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Students Working with Tom Mozdzer Win Awards at AERS Annual Meeting

April 7, 2023
From left: Julia Smeltzer (HC '23), Associate Professor of Biology Thomas Mozdzer, Adelma Argueta Roman (HC '24), Griffin Kaulbach (HC '22), and  Angie Quiroz '26

Julia Smeltzer (HC '23), Adelma Argueta Roman (HC '24, BMC Biology), and Griffin Kaulbach (HC '22, BMC Biology) (who is now a postbac fellow at Bryn Mawr), and research assistant Mayci Shimon all presented research carried out with Associate Professor of Biology Thomas Mozdzer at the Atlantic Estuarian Research Society's spring 2023 meeting. Angie Quiroz '26 attended but did not present.

Smeltzer won an award for Best Undergraduate Poster and Argueta-Roman received an honorable mention.  


Eco-evolutionary changes in Phragmites inflorescence morphology over a decade of exposure to elevated nitrogen and CO2
Argueta-Roman, Adelma1, Sean Lee2 , Melissa McCormick3 , Mike Blum3 , Thomas J Mozdzer4
1. Haverford College, 2. University of Connecticut, 3. Smithsonian Environmental Research Center, 4. Bryn Mawr College

It is known that global change factors can alter coastal marsh ecosystems. However, it is still undetermined whether a species’ fitness varies in response to global change, and whether shifts in fitness can alter ecosystem functioning. To investigate the fitness variation in Phragmites australis, we measured reproductive output traits collected over a decade of exposure to factorial treatments of elevated CO2 and nitrogen We found that exposure to N enrichment increased fitness by increasing reproductive output, with the effect strengthening over time. The effects of CO2 were less consistent, showing considerable interannual variation. These findings provide further evidence that ecologically important plants can respond rapidly via eco- evolutionary mechanisms


Genotypic variation in decomposition: New insights into integrating eco-evolutionary processes into carbon cycle studies.
Kaulbach, Griffin1, Mayci Shimon1 , Melissa K. McCormick2 , Michael J. Blum3 ,Thomas J. Mozdzer1
1. Bryn Mawr College, 2. Smithsonian Environmental Research Center, 3. University of Tennessee, Knoxville

Salt marsh ecosystems store disproportionally more carbon than terrestrial ecosystems due in part to high rates of productivity and low decomposition rates. These ecosystems also have well documented responses to global change factors including elevated CO2 , nitrogen enrichment, and sea level rise. It is widely assumed that marshes change due to plastic responses of foundation species, but there is growing evidence that plants can rapidly evolve in response to global change and that heritable changes in plant traits can alter ecosystems. Building on evidence that exposure to elevated nitrogen and CO2 changes genetic diversity and identity in the common reed, Phragmites australis, we examined whether aspects of the carbon cycle are susceptible to shifts in genetic variation. Preliminary analyses detected significant differences in decomposition rates and rates of litter respiration at both the genotype and population level, and the possibility that the effects of genotypic variation can be as important as species-level effects on carbon cycling. Our results suggest that carbon cycling is also subject to rapid evolution in response to global change.


Impact of global change factors on phenotypic traits and the eco-evolutionary implications
Smeltzer, Julia1, Melissa K. McCormick2, Thomas J. Mozdzer1

1. Bryn Mawr College, 2. Smithsonian Environmental Research Center

Salt marshes are incredibly important ecosystems that provide a variety of ecosystem functions. Global change factors, specifically elevated CO2 and nitrogen enrichment, have the potential to greatly affect salt marshes by impacting plant phenotypic traits and putting selective pressures on plants. Phragmites australis is a common reed that has invaded salt marshes all over the US. Phragmites is an ecosystem engineer that has been known to take advantage of elevated CO2 , nitrogen enrichment, and the combination of the two. This project investigates the impact of global change factors on phenotypic traits of Phragmites and the eco-evolutionary implications.

The Bi-Co Environmental Studies Major combines the strengths of our two liberal arts campuses to create an interdisciplinary program that teaches students to synthesize diverse disciplinary knowledge and approaches, and to communicate effectively across disciplinary boundaries as they engage with environmental issues. In addressing these issues, ENVS students will apply critical thinking and analytical skills within a holistic, systems framework that includes social justice as an essential component.

Environmental Studies