Movies
These QuickTime movies show the East Pacific Rise. The first
is a flyover of the topography around 9°N. The second shows video of
ALVIN and of the seafloor along the spreading axis in the same area.
The third is footage from 17-18°S, and the last is just for fun.
EPR flyover
The first few seconds show a still of the East Pacific Rise near 9-10°N looking to the North. (The area is ~100X100km) The hot colors (red, yellow) are shallow depths, less than 2800m; greens and blues are deeper extending to a maximum depth of ~3300m. (Vertical exaggeration is ~40X.) The spreading center here is an axial high (in yellow and red) which rises ~200-400m above the older seafloor.
The original of this animation was produced by Larry Mayer,
now at Univ New Hampshire using data from Wilcock,
W. S. D., D. R. Toomey, et al. (1993).
The renavigation of Sea Beam bathymetric data between
9°N and 10°N on the East Pacific Rise. Mar. Geophys. Res. 15: 1-12.
EPR 9N
These are a few clips from dives using the submersible ALVIN (funded by NSF, operated by WHOI). MANY scientists participated in this effort, for an introduction to the ARGO and ALVIN expeditions, see Haymon, R. M.; Fornari, D. J.; Edwards, M. H.; Carbotte, S.; Wright, D.; Macdonald, K. C., 1991,
Scene 1: Ken Macdonald climbing on board ALVIN for a dive on the site of
the 1991 eruption. The sub holds 3 people.
Scene 2: Surface divers check out ALVIN making sure it is ready
to submerge. ALVIN will sink like a stone, taking 1 1/2 hours
to reach the bottom. It becomes pitch black about 500m deep
and this dive will go to 2600m.
Scene 3: On the seafloor at a depth of ~2600m on the crest
of the East Pacific Rise between 9 45N to 9 52N.
The glassy black lava flow of April 1991 lies
on top of older, grey lavas, probably decades old. The field of view in
the video clips is typically 1-5 m across.
Scene 4: The ALVIN robotic manipulator is used to collect a sample of the
very glassy delicate 1991 lava flow. The orange columns in the background
are hydrothermal chimneys made of polymetalic sulfides.
Scene 5: The 1991 lava flow killed a large number of tubeworms
as the 1200° C lava barbequed the hapless victims.
All that are the white tubes of the
worms enveloped by the flow. The area is called Tubeworm BBQ.
Scene 6: One of the biggest surprises was that the 1991 eruption
was accompanied by a blizzard of white bacterial material.
Some the bacteria may have been
released from depth within the crust during the eruption; in addition the
eruption may have introduced enough nutrients into the system to produce
a bacterial bloom.
Scene 7: Another shot of the recent lava flow completely covered
by bacterial material, here it appears that some of the bacterial matter
is being ejected out of a hole in the lava crust.
Scene 8: With all of the carnage on the seafloor after the eruption, it
does not take long for predators to move in. These are brachyuran crabs
which consume the white bacterial snow and, in this scene, are attacking
one of the surviving tube worms.
Scene 9: A trio of black smoker hydrothermal vents.
The water exits at ~350-400C.
The water is blackened by polymetalic sulfide particles which precipitate
upon contact with seawater. The chimneys are very small because they are
only a few weeks old.
EPR ARGO
Based on an ARGOII survey of the super-fast spreading East Pacific Rise at 17-18°S (EPR ARGO). I added some music and sound effects to this for amusement. Rachel Haymon was the Chief Scientist, Ken Macdonald was the Co-Chief Scientist; other scientists included Scott White, Dan Scheirer, Dawn Wright, Lisa Crowder, Susan Baron, Phil Sharfstein, Laura Magde, Cindy Van Dover, and I know I am forgetting someone.