Each of those tube structures is actually a worm. Tube worms are one type of life that is found near hydrothermal vents.
Tube worms vary in size depending on where they live.
These particular tube worms are fairly large compared to the tube worms at the Juan de Fuca Ridge site that this expedition is visiting. This photograph was taken at the hydrothermal vent site located at 9 50' N on the East Pacific Rise.