Joanna Ridgeway was born and raised in West Virginia’s great outdoors. But for this CABBI Sustainability researcher, endless hours spent camping, backpacking, kayaking, and rock climbing didn’t just amount to a love for nature — they kickstarted her career.
“When I was growing up, I loved being outdoors,” she said. “When I learned about how climate change would put the ecosystems I loved into danger, that’s what inspired me to go into this research.”
Ridgeway remained in the Mountain State for her undergrad, and obtained an environmental engineering Bachelor’s from West Virginia University (WVU). At the time, her research in materials science focused on solar power, and this inaugural experience with renewable energy solidified her desire to one day work professionally in the sector.
After a detour through the working world with a firm called Allstar Ecology, Ridgeway returned to WVU for her graduate degree, seeking opportunities to “study biological processes impacting large-scale sustainability of different ecosystems, and look at how we can make changes to mitigate climate change”. Now, she is pursuing her Ph.D. through WVU’s Biology Department, focusing on how small-scale interactions between plants and microorganisms can affect greenhouse gas emissions in agricultural systems.
Ridgeway’s role within CABBI’s Sustainability theme intersects with her research focus. As a member of Co-PI Eddie Brzostek’s lab group, Ridgeway is able to apply her existing interest in microbial processes to bioenergy crops in particular.
As evidenced in the name, bioenergy agriculture’s primary purpose is to derive viable, renewable energy sources from the feedstock itself. But a second important function is the carbon sequestration that takes place in the soil. By studying and quantifying how carbon is sequestered by bioenergy crops, Ridgeway can help bolster the effectiveness of bioenergy agriculture in achieving intended emissions reductions.
This notion of bioenergy assuming a robust renewable energy portfolio drives Ridgeway’s commitment to her research.
“Bioenergy crops can replace fossil fuels,” she said, “but if they can also store carbon in the soil, bioenergy has an increased potential to compensate for other emissions and contribute to an energy economy with no net carbon emissions.”
As part of her quest to quantify belowground carbon sequestration, Ridgeway has been hard at work developing a project that allows her to study the specific plant microbial interactions that have to do with carbon storage in soil organic matter — dead plant and microbial materials that decompose and provide nutrients to the soil. To achieve this, she sets up “soil microcosms,” jars filled with isolated soil samples and bioenergy crop litter — dead plant material such as roots and leaves. From there, Ridgeway will “trace the fate of the litter through the soil,” answering questions like How do interactions between plants and soil microbes impact how much carbon remains in the soil when the litter decomposes? and Why do certain crops store more (or less) soil carbon than others?
“With this experiment, I’m going to be able to fill in some of the blanks that haven’t been empirically determined in bioenergy systems,” she said.
An example of one of these “blanks” is a metric called carbon use efficiency (CUE). “Because the soil carbon and nitrogen cycling model we use is driven by microbial litter decomposition, it relies heavily on traits like carbon use efficiency,” she said. If microbes have low CUE, much of the carbon in the litter doesn’t stay in the soil; instead, it gets respired into the atmosphere and contributes to greenhouse gases while higher CUE leads to more carbon remaining in the soil.
However, this and other microbial traits like growth and turnover rates are largely undiscovered and unquantified — for now. Using the microcosm experiment, Ridgeway can identify how much litter is taken up by microbes and respired (released back into the air) or assimilated (sequestered in biomass) and how much of this ends up remaining in soil organic matter, ultimately informing model simulations of bioenergy soil decomposition and carbon cycling.
“One major challenge to working this way is that I’m looking at really small microcosms. Scaling that up to the ecosystem level isn’t the easiest,” Ridgeway said.
However, if these results can be scaled up for larger-scale application, they could potentially change the scientific approach to greenhouse gas mitigation.
“What is really exciting about this project, and what makes me thankful that I’m on CABBI, is that I’m measuring something — these microbial processes and traits — which we’ve known are important but we haven’t been able to quantify. It’s important for understanding what’s been going on in the soil, it’s critical for filling in these missing parameters and models, and all with the end goal of being able to inform best management strategies and inform policies aimed at improving greenhouse gas emissions to be more sustainable.
“Even if I’m just looking at a jar of soil, litter, and microbes, it can potentially have significance when it comes to reducing net anthropogenic greenhouse gases and preventing climate change.”
In October 2019, Ridgeway visited the University of Illinois at Urbana-Champaign campus, where she spent time gathering samples at the Energy Farm and analyzing them back in the lab. But, the most difficult part of the trip didn’t have to do with complex microbial analytics:
“It was challenging to physically get all of the soil from the field! I had almost 480 pounds of soil to bring back from Illinois, which was certainly a lot!”
Aside from Illinois, Ridgeway is always on the lookout for new travel destinations. Whether she’s exploring new backpacking trails with her dogs (a husky and a Great Pyrenees who are “excellent travel companions and hiking buddies”), living on a sailboat off the coast of Florida, or hiking through her favorite Wilderness Areas in West Virginia, her life in and out of the lab revolves around her love of nature.
And, in the future, Ridgeway’s research can help keep that nature — and the ecosystems she loves — safe and secure for the future generations who grow up loving them as well.
— Written by iSEE Communications Specialist Jenna Kurtzweil