Learning from Worms: Forestry Researchers Build New Underground Lab at Michigan Tech

By Jennifer Donovan | Published

The worms crawl in, the worms crawl out, and in their new "mesocosm," Michigan Technological University faculty, students and US Forest Service scientists can monitor their impact on a simulated forest floor under different conditions.

The mesocosm is that construction project you may have noticed next to the USDA Forest Service Forestry Sciences Lab, just above the School of Forest Resources and Environmental Science off MacInnes Drive at Michigan Tech. It's the only one of its kind for northern forest research and one of very few anywhere in the country.

A mesocosm is an experimental enclosure designed to simulate natural conditions while environmental factors are manipulated. Its name refers to its size: It's larger than a microcosm or miniature model but smaller than a macrocosm or large-scale representation of reality.

This mesocosm will be an underground tunnel containing 24 one-meter stainless steel cubes. The surface will be open to the air, but the temperature, moisture, type of soil, organisms such as worms, and other below-ground variables can be controlled independently in each cube. Researchers and their students will be able to monitor the effects of their manipulations of the environment in each cube visually through portholes and windows, as well as by data collected remotely.

In their first mesocosm research project, research ecologists Erik Lilleskov and Chris Swanston, will be tracking what they call "the ecosystem engineers" of the forest floor. Swanston and Lilleskov, who work for the USDA Forest Service, also are adjunct faculty members at Michigan Tech. Their research will be a uniquely integrated analysis of the impact of invasive earthworms on the ecology of northern forests.

Lilleskov, Swanston and Michigan Tech collaborators will use the mesocosm to study the impact of the Eurasian earthworms that wriggle through this area's soil on the cycling of carbon, water and nutrients under controlled conditions. Native species of earthworms were killed off long ago by the glaciers that formed the Great Lakes, but their Eurasian cousins found their way here on ships and flourished.

"We know the worms have a major impact on the soil," said Swanston. In soil without worms, he explained, the rich humus or decomposed organic matter on the forest floor remains in a distinct mat on the forest floor. Worms eat the hummus, and as they move through it, they move it around.

"The worms don’t make the forest better or worse, just different," Swanston noted. "They change the way roots grow, where they grow and how they grow."

This will be the first mesocosm-scale study of the effects of non-native earthworms on northern forest ecology. The researchers can manipulate and study carbon cycling above and below ground, hydrology (the effects of various levels of moisture biochemical interactions of the worms with the soil, nutrient levels in the soil and plant responses.

"Studying all of these cycles in the same plots of soil under controlled conditions will provide a more comprehensive perspective on the impacts of earthworms on forest ecosystems than we have previously been able to attain," Swanston explained.

Margaret Gale, dean of Michigan Tech's School of Forest Resources and Environmental Science, said the mesocosm "will continue to strengthen the ties between Forest Service researchers and Michigan Tech faculty and students. It has the potential to further excite our students and faculty about discovering new ways of looking at forested ecosystems and developing rigorous scientific studies that will help us explain the complexities of belowground processes."

K-12 students and teachers in the Global Change Teachers’ Institutes and the Lake Superior Stewardship Initiative at Michigan Tech will have opportunities to visit the mesocosm and to conduct classroom mesocosm studies, Swanston said.

Construction of the research facility is scheduled for completion in early 2009.

Michigan Technological University is a leading public research university, conducting research, developing new technologies and preparing students to create the future for a prosperous and sustainable world. Michigan Tech offers more than 120 undergraduate and graduate degree programs in engineering, forestry and environmental sciences, computing, technology, business and economics, natural and physical sciences, arts, humanities and social sciences.

Michigan Technological University is a public research university, home to more than 7,000 students from 54 countries. Founded in 1885, the University offers more than 120 undergraduate and graduate degree programs in science and technology, engineering, forestry, business and economics, health professions, humanities, mathematics, and social sciences. Our campus in Michigan’s Upper Peninsula overlooks the Keweenaw Waterway and is just a few miles from Lake Superior.