Lubomirskia baikalensis


Lubomirskia baikalensis is a freshwater species of sponge that is endemic to Lake Baikal, Russia. It is the most abundant of the 14 species of the family Lubomirskiidae found in the lake. All the sponges in the family are commonly known as Lake Baikal sponge.
Lubomirskia baikalensis is found on hard bottoms of shallow water at depths between It is bark-like, and covers stones somewhat like a carpet. From a depth of it starts to have branches, and can reach a height of more than, which is unusually large for a freshwater sponge. On rocky grounds at depths of the branching form is particularly common and may form "forests". This sponge is in mutual symbiosis with a green dinoflagellate, making it green in appearance. Okadaic acid produced by the dinoflagellate assists the sponge to survive when Lake Baikal is iced over in winter, and the water temperature is close to. It takes 1 year for it to grow taller.