Graduate Students


Stephanie Tsui

I am interested in biogeochemical processes in coastal systems, specifically looking at nitrogen pathways. Before joining the Bowen Lab, I earned my B.S. from the University of California, Davis in Environmental Science and Management with a minor in Soil Science. I also worked as a technician at Iowa State University studying greenhouse gas fluxes in wetland environments. Additionally, I am passionate about STEM outreach and worked as a STEM Educator for the Liberty Science Center in New Jersey. With the Bowen Lab, I hope to investigate nitrogen dynamics in the sediments below oyster aquaculture or salt marsh ecosystems, and the denitrifying communities involved.

Johanna photo.jpg

Johanna L'Heureux

Broadly, I am interested in host-microbe interactions and how they respond to and shape their environment. Before starting at Northeastern, I received my bachelor’s degree from UMass Amherst in Biochemistry where I studied the intricate symbiosis between legumes and nitrogen fixing soil bacteria. Other past research experiences have involved formulating probiotics to increase viability throughout storage as well as characterizing the effects of mixtures of plant growth-promoting bacteria on seedling germination when subjected to heat stress. While in the Bowen lab, I hope to conduct research related to plant-microbial associations in salt marsh ecosystems and the role they play in the cycling of carbon and nitrogen. I also hope to learn more about how to better communicate scientific topics so that science can have the greatest impact in helping solve the global challenges we are currently facing.


I am interested in how ecosystem functioning is altered by anthropogenic activities. More specifically, I study how salt marsh nitrogen cycling and related processes change in the face of shifting climate and altered human activity. During my PhD, I expect to delve deeper into the mechanisms that drive crucial biogeochemical processes. Prior to joining the Bowen lab, I received my B.A. and M.S. from Clark University. I also worked as a Lab Manager in a biogeochemistry lab at the Louisiana Universities Marine Consortium, and a Research Assistant at the Marine Biological Laboratory in Woods Hole, MA. I have worked at the Woods Hole Research Center for the past three years, and will continue here full-time while working toward my PhD. 

Hillary Sullivan

I am interested in nearly all things microbial.  I use computational tools to understand how microbial populations evolve and interact with their environment at the molecular level.  As a Ph.D student in the Bowen lab, I aim to characterize microbial genes and genomes within salt marshes to provide increased resolution on the mechanisms that drive biogeochemical processes, primarily related to nitrogen cycling.  I’m also interested in the evolution of plant microbe interactions.  Specifically, how do microbial populations impact plant fitness, what factors drive the stability of the plant microbiome, and how do these factors potentially drive plant and microbe distributions across the landscape.   Prior to joining the Bowen lab, I received a masters degree from SUNY ESF and spent six years as a research assistant in the Josephine Bay Paul Center at the Marine Biological Laboratory.  

Joe Vineis


Brian Donnelly

I  joined the Bowen Lab after working as a laboratory technician at Villanova University. At Villanova, I worked in a biogeochemistry lab that focused on marshes and how changes in the environment can impact metabolic rates.  I hope to continue biogeochemical work in marsh systems, but also investigate how microbial community structure and function shifts  as a result of environmental change. I hope to investigate how denitrifying communities change as a result of pulse and press changes in salinity and temperature, as I believe these are the most relevant global climate change drivers. Investigating these shifts in denitrifying communities could give us valuable information on how the nitrogen cycle responds to global change. Also, as a gay person in STEM, I hope to find ways to make the LGBTQ community more visible in STEM, act as a mentor to young LGBTQ people pursuing a career in STEM, and let this underrepresented community know they are not alone!

Undergraduate Students

Screen Shot 2021-04-16 at 11.03.16

Julia Holtzer
I joined the Bowen Lab for my co-op as an undergraduate assistant for the TIDE Project. I am interested in studying how benthic microalgae change due to nutrient enrichment. I will graduate with my B.S. in Marine Biology in Spring 2021 and am excited to continue my studies with the TIDE Project for my Three Seas Plus One Internship.

Catherine Hexter
I recently joined the Bowen lab as an undergraduate assistant interested in environmental genomics. I am currently working with other people in the lab to help investigate denitrification genes and their diversity within salt marshes. I hope to continue doing similar work to this in a PhD program when I graduate next year. 


Justine Canna
I joined the Bowen lab as an undergraduate interested in environ chemistry.   I assist with projects on  carbon cycling and plant-microbe interactions in salt marshes.  I am also interested in kin recognition in marshes. I will graduate in Spring '23 with my BS in Environmental Science and am excited to continue exploring many facets of environmental science.

Former graduate students and postdocs

Andrea Unzueta Martinez

Currently a postdoc at Harvard

Patrick Kearns (PhD)

Currently an Assistant Professor at Fisher College

Annie Murphy

Currently a Senior Scientist  at Inspire Environmental

John Angell (PhD)

Currently a post-doc at Boston University

Currently at Clearwater Aquarium

Kerry McNally

Currently a post-doc at MBL

Ashley Bulseco McKim (PhD)

Sarah Feinman (PhD)

Currently in LIBERIA!!!!!!

Kenly Hiller (PhD)

Currently an analyst at Tessella

Chris Lynum (MS)

Currently in Minnesota

Former undergrads

NSF Funded REUs

UMass Undergraduate Honors students

Katie Conese (2019; Notre Dame) 

Ross Ackerman (2017; Bates College)

Helen Hoyt (2016; Carleton College)
Taylor Matthew (2016; Wesleyan University)
Rachel Vincent (2015; U. Massachusetts Boston)
Andrea Unzueta Martinez (2015; University of Hawaii)
Dakota Holloway (2014; Washington and Jefferson)
Jonathan Bauer (2014; Central Connecticut State)
Abigail Tyrell (2013; Tufts University)
Collin Knauss (2012; Colorado College)
Codi Leitner (2012; Wesleyan University)
Snezhana Sharipova (2012; U. Massachusetts Boston) 
Patrick Kearns (2011; U. Massachusetts Boston)

Michelle Jimenez (2011; Brown University)

Northeastern University Interns/Honors/Co-op students

Julia Holtzer (2020)

Abigail Eilar (2020)

Heather Welch (2019)

Sean Osborne (2018)

Emma Riccardi (2018)

Itxaso Garay (2017)

Rachel Vincent (2016)

Pablo Joshua Aguirre (2016)

Khang Tran (2016)

Ian Craick (2015)

Yuna Farah (2015)

Samantha Brown (2014)

Jennifer Yu (2014)