Spongilla lacustris is a species of freshwater sponge from the Spongillidae family. It is only found mostly in clear freshwater lakes in North America, Europe and Asia. It is often found growing under rocks or logs, and can sometimes be found in slow-moving streams.
This particular species is soft and fragile with whitish to greenish coloration. It has irregularly scattered and barely visible water exit holes. The surface is uneven and covered in rough spicules (spikes).
This species has the ability to reproduce asexually by forming buds in late summer that spend the winter in a dormant state and emerge from the adult in the spring. It can also reproduce sexually during the summer, giving birth to live larvae.
Freshwater sponges are of no known significance to people, except for the fact that scientists believe they may be helpful as indicators of water pollution. The species is neither threatened nor endangered.
Image Caption: The freshwater sponge, Spongilla lacustris, in the Hanford Reach of the Columbia River in Washington State, USA. Credit: Kirt L. Onthank/Wikipedia(CC BY-SA 3.0)