• Skip to Content
  • Skip to Main Navigation
  • Skip to Search

Indiana University Bloomington Indiana University Bloomington IU Bloomington

Open Search Menu

The College of Arts & Sciences

Department of Biology

  • Home
  • About
    • Message from the Chair
    • Faculty
    • Research Associates & Postdocs
    • Staff
    • Graduate Students
    • Administration
    • Offices & Centers
    • Diversity & Inclusion
    • Outreach
    • History
    • About Bloomington
  • Undergraduate
    • Biology
    • Biotechnology
    • Microbiology
    • Molecular Life Sciences
    • Research & Teaching Opportunities
    • Honors Program
    • Advising
    • Awards & Scholarships
    • Student Experience
    • Graduate & Professional Program Preparation
    • Career Preparation
  • Graduate
    • Evolution, Ecology, and Behavior Ph.D.
    • Genome, Cell, and Developmental Biology Ph.D.
    • Microbiology Ph.D.
    • Biotechnology M.S.
    • Multidisciplinary & Affiliated Programs
    • Advising
    • Financial Support
    • Awards & Fellowships
    • Life Assistance
    • Career Preparation
    • Alumni Career Spotlights
    • How to Apply
  • Research
    • Research Faculty
    • Associated Research Faculty
    • Research Strengths
    • Centers, Instrumentation, & Resources
    • Faculty Awards
  • News & Events
    • News
    • Events Calendar
    • Seminars
    • Named Lectures
    • Discussion Groups & Journal Clubs
    • Annual GCDB Retreat
    • Annual Microbiology Retreat
    • Newsletters
  • Alumni & Giving
  • Search
  • Contact
  • Student Portal
  • Donate
  • News
  • Events Calendar
  • Seminars
  • Named Lectures
  • Discussion Groups & Journal Clubs
  • Annual GCDB Retreat
  • Annual Microbiology Retreat
  • Newsletters
  • Home
  • News & Events
  • News
  • 2019 News
  • IU study predicts how air pollutants from U.S. forest soils will increase with climate change

IU study predicts how air pollutants from U.S. forest soils will increase with climate change

By: Kevin Fryling, News and Media Specialist, IU Bloomington

Tuesday, January 22, 2019

Panoramic view of Lilly-Dickey Woods, a hardwoods forest in Brown County, Indiana.
Lilly-Dickey Woods, a forest in Brown County, Indiana. Photo courtesy of the IU Research and Teaching Preserve

[View original story from source]

Tree changes in the midwest and eastern U.S. will lead to more atmospheric chemicals that cause air pollution and respiratory illness.

A study from Indiana University has found that trees influence whether soil can remove or emit gases that cause smog, acid rain and respiratory problems.

The chemicals, collectively known as reactive nitrogen oxides, are produced by soil bacteria that feed on naturally occurring ammonium -- as well as nitrogen fertilizers from industrial and agricultural sources that enter soil from the atmosphere.

The study was reported Jan. 18 in the Proceedings of the National Academy of Sciences.

"This study has profound implications for future air quality," said Jonathan Raff, associate professor in the School of Public and Environmental Affairs at IU Bloomington. "Human activities, such as fire suppression, fertilizer use and climate change, are causing forest populations to shift from stands of trees whose soils do not emit these gases to those that do.

"Reactive nitrogen oxide gases from fossil fuel burning have been well curbed over the past several decades due to effective policy," he added. "However, our study shows that, as forests change, we can expect higher background levels of nitrogen oxides, which could make it more difficult for some regions to achieve the National Ambient Air Quality Standards for nitrogen oxides and ozone."

Raff's laboratory is one of the few university-based facilities in the country able to accurately measure reactive nitrogen oxides emitted from soil. The gases include nitric oxide, nitrogen dioxide and nitrous acid.


 

A map of the eastern United States showing the forested ecological provinces and the amounts of predicted NOy Flux.  IU scientists predict higher levels of harmful reactive nitrogen oxides in the Midwest, Mississippi River corridor and eastern United States (in red) based on the location of forests whose trees enhance the activity of soil bacteria that release these chemicals.
IU scientists predict higher levels of harmful reactive nitrogen oxides in the Midwest, Mississippi River corridor, and eastern United States (in red) based on the location of forests whose trees enhance the activity of soil bacteria that release these chemicals. Image courtesy of Ryan Mushinski, IU School of Public and Environmental Affairs

"In forests, these gases are really under the radar, partly because they're so difficult to detect," said Ryan Mushinski, a postdoctoral researcher at IU who led the study. "A lot of people also simply don't think about soil as a significant producer of harmful air chemicals."

