Introduction of Zebra Mussels has had this effect in the Great Lakes... a positive effect, the zebra mussels have helped clear the water of algae, which has been beneficial for all aquatic life in the lakes. b positive effect, the zebra mussels have helped to plant numerous aquatic plants when they deposited partially digested seeds from Eurasia, where they originated. c negative effect, the zebra mussels have caused a decrease in fertile soil when the lake floods, which has caused direct harm to neighboring farms. d negative effect, the zebra mussels consume too much algae causing a change in the community of organisms in the lakes.
