The effects of microplastic on freshwater Hydra attenuata morphology & feeding

Microplastic refers to small pieces of plastic Hydra attenuata. Microplastics (polyethylene) used were sourced by vacuum filtering a face wash product containing microbeads. Hydra were then exposed to different concentrations of these microplastics (Control, 0.01, 0.02, 0.04, 0.08 g/ml) and morphology was recorded at 24, 48, 96 hrs and 1 week. Feeding tests were also carried out using the same concentrations as the exposure by recording the amount of Artemia ingested over a period 120 min. Hydra were found to be able to ingest the microplastics (22 - 444 μm) and feeding was affected by the presence of microplastics even at the lowest concentration used (0.01 g/ml). After 60 min of exposure the Hydra ingested a lower amount of Artemia at all concentrations of microplastic compared to the control. This became particularly evident at the 90 and 120 min mark. Exposure to the microplastics did cause changes to the morphology of the Hydra, however these changes were non-lethal. The preliminary results of this study show that Hydra attenuata are capable of ingesting microplastics. The presence of microplastics disrupted the feeding behaviour of the Hydra thus negatively impacting its ability to feed. Continued research in this area will provide valuable insight in determining the potential impact microplastic can have on the health of freshwater biota.