What does Euglena Gracilis do?

As in, what would happen if it were in a lake/body of water? Would it affect the body of water in a negative, positive, or neutral way?

Question

What does Euglena Gracilis do?

As in, what would happen if it were in a lake/body of water?  Would it affect the body of water in a negative, positive, or neutral way?

praetorian.10 · Answer

"Euglena gracilis is just one of many species of Euglena. They do not have common names like birds or trees, so we have to refer to them by their scientific name. Euglena are interesting because they are a sort of combination of plant and animal."

anonymous · Answer

I'm sorry, but this doesn't answer my question.  Thank you for your effort though.