A Novel Approach to Bio-Friendly Microplastic Extraction with Ascidians
Yuntong Li, Rowan Ross
Burnaby North Secondary
Floor Location : S 119 V

BACKGROUND: Microplastics are fragments of plastic that are 5mm or smaller, forming from the degradation of larger pieces of plastic. Microplastics in the oceans and great lakes are a devastating problem since marine wildlife are accidentally ingesting microplastics as food. This is extremely harmful to living organisms because once ingested, microplastics can cause digestive system blockage, physical injury, altered feeding behaviour, and changes to their cells. This leads to issues that affect growth and reproduction, often resulting in the disruption of an entire food chain. Although research has now begun to explore the subject of microplastics and their respective extraction, there still remains a lack of solutions to remove microplastics from the ocean.

PURPOSE: A successful solution for the extraction of microplastics from the ocean must be both feasible and bio-friendly. In a search to meet those goals, we explored the potential utility of filter feeders to extract microplastics from the ocean. We investigated the ability of solitary filter-feeders, specifically Ascidians, to remove microplastics from ocean water and to act as a potential bio-filter to reduce ocean pollution.

HYPOTHESIS: We hypothesized that Ascidians will filter microplastics from water. Specifically, if Ascidians are exposed to microplastics in a body of water, then the concentration of microplastics would decrease after the Ascidians filtered the water.

METHOD: Microplastics were added to three tanks of saltwater that contained living Ascidians. A similar quantity of microplastics was added to three control tanks that did not contain Ascidians. To simulate the microplastics found in the ocean, 10μm diameter microbeads were added to each tank. Water samples were then recorded and tested with a fluorescent-activating microscope and a fluorescence scanner.

RESULTS: The concentration of microplastics in the tanks housing the Ascidians demonstrated a rapid 24.7% decrease within 1 day. By day 4, the concentration of microplastics had decreased by 94.7%. In contrast, there was no change in the microplastic concentration in the control group.

CONCLUSIONS: Ascidians efficiently filtered microplastics from water through their natural feeding and respiratory process. Our research demonstrates that this method of bio-filtration is an effective and viable option for extracting microplastics from polluted water. These findings could lay the path for future research in safe microplastic extraction from the ocean using invertebrate filter feeders. Based on our results, we can extrapolate that a 5m x 5m x 5m cage of Ascidians would filter out almost 50kg of microplastics every day. This newfound knowledge can lead to many practical applications in the field of ocean pollution such as commercially farming Ascidians for microplastic extraction.