The fact that marine fish are sharing their natural habitat with plastic debris makes for a very bleak situation. Plastic is a material which is very difficult for them to discern by sight, and now we have realised, also by smell and taste.
Scientists from the Marine Biological Laboratory (MBL) at the University of Chicago have discovered that this pollution becomes covered in a biofilm of microbes and bacteria.
The ’Plastisphere’, a phrase coined by team leader Linda Amaral-Zettler, is made up of many different diatoms and bacteria, with three phyla being the most common, namely Protobacteria, Cyanobacteria and Bacteriodetes.
This biofilm can have a strong influence on the nature of our plastic waste. Plastics become more likely to sink and to break up into smaller pieces. The smell of the material can even change, giving birds and fish the impression that it is an item of food.
The ability to see the spatial organisation of microbes is the result of further work carried out by teams from the MBL. This research involved a fluorescent imaging technique which was developed by Jessica Mark Welsh and colleagues.
"We now have a toolkit that enables us to understand the spatial structure of the Plastisphere and, combined with other methods, a better future way to understand the Plastisphere's major microbial players, what they are doing, and their impact on the fate of plastic litter in the ocean," said Amaral-Zettler.
Amaral-Zettler, Mark Welsh and Cathleen Schlundt collected samples from three ocean sites, each with differing biogeography.
Physical and chemical properties of plastic waste can be altered by microbes and biofilms, thereby promoting the breakdown of plastics. Investigations therefore continue in this area.
However, where floating plastics are concerned, the biofilm protects their surface from the sun’s UV radiation, possibly the fastest acting abiotic influence for plastic degradation.
For further information see Molecular Ecology Resources.