Operation Deep Slope 2007. A large benthic crab crawling across the seafloor.

Operation Deep Slope 2007. Large yellow-brown mussels and small white brittlestars at a cold seep.

Operation Deep Slope 2007. Black mussels and shrimp at a cold seep.

Operation Deep Slope 2007. One of approximately 120 images used to stitch together a large photomosaic of what is unofficiallybeing called the "Big" Mussel Bed at Atwater Valley 340.

Operation Deep Slope 2007. A large benthic crab on the edge of a chemosynthetic seep mussel community.

Operation Deep Slope 2007. Close-up view of one of the undescribed species of Lamellibrachia tubeworm that scientists discovered previous year.

Operation Deep Slope 2006. The results of a successful collection with the Bushmaster Jr. as deployed on ALVIN. A large assemblage of tube worms has been harvested for study.

Operation Deep Slope 2006. Evidence of human activity extends even hundreds of miles offshore and in this instance to 2200 meters depth. Note the sea urchins plowing up the bottom.

Operation Deep Slope 2006. Bacterial mats, mussels, and tubeworms are common at cold seeps. This image was taken at the Atwater Valley site at 340 meters water depth from ALVIN.

Operation Deep Slope 2006. A large aggregation of sea urchins plowing through the bottom sediments near cold seep sites. These are just a few of the urchins seen during this ALVIN dive.

Operation Deep Slope 2006. A closeup of a Lamellibrachia sp. community in the deep Gulf of Mexico. Besides tube worms, shrimp and what appears to be a tiny white coral species attached to the tubes in the foreground.

Operation Deep Slope 2006. ALVIN pilot Gavin Eppard snagged this heaping scoop of mussels at Atwater Valley at 340 meters.

Operation Deep Slope 2006. This sample of a seep community off of the western coast of Africa was taken with a box corer. Even though this community is on the opposite side of the Atlantic from the Gulf of Mexico, it bears a striking resemblance to the seep communities being studied in the Gulf of Mexico.

Operation Deep Slope 2007.

Giant tube worms, Riftia pachyptila, from hydrothermal vents at the East Pacific Rise.

Chemoautotrophic whale-fall community, including bacteria mats, vesycomyid clams in the sediments, galatheid crabs, polynoids, and a variety of other invertebrates. The 35-ton gray whale was originally implanted on the seafloor at 1674 meters depth in 1998. This picture was taken 6 years later.

Starfish graze on an extensive bed of mussels on the outer flanks of a volcanic cone.

Mussels inhabit every bit of seafloor in order to feed in the ambient flow from seafloor hotsprings.

Enormous numbers of crabs were seen in the Mussel Ridge vent area often fighting over their next meal. Shrimp and an unidentified eel-like fish also seem to be attracted to the mussel environment.

The mussels at Rumble V volcano are tightly packed together, no room to even put a toothpick between them.

Extraordinary numbers of mussels are fighting for a piece of real estate on this rocky outcrop where warm hot-spring water discharges from the seafloor.

Mussels dominate the hydrothermal biological community at Rumble V volcano just as at all the other large volcanoes explored along the Kermadec Arc . However, the Rumble V mussels are much larger (over a foot long) than those found at other vent sites in this area.

The chemosynthetic biological communities of the Kermadec Arc are dominated by mussels.

Tubeworms grow at the base of a rock outcrop that is covered with bivalves at Volcano W.

Spaghetti-like tubeworms living happily amongst mussels, anemones, a vent fish, and hungry crabs. Most of these animals are only found at seafloor hot spring sites.

Deepsea urchins (reminiscent of cacti) grow on the lavas at Rumble V volcano. This is the first time that this species has been observed alive on the seafloor

A colony of barnacles at a hydrothermal vent on Clark volcano at 880 meters depth. Barnacles were the dominant macrofauna at this site.

This species of pinkish vent shrimp has been known to science for only a few years now, but clearly it's well adapted to life in this extreme environment, a small active vent on Rumble V.

The shallow depth to the top of Giggenbach volcano (less than 100 meters) meant that sunlight penetrated the ocean, enabling PISCES V to navigate without lights at times. A large chemosynthetic mussel community in the photosynthetic zone.

The darkness of the seabed at over 500 meters depth was sprinkled with small white sea urchins to create a vista that in the words of the submersible pilot, Colin Wollerman, looked like the Milky Way. The pink and white creatures are probably a species of holothurian.

The suction sampler on PISCES V (upper left) vacuums up some orange microbial mat while a probe records the temperature (lower left) at Volcano W.

The extensive iron-dominated venting at Healy volcano was a surprise. Large areas (acre size) on several young volcanic cones were covered with actively forming or recently active bacterial mat.

An unidentified fish, or eel, spotted on PISCES V dive P5-627.

Rocks that have been totally altered by hot (hydrothermal) fluids. Their original minerals are now completely replaced by different minerals, often much lighter in color.

Metal rich high-temperature venting on the northwest caldera wall of Brothers Volcano produces these black smoker chimneys.

Hot fluids (up to 290 C, 550 F) were sampled from this chimney. Several crabs are "hanging out" on the sides of the edifice.

The hydrothermal systems at Giggenbach volcano are well within the photic zone. Schools of fish are seen here swimming among extinct hydrothermal chimneys. The microbial mat on the seabed indicates that there is still heat rising and that chemosynthesis is occurring.

Iron and silica rich chimneys on the summit of Giggenbach volcano are evidence of warm springs that were active at this site in the past.

Hot water (221 C, 430 F) was sampled at the base of this sulfide chimney which is almost 6 meters high.

Sulfur (yellow) is associated with many of the vent sites at Mussel Ridge. These occurrences tell us that large amounts of sulfur gases are dissolved in the vent fluids. The small terrace in the foreground suggests that the sulfur was molten (at least 119 C) before it solidified after contact with the cold seawater.

Spectacular tubes of lava covered in limpets wind their way down the slopes of this volcanic ridge. A swarm of shrimp are busy feeding near the base of one of the tubes.

Toothpaste-like lava at Volcano W oozed from this tube before it solidified in place.

Areas of brownish-yellowish and sometimes whitish crust are observed on the slope of Rumble V. Here bacteria survive among percolating fluids at 20 C (68 F ) where no larger organisms appear to be able to live.

A basketball-sized jellyfish passes directly in front of the viewport on the PISCES V submarine.

The submersible encounters a brightly colored octopus near a hydrothermal vent area at Monowai caldera at about a depth of 1050 meters.

A squid swims by the PISCES V submersible during dive P5-625

A closeup of the three viewports on the front of the PISCES V submersible which was the main vehicle used to explore the submarine volcanoes of the Kermadec Arc.

Sampling hydrothermal oxide/silica crusts and a sponge at Clark Volcano ( 994 meters depth).

Boiling of vent fluids is relatively rare. Here, the manipulator arm of PISCES V holds a gas-sampling device over a vent where bubbles are streaming out of the the seafloor.

The cloudy gases collected from the boiling vent can be seen in the top third of the sample tube. Analyzing the gases will enable scientists to determine the origin of the hydrothermal fluids.