Melissa Anderson’s research focus lies thousands of metres beneath the ocean

May 29, 2024 by Chris Sasaki - A&S News

In 2015, Melissa Anderson embarked on her first Schmidt Ocean Institute (SOI) expedition aboard the research vessel Falkor to a tectonically interesting region in the western Pacific. A second-year graduate student, she was on board as the first candidate accepted into SOI’s student opportunities program.

In the spring of 2023, Anderson was back on board the Falkor, this time as lead of the geology team and a member of a large international, interdisciplinary group of researchers. The scientists spent 40 days at sea searching the ocean floor for hydrothermal vents along a section of the mid-Atlantic ridge.

Anderson, an assistant professor in the Department of Earth Sciences in the Faculty of Arts & Science, studies the tectonic forces that power undersea volcanoes and hydrothermal vents on the seafloor. The vents are fantastic chimney-like formations which discharge superheated, mineral-laden water that seeped into the sea floor, was heated by magma and spewed back into the ocean.

The vents, sometimes referred to as “smokers” for the great plumes of dark water they discharge, are typically located thousands of metres below the surface and are found along geologically active mid-ocean ridges where new ocean floor is being formed.


“We were looking for a rare type of vent that has only been found in a few locations,” says Anderson. “Unfortunately, we didn’t find them — but we did discover three new ‘classic’ vent sites, like ones we’d seen before. So, we studied them and collected lots of samples.”

On board the Falkor were oceanographers, geochemists, biologists, mapping experts, as well as the ship’s operational and support crew. The researchers used water chemistry data from a previous study that hinted at the approximate location of vents. Then, an autonomous underwater vehicle (AUV) mapped the ocean floor in enough three-dimensional detail to narrow down the search area. A conductivity, temperature and depth system (CTD) deployed near the candidate site analyzed the water for telltale signs of volcanic activity.

As the researchers closed in on their target, remotely operated vehicles (ROV) equipped with video cameras plunged thousands of metres to the ocean floor allowing Anderson and her colleagues to conduct the final search with their own eyes.

The team also included Jonathan Umbsaar, a PhD student supervised by Anderson, who was enjoying his first experience as part of an oceanic scientific voyage.

“On board, there were long periods of anticipation punctuated by moments of excitement when we discovered new vents. Each discovery felt uniquely thrilling and there was emotional electricity in the control room,” he says.

“This research expedition was one of the most rewarding experiences of my life,” says Umbsaar. “I gained skills, confidence and friends. I’m incorporating the results of this cruise into my own PhD thesis and pivoting the skills I gathered towards another research cruise.”

 We shouldn’t even think about mining at sites we don't know anything about right now. Before we cause irrevocable damage, we need to go very slowly, do the science first and do it right.

Remarkably, despite pitch-dark depths, crushing pressures and frigid waters barely above freezing, undersea vents are home to a collection of otherworldly lifeforms: snails, tube worms, crabs, shrimp, fish and more — including some species found in no other habitats on the planet. The sites, heated by water from the vents, are like teeming oases surrounded by frigid, dark, lifeless ocean floor.

Because of the geologic forces at play, deposits of minerals such as manganese and cobalt are commonly found near vents. These minerals and others are critical to burgeoning, sustainable technologies and are in high demand for use in electric vehicles, wind-generation turbines, solar panels, etc. As a result, the mining industry is actively eyeing undersea vents.

Anderson accepts the reality that such minerals are needed for a more sustainable future and holds out hope that we can proceed in a responsible manner. “We have to consider, where are we going to get our cobalt for a green revolution? Do we want to mine it in places on the planet’s surface where the environmental cost is enormous or in a country where they use child labour or worse?”

At the same time, Anderson unequivocally supports current efforts to impose a moratorium on mining of active vent sites.

“One of my research goals is to understand the conditions that lead to the formation of these mineral deposits,” she says. “Because once we understand these fundamental conditions, we can look for those same factors at inactive sites where there is no life. So, we can eliminate active sites with all their diverse lifeforms as potential sites for mining.

“We shouldn’t even think about mining at sites we don't know anything about right now,” she says. “Before we cause irrevocable damage, we need to go very slowly, do the science first and do it right.”