Impact of plastic degradation in the biogeochemistry of the ocean

Abstract

More than 250,000 metric tons of plastic are currently floating on the sea surface threatening marine fauna from small copepods to big mammals including human beings. That floating plastic is exposed to sunlight which is its main degradation factor producing scratches and embrittlement. Commercial plastic is never pure and it contains additives and plasticizers to improve the properties required for its purpose and to make it more resistant to degradation. When in contact with water, these additives and the products from plastic degradation can leach out to the aquatic medium becoming part of the dissolved organic matter (DOM) pool naturally present in the ocean. That leaching is enhanced by sunlight irradiation. The chemical compounds leached from plastic can alter the biogeochemistry of the seawater with consequences for the carbon cycle and the marine organisms. Through several lab experiments using different types of plastic (including biodegradable and aged polymers), we will see how plastic photodegradation can alter the chemistry of seawater and how it will affect marine microorganisms. We will also see which marine heterotrophic bacteria are able to degrade such compounds