ISU biologist studying tiny organisms for large, global issue

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Kirsten Hofmockel and soggy soil samples from a Minnesota peatland.

To help address a global issue, Kirsten Hofmockel is thinking small – microscopic small.

The Iowa State University biologist, who studies the interactions of microorganisms and plants in the soil, believes the invisible microbes could play a large role in answering important questions about global warming.

That’s why she was awarded a $707,000 U.S. Department of Energy grant in 2012 to join a large 10-year federal study of the effects of rising temperatures and carbon dioxide levels on a boreal forest ecosystem in Minnesota.

Scientists say unprecedented high concentrations of human-made and naturally occurring carbon dioxide, nitrous oxide and methane are increasing global temperatures. Carbon dioxide traps heat in the atmosphere. The resulting increase in global temperatures is believed to be disrupting climate patterns, leading to more frequent extreme weather events such as massive storms or droughts.

At the boreal forest project in north central Minnesota, scientists will artificially manipulate the climate in large chambers and determine how the simulated global warming will affect the ecosystem. Some of the scientists will study trees, moss and other plant life. Hofmockel and her research team will attempt to understand more about the roles of soil microbial communities on the carbon cycle. She said there is much to learn from the colonies of one-celled creatures living in the soggy, carbon-rich and fragile peat bog.

"Microbes have been largely ignored by researchers for good reason – they are hard to get at," said Hofmockel, an assistant professor in the Department of Ecology, Evolution and Organismal Biology. “However, at the most basic biological level, microorganisms are key to determining whether carbon and nitrogen stay in the soil – the preferred long-term storage site – or go into the atmosphere where the gases can add to the greenhouse effect.

“It’s sort of mind blowing that single-cell organisms can affect the global climate.”

The experiment is named SPRUCE – Spruce-Peatland Response Under Climate and Environmental Change. It’s located on remote, black spruce-covered U.S. Forest Service land where scientists have been collecting scientific readings for 50 years.

When completed this year, SPRUCE will have 10 octagonal-shaped chambers about 35 feet in diameter and about 30 feet tall sticking out of the ground. Connected by a series of aluminum boardwalks inches above the soft peat, some of the open-ended, artificial climate chambers will go into the ground as far as 10 feet. Each chamber is large enough to hold 20 to 30 threes and some are tall enough to touch the forest’s canopy.

Scientists will begin blowing warm air into some of the transparent chambers this summer and later will raise carbon dioxide levels. Over the next few years, researchers will study how the microorganisms, trees, shrubs and other plants adapt to the simulated global warming. The project is considered the biggest ecosystem manipulation experiment ever.

Peatlands are an important ecosystem to study, Hofmockel said. Peatlands cover only about three percent of the planet’s land surface, but scientists believe they contain 30 percent of the planet’s total carbon stored underground. She said if the earth’s temperatures continue to rise as predicted, peat bogs could release huge amounts of carbon dioxide and other greenhouse gases, which could significantly speed up global climate change.

"What we want to do with our research," Hofmockel said, "is to generate information that is relevant to a large-scale global climate change model."

She is particularly interested in the roles of microorganisms in ecosystems and how microbes regulate carbon and nitrogen cycling from the soil into the atmosphere. She wants to start identifying microbial groups her team considers as indicator species that will show changes resulting from the warmer temperatures and higher concentrations of carbon dioxide.

"There might be specific groups of microbes that tend to really be responsive to warming," she explained. "So if we monitor just those organisms, we might actually be able to learn how they adapt to the changes a lot faster than trying to understand a whole community of microbes. We need to narrow it down because right now we don’t know which organisms to pinpoint, so we are looking at all of them to see how they respond."

The Minnesota experiment is one of several the Department of Energy is conducting in various ecosystems across the country. Hofmockel has conducted research at two, a North Carolina pine forest and a Wisconsin aspen forest.

ISU’s College of Liberal Arts and Sciences and the College of Agriculture and Life Sciences jointly administer Ecology, Evolution and Organismal Biology. -30-

About Liberal Arts and Sciences The College of Liberal Arts and Sciences is a world-class learning and research community. Iowa State’s most academically diverse college, LAS educates students to become global citizens, providing rigorous academic programs in the sciences, humanities and social sciences within a supportive personalized learning environment. College faculty design new materials, unravel biological structures, care for the environment, and explore social and behavioral issues. From fundamental research to technology transfer and artistic expression, the college supports people in Iowa and around the world.

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Contacts: Kirsten Hofmockel, EEOB, (515) 294-2589, Steve Jones, Liberal Arts and Sciences Communications, (515) 294-0461,