Introduction: Paramecium bursaria, found in almost all kinds of freshwater habitats, is a species of ciliate protozoan that has a mutualistic symbiotic relationship with green alga called Chlorella.Whereas natural populations of P. bursaria are known, their Chorella-bearing counterparts are commoner in natural habitats.he algae live inside the cytoplasm of P. bursaria and provide it with food, while in return, P. bursaria provides the algae with movement and protection (as depicted in the video below). Video 1. Mutualistic relationship between Paramecium bursaria and green algae Chlorella.