A simplified method for extracting microplastics in laboratory-cultured coral and water samples
Citation:
Duffy, A., C. Hankins, AND K. Drisco. A simplified method for extracting microplastics in laboratory-cultured coral and water samples. Sixth International Marine Debris Conference, San Diego, CA, March 12 - 16, 2018.
Impact/Purpose:
Present new methods for extracting microplastics from coral samples
Description:
The deleterious effects of microplastic ingestion by marine organisms and the impacts across trophic levels are widely unknown. Due to the extensive ecological and socioeconomic benefits provided by coral reefs, investigating the impacts of microplastics on reef ecosystems is of growing concern. Current methods for extracting microplastics from tissue samples require the use of harsh chemicals that may degrade the surface of plastics, which could hinder accurate polymer identification. The method presented here was developed to extract microplastics from coral and water samples using a sonic cell disruptor. This technique was tested for efficacy in an effort to eliminate the need for chemicals and ensure chemical properties of microplastic surfaces are not altered for polymer identification. This method was performed using laboratory-cultured coral species Montastrea cavernosa and Orbicella faveolata as well as culture water samples exposed to cured, fluorescent microplastics (Cospheric® 850-1000µm, 425-500µm, 90-106µm). Both coral and water samples were exposed to a sonic cell disruptor to emulsify fine organic matter. Samples were then vacuum filtered to separate out microplastics, whereby dry weights of microplastics were determined and compared to initial dose weights. The sonic cell disruptor method could not effectively emulsify large quantities of organic debris or mineral debris. Furthermore, it can fragment the microplastics into smaller pieces and is thus recommended for applications using measured doses of plastics. Overall, the use of sonic cell disruption in place of chemicals for organic digestion is an effective method for use with coral samples and water with little organic debris, and is recommended for specific laboratory-based applications.