Freshwater mussels, important creatures that help clean natural water, are declining in the United States and are having a major impact on the ecosystem.
A cloudy water tank without freshwater mussels (left) and a tank with 15 mussels (right) after 90 minutes, the water becomes transparent. Image: D. Kreeger/Partnership for the Delaware Estuary
Freshwater rivers and lakes in the United States are losing an important weapon: freshwater mussels. As an integral part of nature’s cleaning “team,” their absence could negatively impact countless bodies of water across the United States and even beyond. IFL Science reported on November 8.
To emphasize the importance of these shelled creatures, the US Fish and Wildlife Service (FWS) shared photos from the Partnership for the Delaware Estuary, demonstrating impressive filtering capabilities. The photo shows two tanks filled with murky lake water containing mud and algae, but one tank had an additional 15 clams. In just 90 minutes, the tank with mussels became transparent, while the tank without mussels remained cloudy. “Never underestimate the power of freshwater mussels,” FWS wrote.
According to estimates, a freshwater mussel can pump and filter 30 – 57 liters of water per day. Working like mini vacuum cleaners, they help improve water quality by filtering out bacteria, algae and pollutants. If a freshwater body suddenly loses mussels, water quality will plummet, causing major changes to the ecosystem.
Many species of freshwater mussels can live for a century. Although they are very resilient, they are facing serious trouble in many parts of the United States. In recent years, many freshwater mussel populations have experienced mass die-offs across Michigan, Minnesota, North Carolina, Ohio, Oregon, Virginia, Washington and Wisconsin.
Due to the filtering ability and foraging behavior of freshwater mussels on the bottom of rivers and lakes, pollution and environmental contaminants are often blamed for mussel deaths. However, none of those factors have been identified in the recent deaths.
Another possibility is that there is a new virus at work. A 2020 study discovered a virus never before seen in the virus subfamily Densovirinae occurs more commonly in sick boys than in healthy boys. Thus, viruses may be a factor leading to mass die-off events.
While the new discovery is a breakthrough, there are likely many other threats at play, including various types of pollutants and pathogens. “If we lose mussels, rivers and lakes and everything that depends on them will never be the same. They are the foundational organisms for freshwater ecosystems,” Tony Goldberg, professor of Pathology at the University Wisconsin-Madison, review.