The Different Forms of Plastic

This week was an amazing week. After months of research, including sampling trips, washing samples, and lots of time in front of a microscope, I finally have microplastic abundance data for 139 of the samples I have collected. The 139 samples represent two seasons worth of samples from Panama City Beach and 8 control samples in the lab. Control samples are exceptionally important in microplastics research, as there is evidence that microplastics are found in the air and are ubiquitous. Control samples allow researchers to accurately quantify which plastics are found in the samples, and which are due to contamination. Although I won't be sharing data now, as it is against my best interest to be making determinations, claims, etc. about an unfinished data set, I can say that I am glad to see that there are microplastics in the samples. Without microplastics in the Panama City Beach samples, I would be left to figure out a new direction for my dissertation, which would not be optimal, given the amount of time I have spent developing my research ideas and plan.

What I can share is that there are multiple different types of plastics in the samples I have collected, which give some indication to the source of the pollution. Primary microplastics, as I have talked about before, are plastic particles developed at a small (less than 5 mm) size, while secondary microplastics are larger plastic products that degrade into small particles. Most of the plastic in the ocean will become secondary microplastics as the fishing line, plastic packaging waste, and large plastics degrade into these small microplastics, but primary microplastics end up in the ocean from tire wear, cosmetic wash-off, and clothing fibers.

In one of the samples that I processed this week (shown below), you can see two different types of plastics: a fiber and a fragment. Although this fiber is likely not a microplastic, based on my rough measurement (it's approximately 1 cm in length), it is likely from clothing. The fragment, however, is definitely small enough to be a microplastic, and is the result of a larger plastic item breaking due to contact with rocks or rubble, or through degradation in the sun. Importantly, it is exceptionally unlikely that the fragment is not plastic; there are very few things in the ocean that have an uneven shape, are this small, and are this color. The fiber could potentially be biological material (like cellulose), but I'd also assume not given the way the fiber is coiled at the end. At the end of this week I will be learning how to analyze these tools using the lasers that I talked about previously, and the process will allow me to determine the chemical composition of these and other particles from my samples.

After 8 months of collecting samples and processing them, it feels so great to have data. Even though I have 139 data points with many more to go, the validation of having an artifact from all of the work that I have put in drives me to keep going (and also the excitement of working on such an important topic in marine biology). In a few weeks I will probably have enough information to share a little of what I have learned about the fall and spring samples, and stay tuned for next week's blog on using lasers to assess material compositions of unknown particles.

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