Post Doctoral Researcher

Dr. Cleo Davie-MartinDr. Cleo Davie-Martin

Cleo is an environmental scientist studying the production and consumption of volatile organic carbon compounds by marine plankton. She runs and maintains the PTR-TOF-MS (proton transfer reaction time of flight mass spectrometer) combining new technology with unique incubation methods to study VOCs that are notoriously difficult to measure because of their low molecular weights and concentrations.


Graduate Students

IMAG0928Eric Moore

Eric is pursuing an M.S. in Microbiology. He is studying phytoplankton-bacterial interactions using pure cultures and transcriptomic analyses. Along the way, Eric made an important and serendipitous discovery about how to trigger centric diatoms into the sexual lifecycle.  His magic touch extended to the model centric species, Thalassiosira pseudonana, which has long been considered to be asexual. Through this work, Eric has found how exciting AND challenging it can be to make not one, but two landmark discoveries (see  Eric’s graduate program has been supported by a Graduate Teaching Assistantship, funding from the Dept. of Microbiology Tartar Fund, and a Middlekauf Outstanding Graduate Teaching and Service Scholarship.

Kelsey McBeain (GRADUATED! – see Posts)

Kelsey is pursuing an M.S. in Microbiology. She is studying the effects of nutrient limitation on the transfer of energy between phytoplankton and microzooplankton ~ the first two trophic levels in the marine ecosystem. Her work has important implications for food web dynamics, especially in the face of expanding areas of nutrient depletion in the open ocean.  She recently received a Dick and Toshi Morita scholarship.

img_5699Bryce Penta

Bryce is pursuing a Ph.D. in Microbiology. He is interested in studying the impacts of mixotrophic metabolism on ecoystem production. Mixotrophs are abundant players in marine environments that can supplement photoautotrophic growth with direct consumption of preformed carbon. Bryce’s goal is to use new information about the physiological responses of these understudied protists to constrain ecosystem models.  This is an exciting project that combines lab and field-based studies with computational modeling.

Undergraduate Students

tam-rim-for-kimDuncan Ocel (BPP)

Duncan is working to understand photosynthetic processes in the globally abundant cyanobacterium, Synechococcus sp. He is combining traditional measurements of photosynthesis with our new PTR-MS technologies to study volatile organic carbon production by this species and to quantify the amount of photosynthetically fixed carbon that is lost to the atmosphere.

Previous Lab Members

Brianna Bullington (BS, Microbiology, 2016)

Brianna contributed to two major projects in the Halsey lab. She carefully conducted some diatom growth experiments that will be included in an upcoming manuscript, thus garnering her co-authorship. Brianna’s dedication to aquatic microbiology and environmental health is obvious. She is now working at the Veterinary Diagnostics Lab in the OSU Vet school.

NLFish1Nerissa Fisher (MS, 2015)

Nerissa graduated with an M.S. in Microbiology. She conducted a comprehensive evaluation of light limited photosynthetic energy use in the model diatom Thalassiosira pseudonana. A manuscript on this work was published in Photosynthesis Research and can be found here (Mechanisms that increase the growth efficiency of diatoms in low light). Nobody enjoys research cruises as much as Nerissa, and together, we had the opportunity to work in the Atlantic for 21 days on the NASA-supported SABOR cruise measuring primary production and diel carbon allocation. She is now a research technician in the Behrenfeld lab at OSU where she will be cruising for the next five years as part of the NAAMES project.

BethanRocksScienceDr. Bethan Jones (post-doctoral researcher, 2013-2015)

Bethan researched photosynthetic energy use strategies in nutrient limited Thalassiosira pseudonana. Her work has led to new insights on the molecular regulation of carbon assimilation and catabolism in response to nutrient-driven growth rate.  She is now a post-doctoral researcher in the Behrenfeld lab at OSU where she is developing new methods for measuring phytoplankton growth rate in the field.



Marius_Blog_Header Marius Ibuye (BHS, UHC, 2015)

Marius graduated with a B.S. in BioHealth Sciences from OSU’s Honors College. He conducted his Honors thesis research on the effect of dark period duration on the growth of Synechococcus WH8102. He is now in the Pharm. D. program at Oregon State University. Marius’ story is one of inspiration and absolute positive conviction.

Rachel3Rachel Tullsen (MB, 2015)

Rachel graduated with a B.S. in Microbiology from OSU. She was the recipient of a URISC award that funded her undergraduate research on how the carbon composition of Synechococcus WH8102 changes in response to nutrient limitation. This was a challenging project, and Rachel’s perseverance was reflected in the success she found in developing specialized methods for growing these finicky open ocean cells in chemostat culture.


Bethany Moua (BS, BioHealth Science, OSU Honors College, 2016)

Bethany completed her Honors thesis studying physiological acclimation strategies in green algae and diatoms. This work was part of a larger, NASA-funded effort to understand timescales of acclimation to nutrient availability. Her work showed very different responses in the two groups of algae that may have important consequences in carbon and energy trophic transfers.

Rebecca Wiseman (BHS, STEM Leaders program, 2015-2016)
Jake Dittrich (BRR, UHC, 2013)
Janet Berkstresser (MB, 2013)
Jennifer Flannery (summer, 2012)
Ihadira Lopez (BRR, 2012)