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Weighting for Alvin

March 21, 2016

Alvin can’t carry enough batteries to power its way to the seafloor. Instead, dive preparations include attaching stacks of iron plates to the outside of the sub so it can sink to the depths. Once there, the pilot releases some to make the sub neutrally buoyant. To return to the surface, he jettisons the rest and the sub floats back up. Alvin is currently on a mission to the mid-ocean ridge in the Atlantic to search for special volcanic rocks with tiny pockets that contain gases from deep within Earth’s interior. Follow the expedition at Popping Rocks. (Photo by Mark Kurz, Woods Hole Oceanographic Institution)