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Lubomirskia baicalensis is a freshwater demosponge that is found only in Lake Baikal. It is commonly called Lake Baikal sponge. The 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 0° Celsius. L. baicalensis can grow to a large size, however it takes 1 year for it to grow one centimeter taller.