Oct. 12, 2025
Congrats to Ph.D candidate Emily Speciale for being awarded a UNC Kenan Galapagos Fellowship! Emily is investigating the influence of different nutrient delivery modes on Galapagos phytoplankton composition and functional traits. She recently spent a month in the Galapagos on the R/V Marcus Langseth sampling the waters around San Cristobal and Isabela Islands.
Charting the Future of Island Ecosystems: UNC Kenan Galapagos Fellows 2026
For more information about the cruise, check out the links below.
Scientists Study the Impact of Ocean Processes on Marine Biodiversity in the Galápagos
en foco video
Voyage to the Galápagos Explores How Ocean Nutrients Sustain Life
Sept. 22, 2025
A new publication in the Journal of Phycology led by former graduate student Meredith Meyer explores the potential contributions of the small chlorophyte Micromonas from the Northeast Pacific Ocean to new production and their molecular response to iron limitation. Meredith and coauthors found that although small, this frequently abundant picophytoplankton can contribute appreciably to carbon export, even when iron-limited.
The effects of iron limitation on the small chlorophyte Micromonas from the Northeast Pacific Ocean
July 18, 2025
Former MSc student Prisca Lim led this study examining how phytoplankton communities in the waters surrounding the Galápagos Archipelago are shaped by their environmental conditions. Prisca compiled measurements over five research cruises spanning from 2014 to 2022. Included in the time series is an El Niño event in 2015 and a La Niña event in 2022. Taxonomic variability reflected heterogeneous environmental conditions generated by the convergence of multiple ocean currents.
Drivers of Marine Phytoplankton Diversity and Connectivity in the Galápagos Archipelago Spanning an ENSO Cycle
June 24, 2025
Former PhD student Johnson Lin led this study examining the phytoplankton response to different phases of upwelling in the California Current System. This study was conducted during the Pupcycle I cruise, which took place in 2019. By incorporating metatranscriptomic analyses and stable isotope incubations to measure nutrient uptake kinetics into our assessment of early and later upwelling stages, we observed variability in phytoplankton assemblages and differential gene expression of phytoplankton that were de-coupled from their physiology.
Phytoplankton Exhibit Diverse Responses to Different Phases of Upwelling in the California Current System.
April 7, 2025
Congratulations to Emily Speciale who successfully defended her MSc thesis entitled ‘The molecular physiology of mixotrophic phytoplankton under iron-limited upwelling conditions’. Emily investigated how the gene expression of mixotrophs in the Califormia Current System respond to varying iron states. Emily will continue in the Marchetti Lab as a PhD candidate.
June 28, 2024
Johnson successfully defended his Ph.D dissertation titled ‘Phytoplankton molecular physiology associated with upwelling dynamics through field and laboratory studies’. He used a combination of physiological and molecular approaches to examine how phytoplankton respond to upwelling cycles under varying iron states. He also performed laboratory experiments to examine how diatom isolates from the California Current System are influenced by the Upwelling Conveyor Belt Cycle. Johnson will continue in our lab as a bioinformatic specialist.
April 18, 2024
Meredith successfully defended her Ph.D dissertation titled ‘The Influence of Phytoplankton Productivity and Molecular Physiology on Biogeochemical Dynamics of Two Contrasting Ocean Environments’. Meredith examined primary productivity dynamics as part of the NASA EXPORTS program field campaigns in the North Pacific and North Atlantic. She used a combination of physiological and molecular methods to elucidate how phytoplankton respond to their environment and influence the export of carbon from the surface ocean. She also conducted laboratory studies on Bathycoccus, an important picoeukaryote from the North Pacific. Meredith will be starting a post-doc at the University of East Anglia this summer.
March 22,2024
Congratulations to Prisca Lim who defended their M.Sc. thesis titled ‘Drivers of marine phytoplankton diversity and connectivity in the Galápagos Archipelago spanning an ENSO cycle’. Prisca analyzed DNA sequences from our Galápagos cruises from 2014 – 2022 spanning the El Niño in 2015/16 and the La Niña event from 2020-2022. Phytoplankton composition and size structure are highly dependent on the environmental conditions across the region which exhibit both high spatial and temporal variability. Publication soon to follow.
February 27, 2024
Former PhD student Carly Moreno has led a study just published in mSystems examining how diatom natural assemblages respond to changes in environmental conditions in waters adjacent to the Western Antarctic Peninsula using metatranscriptomic approaches. She also opportunistically examined a bloom of the centric diatom Actinocyclus in coastal waters.
Molecular physiology of Antarctic diatom natural assemblages and bloom event reveal insights into strategies contributing to their ecological success
February 24, 2024
Ph.D student Johnson Lin is the lead author on a study recently published in Limnology and Oceanography where we examined how diatoms respond to upwelling when under various iron states at narrow and wide shelf regions in the California Current System.
Variability in the phytoplankton response to upwelling across an iron limitation mosaic within the California current system
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