Sponges are very basic animals with no circulatory, digestive or nervous systems. Their structure involves a tubular network that allows water to flow through their bodies bringing food and oxygen. Their growth form may be mounds or mats attached to hard surfaces, and often they have a crunchy texture due to a “scaffolding” of mineral spicules.
Sponges attach to hard surfaces in streams, most commonly stones but sometimes woody material or snail shells.
Sponges usually feed on microscopic floating food particles including bacteria, but some have symbiotic algae growing within the sponge generating organic matter internally.
Sponges are common in habitats with good water quality, but also in urban streams with obviously degraded water quality. No tolerance values have been assigned.