Virginia Armbrust
· OceanographyUniversity of Washington · Program on the Environment
Active 2005–2020
About
Virginia Armbrust is a biological oceanographer specializing in the study of diatoms, a type of plankton. Her research combines lab- and field-based techniques to investigate these organisms, focusing on their roles from the cellular level to community interactions. She aims to understand how diatoms shape and are influenced by their environmental conditions, contributing to the broader understanding of marine ecosystems. In addition to her research, Virginia Armbrust serves as the associate dean for research at the College of the Environment. She has been recognized for her contributions by being elected a Fellow of the American Association for the Advancement of Science, the American Academy of Microbiology, and the Washington State Academy of Science. She has also been twice named a Gordon and Betty Moore Foundation Marine Microbiology Investigator, highlighting her significant impact in the field of marine microbiology.
Research topics
- Geology
- Geography
- Oceanography
- Climatology
- Environmental science
- Political Science
- Biology
- Meteorology
- Fishery
- Paleontology
- Ecology
- Economics
- Mathematics
Selected publications
Proceedings of the National Academy of Sciences · 2022 · 61 citations
- Biology
- Ecology
- Oceanography
Intricate networks of single-celled eukaryotes (protists) dominate carbon flow in the ocean. Their growth, demise, and interactions with other microorganisms drive the fluxes of biogeochemical elements through marine ecosystems. Mixotrophic protists are capable of both photosynthesis and ingestion of prey and are dominant components of open-ocean planktonic communities. Yet the role of mixotrophs in elemental cycling is obscured by their capacity to act as primary producers or heterotrophic consumers depending on factors that remain largely uncharacterized. Here, we develop and apply a machine learning model that predicts the in situ trophic mode of aquatic protists based on their patterns of gene expression. This approach leverages a public collection of protist transcriptomes as a training set to identify a subset of gene families whose transcriptional profiles predict trophic mode. We applied our model to nearly 100 metatranscriptomes obtained during two oceanographic cruises in the North Pacific and found community-level and population-specific evidence that abundant open-ocean mixotrophic populations shift their predominant mode of nutrient and carbon acquisition in response to natural gradients in nutrient supply and sea surface temperature. Metatranscriptomic data from ship-board incubation experiments revealed that abundant mixotrophic prymnesiophytes from the oligotrophic North Pacific subtropical gyre rapidly remodeled their transcriptome to enhance photosynthesis when supplied with limiting nutrients. Coupling this approach with experiments designed to reveal the mechanisms driving mixotroph physiology provides an avenue toward understanding the ecology of mixotrophy in the natural environment.
Viruses affect picocyanobacterial abundance and biogeography in the North Pacific Ocean
Nature Microbiology · 2022 · 72 citations
- Oceanography
- Ecology
- Biology
The photosynthetic picocyanobacteria Prochlorococcus and Synechococcus are models for dissecting how ecological niches are defined by environmental conditions, but how interactions with bacteriophages affect picocyanobacterial biogeography in open ocean biomes has rarely been assessed. We applied single-virus and single-cell infection approaches to quantify cyanophage abundance and infected picocyanobacteria in 87 surface water samples from five transects that traversed approximately 2,200 km in the North Pacific Ocean on three cruises, with a duration of 2-4 weeks, between 2015 and 2017. We detected a 550-km-wide hotspot of cyanophages and virus-infected picocyanobacteria in the transition zone between the North Pacific Subtropical and Subpolar gyres that was present in each transect. Notably, the hotspot occurred at a consistent temperature and displayed distinct cyanophage-lineage composition on all transects. On two of these transects, the levels of infection in the hotspot were estimated to be sufficient to substantially limit the geographical range of Prochlorococcus. Coincident with the detection of high levels of virally infected picocyanobacteria, we measured an increase of 10-100-fold in the Synechococcus populations in samples that are usually dominated by Prochlorococcus. We developed a multiple regression model of cyanophages, temperature and chlorophyll concentrations that inferred that the hotspot extended across the North Pacific Ocean, creating a biological boundary between gyres, with the potential to release organic matter comparable to that of the sevenfold-larger North Pacific Subtropical Gyre. Our results highlight the probable impact of viruses on large-scale phytoplankton biogeography and biogeochemistry in distinct regions of the oceans.
bioRxiv (Cold Spring Harbor Laboratory) · 2021 · 14 citations
- Computer Science
- Data Mining
- Computer Science
Abstract Simons Collaborative Marine Atlas Project (Simons CMAP) is an open-source data portal that interconnects large, complex, and diverse public data sets currently dispersed in different formats across different Oceanography discipline-specific databases. Simons CMAP is designed to streamline the retrieval of custom subsets of data, the generation of data visualizations, and the analyses of diverse data, thus expanding the power of these potentially underutilized data sets for cross-disciplinary studies of ocean processes. We describe a unified architecture that allows numerical model outputs, satellite products, and field observations to be readily shared, mined, and integrated regardless of data set size or resolution. A current focus of Simons CMAP is integration of physical, chemical, and biological data sets essential for characterizing the biogeography of key marine microbes across ocean basins and seasonal cycles. Using a practical example, we demonstrate how our unifying data harmonization plans significantly simplifies and allows for systematic data integration across all Simons CMAP data sets.
