NOAA Researchers Find Massive Rare Sponge Mounds Off California

In October 2020, Ocean Exploration Trust’s E/V Nautilus crew discovered something extraordinary—a potential deep-sea sponge reef within the Channel Islands National Marine Sanctuary! The vast mounds of glass sponges and their skeletons are rarely seen anywhere in the world. The discovery is even more unexpected considering the area is generally well explored.

The sponge mounds were found off the California coast, which is home to various protected areas. Researchers have heavily explored habitats shallower than 300 meters (~1,000 feet) in the region’s two best-studied sites, Footprint Ridge and Piggy Bank. During this late 2020 expedition, the survey team decided to use a remotely operated vehicle (ROV) to record and transmit live video in hopes of discovering what lurks in the 600 meter (~2,000 foot)-deep valley between the two sites.

NOAA experts were on the Nautilus live chat when the ROV descended into the valley and stumbled across a crunchy-looking sponge bed. As the ROV followed and climbed up the outcrop, the scientists realized the bed seemed endless. Large sponge mounds like these are an important find. They can provide habitat for a variety of life forms and teach us more about how the deep ocean responds to changing environmental conditions.