Loihi expedition dives to new low point

The latest expedition to Loihi Seamount has provided scientists with a deeper understanding of the underwater volcano’s geography and the mats of iron-eating bacteria that exist at its base.

How much deeper?

The expedition aboard the research vehicle Falkor, which took place from June 25 to July 8, involved the deployment of an autono­mous underwater vehicle and a conductivity, temperature and depth sensor to the lowest reaches of the seamount, some 16,000 feet below the surface of the ocean.

The effort was led by University of Hawaii associate professor of oceanography Brian Glazer and included experts from the Schmidt Ocean Institute, Woods Hole Oceanographic Institution and the University of Minnesota, as well as scientists from France and Germany.

Data gathered from the expedition will be closely examined over the next six months but already promises new insights into how seamounts grow, how the volcano’s iron-rich plumes affect the chemistry of the surrounding ocean, and how the microbiology of the system interacts with its surroundings.

The scientists are particularly interested in how thick mats of iron-oxidizing bacteria may help to balance ocean chemistry.

"Microbes are actually taking advantage of the energy that’s locked up in the rock and locked up in the hydrothermal fluids, rusting that iron and making a living at it," Glazer said in a UH news release. "There are acres and acres of this energetic microbial community that was previously unaccounted for."

The autonomous underwater vehicle Sentry was deployed seven times to two lesser-known regions of the seamount, FeMo Deep and Shinkai Deep, where it mapped terrain and collected data related to temperature and oxygen content.

The Rosette, a conductivity, temperature and depth sensor, was also deployed 18 times to collect water samples in different areas along the seamount, including Pele’s Pit, Pit of Death and Loihi Summit.

Ultimately, the data drawn from the expedition could inform scientific understanding of how life might develop elsewhere in the universe.

"At various times in Earth history, much of the world ocean was dominated by processes that are occurring at Loihi today," Glazer said. "In accessing Loihi, we have a window to the ancient Earth that also provides clues about the potential for life ‘out there’ in habitats that could exist on places like Mars or Europa."

Europa, one of the moons of Jupiter, has an icy crust believed to cover an ocean that stays liquid from heat produced by the gravitational forces of the giant planet.