Unless rapid action is taken, the health of the marine ecosystem might be under threat from microfiber pollution in the very near future, according to a new study by the Ocean Wise Plastics Lab in collaboration with the University of British Columbia. This study shows how microfibers, which are tiny fibers shed from clothing during washing, affect organisms in the lower trophic levels of the marine the food web, identifying direct impacts of microfiber pollution on ocean ecosystems. As microfibers continue to increase in the ocean, they pose health risks to marine life.
Microfibers are fibers less than 5 millimetres long, known for shedding from clothing during washing. By Ocean Wise’s estimate, American and Canadian households combined release the weight of ten blue whales in microfibers through laundry washes every year. Once they end up in our ocean, microfibers make their way into the ecosystem, as they are ingested by zooplankton, small animals that feed on algae and other organic matter.
The study, published in the journal Science of the Total Environment, was created to be a miniature version of British Columbia’s Strait of Georgia, an ecosystem rich in biodiversity. Researchers exposed zooplankton to environmentally relevant concentrations of microfibers over a series of days, and the results were twofold.
First, zooplankton confused fibers for their normal food, eating less prey and more fibers as microfibers levels increased in seawater. Zooplankton may become malnourished as a result, and therefore might not be a nutritious food item for their predators, which include juvenile salmon, herring and groundfish – which then impacts larger predators. In this way, entire marine food webs may be negatively affected by microfibers.
“We are finding that zooplankton are eating microfibers instead of their food, hence missing out on energy and nutrition,” said Dr. Oladimeji Ayo Iwalaye, a postdoctoral researcher at Ocean Wise and UBC. “This can have ripple effects on the marine food web, as zooplankton are a key food source for many species.”
Second, zooplankton retained microfibers in their gut, even after a depuration period (ie. The period of time after the zooplankton is placed in a clean water environment). This is not just concerning for zooplankton – it spells trouble for their predators too. For example, marine fish may acquire microfibers directly as they drink water or as they move water through their gills. The fact that their zooplankton prey retain microfibers in their gut, suggests that contaminated prey might be an additional entry pathway of microfibers into fish.
“Zooplankton could serve as concentrators of microfibers in the ocean for their predators,” said Dr. Iwalaye.
Lastly, zooplankton excrement is full of energy and carbon and is a big driver of the carbon cycle in marine sediments. Their poop aids in the recycling and downward flux of organic carbon from the surface to the deep ocean. Many microbes and bottom-dwelling creatures such as worms, crabs, bottom-feeding fish, sea cucumbers, and sea stars rely on zooplankton poop for nutrition, keeping a healthy ecosystem. However, when packed with microfibers, that zooplankton poop sinks faster, making these microfibers available to deep sea creatures. The consequences of this are not yet well understood, but hints at the impacts that microfibers have on both the surface and deep ocean environments.
The study adds to the growing evidence of the harm that microfibers cause in ocean ecosystems. Previous research from Ocean Wise suggests that a key mitigation to prevent the shed of microfibers is to wash laundry on cold and gentle settings. This can reduce microfiber shed up to 70%.
Ocean Wise extends its gratitude to UBC Prof. Maite Maldonado for her invaluable thought leadership concerning microplastic pollution in British Columbia and her support for this research. Additionally, we acknowledge and appreciate the assistance offered by Kevin Landrini from Ocean Wise during the course of this study.
About Ocean Wise
Ocean Wise is a globally focused conservation organization on a mission to restore and protect our ocean. Through research, education, public engagement, and international collaborations, we empower communities to fight three major ocean challenges: ocean pollution, overfishing and climate change. By equipping and empowering individuals, communities, industries, and governments, we can create a future where people and our ocean can thrive. Ocean Wise is headquartered in Vancouver, British Columbia with staff across Canada, Mexico, and Chile, and operates conservation projects that make national and international impact.