Lubomirskia baicalensis

Lubomirskia baicalensis
Scientific classification
Kingdom:	Animalia
Phylum:	Porifera
Class:	Demospongiae
Order:	Haplosclerida
Family:	Lubomirskiidae
Genus:	Lubomirskia
Species:	L. baicalensis
Binomial name
Lubomirskia baicalensis (Pallas, 1773)

Lubomirskia baicalensis is a freshwater demosponge that is found on hard bottoms at depths between 1 and 120 m (3–394 ft) in Lake Baikal, Russia. It is commonly called Lake Baikal sponge and it is the most abundant sponge in the lake, but all 14 species in the family Lubomirskiidae are Baikal endemics.

In shallow water L. baicalensis is bark-like, covering stones somewhat like a carpet. From a depth of 3–4 m (10–13 ft) it starts to have branches, and can reach a height of more than 1.2 m (4 ft), which is unusually large for a freshwater sponge. On rocky grounds at depths of 5–12 m (16–39 ft) 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 0 °C (32 °F). It takes 1 year for it to grow 1 cm (0.39 in) taller.

...
Wikipedia