Microplastics

Microplastics are a ubiquitous pollutant that has emphasized major concern for several benthic ecosystems and for the species that inhabit them especially as temperatures have begun to warm at an exponential rate. This study has investigated the abundance and trophic transfer intensity of microplastics through exposure experimentation to two different benthal organisms, the stone crab (Menippe mercenaria) and hard clam (Mercenaria mercenaria), under three different temperature gradients. Within a laboratory setting, hard clams were exposed to a concentration of different sizes and types of microplastics in three different temperatures to observe the accumulation rate of these particles from direct ingestion. The exposed clams were then fed to predatory stone crabs from the Indian River Lagoon, under the same three temperature treatments, to detect MP trophic transfer. To examine the disposition of ingested plastics, histology and fluorescent microscopy were used to quantify the locations and numbers of microplastics in the tissues.

Plastic pollution in the marine environment is a global occurrence. Microplastics have been documented in numerous marine systems and organisms. Coastal estuaries and beach systems are at high risk for microplastic pollution. The distribution, abundance, and hazards microplastics present in these marine environments is not fully understood but are widely recognized as needed to support efforts aiming to protect and enhance these extremely valuable marine systems. This project aimed to quantify the abundance and variation of microplastics in estuarine mangrove and open coast beach sediments on Southeast Florida barrier islands, which are vulnerable and important coastal ecosystems. Barrier islands serve as a buffer between Florida’s wetland environments, reefs, and other marine habitats and may serve as a conduit or temporary sink for microplastics entering the ocean. The microplastic pollution present in estuarine mangrove and open coast beach systems may also elucidate patterns of microplastic pollution in the surrounding or similar coastal environments. There have been no extensive studies or monitoring efforts evaluating microplastics in Southeast Florida barrier islands sediments, nor comparing geomorphic properties of an area on microplastic accumulation. Study sites included back barrier estuarine mangroves and open coast beaches at three regionally similar but geomorphically distinct study sites throughout Palm Beach County, Florida. The sites were sampled seasonally in 2022 (i.e., summer and winter) to quantify the spatiotemporal distribution of microplastics.