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Discovery
The plastisphere was first described by a team of three scientists, Dr. Linda Amaral-Zettler from the Marine Biological Laboratory, Dr. Tracy Mincer from Woods Hole Oceanographic Institution and Dr. Erik Zettler from Sea Education Association. They collected plastic samples during research trips to study how the microorganisms function and alter the ecosystem. They analyzed plastic fragments collected in nets from multiple locations within the Atlantic Ocean. The researchers used a combination of scanning electron microscopy and DNA sequencing to identify the distinct microbial community composition of the plastisphere. Among the most notable findings were "pit formers," crack and pit forming organisms that provide evidence of biodegradation. Moreover, pit formers may also have the potential to break down hydrocarbons. In their analysis, the researchers also found members of the genus Vibrio, a genus which includes the bacteria that cause cholera and other gastrointestinal ailments. Some species of Vibrio can glow, and it is hypothesized that this attracts fish that eat the organisms colonizing the plastic, which then feed from the stomachs of the fish.

Diversity of the Plastisphere
Large scale sequencing studies have found alpha diversities to be lower in the plastisphere relative to surrounding soil samples due to a decrease in species richness in the plastisphere. Polymer film fragments affect microbes in different ways, leading to mixed effects on microbial growth rates in the plastisphere. Certain polymer degrading bacteria release toxic byproducts as a result of the degradation of the plant fragment, serving as a deterrent to the colonization of the plastisphere by susceptible species. Phylogenetic diversity is also decreased in the plastisphere relative to nearby soil samples.

The bacterial and microbial communities in the plastisphere are significantly different from those found in surrounding soil samples, creating a new ecological niche within the ecosystem. The specific growth of bacteria caused by film fragments is a primary cause for the creation of a unique bacterial community. Changes in bacterial community composition over time in the plastisphere have also been shown to drive changes in surrounding land.

In another study which looked at the factors influencing the diversity of the plastisphere, the researchers found that the highest degree of unique microorganisms tended to favor plastic pieces that were blue.

Plastisphere Taxonomy
The growth of specific bacteria in their plastisphere occurs because of the ability of certain bacteria to degrade polymers. Phyla of bacteria that have increased presences in the plastisphere relative to soil samples without plastic micro-fragments include Acidobacteria, Actinobacteria, Bacteroidetes, Chloroflexi, Firmicutes, Planctomycetes, and Proteobacteria. Furthermore, bacteria of the order Rhizobiales, Rhodobacterales, and Sphingomonadales are enriched in the plastisphere. Interactions within the unique bacterial community composition in the plastisphere influence local biogeochemical cycles and ecosystems’ food web interactions.

Plastisphere Community Metabolism
The metabolism of bacterial communities in the plastisphere are enhanced. KEGG Pathway enrichment analyses of plastisphere samples have also demonstrated increases in genetic and environmental information processing, cellular process, and organismal systems. Enhanced metabolic functions for communities in the plastisphere include nitrogen metabolism, insulin signaling pathways, bacterial secretion, organophosphorus compound metabolism, antioxidant metabolism, Vitamin B synthesis, chemotaxis, terpenoid quinone synthesis, sulfur metabolism, carbohydrate metabolism, herbicide degradation, fatty acid metabolism, amino acid metabolism, ketone body pathways, lipopolysaccharide synthesis, alcohol degradation, polycyclic aromatic hydrocarbon degradation, lipid metabolism, cofactor metabolism, cellular growth, cell motility, membrane transport, energy metabolism, and xenobiotics metabolism.

Relationship to Carbon, Nitrogen, and Phosphorus Cycling
The presence of hydrocarbon degrading species in the plastisphere proposes a direct link between the plastisphere and the carbon cycle. Metagenome analyses suggest that genes involved in Carbon degradation, Nitrogen fixation, organic Nitrogen conversion, ammonia oxidation, denitrification, inorganic Phosphorus solubilization, organic Phosphorus mineralization, and Phosphorus transporter production are enriched in the plastisphere, demonstrating the potential impact on biogeochemical cycles by the plastisphere. Specific bacterial phyla present in the plastisphere due to biodegradation abilities but also play a role in Carbon, Nitrogen, and Phosphorus cycling include Proteobacteria and Bacteroidetes. Specifically, some Carbon degrading bacteria are able to use plastics as a food source.

Research in the South Pacific Ocean has investigated the plastisphere’s potential in CO2 and N2O contribution where fairly low greenhouse gas contributions by the plastisphere were noted but concluded that greenhouse gas contribution was dependent on the degree of nutrient concentration and the plastic type.

Significance to Human Health
KEGG Pathway enrichment analyses of plastisphere samples suggest that sequences related to human disease are enriched in the plastisphere. Cholera causing Vibrio cholerae, cancer pathways, and toxoplasmosis sequences are enriched in the plastisphere. Pathogenic bacteria are sustained in the plastisphere in part due to the adsorption of organic pollutants onto biofilms and their usage as nutrition. Current research also aims to identify the relationship between the plastisphere and respiratory viruses and whether the plastisphere affects viral persistence and survival in the environment.