less understood. This study investigates the relationship between plant density and microplastic concentrations in Lake Bemidji, a smaller freshwater lake. A total of 30 water samples were collected across varying vegetation conditions, ranging from open water (0%) to 90% plant coverage. Microplastics were identified and categorized into six morphological types: fibers, fragments, films, spheres/beads, and foam. The samples contained a total of 2,790 microplastic particles, with an average of 93 particles per sample and an average concentration of 8.16 microplastics per liter (SD = 3.06). The most abundant colors were blue (2,204 particles) and black (460 particles), while red and green were the least common. A regression analysis was conducted to directly test the relationship between the total count of microplastics and plant density, and there was a significant negative relationship between microplastic count and plant density (P < 0.01). The findings suggest that plant density does influence the distribution and deposition of microplastics in freshwater systems, with higher concentrations observed in areas with lower plant coverage.

Publication Date

2025

Comments

Faculty sponsor: Dr. Andrew Hafs, Department of Biology, Aquatic Biology Program

Recommended Citation

Garcia, Arian, "The Relationship Between Plant Density and Microplastic Concentration in the Water in Lake Bemidji, MN" (2025). Journal of Earth and Life Science. 76.
https://pines.bemidjistate.edu/j-earth-life-sci/76