PSU professor is leading scientific expedition to study undersea volcano in Pacific
Author: Cristina Rojas, College of Liberal Arts and Sciences
Posted: March 20, 2018

A Portland State University professor is leading a research cruise to study an active undersea volcano off the coast of New Zealand and the life forms that surround it.

The 20-day trip — which chief scientist and PSU professor Anna-Louise Reysenbach has been leading since March 7 — is studying the geology, biology, chemistry and geophysics of Brothers volcano, the most hydrothermally active undersea volcano system on Earth. Brothers, with a depth of 6,000 feet below the sea surface, has two types of hot springs — black-smoker vents that spew out mineral-laden liquid as hot as 310 degrees Celsius (590 degrees Fahrenheit), and cooler seeps that release fluids that are more acidic than car battery acid.

Reysenbach, a biology professor in PSU's College of Liberal Arts and Sciences, said undersea volcanoes can help scientists better understand how many of the copper and gold-rich deposits exploited on land today were formed, as well as open new windows into the deep subsurface biosphere and microbial life never seen before.

The expedition team of more than 25 scientists and researchers is using a pair of remotely operated vehicles (ROVs) that allows them to search the deep seafloor without having to leave the deck of the research vessel. Jason and Medea, as they're called, will take photos and video and collect samples of rock, sediment and marine life.

The trip to Brothers volcano, about 210 miles northeast of Auckland, New Zealand, took about 18 hours. But the team had to turn back around after a few days because of problems with the electrical power supply used to operate Jason as well as an approaching storm that was expected to bring very strong winds. After nearly five days in Auckland, the team began making their way back to the dive site on March 14.

Reysenbach said the team is interested in exploring whether there is a single magma chamber fueling the volcano and whether the differences in the vent areas have different processes resulting in different geochemistry of the fluids and different types of microbial life.

"This will add to our greater understanding of the extent and diversity of life in high-temperature ecosystems," she said. "I know that using genomic methods, we will find new clades of life that have never been detected before."

Reysenbach, who studies microbes in extreme environments, has also worked in the terrestrial hot springs in New Zealand and the deep-sea vents off Tonga. She hopes to find connections between the life found at all three sites.

The expedition is also setting the stage for a more ambitious effort in May to drill deep into the volcano to gather samples that will help them better understand how undersea volcanoes work.

The team includes scientists from the Woods Hole Oceanographic Institution in Massachusetts and GNS Science in New Zealand, as well as other institutions. 

The public is invited to follow along on the journey and ask scientists questions with WHOI's Dive and Discover website.

Photos: At top, PSU biology professor Anna-Louise Reysenbach shows the crew where they'll be diving on a 3D-printed model of Brothers volcano. At bottom, a gas-tight sampler in ROV Jason's manipulator arm collects a fluid sample from a hydrothermal vent. (Erik Olsen/Woods Hole Oceanographic Institution) 

Credit: Anna-Louise Reysenbach, chief scientist, Portland State University; Funder, NSF; ROV Jason. ©Woods Hole Oceanographic Institution