Zooplankton might be some of the smallest creatures in the sea, but they are crucially important to oceanic aquatic ecology. In their tiny, hidden world under the water, they perform some of the most vital functions in the food chain. Not only does this impact the natural ebb and flow of the oceans, but it also eventually influences the way land-based food chains operate.
Study discovers zooplankton are eating plastic
This is why many in the scientific and environmental community were troubled by the recent discovery that zooplankton were ingesting plastic. Two specific types of zooplankton species, copepods and euphausiids, were examined in a study that was published in the journal Archives of Environmental Contamination and Toxicology. Copepods and euphausiids, which are miniscule crustaceans, are "foundation species" in the Northern Pacific Ocean, according to study authors, so the impact of these digestion methods has the potential to be wide-reaching across the Pacific.
Up until this study, there was little scientific evidence about marine biota and microplastics, even though there is a well-known consensus in the scientific community about plastics and marine life as a whole. Over time, microplastics can become tiny enough for even the smallest marine organisms to digest, which could present devastating effects for food webs on sea and land.
This is the first time it has been confirmed that plastic is being consumed by these important sea creatures. Co-author of the study Peter Ross, who is also the head of the Ocean Pollution Research Program at the Vancouver Aquarium, explained to ThinkProgress that while some previous studies had identified plastic ingestion in zooplankton in lab settings, this was the first time microplastic ingestion was captured on camera. A 2013 study published in Environmental Science and Technology also discovered microplastic ingestion in zooplankton, so scientists have been aware of the issue for several years.
Below is a YouTube video posted by New Scientists showing the zooplankton eating plastic on camera for the first time. In the video, it's clearly apparent that the creatures are swallowing tiny beads of this substance.
The reason why zooplankton species are attracted to microplastics is because they are naturally inclined to look for food that is the size of phytoplankton. Because these tiny pieces of plastic resemble the micro creatures, zooplankton are beginning to mistake the plastic for their normal food intake.
"They are about the same size as fish eggs, which means that, essentially, they look like food. To any organism that lives in the water, they are food," Sherri Mason, an associate professor of chemistry at the State University of New York, Fredonia, explained to NPR in 2014. "So our concern is that, essentially, they are making their way into the food web."
Mason is speaking specifically to plastic pollution in the Great Lakes, another vital water body experiencing the same phenomenon. In fact, plastic pollution has gotten so bad in Lake Michigan that Illinois lawmakers banned soaps and skin exfoliants with microbeads throughout the state last year, and New York is making plans to do the same.
What does this mean for marine life?
This discovery shows a potential of a ripple effect across the world's oceans. Ross explained that though the study did not look into the immediate effects of plastic ingestion for zooplankton, he says that the plastic could block digestion completely or leach into their bodies. However, the impact on the oceanic food chain seems to be the greatest concern for study authors.
"We're concerned, obviously, that this is a way in which even if you're a salmon and you don't deliberately target a piece of plastic, you're going to get exposed as a result of feeding on zooplankton," Ross explained to ThinkProgress.
The fascinating world of zooplankton
Like outer space, the depths of the ocean are mysterious. Few humans have ever seen how zooplankton thrive and contribute to the overall health and balance of the oceans, but one thing is abundantly clear: these miniscule ecosystems have wide-reaching effects on marine and human health.
Zooplankton are diverse creatures that are mostly known as food for larger fish species like shrimp, salmon and even animals like whales. According to a TED Talk by Tierney Thys and the Plankton Chronicles Projects, just a teaspoon of ocean water can contain up to a million zooplankton:
Phytoplankton in particular are fascinating, as they represent the foundation for the largest food web on earth. In addition to providing a food source to myriad species, they also reveal a lot about the health of water bodies, which is why many scientists and ecological consulting services tend to examine them.
Oceanic plastic: A growing problem
The health of our oceans is currently in peril on the microscopic level, but many fish species and larger marine animals have also been feeding on plastic. A 2010 study highlighted by the National Geographic Society discovered that worldwide, 8 million tons of plastic makes its way into the ocean on a worldwide scale annually. In fact, it amounts to five plastic grocery bags to every foot of coastlines throughout the world.
One of the biggest sources of this problem is the Great Pacific Ocean Garbage Patch. While the National Ocean and Atmospheric Administration states that tracking oceanic plastic pollution is difficult, there is a serious marine problem happening throughout the Northern Pacific.
The term "garbage patch" in particular references concentrations of debris, but because ocean currents move rapidly throughout the Pacific, predicting the debris patterns is very challenging for scientists. Although there have been reports of patches being so large that they are the size of Texas, the NOAA states that the exact size and scale of Pacific garbage is unknown.
The NOAA does claim, however, that there are high concentrations of plastic on the western and eastern sides of the Pacific, so this isn't just a problem for North America, but also Asian countries and Australia.
Plastic ingestion in zooplankton is a sign that our oceans as well as freshwater bodies are in peril. Now is the time for sound environmental consulting services and research efforts to understand the health of our waterways and how plastic ingestion will impact the food chain further down the road.