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Research Technical Report

A PDF version of this poster is available here:

Kashiwabara_2019_MicroplasticsSummerPoster.pdf (4.5 MB)

Microplastics in the Surface Seawater of the Monterey Bay National Marine Sanctuary

Kashiwabara, L.M., M.S Savoca, M. DeVogelaere, C. King, and J.A. Goldbogen (Fall 2019)

Poster presentation, Undergraduate Research Opportunities Center (UROC), California State University Monterey Bay, Fall 2019

Poster presentation, 2019 SACNAS: The National Diversity in STEM Conference, Honolulu, Hawai'i, 31 Oct - 2 Nov 2019


Microplastics, small pieces of plastic (‹5mm), are the most common type of marine debris. Nearly 1000 marine species ingest microplastics, and the effects on the food web and ecosystem is of increasing concern. This has implications for the Monterey Bay National Marine Sanctuary (MBNMS) because of the sanctuary’s mandate to understand and protect this area of national significance. The vertical distribution (5-1000m) of microplastics within the bay has been recently reported, finding the highest concentrations (15 particles m-3) at 200m depth, with higher concentrations of microplastics in offshore samples as compared to nearshore samples (Choy et al., 2019). To contribute to the limited research concerning microplastics in the MBNMS, we sought to understand the concentrations of microplastics surface seawater samples. In the summers of 2017 and 2018, we collected surface water samples using a manta trawl net (355μm mesh size) from two nearshore locations (Santa Cruz Boardwalk and Marina Sewage Outfall) and two offshore locations (Sur Ridge and Davidson Seamount) within the MBNMS. To isolate and extract synthetic material from our samples, we developed a process of density separation, chemical digestion, and vacuum filtration. We then used epifluorescence microscopy and ImageJ software to quantify the number of microplastics per cubic liter of seawater. To link the polymer type of our subset of our samples to their plastic source, we used Fourier-transform infrared spectroscopy (FT-IR). Our results will provide vital baseline information on the extent of microplastic pollution in the surface waters of the MBNMS at nearshore and offshore locations.

Reviewed: April 11, 2024
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