Impacts of Microplastics on the Marine Environment
Updated: Oct 8, 2021
In the last decade, many of us have been exposed to the images of wildlife being caught in ghost fishing nets, ingesting plastic bags, and getting caught in many types of plastic debris. More than 700 species in the marine environment are known to have been affected by plastic either through entanglement or ingestion, from marine mammals, to seabirds to marine reptiles like turtles.
All over the world, research on microplastics is intensifying, and this new threat to wildlife and human population is being scrutinized. Microplastics come in many forms, such as fibres, fragments and microbeads, adding yet another layer of complexity on understanding where they come from, and where they end up.
A direct impact of microplastics on wildlife is the effects that is brought about when these particles have been ingested. Scientists have found microplastics in 114 aquatic species, that accumulate further up the food chain. The consumption of microplastics leaves species feeling ‘full’ and can result in mortality due to malnutrition or clogging of their internal organs.
Since plastic particles cannot be digested, microplastics eaten by marine mammals will sit in their gut and release toxic chemicals that accumulate in their bodies.
An experiment carried out by researchers on filter feeders such as oysters, showed that oysters with microplastics in their system have interference with energy uptake and allocation, reproduction, and offspring performance (Sussarellu et al., 2016). This of course, can have long lasting effects on populations and marine ecosystems as a whole.
One must also consider that plastic can contain a wide range of additives – pigments, water repellents, etc. These toxic chemicals, such as Bisphenol A (BPA) can leach within the organism, effecting hormone function, and reproductive success in different species.
Even marine bacteria such as Prochlorococcus can be affected by the chemicals leached from plastic pollution. Exposure to chemicals interferes with the growth, photosynthesis and oxygen production of these photosynthetic organisms which are responsible for producing 10% of the oxygen we breath (Tetu et al., 2019).
The wide distribution of microplastics in the marine environment is worrying , not just for the species which inhabit the oceans, but also those species that consume marine-bourne food. Project IMPACT aims to understand the scale and extent of microplastics around Malta, however this is just a small piece of the puzzle, with studies on their impacts on humans and species in the Maltese Islands still in its infancy.