Microplastics in Aquatic Environments

The high surface areas of the microplastics adsorb organic and inorganic compounds from the water column and turn them into nutrient resources for microbial taxa. Their capacity to attract microbial taxa and preferences of microorganisms to make the microplastics their habitat has earned the dubious name plastisphere or ecocorona. Due to their inherent characteristics of hydrophobic nature and higher surface to volume ratio, microplastics coexist with many other types of contaminants such as polycyclic aromatic hydrocarbons, persistent organic pollutants (POPs), trace metals, and pharmaceutically active compounds, consequently changing their environmental fate and ecological impacts in the aquatic environments. Substantial quantities of plastic litter dumped into the oceans illegally by offshore platforms and vessels, coastal tourism, marine aquaculture, fisheries (abandoned and relict fishing gear), commercial and other fleets, and lost cargo shipping containers also contribute plastic into the oceans. The dispersal of microplastics in aquatic environments is similar to that of natural sediments with coarse-grained and dense particles deposited close to the source, while finer and less dense particles remain in suspension and settle in low-energy environments. Microplastic contamination in bottom waters is considerably higher than in surface waters, suggesting their vertical migration into deeper waters with eventual deposition and burial within bottom sediments.