Soil scientist awarded $1.6M NSF grant to study ‘living skin’ of arid ecosystems

UNIVERSITY PARK, Pa. — A Penn State soil scientist has received a $1.6 million, five-year grant from the U.S. National Science Foundation (NSF) to fund her team’s study of how increasing temperature fluctuations impact the biocrust microbiome — the complex, thin-layer microbe community that stabilizes soil, fixes nitrogen and drives nutrient cycling in drylands.

Estelle Couradeau, assistant professor of soils and environmental microbiology in the College of Agricultural Sciences, is the recipient of the award from NSF’s Faculty Early Career Development Program (CAREER). She said she is extremely grateful for the opportunity to expand her team’s study of what she called the “living skin” of arid ecosystems and emphasized the importance of the research, which will officially begin in August.

Rapid changes in environmental conditions make it increasingly important to safeguard biocrusts, which are dominated by cyanobacteria, lichens, mosses and algae, and enhance their establishment in arid lands, Couradeau noted.

“Recent studies have indicated that current patterns of temperature variations drive more species loss than the fact that average temperatures are overall increasing,” she said. “In this project, I will ask, ‘how do biocrust microbes acclimate or adapt to thermal fluctuations?’ Answering this question will help predict biocrust thermal fluctuations under present and future climate conditions, with implications for biocrust inoculant production and biocrust-covered land management and restoration.”

Every minute, up to 57 acres of vegetated land are lost to desert due to aridification — the transition from a wetter to a drier climate — according to Couradeau, and 70% of dryland soils are currently degraded. The lack of restoration of these lands will put about 1 billion people at risk in the coming decades, she added.

“These microbially built soils in arid lands are the pioneer soils, sustaining the productivity and resiliency of these systems,” Couradeau said. “It is estimated that their coverage will decline by 25% to 40% within 60 years, reducing the ecosystem services they render proportionally, including soil stability and fertility. That has implications for global carbon, nitrogen cycles, the amount of dust in the air and human health.”

The research project will include a number of novel components, Couradeau said.

First, to learn how biocrust microbiomes will be affected by increased temperature fluctuations and gain a functional understanding of the associated shift in microbes’ metabolisms, Couradeau and her team will conduct experiments to determine the “tipping point” of temperature fluctuations for the biocrust system. The researchers will perform mesocosm experiments — using mason jars to create controlled thermal cycles and follow biocrust microbiome response using a combination of activity analysis and genetic sequencing.

Insights gained from this experiment, Couradeau explained, will be used by the researchers to mine the BIODESERT global survey dataset — which is led by the European Research Council — to see if comparable trends can be observed in biocrusts around the world, spanning a large set of latitudes and daily thermal ranges.

Second, the researchers will measure the physiological and behavioral response of the biocrust keystone cyanobacteria called Microcoleus to temperature fluctuations using SoilChips — transparent devices used by scientists to study the hidden world of soil microorganisms in real-time. Developed by project collaborator Edith Hammer, an associate professor at Lund University in Sweden, these microfluidic chips act as a window into the world of soil microbes.

Couradeau plans to use these thin chambers colonized by microbes to directly observe them, measuring with microscopic evaluation their metabolic tradeoffs between thermal adaptation and other cellular functions.

Third, Couradeau — in collaboration with Sarah Bordenstein, associate research professor in Penn State’s Eberly College of Science — will incorporate SoilChips and cyanobacteria behavior into science education. The researchers will introduce biocrust as a model system for soil science education by guiding students to create experiments utilizing SoilChips. They will conduct a pilot program with four partner high schools spanning arid and semi-arid regions of the western United States.

That educational activity, which includes publishing a curriculum building around SoilChip science, will include a citizen-science benefit as the classes’ work will provide more biocrust data for researchers to screen for cyanobacterial behavior.

Finally, in another creative component that Couradeau called “Breaking Ground,” the team will develop an online gallery of portraits of biocrust scientists to showcase their expertise. It will consolidate the biocrust research community to promote role models and career awareness in soil science, Couradeau explained, and provide teachers and instructors with a ready-to-use resource to broaden soil science curriculum in the classroom.

Other major collaborators on the project are Fernando Maestre, professor, KAUST, Saudi Arabia; Daniel Shay, high-school teacher at North Central High School in Spokane, Washington; Crystal Davis, high school teacher at California Academy of Mathematics and Science in Carson, California; Miranda Thornton, High-teacher at Basha High-School in Chandler, Arizona; Mary Ann Rall, teacher at Torrey Pines High School in San Diego, California; Anita Antoninka, assistant research professor, Northern Arizona University; Sonia Chamizo, postdoctoral scholar, University of Almeria, Spain; Yolanda Canton, professor, University of Almeria, Spain; Sasha Reed, researcher, U.S. Geological Survey, Utah; Miriam Munoz Rojas, research investigator and senior lecturer, University of Sevilla, Spain and University of New South Wales, Australia; Nicole Pietrasiak, associate professor, University of Las Vegas; Kristina Young, adjunct assistant professor, College of Natural Resources, Utah State University; and Ferran Garcia-Pichel, professor, Arizona State University.