Principal Investigator
Dr. Meredith Holgerson (PI)
Department of Ecology and Evolutionary Biology
Corson Hall
Cornell University
EEB Profile
Google Scholar
Email: meredith.holgerson [at] cornell.edu
Postdoctoral Researchers
Dr. Pascal Bodmer
I am an aquatic biogeochemist, and my research centers around carbon dynamics in freshwater ecosystems ranging from streams and rivers to ponds, lakes, and reservoirs. Generally, I am interested in spatial and temporal carbon dioxide and methane dynamics from the water-air interface to the sediments, especially the processes and factors driving these dynamics.
Find Pascal on Google Scholar and ResearchGate
Dr. Anthony Stewart
My research and work investigates the distribution of carbon cycling across spatial scales. Primarily I’m interested in how we can upscale soil carbon, greenhouse gas flux, and carbon burial measurements in wetlands over landscapes and regions. I hope to utilize these upscaled estimates to improve the potential to management of wetland ecosystems under climate change.
Dr. Joe Rabaey
As an aquatic ecologist, I am interested in many aspects of freshwater ecology and biogeochemistry. My past research has focused on carbon cycling and greenhouse gas emissions from freshwater systems, as well as the impact of humans on aquatic carbon cycling, from man-made ponds to invasive species in natural lakes. I received my PhD from the University of Minnesota in 2023, working with Dr. Jim Cotner. Outside of research, I enjoy many outdoor hobbies, including fishing, running, and nordic skiing.
PhD Students
Meredith Theus
I am a PhD candidate in the Holgerson lab and am interested in ecosystem ecology and the ways in which phytoplankton and other organisms interact with and influence the chemical environment. I received my undergraduate degree in biology from Reed College where my research focused on the interactive effects of multiple abiotic factors on phytoplankton populations and communities. In the Holgerson lab, I hope to develop a better understanding of how biotic factors and processes, such as food web structure and phytoplankton community dynamics, affect carbon cycling in ponds. Generally, I am also interested in how human activity affects aquatic ecosystems. If I am not doing work, then you can find me doing some gardening, attempting to master embroidery, or playing with my dog!
Email: met224 [at] cornell.edu
Kathy Stenehjem
As a PhD candidate in the Holgerson Lab, I am studying biogeochemistry and freshwater ecosystem ecology. I’m particularly interested in the abiotic and biotic drivers of carbon, nitrogen and phosphorus cycles in small freshwater systems. Before coming to Cornell, I completed a B.S. in Conservation Biology & Microbiology at the University of Wisconsin – Madison and spent four years working at the USGS Upper Midwest Water Science Center studying phosphorus mobility in urban stormwater ponds and green infrastructure best practices. Outside of work, you can find me cycling, cooking, hiking, or trying to learn a new musical instrument.
Email: kjs297 [at] cornell.edu
Ellie Socha
I’m a PhD candidate originally from the cheese state, Wisconsin! My primary research interests surround how seasons are connected and impact aquatic ecosystem processes in the context of changing climate. Specifically, I hope to explore how seasonal succession and biological community composition might change as temperate ponds “green,” “brown,” and experience milder winters. Prior to starting at Cornell, I received my Master’s in Freshwater and Marine Science from the University of Wisconsin – Madison at the Center for Limnology. There, I studied how future winters with less snow might impact under-ice plankton communities. In my free time I enjoy spending time with my mom, watching reality TV, canoeing and hiking, and crocheting.
Email: es873 [at] cornell.edu
Kaci Zarek
I am a PhD student interested in greenhouse gas dynamics, redox, aquatic-terrestrial linkages, and N and C cycling in freshwater systems, whether that be a pond, wetland, or stream or a combination of all three. Prior to Cornell, I received my MS in Biological Sciences from the University of Alabama (Rolltide) that focused on nitrogen removal versus export in headwaters across an annual drying event. Prior to Bama, I obtained my BS in Environmental Studies at the University of Kansas (Rockchalk), where I learned my love for team science and aquatic biogeochemistry! Beyond research, you can find me watching football and softball, going for walks, mountain biking, doing yoga, arm wrestling, and admiring sunsets.
Email: kz367 [at] cornell.edu
Lab Technician
I am the research technician in the Holgerson Lab. I am interested in carbon dynamics in wetlands, specifically looking at how vegetation impacts these dynamics. I graduated from Kenyon College with degrees in Biology and Environmental Studies in 2025. There, I studied restored wetlands in the Conservation Reserve Program, focusing on carbon dynamics and the vegetative drivers of methane production. Here, I hope to enrich my knowledge of wetlands, ponds, and freshwater systems and understand more about drivers of aquatic methane emissions. When I am not in the lab, I enjoy hiking, photography, bird watching, and being around water.
Undergraduates
Mira Lamble
I am a rising junior from Seattle, WA. I’m studying Biological Sciences with a concentration in Ecology and Evolutionary Biology in the College of Arts and Sciences. I plan to minor in either Climate Change or Fungal Biology. In summer 2024, I helped to sample ponds across four ecoregions of New York state. I am now exploring wetland greenhouse gas production. Outside of academics, I enjoy rock climbing, backpacking, playing violin, and teaching through Cornell Outdoor Education. Email: ml2668 [at] cornell.edu
Elif Aydogan
I am in the Class of 2028 majoring in Environment & Sustainability with a concentration in Environmental Biology and Applied Ecology, and I also plan to pursue a double major in Information Science. I’m interested in aquatic ecosystems, their resilience to climate change, and how they are perceived. In summer 2025, I conducted social science surveys across the greater Ithaca area and processed sediment cores to examine carbon burial from wetlands. Outside of the Holgerson Lab, I’m a Research Assistant on Freshwater Fish Bioacoustics at the Cornell Lab of Ornithology. I also serve as vice president of EcoArtivism, a sustainable art club, and am a member of the Big Red Color Guard.
Caroline Darling
Sophia Pushlar
Janice Yohannan
Maura Beatty
Jianna Simcik