By Angela Fichera

Research being led by SNRE Professor Don Zak has received an additional five years of federal support, enabling researchers to continue an unprecedented study of how changes in climate are affecting the DNA of forests.

The new round of National Science Foundation funding allows work to continue through 2018. The experiments are taking place in northern Michigan, and examine how climate change is influencing the activity of soil microbes, which decay dead leaves and roots in a process that controls the amount of carbon stored in soils.

When finished, the project will have received nearly $381,000 from NSF over 10 years.

“With this funding, this experiment becomes the largest-scale, longest-term experimental manipulation of atmospheric nitrogen deposition in any forest worldwide,” said Zak, who teaches in the Conservation Ecology field of study and who holds the Burton V. Barnes Collegiate Professor of Ecology at SNRE. He also has a dual faculty appointment with the Department of Ecology and Evolutionary Biology in the U-M College of Literature, Science, and the Arts.

The funding comes from a special NSF source called the Long-Term Research in Environmental Biology (LTREB) program. Through LTREB, NSF encourages the submission of proposals that generate extended time series of biological and environmental data. Researchers must have collected at least six years of previous data to qualify for funding, and these data must motivate the proposed research. The proposal also must present a cohesive conceptual rationale or framework for 10 years of research. Typical NSF grants provide funding for only three years.

The NSF funding complements related work by Zak and others that dates to 1987. For example, he and fellow researchers in 2010 received a $1.8 million Department of Energy grant for a project titled “Atmospheric Nitrogen Deposition and Microbial Mechanisms Enhancing Soil Carbon Storage.”

In general, the research across all funding sources tests two hypotheses:

• The response of the ecosystem – and “the interaction among plants, trees, soils and microscopic organisms” in absorbing and storing nitrogen – is being governed at the genetic level.
• Simulated nitrogen deposition has slowed the decay of dead plant tissues by negatively impacting expression of fungal genes, which encode enzymes that are the chemical agents of decay.

The work is significant not only for its contributions to basic science, but because of the insights afforded by its longevity.  Globally, human activity has doubled the amount of growth-limiting nitrogen entering terrestrial ecosystems. Zak’s research has been able to show that rates of nitrogen deposition that are expected to occur in the future, will slow decay of dead leaves and roots, thereby increasing ecosystem carbon storage. This response could potentially slow the accumulation of human-produced carbon dioxide in the atmosphere and slow the pace of climate warming.

“However, more nitrogen is not always a good thing. It leads to ground water and surface water pollution and excess nitrogen is the cause of dead zones in the Gulf of Mexico,” said Zak. “That’s the crux of the situation: trying to understand how all these global changes humans are causing are going to affect the way the Earth functions.”

Key collaborators on both the NSF and Department of Energy projects include Kurt Pregitzer from the University of Idaho and Andy Burton of Michigan Tech. The research team also is composed of SNRE doctoral students Lauren Cline and Elizabeth Entwistle as well as post-doctoral scholar Zac Freedman, research associate Rima Upchurch and research associate and former SNRE student Sarah Eisenlord.

“Studies such as this are so great for SNRE students because they get the opportunity to work as part of an interdisciplinary research team and put their skills and intellect to work to solve a problem of global proportion that one day, will matter to our day-to-day lives,” said Zak.