The Art of Arctic Research

For Postdoctoral Scientist Alex Michaud, the most impressive presence in the Alaskan Arctic is not the titanic Brooks Range, the countless lakes flecking the expansive tundra, nor anything that can be seen with the naked eye — it is the microscopic iron-oxidizing bacteria.

"You don't really notice how prevalent they are until you go for a walk across the tundra," Michaud said. "But most of the ground you step on is habitat where iron-oxidizers live. As you look out over the landscape, it becomes clear that they are one of the most abundant types of organisms."

Michaud spent last summer studying iron-oxidizing bacteria at Toolik Field Station on the North Slope of Alaska. He is part of an unusually interdisciplinary team working to understand this microscopic yet major feature of the landscape — and its outsized role in the carbon cycle and other global processes.

Geomicrobiologist and Senior Research Scientist Dave Emerson leads the project, working alongside Michaud, a geochemist and microbiologist. Also on the team are mathematician and modeler Senior Research Scientist Nick Record, intern Remi Masse, artist Philippe Villard, and researchers from the University of Vermont. Their diverse range of specialties allows the team to tackle this research from multiple angles, propelling the project toward new discoveries and deepening the scientific understanding of climate change.

The chaos of global climate change is felt nowhere more powerfully than in the Arctic. Though less visible than retreating glaciers and melting sea ice, increasing global temperatures are melting another essential type of ice as well — the permafrost that underlies the region. As climate change advances, understanding how permafrost melting influences the release of potent greenhouse gases will be essential to understanding how Earth will respond.

"The changes in the Arctic are rapidly rewriting the natural cycles that distribute vital elements like iron and carbon in the environment," Emerson said. "What we are learning through this project will be essential to understanding how Arctic ecosystems are responding and how those changes will affect the rest of the planet."

Emerson's expertise in iron-oxidizing bacteria has led him from underwater volcanoes to freshwater wetlands to the Maine coast — and now it brings him to the Alaskan tundra. He is seeking to identify and characterize the iron-oxidizing bacteria that thrive in this harsh place, assess their abundance for the first time, and quantify the processes and pathways by which they interact with and shape their environment. What he discovers about these microscopic organisms will be expanded upon by mathematical models that Record will create to determine how iron cycling processes are occurring across the Arctic.

This project could yield the discovery of new microbial species, a fresh perspective on tundra ecosystems around the world, and an understanding of the intersections between essential global cycles. Its novel approach fuses the microscopic and the macroscopic, the field and the laboratory, and even the practices of science and art in an effort to engage the public.

"It's humbling to see firsthand how much effort goes into great science, and to imagine how art can convey its discoveries in a unique and powerful way," Villard said. "Art allows us to capture the natural environment and show people what is happening far beyond what the eye can see."

RESEARCH EN PLEIN AIR

The North Slope of Alaska is vast, bare — and vibrant.

"You feel as small as a microbe when you're there," Villard said. "The absence of human development and minimal vegetation create a huge contrast between what one can see on the macroscopic level compared to the microscopic. Up close, you see an entire other world, like many cities built by bacteria in the permafrost."

Permafrost is a layer of soil that remains frozen from year to year, and it is one of the underlying reasons why iron-oxidizing microbes across the Arctic tundra power such a vigorous iron cycle. On the North Slope, the permafrost layer is extensive and impermeable. Any efforts to dig a hole in the tundra are stymied after only a few shovelfuls of soil — which is typically red from the rust minerals produced by iron-oxidizing bacteria.

Constrained by the permafrost, water from rain and snowmelt create a soggy upper layer of soil about as thick as a plush mattress. The iron contained in this water gets trapped there, too. With no way of escape, iron concentrates in the surface soil, where it feeds thriving colonies of bacteria that derive energy from oxidizing iron.

"On the North Slope, you see the conspicuous red mats and red minerals they form almost everywhere," Michaud said. "It's clear that microbes are rusting the tundra."

Permafrost will play an increasingly large role in our changing climate. Globally, this icy layer holds an enormous store of organic carbon — double that of the atmosphere. As warming temperatures melt the permafrost, this trapped carbon will become food for microbes, converted into either carbon dioxide or methane, and ultimately released into the atmosphere.

Both are powerful greenhouse gases, but methane is about 30 times more potent. Which gas is produced depends upon which strategies the microbes use to gain energy from iron molecules. Emerson suspects that increased microbial activity resulting from melting permafrost may actually favor the production of carbon dioxide — the lesser of the two evils.

Iron also exerts a strong control on the availability of phosphorus, an important nutrient in the rivers and streams of the North Slope. Breck Bowden, a stream ecologist at the University of Vermont, and graduate student Will Sutor are working with the team to understand how plentiful iron oxides may determine the abundance of phosphorus in Arctic ecosystems — both now and in a warmer future.

"The scientific community doesn't know much about Arctic microbiology in general, and we know even less about the community directly involved in the iron cycle," Emerson said. "And yet, we're discovering evidence that there is far more iron cycling on the North Slope than in temperate habitats. This is an important piece of the climate change puzzle that we know far too little about."

