The Ocean Portal (http://ocean.si.edu) asks Carole Baldwin, a research zoologist at Smithsonian's National Museum of Natural History, "why are manned submersibles important?" Find out why! Visit the Ocean Portal: http://ocean.si.edu On Facebook: http://facebook.com/OceanPortal On Twitter: http://twitter.com/OceanPortal Credits: Editing & footage: Emily Frost, Smithsonian's Ocean Portal