How microplastics, marine aggregates and marine animals are connected
Prior research has suggested that mussels are a robust indicator of plastic debris and particles in marine environments. A new study says that's not the case because mussels are picky eaters and have an inherent ability to choose and sort their food.
More than 10 million tons of plastic debris enter the oceans every year and are found in nearly every oceanic layer. They start out as large floating items and eventually break down into much smaller pieces called microplastics. These particles are pervasive and have been found in the digestive tracts of more than 100 different species, posing physical, chemical and even potential biological harm to these animals. Mussels and other bivalves like oysters and clams are eaten whole without removal of the gastrointestinal tract and therefore represent a pathway for microplastics to enter the human food chain.
Contrary to prior research, a first-of-its-kind study from a team of scientists suggests that mussels are not a robust indicator of microplastics in the marine environment because of their inherent ability to selectively feed, making them very picky eaters. Instead, marine aggregates, also referred to as "marine snow," have much more to say about the fate of microplastics in the environment.
Marine aggregates are a predominant form of sinking particulate carbon in the marine water column and form the basis of the food chain in the ocean. These aggregates also represent a mechanism for transporting microplastics to the sea floor. The study demonstrates that they play an important role in removing microplastics from the ocean surface, vertically transferring them through the water column, and facilitating their transfer to marine food webs.
Using a powerful tool called spectroscopy, researchers from Florida Atlantic University, East China Normal University, Woods Hole Oceanographic Institution, the University of Connecticut, and the University of New England, are the first to identify a connection, under field conditions, between microplastics within marine aggregates and mussels (Mytulis edulis). Results of the study, published in the journal Environmental Science & Technology, have important implications for the fate of plastic particles in marine environments. Read full article.