Originally published here by The University of Georgia Institute for Resilient Infrastructure Systems.
I first interviewed Laura Naslund as the sun rose over a pond near Watkinsville, Georgia in June of 2022. I was an intern at the River Basin Center helping with Naslund’s field work, and we had just finished two hours of paddling a canoe to collect her homemade gas traps. These traps were upside-down funnels set up across the surface of the pond, with syringes on top to collect gas bubbling up from the sediment at the bottom. We spent a lot of time together that summer paddling through duckweed, hiking in thick brush and checking for ticks, and reminding each other to stay hydrated.
In the two years between our interviews, Naslund has been a powerhouse of a graduate student: co-authoring numerous papers on biodiversity, infrastructure and the Clean Water Act, working as an intern for the US Environmental Protection Agency since August of 2023, and camping for over 24 hours at a time at her field sites, often multiple times per week, for several months.
Following her graduation from Duke University in 2019, Naslund came to UGA on a GREAT Fellowship from the UGA Graduate School (this specific fellowship is no longer offered). At Duke, she had worked in Dr. Emily Bernhardt’s aquatic biogeochemistry lab studying the movement of contaminants between water and land in a mountaintop removal coal mining case study. This experience involved looking closely at contaminant uptake in aquatic insects, leading her to study aquatic entomology further when she began her PhD program at the Odum School of Ecology in Dr. Amy Rosemond’s lab. Her original idea was to study how stream warming would impact the emergence of aquatic insects.
After a year and a half of field work, Naslund began questioning this path. “I had a little bit of a science identity crisis,” she explained. “The part of it that I thought I thought was interesting was the bugs component, and then I realized the part I actually thought was interesting was the biogeochemistry component. I was really interested in looking at bugs as carbon.”
Naslund recruited Dr. Seth Wenger to her advising team and shifted her focus from an entomological to a biogeochemical one. She began exploring the concept of the climate impact of reservoirs and how removing dams may influence reservoir emissions. Through this process, Naslund became connected with the Institute for Resilient Infrastructure Systems (IRIS) and the Network for Engineering With Nature (N-EWN), where she began interacting more with engineers and infrastructure managers and learning more about how reservoirs and dams are managed.
After further reflection and research, Naslund’s renewed dissertation began to take shape. She started on a new season of field work in the summer of 2022, quantifying emissions from four small reservoirs around Athens, GA.
“Dams flood terrestrial environments, which generates carbon dioxide (CO2) emissions, and they also concentrate organic matter under low oxygen conditions, which produces methane (CH4) emissions,” she explained. “Both gases can be emitted by diffusion as they move from higher concentrations in the water to lower concentrations in the air. Methane can also build up in bubbles in the sediment, which rise through the water column and release the gas at the surface in a process called ebullition.”
Naslund measured these gases by spending 24 hours at a time at each field site, allowing her to measure not only the emissions themselves, but also any diel (daily) patterns in reservoir emissions. This work ultimately turned into the first chapter of her dissertation.
In the second chapter, she focuses on dam removal and the relationships between emissions and a potential removal. To do so, she looked at two different case studies, showing the emissions before, during and after a dam removal. She was able to show how one reservoir that was originally a weak source of carbon became an even larger source following the dam removal, and another reservoir that was a significant carbon sink became a weaker sink following the removal. Naslund clarified that her second chapter does not conclude that all dam removals decrease carbon storage, rather that carbon storage in reservoirs is incredibly sensitive and complex. This, along with her connections with the N-EWN, led to her third and final chapter.
To conclude her dissertation, Naslund and a team of N-EWN researchers created a web tool for evaluating the carbon costs and benefits of dam removal. “We pretty quickly found that lots of tools support a couple of objectives, like supporting fish or generating power,” she explained, “but a lot of the common considerations of dam removal, like safety hazards and recreation and historic preservation, were not included in existing decision support tools.” This inspired the team to create a tool that could look at many objectives simultaneously when evaluating a potential removal. The team consisted of ecologists and engineers from UGA and the US Army Corps of Engineers, including Daniel Buhr, Matt Chambers, Kyle McKay, Suman Jumani, Brian Bledsoe, and her co-advisors Rosemond and Wenger. The group evaluated the stakeholders in a dam removal scenario and created a list of 18 main priorities from transportation to biodiversity.
A principal aspect of this tool is the value of interdisciplinary perspectives, something Naslund explored in detail throughout her time at UGA. “I audited Dr. Bledsoe’s River Mechanics class,” she described. “Having studied rivers for probably about five or six years at that point, I remember going out to the field with my classmates and my brain instantly goes to like, there’s a log jam over there. So if I wanted to find bugs I would look at the leaf pack and the log jam… and oh, they’re talking about the Manning’s n* and the geomorphology of the stream, things that I had never really thought about before.” Her “eye-opening” realization of the number of viewpoints involved in each research project informed not only the dam removal tool, but her current and future work outside of academia.
Ahead of her graduation this summer, Naslund hopes to continue her work with the EPA Office of Research and Development. “I find that for me personally, I can be really creative in the context of being given a specific problem,” she said. “I think I’ve wanted to be a federal scientist in part because of the experience I’ve had working with the Army Corps of Engineers. I really liked doing science that’s very problem-driven.”
On April 12, 2024, Dr. Laura Naslund successfully defended her doctoral dissertation on UGA’s campus in front of her advisors, peers and friends. UGA’s Spring 2024 Commencement Ceremonies will be held on May 9 and 10. It’s been a while since I last sat in a canoe with Laura, but it’s been amazing to see her grow. Congratulations to Dr. Naslund and the rest of our soon-to-be alumni- we’re excited to see what you do next!
*Manning’s n: A roughness coefficient used to calculate flow in open channels, often describing boundary and vegetation effects.
Photos by Olivia Allen.
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