Sponges are important components of benthic, hard-bottom communities in Florida Bay and the Florida reef tract. However, phytoplankton blooms have resulted in massive sponge die-offs that have had a cascading effect on the ecosystems they support (e.g., spiny lobster nursery, commercial sponge fishery). Over the past decade, a coalition of scientists and resource managers from academia, state agencies, non-government organizations, and community volunteers undertook a large-scale sponge restoration project in Florida Bay. While this effort has been very successful, the disadvantage is that dozens to hundreds or even thousands of healthy sponges are needed to supply cuttings for large-scale restoration. We are investigating a complementary approach: grow sponge juveniles from 3-D sponge cell aggregates. Our laboratory has pioneered the technology for sponge cell culture. During Project NEPTUNE 100, we will establish cell cultures from freshly collected individuals of 3 common shallow water sponges and monitor their development into 3-D cell aggregates, the precursor to a fully functional sponge. We hypothesize that the increase in partial pressure of oxygen at depth will stimulate both cell division and differentiation.