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Full-Text Articles in Life Sciences
The Effect Of Plastic On Leaf Litter Breakdown In Urban Streams, Lisa Haneul Kim
The Effect Of Plastic On Leaf Litter Breakdown In Urban Streams, Lisa Haneul Kim
Master's Theses
The plastic component of anthropogenic litter (AL) is an emerging ecological concern and has been a focus of research, as it is long-lived, mobile, interacts with physical and chemical components of aquatic ecosystems, and breaks down into smaller pieces (i.e., microplastic, <5mm particles). Rivers are considered a major source of plastic to oceans, but little is known about plastic's abundance, distribution, and effects on ecological processes in urban streams. Previous studies report plastic is abundant in freshwater systems, especially in naturally occurring debris dam structures and overhanging vegetation which accumulate high quantities of AL, especially plastic items (i.e. bags, wrappers, packaging material), along with leaf litter and other coarse particulate organic matter. in temperate, forested streams, leaf litter is a critical food source and plays an essential role in the stream food web. the rate at which leaves break down is affected by many variables such as hydrology, water chemistry, and macroinvertebrate and microbial communities. We predicted that plastic accumulation along with leaf litter can slow leaf breakdown by reducing diversity and abundance of microbial decomposers, as well as macroinvertebrate consumers. We measured leaf breakdown, and characterized macroinvertebrate and microbial (i.e., bacterial, fungal, algal) communities in 3 litter bag treatments: leaves alone, plastic alone, and leaves mixed with plastic. Although plastic did not reduce leaf breakdown rates or have a significant effect on macroinvertebrate consumer communities, it showed distinct microbial communities compared to leaf substrates. Results will provide a new understanding of how plastic and microbial communities interact, and set the framework for future studies to look at microbial succession and macroinvertebrate diversity on other synthetic substrates in freshwater systems.
Anthropogenic Litter And Microplastic In Urban Streams: Abundance, Source, And Fate, Amanda Rae Mccormick
Anthropogenic Litter And Microplastic In Urban Streams: Abundance, Source, And Fate, Amanda Rae Mccormick
Master's Theses
The accumulation and ecological effects of anthropogenic litter (AL) and microplastic are well-documented in marine ecosystems, but these materials’ abundances in rivers is unknown. AL enters rivers from recreation, runoff, and illegal dumping. Microplastic fibers and pellets are abundant in wastewater treatment plant (WWTP) effluent which enters rivers. Our objectives were to: (1) quantify AL abundance and composition in urban streams, (2) measure AL flux, accumulation, and export, and (3) measure riverine microplastic concentration and analyze its bacterial communities. We collected AL from 5 urban streams and observed greater AL density in riparian habitats and greater mass in benthic habitats. …