# Microbial Life on the Surface of Microlgistics in Natural Waters
## 6 Factors Influencing the Microbial Composition of Plastisphere  
Once in the aquatic environment, the microplastics become the object for microbial colonization and biofilm development. At the present time there is no clear understanding of what and how different factors affect the composition of biofilms and their function. We shall try to briefly summarize what is known. It was shown that the structure and taxonomic composition of microbial communities on plastic debris depend on plastic material, geographical location and season [59]. _Factor 1. Geographic origins._ Geographical location has a significant influence on the microbial composition of \"Plastisphere\". It was shown that bacterial communities of plastic samples from the North Pacific and North Atlantic subtropical gyres differed between ocean basins [78]. Study of composition of microbial communities from the surfaces of polypropylene and polyvinyl chloride microplastics being incubated for one year in seawater in China showed significant differences depending on geographical locations. _Factor 2. Location of plastic in the water body_. Composition of marine plastic bacterial communities showed a great variability depending on plastic locations (sediment, seawater, and resin pellets sampled on the beach) across the Belgian part of the North Sea [97]. _Factor 3. Surrounding Environment and seasonal variation_. Such factors as salinity and nutrient concentration affect biofilm formation and microbial composition [78; 89]. Salinity is considered to be the most essential factor affecting bacterial diversity in the biofilms developed on microplastic particles [87]. Low nutrient levels trigger the attachment to surfaces in many bacterial species, while under high nutrient levels biofilm formation seems less advantageous [98]. The temperature of water obviously plays an important role in formation of the \"Plastisphere\", as well as oxygen content in the surrounding environment [99]. It was found that microbial communities on fragments of polyethylene terephthalate bottles in the North Sea (UK) varied from season and location [59; 70]. _Factor 4. Plastic properties_. Physical characteristics of plastic such as density play an important role in its ability to float on the water surface and vertical distribution in the water column. Microplastics with density lower than the density of water are floating on the water surface and could be displaced over long distances; meanwhile microplastics particles with a density higher than the density of water sink in the water column and distribute attached microorganisms in the bulk water. The hydrophobic surface of plastic and its long half-life make it an attractive substrate for microbial colonization [80]. Microplastic has a large specific surface area that enhances microbial cells adhesion on it. Composition of microbial communities depends on the composition of the polymer type they colonize. Significant differences in the community composition of biofilms formed on polyethylene in comparison with polypropylene and polystyrene floating in the Mediterranean Sea were found [71]. It was shown that bacterial communities of biofilm on polystyrene had different bacterial communities than polyethylene and propylene [100]. The same results were obtained previously by [PERSON] with co-authors, who found considerable differences in composition of bacterial communities between polystyrene and polyethylene and between polystyrene and polypropylene [78]. Similar results were obtained by [PERSON] and co-authors [87] showed selectiveness of bacterial genera to colonize different types of microplastics such as polyvinyl chloride, polypropylene, polyethylene, polystyrene, and polyurethane. The difference between microbial communities of the biofilms from plastic materials such as polyethylene, polypropylene and polystyrene, native material cellulose and inert glass beads particles placed in ambient Baltic bacterioplankton for 2 weeks was shown [83].