An invasive species of zooplankton known as the spiny water flea could pose a huge threat to the Great Lakes, as well as to the bodies of water around them, a study in the Proceedings of the National Academy of Sciences reports.
The reason the flea — no bigger than the width of a pinky finger — is such a problem is because it feasts on tiny zooplankton known as Daphnia pulicaria.
D. pulicaria is a species native to Wisconsin’s Lake Mendota that eats algae. As it eats the algae the water becomes clear, raising both the visibility and quality of lake waters.
However, because of the spiny water flea’s voracious appetite, Daphnia numbers have drastically dropped in Lake Mendota. The decline has led to large algae blooms that have decreased overall water quality.
Such blooms are dangerous because they release harmful toxins that kill local wildlife. They also can suck so much oxygen from the water that fish and other aquatic life can no longer survive.
Spiny fleas first came over to America in Russian cargo ships that took water from the eastern world and dumped it into the Great Lakes. If left alone, the species could eat more Daphnia than every other predator of the zooplankton combined. That alters the entire food web of the lake and leads to the harmful rises in algae.
In addition to their large ecological impact, the spiny water flea is projected to take a major economic toll as well.
This is because, in order to keep a healthy ecosystem despite the drop in Daphnia numbers, officials would have to reverse the growth of the algae. The only way to do that would be through a 71 percent reduction in phosphorous pollution, The Washington Post reports.
To calculate the overall cost of that reduction, researchers from the University of Madison-Wisconsin used models that showed such an endeavor would run up a bill of between $86.5 million and $163 million. Even those numbers could rise if secondary invasions — such as the ones seen in Lake Mendota — are factored in.
“There are hundreds of billions of dollars’ worth of damages we can account for right now. If you add in invasive species’ impact on ecosystem services and look at secondary invasions, then that number is likely to be trillions,” said lead author Jake Walsh, a PhD. candidate at the University of Wisconsin Center for Limnology, in a statement.
Over 180 invasive species have been introduced into the Great Lakes. While Lake Mendota is not a Great Lake, it was used in the study because secondary invasions — places where invasive species have spread to since coming to the Great Lakes — are an important part of understanding the impact that such species can have.