Development and application of label- free imaging to microplastic detection and characterisation in corals

Thousands of tons of plastic waste are generated every year, and most of it ends up in the sea. Pieces of plastic get decomposed until only small particles, so called microplastics, are left. They get coated with biofilms, or attached to other particles, or ingested by microorganisms while floating in the ocean, and get transported to all parts of the oceans. The global awareness of pollution of marine and other aquatic environments by microplastics has risen recently. While spectroscopic techniques such as Fourier transformed infrared and Raman spectroscopy have been widely used for identification of plastics collected from aquatic environments, these are time-consuming due to the need for separation from other organic and inorganic particles, filtration, and long measurement time [2]. Furthermore, organisms such as corals can potentially uptake and ingest microplastics. Not much is known about the size distribution or the nature of microplastics found in corals. Corals grown in the lab can help understand this. Field harvested corals can potentially indicate the temporal scale and the seasonal variation the microplastic uptake. In this work, a novel method for non-contact fast identification of microplastics suspensions and their uptake by corals will be developed. The new method based on Raman spectroscopy and non-linear imaging techniques. The data will be further correlated with mass spectrometric imaging in corals to gain further insight on their distribution, morphology and chemical nature of microplastics.