Negative Impacts on the Environment

Zebra mussels harm our Great Lakes in multiple ways. One problem with the species is that they are filter feeders, who completely drain the food source out of the water. The adult zebra mussels can averagely filter greater than 1 liter of water per day. The food they eat include phytoplankton, bacteria and some small zooplankton, which are also the food source of the native animals. Small fish like minnows and sportfish all depend on this food source in order to survive. Zebra mussels continue to destroy our ecosystems by taking away most of the food and, in return, starving native fish and wildlife in our Great Lakes.

They even kill off clams by preventing them from opening their shells to obtain food. Sometimes several thousand zebra mussels can be found on one single native clam or mussel. Native North American mussels and clams have suffered immensely once they are coated with zebra mussels. In the lakes St. Clair and Erie, the invasive species have greatly lowered populations of native mussels and clams. As they spread, zebra mussels are on the verge of threatening the extinction of around 30 native freshwater mussels. Not only reduction of mussels and clams, but also losses of crayfish and snails have been caused by zebra mussel colonization.

Zebra mussels are also completely changing the habitat and environment. There has been great increases in water clarity at the lakes, like how Lake Erie changed between 1989 and 1991. Since sunlight now penetrates deeper and with more intensity, the lakes are being recolonized by invasive aquatic plants like harmful algae. Scientist are even linking the mussels to the cause of Michigan's harmful blue-green algae blooms, the kind that can make individuals ill and have greatly harmed the species that drink the water. A certain type of toxic blue-green algae, Microcystis, produces a poison that causes liver damage when ingested by humans and wildlife. The problem is that zebra mussels eat the good algae but release organisms like blue-green algae back into the water intact. This creates a disproportionate amount of blue-green algae that sometimes gets out of control. The toxic algae growth can eventually make the waters uninhabitable.

Harmful algae blooms in Lake Erie

#dangerous #needstobestopped