New publication in mSystems!

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

New Publications in L&O!

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

New publication in L&O Methods!

September 28, 2023

Former undergraduate student Emily Pierce led a publication on comparing different methods for identification of diatoms in dynamic coastal communities. In this study, Emily compared 18s rRNA gene analysis with FlowCam imaging and light microscopy. Her findings show some consistencies, although cross-method comparisons should proceed with caution.

Comparison of advanced methodologies for diatom identification within dynamic coastal communities

Trends in new production during NP NASA EXPORTS

September 16, 2022

Our first paper contribution to the NASA EXPORTS program was recently published in Elementa: Science of the Anthropocene. In this study, Ph.D. candidate Meredith Meyer provides our findings on trends in new and regenerated production during the North Pacific EXPORTS field campaign. Meredith and coauthors show that the majority of net primary production (NPP) is performed by small cells growing on regenerated sources of nitrogen. Yet, any variations in NPP are primary driven by changes in nitrate-based new production.

Phytoplankton size-class contributions to new and regenerated production during the EXPORTS Northeast Pacific Ocean field deployment

New publication in Frontiers in Marine Science!

May 18, 2022

Our second publication investigating the protistan communities in the Galápagos Archipelago was published recently in Frontiers in Marine Sciences.  Former post-doc Se Hyeon jang led this effort to examine how environmental conditions influence marine protists with an emphasis on the micrograzer communities.  We also report observation from a red tide bloom in Elizabeth Bay, Isabela Island.  A bloom of the dinoflagellate Scripsiella lachrymosa was being actively grazed by another dinoflagellate, Polykrikos kofoidii.

Protistan communities within the Galápagos Archipelago with an emphasis on micrograzers

New publication in Environmental Microbiology!

Dec. 19, 2021

Our new publication led by former graduate student Erika Neave was recently published in Environmental Microbiology.  This publication is the first highlighting my groups research in the Galápagos Archipelago where we participated on annual research cruises that spanned the 2015/16 El Niño event.  In this study, we found that the composition of the marine protist community was significantly influenced by deep water masses. This suggests that the ocean currents are a major source of plankton seed populations to the surface waters in the Galápagos and thus substantially influences plankton composition when these currents change as a result of El Niño-Southern Oscillation (ENSO) events.

Protistan plankton communities in the Galápagos Archipelago respond to changes in deep water masses resulting from the 2015/16 El Niño

Phytoplankton: Thinking in microns

Dec. 13, 2021

The video below was made by UNC undergraduate Heidi Hannoush, who was a student in my Marine Phytoplankton (MASC444) class last semester.  She was inspired by all the phytoplankton groups she learned about and so made this video for an assignment in another class. Enjoy!


Iron limitation in diatoms impairs viral infection

April 10, 2021

In a recent study published in Nature Geosciences led by Chana Kranzler from the Thamatrakoln Lab at Rugers University, we examined how iron limitation in diatoms may affect viral infection.  Molecular datasets used in the study were derived from incubation experiments led by members of the Marchetti lab during the IrnBru cruise in the California Upwelling Zone in 2014 and a Line P cruise in the Northeast Pacific in 2015. The study found an interesting ecological trade-off in how growth limitation by low iron availability may result in diatoms being less vulnerable to viral infection by slowing down mortality and reducing viral replication.

Impaired viral infection and reduced mortality of diatoms in iron-limited oceanic regions

A Nature Geosciences news and views article about the study is available here.

New publication in mSystems!

March 30, 2021

Chaetoceros decipiens

Our new publication led by former Master’s student Rob Lampe was recently published in mSystems.  In this study we simulated the upwelling conveyor belt cycle (UCBC) to examine how a common diatom and coccolithophore originally isolated from the California upwelling zone respond to changes associated with the cycle.  In addition, we examined the effects of iron-limitation on how these two phytoplankton species cope with the UCBC.  Our findings show that the diatom Chaetoceros decipiens is particularly well-adapted to upwelling cycles.  Co-authors include current graduate student Johnson Lin and former undergraduate researcher Gustavo Hernandez.


Representative Diatom and Coccolithophore Species Exhibit Divergent Responses throughout Simulated Upwelling Cycles

Carly defends her Ph.D. thesis!

Oct. 29, 2020

Congratulations to Dr. Carly Moreno who successfully defended her Ph.D. thesis titled ‘Coupled molecular physiology and ecology of Southern Ocean diatoms in response to shifting iron and light availability’. Carly’s research investigated how polar diatoms acclimate and adapt to varying iron concentrations and light levels, providing new insights into how phytoplankton communities may shift in rapidly changing polar environments.  The punchline is that not all diatoms are created equal!