SEASONAL MICROPLASTIC ABUNDANCE AND COMPOSITION IN RIVER BIOTA LINKED WITH LAND USE AND SPECIES TRAITS

Microplastics (MPs; < 5 mm) are a pervasive contaminant in freshwater habitats and biota. Terrestrial-aquatic exchanges move plastic litter into aquatic habitats where they may fragment into MPs and enter the food web. We sought to understand the importance of watershed land use and landcover (LULC) and river tributaries in connection to the sources, abundances, and compositions of MPs entering a freshwater lake. We investigated 1) if seasonal MP abundance in freshwater biota vary with species traits across a LULC gradient, and 2) the potential relationships between MP patterns in biota and their habitats. Eight river tributaries differing in dominant LULC were sampled seasonally for MPs in surface water, benthic sediments, fish, and macroinvertebrates. Preliminary results from 3 of the rivers indicated MP contamination was present in river habitat, fish, and macroinvertebrate samples, with fibers contributing approx. 97-100% of all MP particles. Surface water samples contained an average of 16 particles/sample. Eighty-five percent of fish individuals across functional feeding groups (e.g., detritivore) contained an average of approx. 13 MPs/fish. There was a positive relationship between MP concentrations and fish trophic fraction, suggesting that MPs may move through the food web due to species trophic traits (X²= 14.18, P= 0.001). This study is anticipated to further reveal potential links of MP pollution to environmental variables (e.g., season). This will inform targeted MP mitigation strategies and increase our knowledge of the ecological consequences of MP pollution.

Presentation Preference: Poster

Primary Presenter: Alexandra Brown, California State University Bakersfield (abrown84@csub.edu)

Authors:

Alexandra Brown, California State University Bakersfield  (abrown84@csub.edu)

Rae McNeish, California State University Bakersfield  (rmcneish@csub.edu)