Research in Brief
Bacteria key to copper clean-up
When miners abandoned Michigan’s Copper Country, they left a lot of the red metal behind. Waste from the mining operations still contains so much copper that almost nothing can grow on it, leaving behind moonscape expanses that can stretch for acres.
Now a team led by Michigan Tech biologist Ramakrishna Wusirika has discovered how to make two types of plants grow in the mine waste and soak up some copper while they are at it. They added copper to soil samples and inoculated them with a copper-resistant strain of bacteria. They planted maize and sunflower seeds and waited.
As expected, seeds planted in copper-free soil thrived, and seeds planted in the copper-tainted soil without bacteria were stunted. But seeds planted in the coppery soil enriched with bacteria did much better; some were nearly as vigorous as plants grown without the toxic metal.
“The bacteria seem to help with plant growth, and they also help maize and sunflower uptake copper,” said Wusirika. That means some kinds of naturally occurring bacteria could make soil more fertile and, in concert with the plants, remove at least some of the copper.
Alaskan forests: From carbon sink to carbon source
Alaskan forests used to take up carbon dioxide and give off oxygen. But now, researchers at Michigan Tech and the University of Guelph, in Ontario, report that climate change is causing wildfires to burn larger swaths of Alaskan trees, turning black spruce forests from repositories of carbon to generators of it.
“Since the proliferation of black spruce, Alaskan soils have acted as huge carbon sinks,” says Evan Kane, a research assistant professor in the School of Forest Resources and Environmental Science. “But with more frequent and more extensive burning in recent decades, these forests now lose more carbon in any fire event than they have historically been able to take up between fires.”
The researchers found that the annual carbon losses from forest fires from 2000 to 2009 were more than twice the carbon lost during each of the previous five decades.
In addition, the new forest types likely to replace the black spruce act as much weaker carbon sinks. And the researchers say that these fires are likely to increase permafrost loss, in turn accelerating climate change by exposing deeper carbon pools to burning.
Bringing back the grayling?
Overfishing and habitat destruction drove the Arctic grayling from most of its native Michigan waters a century ago. Now the Little River Band of Ottawa Indians and Michigan Tech biologists Nancy Auer and Casey Huckins are looking to bring them back.
The research team is studying the viability of reintroducing Arctic grayling in the Big Manistee River watershed, where, Auer says, “in days of old, they used to be very abundant.”
With a $200,000 grant from the US Fish and Wildlife Service, the Little River Band of Ottawa Indians is supporting their work, which includes electro-fishing on the Manistee to record the resident fish and evaluating the river to see if it could support these iridescent fish with their sail-like dorsal fin.
The Manistee flows southwest for about 230 twisty miles, from near Alba to Manistee, where it empties into Lake Michigan. The Little River Band and Michigan Tech are focusing on an eleven-mile section of the river between the Tippy and Hodenpyl dams.
After the study is completed, the Little River Band and partners will decide whether to attempt a reintroduction. “It’s exciting to think that it might be possible,” Auer says. “We hope to get people aware of how beautiful these fish are and how wonderful these ecosystems are. These big rivers are our lifeblood.”
Solving a genetic puzzle
Molecular biologist Hairong Wei turned to his passion for computer science to help overcome a major research roadblock. His efforts have produced a new tool to quickly and accurately identify transcription factors—regulatory genes that work together to control a biological process or trait.
Wei, an assistant professor in the School of Forest Resources and Environmental Science, built a virtual map of the genes that have the greatest influence on a given biological process and broke that network down into its separate components. This enabled him to efficiently identify a cluster of transcription factors. “Once these transcription factors are identified,” he explains, “scientists will know which genes to manipulate to get the results they want.”
To test his algorithm, Wei identified twenty-four transcription factors in the human genome that maintain a stem cell in its ready-and-waiting state. The process took him a day. It took biologists a decade and at least a few million dollars to identify twenty-two transcription factors, says Wei. Of those, Wei matched seventeen.
“We were surprised,” he says. His group applied the technique to several data sets from Arabidopsis plants, poplar trees, and the Axolotle salamander. Based on existing research findings, their method identified transcription-factor clusters with a degree of accuracy ranging from 50 to 95 percent.
Students at Michigan Tech have designed and built a smokestack that can capture carbon dioxide and turn it into a useful product.
