A translucent glass sponge with a bulbous bell and long stem, floating against a dark underwater background.
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Glass Sponge
A close look at a glass sponge seen during the eighth dive of the 2026 Cook Islands ROV Exploration cruise. We saw several sponges during the dive, affixed to nodules and rocks.
Credit

NOAA Ocean Exploration, 2026 Cook Islands ROV Exploration