A Day in the Field

On Monday I was able to get out in the field to start work on the first part of my PhD dissertation. My work, if you have been reading the blog, focuses on how microplastics affect nutrient cycling in coastal sediment systems, but what you might not know is that many individuals are unaware of the amount of plastics in the ecosystem. A few weeks ago I wrote about some recent work in Australia that suggested there may be 14 million metric tons of microplastics in global sediments, but the problem is that there are a lot of coastal areas that have not been studied. Some individuals in the microplastics research community have conducted laboratory experiments without first assessing the local concentrations of microplastics in sediments, and therefore likely used amounts of microplastics not found in nature. The first part of my research, therefore, is to understand what the microplastics levels are in local sediments before conducting any manipulative experiments, so that the results of my work can be applied to local ecosystems.

Wastewater treatment plants are one of the top sources of microplastics pollution, as the water treatment processes often do not use sieves small enough to trap microplastics. Therefore, microplastics that enter in the wastewater influent often get exported to the ocean (or terrestrial systems, in some cases). Work done by Gies et al. (2018) estimates that wastewater treatment plants may release 32-97 million microplastics into the environment on a daily basis, but there seems to be variability in these numbers based on the treatment processes used at the plants. In order to understand what effects microplastics pollution may be having on nutrient cycling in benthic systems, I decided to sample from a wastewater treatment plant system and from reference systems that do not receive wastewater effluent, to determine the variability in microplastics pollution. I am also interested to see if there are seasonal changes to the microplastics concentrations, as I expect highest particle concentrations in the fall and winter, when individuals are more likely to wear synthetic clothing, like fleeces.

Monday was the first sampling trip and I was lucky enough to have Dr. Ingels to assist in the first round of environmental research. As you can see by the pictures, we took a lot of mud and not all of it made it into the sampling containers. I collected a total of 90 samples from approximately 9 am - 5 pm, thanks to the help of Dr. Ingels and also thanks to our boating captain Adam Wendt with Florida State University Underwater Crime Scene Investigation. The next few weeks (probably few months) will involve the processing and analysis of all of the mud that I sampled from Panama City, to see what levels of microplastics pollution exist at the sites, and to see what nematodes are living in the sediment. The results from this project will help me structure the second part of my work, where I will introduce microplastics to sediment microcosms to determine how oxygen and nitrogen levels change over time.

Stay tuned for more fun in the mud, and please use the contact form on the home page if you are interested in learning more or collaborating.

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Gies, E.A., LeNoble, J.L., Noel, M., Etemadifar, A., Bishay, F., Hall, E.R., & Ross, P.J. (2018). Retention of microplastics in a major secondary wastewater treatment plant in Vancouver, Canada. Marine Pollution Bulletin, 9.