Photo: This iridescent nudibranch looks like a creature from another planet. Larger photo.

The United States National Oceanic and Atmospheric Administration (part of the U.S. Department of Commerce?) includes a huge photo and videocast gallery including: invertebrates, vertebrates and seafloor.

Also see an exploding volcano under the sea for the first time ever, from the:Submarine Ring of Fire 2006 Exploration, NOAA Vents Program.