SKETCHING AN ECOSYSTEM

For Villard, a printmaker, iron-oxidizing bacteria are not simply an abstruse genre of microbe or players in a global game of carbon chess. They are also an artistic subject matter, a source of inspiration and discovery, and a tool for creating art.

"This field season was a true exploration in the sense that I had no idea what we would find," Villard said. "There's so little vegetation on the North Slope that I wondered, 'well, what am I going to do with nothing?' But if you stick your nose to the ground, all of a sudden you start seeing incredible things."

Villard found plenty to spark his imagination. He took photographs and videos, sketched the landscape, and made prints in the field. Several of what Villard calls his "experiments" utilized the rust minerals the bacteria produced as pigment, such as when he used rocks coated with iron oxides like charcoal to sketch the mountains before him.

On his third day in the Arctic, Villard used his artistic penchant to render the invisible, visible. During his initial explorations of the area, Emerson had identified a promising study site, an unusually deep trench carved by melted permafrost that offered the perfect habitat for microbes. Villard used a GoPro camera to explore the trench, offering the researchers their first high-resolution underwater view of that microbial environment — which turned out to be dominated by similar species to those Villard portrayed in a woodcut during his first collaboration with Emerson a decade ago. The team named the location Gallionella Gulch, in honor of its prosperous microbial inhabitants.

"Seeing that video was like visiting another planet," Record said. "Having Philippe in the field let us see the environment we were studying in entirely new ways. His creativity and insight helped us look beyond our typical scientific processes to learn and observe more deeply."

Discovering the flourishing community of iron-oxidizing bacteria in the gulch inspired the researchers to ask a host of new questions. How common were such pools of water? Were they typically of similar size? How deep were they? What were their other common characteristics?

The team decided to find out. They borrowed a drone from the field station and conducted an aerial photography survey of Gallionella Gulch and the surrounding area. They were able to identify the characteristic red color that signifies iron-oxidizing bacteria in the photographs, and will use the images to learn about this type of feature across the landscape.

"The expansiveness of iron in the landscape was stunning, and I saw things I had never seen in a career of studying iron-oxidizing bacteria," Emerson said. "The Arctic is definitely more dynamic than you would expect for a system that's frozen most of the year."

TAKING SHAPE

Next summer, the team will return to Toolik Field Station. Until then, its members are focused on developing their individual project components and preparing for next season.

"It was very energizing to be in the field, surrounded by such interesting and passionate people and in such a huge landscape," Villard said. "I'm glad that it's a two-year project, because it's so overwhelming how much there is to explore."

Villard is spending the winter capturing the sensory experience of the Arctic through printmaking. Last summer, he collected and dried mud rich in iron oxides, and brought it back to the Boothbay Harbor studio he shares with his wife and artistic partner, Kim Després-Villard. They are using it to make red pigment for a series of fine-art woodcuts expressing the five senses of sight, smell, hearing, touch, and taste — as well as what they consider the sixth sense, instinct. The woodcuts will be interspersed throughout a book of the project team's writing, photographs, and data visualizations.

Masse is now in his junior year at the University of Michigan. Before completing his internship in August, he had the opportunity to begin the next phase of the project in Maine — analyzing the bacteria samples he helped collect in the Arctic. He presented his results to the Bigelow Laboratory community at the annual Research Experiences for Undergraduates Symposium.

"This was the first time I had my own results that were truly something not known before, and it gave me an overwhelming sense of pride," Masse said. "I'm hungry for more, and this project definitely solidified my desire to continue pursuing research as a career."

Emerson and Michaud are now processing their samples, refining their experiments, and planning how to further this research. Emerson suspects that their samples include unidentified species of iron-oxidizing bacteria that they will be able to classify for the first time. Perhaps most importantly for the future of the planet, their findings should help resolve the microbial tug-ofwar that shifts the balance of greenhouse gas production in the Arctic.

"Last summer gave us a taste for how powerful this system is, and the potential for these tiny bacteria to play a huge role in determining what our future climate looks like," Emerson said. "It is important for our understanding of the world and our efforts to mitigate climate change that we understand these processes and the true scale of their global impact."

Record won't return to the field next summer — his job now is solving a landscape-sized math problem. He is using the data from the first field season to begin creating an ecosystem model of iron cycling in the tundra.

The model is fueled by Emerson and Michaud's measurements of chemical processes. Once Record mathematically resolves how iron cycles in the discrete locations they measured, he can scale up these calculations to determine what is happening across the North Slope, and even in tundra around the world. This modeling process extrapolates the team's findings about the microscopic world to yield a global perspective on the iron cycle.

"There are new scientific frontiers all around us, and we have already learned so much about this environment in a single field season," Record said. "That's what happens when you bring people with diverse expertise into the field together — you find ways you never would have expected to push the frontiers of science forward."

The third photo is courtesy of Philippe Villard, and the others are courtesy of Alex Michaud.