Coastal stormwater ponds will retain some microplastics, but research has shown that a significant number of particles will flush through the ponds and end up in receiving estuarine waters. Enhancing the retention and possible degradation of microplastics in stormwater ponds may be achieved by outfitting these ponds with Floating Treatment Wetlands (FTW). The plants in FTWs develop biofilms on their submerged root systems, which can trap microplastics. In addition, microorganisms in the biofilms may actively contribute to the degradation of captured microplastics. At the moment very little to nothing is known about these processes. This Program Development Grant will produce the first results that will direct future research and provide initial results for larger grant proposals like the NOAA Marine Debris Program. This study will form the beginning of an understanding of the role that FTWs can play in the bioremediation of microplastics. Based on the results, practical recommendations can eventually be made on the conditions that will enhance the capability of FTWs to capture and degrade microplastics. These recommendations for pond and coastal water quality managers may consist of plant species selection, plant harvesting, FTW size and density.
The objectives are 1) to investigate if biofilms on root systems of floating treatment wetlands (FTW)in coastal stormwater ponds can trap microplastics, 2) if smaller scale mesocosms can be used to mimic FTW mechanisms for removing microplastics, 3) perform DNA sequencing of bacteria in the biofilms to identify microbiomes on different plant species in FTWs, 4) identify genes in FTW biofilm microorganisms that are involved in plastic breakdown.