Even though there are huge numbers of mussels living around the hydrothermal vents at NW Eifuku, we hardly ever find any dead shells, which is very unusual. We suspect that the high levels of CO2 being released from the volcano increase the acidity of the water and after a mussel dies its shell is quickly dissolved. Documenting this process at NW Eifuku may help us understand the potential impacts of increased CO2 levels in the marine environment caused by human activities. Video courtesy of Submarine Ring of Fire 2006 Exploration, NOAA Vents Program.