Explore the Deep Sea >Expeditions >Expedition 2: Hot Vent Hunting

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Expedition highlights

Six sites containing active vents were mapped in detail for the first time
The first ever photographs of animals living near these vents were collected
More than two tons of rock were dredged up for further analysis back on-shore; analyzing these rocks will tell us more about how the Earth's crust is being stretched in the Lau Basin.

Photostories

Rock detectives: investigating what rocks are made of gives clues to the history of the Pacific
Dr. Paul Asimow from Caltech had not been to sea in more than a decade of studying volcanic rocks from the deep ocean. He jumped at the chance to take part in this expedition, and recorded his impressions

Hot people

…More about researchers on this expedition.
Meet some of the crew of the Research Vessel Kilo Moana.
Sisi Tonganevai, who accompanied the expedition as an observer, was a welcome addition to the team

Hot links

From the American Museum of Natural History, an interactive cartoon of how a CTD recorder is used to locate a plume coming from a seafloor vent

Expedition 2: Hot Vent Hunting

Led by Chief Scientist Charlie Langmuir (left), the second of five expeditions to the Lau Basin (in September 2004) searched within the area mapped by the first expedition. It had several aims:

Chief scientist Charlie Langmuir inspects rocks brought up by the dredge. Image courtesy of K. Kusek

Locate seafloor vents suitable for later expeditions to study
Make detailed maps of these areas and photograph the animals living there
Recover rocks from the seafloor for further analysis back on land

More than twenty researchers and students from over a dozen research institutions took part, studying everything from the chemical composition of seawater to the distribution of animals. Findings were passed to the third expedition. Like all the expeditions in this series, the research is designed to help us understand the relationships between different components of the system in this ocean basin: how and why tectonic plates move and stretch, and how this affects the overlying ocean: its chemical make-up and the life it contains.

New vent-hunting approach works well

The submersible ABE is readied for a trip to the seafloor. Image courtesy of K. Kusek

This September 2004 expedition visited target sites where maps from the previous expedition suggested that vents might be present. Researchers tried a new method of finding active vents by searching near the seafloor in a staged way:

First, an instrument (a CTD, or Conductivity Temperature Depth recorder) is dragged behind the ship to sample seawater near the seafloor. By measuring water temperature and composition, this instrument can detect the mineral-rich plumes of warm fluid that drift up from the vent.
Second, a robot submarine (ABE) is sent out to map areas containing plumes in more detail, using sonar: first from a height of 250 m above the seafloor, then (if the 250 m results look promising) again from 50 m. If the 50 m results suggest a vent is present, ABE is then used to take detailed photographs from just a few meters above the seafloor.
Finally, a camera towed behind the ship (TowCam) is used to take even higher-resolution images.

The approach worked well: several vents were located using this method.

Next: Expedition 3 of 5: From rocks to life