Sponges (Phylum Porifera) are one of the most diverse and abundant benthic components in marine ecosystems. They provide important ecosystem services (e.g., water filtration, nutrient cycling, refuge for other organisms), and they are indicators of environmental conditions. But sponges are susceptible to diseases, abrupt cold-water events, and harmful algal blooms, resulting in massive sponge die-offs; in the deep sea, sponges can be destroyed or damaged from fishery and mining activities. We have recently reported rapid cell division of marine sponge cells cultured in optimized nutrient media and the first marine invertebrate (sponge) cell lines. This discovery forms the basis for the development of a biobank of cryopreserved sponge cells that can be used as a repository for sponge biodiversity, as well as to support future research in habitat restoration, biotechnology applications, and sponge-derived drug development. We have established a biobank of cryopreserved cells from more than 200 individual sponges, representing more than 50 species, 26 families, 15 orders, and 2 classes of shallow and deep water sponges. Of these, exceptionally rapid cell division rates (a two- to ten-fold increase in cell number in 48 hours) occurs in more than one-third of the species tested. This is the first bio-bank of living marine invertebrate cells. Research continues on optimization of nutrient media, as well as development of methods for culture scale-up.