Although it's known that certain types of ammonia-oxidizing bacteria can emit reactive nitrogen from soil, researchers at IU discovered that trees can be divided into two groups: those that enhance nitrogen oxide-releasing bacteria activity, and those that don't.

Tree species that promote the release of nitrogen oxides include maple, sassafras and tulip poplar. The growth of these trees pushes out other species, such as oak, beech and hickory, whose associated microbes absorb reactive nitrogen oxides rather than release them.

The study, which is the first to identify forested regions in the U.S. that emit reactive nitrogen oxides based upon soil types, was facilitated by a review of soil data from 78,000 forest plots across country from the USDA Forest Service Forest Inventory and Analysis Program. The analysis was made possible in part due to work led by Richard Phillips, an associate professor in the IU Bloomington College of Arts and Sciences' Department of Biology, who is a co-author on the study. Phillips has pioneered research that connects specific tree species with specific soil types based upon their underground fungal networks.

Rich Phillips, 2017.
Rich Phillips. Photo by Sandee Milhouse

Indiana, Illinois, Michigan, Kentucky, and Ohio are the states expected to have the highest emissions of nitrogen oxides from forest soil, according to the new study. Higher emissions are also expected from forests along the Mississippi River and some regions of the eastern U.S.

Nitrogen oxide concentrations are regulated under the Clean Air Act, and the EPA regularly monitors their levels. But Mushinski said current rules are not enough to curtail rises in soil emissions, since air quality standards do not regulate fertilizer use or nitrogen deposition.

In addition to pollution regulation, he suggests that revised land management policies permitting greater use of controlled burns could slow the gradual change in forest composition. These fires are an effective way to clear out tree species that promote the soil that emits reactive nitrogen gases.

"It's difficult because people really like trees such as maples and poplars," he said. "But without greater awareness or policy changes, we're not going to see a reduction in the harmful gases they encourage."

This work relates to Prepared for Environmental Change, the second of Indiana University's Grand Challenges initiatives, which brings together a broad, bipartisan coalition of government, business, nonprofit and community leaders to help Indiana better prepare for the challenges that environmental change brings to the state's economy, health and livelihood.

Additional IU Bloomington authors on the study are professor Jeffrey R. White and postdoctoral researcher Rebecca B. Abney in the IU School of Public and Environmental Affairs; Douglas B. Rusch, an assistant research scientist in the Department of Biology; and Zachary C. Payne, a graduate student in Department of Chemistry. Other authors are Insu Jo and Songlin Fei at Purdue University and Salley E. Pusede at the University of Virginia. Mushinski, Raff and White are also affiliated with the Integrated Program in the Environment at IU. Raff is principal investigator on the study.

This work was supported in part by the U.S. Department of Energy and the National Science Foundation.