Their eleven-foot bench-model smokestack gobbles up fully half of the CO2 percolating through it. Their process not only captures carbon, it binds it in a solid form, making an undisclosed product that can be used as a construction material. The liquid itself can be recovered and used again. The group has applied for a patent and hopes to build a pilot plant in cooperation with an industry partner, Carbontec Energy Corporation.
Other scrubbers remove up to 90 percent of the carbon dioxide from a smokestack, but the liquid must be processed to strip away the carbon dioxide, which then must be stored. “This is a very expensive technique, which is probably why we do not see it commonly employed in industry,” says PhD student Brett Spigarelli, a member of the research team.
The group is working to make the scrubber remove even more carbon dioxide. In the meantime, it offers businesses a significant benefit. Their goal is not only to capture the CO2 at the lowest possible cost, but also to manufacture useful, marketable products.
Iron Will: The story of Cleveland-Cliffs
Upper Michigan’s copper legacy has been well documented, the iron legacy less so. Now Terry Reynolds, a professor of social sciences at Michigan Tech, and Virginia Dawson, an independent researcher from Ohio, have published Iron Will: Cleveland-Cliffs and the Mining of Iron Ore, 1847–2006. The new book, published by Wayne State University Press, chronicles a company that was one of the region’s earliest iron ore mining firms and is now the last one standing.
The business initially called the Cleveland Iron Mining Company became Cleveland-Cliffs in 1890, when it absorbed a long-time rival and became the most important producer on the Marquette iron range. It is now Cliffs Natural Resources.
The authors say the book’s title, Iron Will, captures the company’s “resilience in the face of panics, depressions, strikes, technical bottlenecks, and bankrupt partners.”
Cliffs Natural Resources commissioned the history and gave the authors a free hand. Today, it is the country’s leading producer of iron ore pellets. The authors call the company’s survival over more than 160 years—a period marked by alternating prosperity and struggle—simply “remarkable.”
2.2 billion candles
Work by a Michigan Tech geophysicist may have pushed the birthday of the Earth’s inner core back over a billion years.
In the beginning, the Earth’s core was made entirely of molten iron. Most theories suggest that the solid inner core formed about 1 billion years ago in the center of the still-liquid outer core. That would make the inner core a relative newcomer in the history of our 4.5-billion-year-old planet.
New research by Assistant Professor Aleksey Smirnov and colleagues at the University of Rochester and Yale suggests the inner core is much older. They came to their conclusion after tracking changes in the Earth’s magnetic field in some of the planet’s oldest rocks, including some found in the Keweenaw Peninsula.
“We looked at the changes in geomagnetic variation at a very, very long time-scale, and we could explain the variation only if the inner core existed 2.2 billion years ago,” Smirnov said.
That’s about 1.2 billion years older than most of the accepted models. His tentative explanation involves plate tectonics, the process behind many earthquakes and volcanoes.
“When one plate goes under another plate, it goes deep in the mantle and reaches the core-mantle boundary,” he said. That would cool the core, like adding an ice cube to a glass of soda pop. And by chilling the liquid iron, it could have formed the solid center.
It takes a couple hundred million years for a plate to go through the mantle. Plate tectonics probably started 2.5 billion years ago, if not earlier, so the timing fits with Smirnov’s estimate of the inner core’s formation.
DNA analysis reveals immigrant in wolves’ gene pool
Wolves first traveled to Isle Royale over an ice bridge from Canada in the 1940s and have been isolated there ever since, or so the story went. Now, Michigan Tech researchers John A. Vucetich and Rolf O. Peterson have determined that a virile male wolf made it to the remote island national park in northern Lake Superior in 1997.
Dubbed “The Old Gray Guy,” he was larger than most Isle Royale wolves and soon after his arrival became the alpha male of Middle Pack, one of the island’s three packs. As he aged, his fur turned very light, a trait that had not been seen on Isle Royale but has since become common.
The immigrant wolf was discovered after Vucetich and Peterson collaborated with geneticists from Michigan Tech and Arizona State University to examine the DNA contained within wolf droppings they had been collecting for twelve years. The geneticists found a scat that carried several alleles—alternative forms of a gene—that had not previously been seen. Through field observations, Peterson and Vucetich confirmed that this scat belonged to The Old Gray Guy.
The Old Gray Guy died in 2006. But he left his mark, siring thirty-four offspring and twenty-two grand-offspring, “and counting,” the scientists say. Today, 56 percent of all the genes now found in the Isle Royale wolf population trace back to him.