(ORDO NEWS) — Microplastics are widespread in the seas and oceans, and their harmful effects on many different marine animals are well known. However, we know relatively little about microplastics in our freshwater rivers, streams and lakes.
We still don’t know exactly where they come from, where they end up – and most importantly – how much damage they can do if they enter the food chain.
Until now, plastic fragmentation has been largely attributed to processes such as sunlight or wave action, a process that can take years or decades. But it turns out that a tiny creature like a shrimp can do the same job much faster.
I am a researcher who specializes in microplastics in the environment. In my last work, my colleagues and I showed that microplastics (pieces of plastic less than 5 mm in size) in fresh water break down into nanoplastics (less than one micrometer in size), with the help of invertebrates, and that this process takes much faster than previously thought.
Our results, recently published in the journal Nature Science Papers, highlight the role of biological fragmentation in microplastics, which is still not well understood.
It is a 2 cm long crustacean, the freshwater amphipod Gammarus duebeni. This particular species is native to Irish streams, but belongs to a larger group of invertebrates that are found in both freshwater and oceans around the world.
Gammarus duebeni are capable of fragmenting microplastics of various shapes and sizes, including nanoplastics, in less than four days.
Why is it important? We know that microplastics can build up in the intestines of seabirds and fish, and smaller particles can even penetrate cells and tissues where their effects are more difficult to predict.
Therefore, the discovery that a common animal can rapidly fragment huge amounts of microplastics is of particular concern. Since the crustaceans we looked at serve as food for fish and birds, any nanoplastic fragments they produce can also enter the food chain.
We still don’t know exactly what effect this process will have on birds, especially in the early stages of their life. But our findings on the biological fragmentation of microplastics will help us understand the role that animals can play in determining the fate of plastics in our waters.
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