  • Faculty + Staff Intranet

Department of Biology social media channels

  • Twitter
  • Facebook
  • College of Arts & Sciences
  • Department of Biology

The College of Arts & Sciences

Indiana University

Copyright © 2025 The Trustees of Indiana University

Accessibility | College Scorecard | Privacy Notice

  • About
    • Message from the Chair
    • Faculty
      • Tenured + Tenure-Track Faculty
      • Teaching Faculty
      • Research Scientists
      • Faculty Emeriti
      • Faculty Affiliates
    • Research Associates & Postdocs
    • Staff
    • Graduate Students
    • Administration
    • Offices & Centers
    • Diversity & Inclusion
      • DEI Committee
    • Outreach
      • K-12 Educators
        • Biology Summer Institute
      • K-12 Students
        • Holland Summer Science Programs
          • Jim Holland Summer Enrichment Program in Biology (SEP)
          • Jim Holland Summer Science Research Program (SSRP)
          • Jim Holland Research Initiative in STEM Education (RISE)
      • Lessons
      • Outreach Activities
      • Outreach Coordinators
    • History
      • Faculty Emeriti
      • Historical Materials
    • About Bloomington
  • Undergraduate
    • Biology
      • Biology Learning Goals
      • Biology B.S.
        • Areas of Concentration
          • Biology of Disease
          • Cell Biology and Molecular Genetics
          • Integrative and Organismal Biology
      • Biology B.A.
      • Biology Minor
    • Biotechnology
      • Biotechnology Learning Goals
        • Biotechnology BS Learning Goals
        • Biotechnology BA Learning Goals
        • Biotechnology Minor Learning Goals
      • Program Design & Resources
      • Biotechnology B.S.
      • Biotechnology B.A.
      • Biotechnology B.S./M.S.
      • Biotechnology Minor
      • Demand and Employment Analysis
    • Microbiology
      • Microbiology B.S.
      • Microbiology B.A.
      • Microbiology Minor
    • Molecular Life Sciences
    • Research & Teaching Opportunities
      • Research Programs
      • Biology X490 Independent Study
      • Undergraduate Teaching Assistant
    • Honors Program
    • Advising
    • Awards & Scholarships
    • Student Experience
    • Graduate & Professional Program Preparation
    • Career Preparation
  • Graduate
    • Evolution, Ecology, and Behavior Ph.D.
      • Steps to become EEB student
      • Curriculum
      • EEB Faculty
    • Genome, Cell, and Developmental Biology Ph.D.
      • Steps to become GCDB student
      • Curriculum
      • GCDB Faculty
    • Microbiology Ph.D.
      • Steps to become Microbiology student
      • Curriculum
      • Microbiology Faculty
    • Biotechnology M.S.
      • Program Plan + Curriculum
      • Financial Support
      • Biotechnology Faculty
    • Multidisciplinary & Affiliated Programs
    • Advising
    • Financial Support
    • Awards & Fellowships
    • Life Assistance
    • Career Preparation
    • Alumni Career Spotlights
    • How to Apply
  • Research
    • Research Faculty
    • Associated Research Faculty
    • Research Strengths
      • Behavior
      • Chromatin, chromosomes, and genome integrity
      • Developmental mechanisms and regulation in eukaryotic systems
      • Ecology
      • Eukaryotic cell biology, cytoskeleton, and signaling
      • Evolution
      • Genomics and bioinformatics
      • Microbial cell biology and environmental responses
      • Microbial interactions and pathogenesis
      • Plant molecular biology
      • Virology
    • Centers, Instrumentation, & Resources
      • Drosophila Research Resources
    • Faculty Awards
  • News & Events
    • News
    • Events Calendar
    • Seminars
    • Named Lectures
      • Distinguished Alumni Award Lecture
      • James P. Holland Lecture Series
      • Carlos O. Miller Lecture Series
      • Hermann J. Muller Award Lecture Series
      • Norman R. Pace Lecture Series
      • Tracy M. Sonneborn Lecture Series
      • Joan Wood Lecture Series
    • Discussion Groups & Journal Clubs
    • Annual GCDB Retreat
    • Annual Microbiology Retreat
      • Micro-lympics
      • Registration
    • Newsletters
      • BioNews Fall 2022
      • BioNews Archive
  • Alumni & Giving
  • Contact
  • Student Portal
    • Undergraduate
      • Biology
        • Biology B.S.
        • Biology B.A.
        • Biology Minor
      • Biotechnology
        • Biotechnology B.S.
        • Biotechnology B.A.
        • Biotechnology B.S./M.S.
        • Biotechnology Minor
      • Microbiology
        • Microbiology B.S.
        • Microbiology B.A.
        • Microbiology Minor
      • Molecular Life Sciences
      • Courses
        • Biology Exemption Exams
        • Course Scheduling
        • Course Evaluations
        • Biology X490 Independent Study
        • FAQs
      • Advising
      • Research Opportunities
      • Teaching Assistants
      • Honors Program
        • Eligibility
        • Honors Courses
        • Honors Thesis
        • Honors Faculty Advisors
        • How to Apply
      • Internships
    • Graduate
      • Evolution, Ecology, and Behavior Ph.D.
      • Genome, Cell, and Developmental Biology Ph.D.
      • Microbiology Ph.D.
      • Biotechnology M.S.
      • Multidisciplinary and Affiliated Programs
      • Courses
      • Transfer credits
      • Awards + funding
      • Financial Support
      • Teaching Support
      • Dissertation & Thesis Support
      • Services & Outreach
      • Submit News to Biology
      • Facilities & Resources
        • Computing Services
        • Constant Temperature Rooms
        • Dry Ice
        • Lactation Room
        • Room Reservations
          • All Rooms
          • Biology Bldg. 123
          • Biology Bldg. 248
          • Biology Bldg. A310
          • Biology Bldg. 422
          • Biology Bldg. 510
          • Myers Hall 115
          • Myers Hall 140
          • Myers Hall 209
          • Myers Hall 311
      • Student Academic Appointments
      • Bias incident reporting
      • Title IX incident reporting
    • Seminars
    • Ombudsperson
  • Donate

The College of Arts & Sciences