Plastic has become an indispensable material in our lives. The pace dictated by global
production exceeds our ability to responsibly handle generated plastic waste. Therefore,
enormous amounts of plastics end up in our environment every day, where they break
down into smaller particles called microplastics. By entering the environment,
microplastics are subject to a number of physical and chemical factors. They also
encounter microorganisms, which form a biofilm on a particle surface and further affect
behavior of microplastics. The density of particles then increases after biofouling,
affecting their distribution in the aquatic environment and their bioavailability to other
organisms. The presence of biofilm also affects nutrient flow, toxicity, and interactions
with contaminants present in water. In experimental part of the thesis, we exposed
microplastics to surface water and evaluated the development of biofilm on its surface,
as well as changes in the properties of microplastics. Results showed that living
microorganisms can easily colonized microplastics. The viability of the biofilm was
demonstrated by the measurement of activity of the urease enzymes, by the determination
of the photosynthetic pigment (i.e. chlorophyll) and by analysis of extracted extracellular
polymeric substances. After 12 weeks of aging in surface water, the density of
microplastics increased and particles started to agglomerate as a consequence of biofilm
formation.
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