Quantifying Microplastic Abundance and Distribution in Southwest Floridas Coastal-Marine Waters

Microplastic (MP) particles, plastics particles less than or equal to 5 mm in diameter, have become a ubiquitous environmental problem. Microplastics are known to disrupt all levels of the marine food chain from zooplankton to large marine mammals. These microscopic pieces of plastic have been shown to accumulate in marine life, eventually leading to the blockage of intestinal tracks, reducing of appetite, and leaching of chemicals into the organism that fed on them. In the past decade, studies on marine MP have increased exponentially globally, but such studies are rare in Southwest Florida (SWFL). This study provides the first quantification of MP abundance and distribution in SWFL as it flows from groundwater wells, the Caloosahatchee River Estuary, and the Estero Bay into coastal regions of the Gulf of Mexico. Water samples were collected from 35 sampling locations twice, in the wet (June 2020) and dry (Feb. 2021) seasons. The samples were first digested using Fentons Reagent to remove organics and then analyzed under a microscope for identification and quantification of microplastic size, shape, type, color, density, and concentration. Preliminary results from the wet season showed 38-50, 63-79, and 67-90 MP particles per liter in surface water samples respectively in Estero Bay, Caloosahatchee River Estuary, and sites offshore in the Gulf of Mexico. Though analysis of dry season samples is not yet complete, the final results from this study will act as the foundation to bridge into further research aiming to enhance our understanding on the effects and underlying mechanisms of MPs toxicity on aquatic organisms and can guide policy decisions to strengthen and protect SWFL coastal and marine ecosystems.