Limnology and Oceanography Methods · 2021 · 33 citations
- Computer Science
- Data Mining
- Computer Science
Abstract Simons Collaborative Marine Atlas Project (Simons CMAP) is an open‐source data portal that interconnects large, complex, and diverse public data sets currently dispersed in different formats across different Oceanography discipline‐specific databases. Simons CMAP is designed to streamline the retrieval of custom subsets of data, the generation of data visualizations, and the analyses of diverse data, thus expanding the power of these potentially underutilized data sets for cross‐disciplinary studies of ocean processes. We describe a unified architecture that allows numerical model outputs, satellite products, and field observations to be readily shared, mined, and integrated regardless of data set size or resolution. A current focus of Simons CMAP is integration of physical, chemical, and biological data sets essential for characterizing the biogeography of key marine microbes across ocean basins and seasonal cycles. Using a practical example, we demonstrate how our unifying data harmonization plans significantly simplifies and allows for systematic data integration across all Simons CMAP data sets.
Proceedings of the National Academy of Sciences · 2021 · 44 citations
- Biology
- Evolutionary biology
- Cell biology
The 24-h cycle of light and darkness governs daily rhythms of complex behaviors across all domains of life. Intracellular photoreceptors sense specific wavelengths of light that can reset the internal circadian clock and/or elicit distinct phenotypic responses. In the surface ocean, microbial communities additionally modulate nonrhythmic changes in light quality and quantity as they are mixed to different depths. Here, we show that eukaryotic plankton in the North Pacific Subtropical Gyre transcribe genes encoding light-sensitive proteins that may serve as light-activated transcription factors, elicit light-driven electrical/chemical cascades, or initiate secondary messenger-signaling cascades. Overall, the protistan community relies on blue light-sensitive photoreceptors of the cryptochrome/photolyase family, and proteins containing the Light-Oxygen-Voltage (LOV) domain. The greatest diversification occurred within Haptophyta and photosynthetic stramenopiles where the LOV domain was combined with different DNA-binding domains and secondary signal-transduction motifs. Flagellated protists utilize green-light sensory rhodopsins and blue-light helmchromes, potentially underlying phototactic/photophobic and other behaviors toward specific wavelengths of light. Photoreceptors such as phytochromes appear to play minor roles in the North Pacific Subtropical Gyre. Transcript abundance of environmental light-sensitive protein-encoding genes that display diel patterns are found to primarily peak at dawn. The exceptions are the LOV-domain transcription factors with peaks in transcript abundances at different times and putative phototaxis photoreceptors transcribed throughout the day. Together, these data illustrate the diversity of light-sensitive proteins that may allow disparate groups of protists to respond to light and potentially synchronize patterns of growth, division, and mortality within the dynamic ocean environment.
Anthropogenic Asian Aerosols provide Fe to the North Pacific
Ocean Sciences Meeting 2020 · 2020 · 1 citations
- Environmental science
- Climatology
- Oceanography
Anthropogenic Asian aerosols provide Fe to the North Pacific Ocean
Proceedings of the National Academy of Sciences · 2020 · 100 citations
- Oceanography
- Environmental science
- Geology
Fe > -0.65‰) observed in the region that is most influenced by aerosol deposition. An isotope mass balance suggests that anthropogenic Fe contributes 21-59% of dissolved Fe measured between 35° and 40°N. Thus, anthropogenic aerosol Fe is likely to be an important Fe source to the North Pacific Ocean.
Three Years of Observations Show a Sharp Boundary for Diazotrophs and N 2 Fixation Rates near the Northern Subtropical Front of the North Pacific Ocean
2020
- Oceanography
- Geology
- Geography
The ISME Journal · 2020 · 117 citations
- Biology
- Ecology
- Genetics
Ammonia-oxidizing archaea (AOA) are among the most abundant and ubiquitous microorganisms in the ocean, exerting primary control on nitrification and nitrogen oxides emission. Although united by a common physiology of chemoautotrophic growth on ammonia, a corresponding high genomic and habitat variability suggests tremendous adaptive capacity. Here, we compared 44 diverse AOA genomes, 37 from species cultivated from samples collected across diverse geographic locations and seven assembled from metagenomic sequences from the mesopelagic to hadopelagic zones of the deep ocean. Comparative analysis identified seven major marine AOA genotypic groups having gene content correlated with their distinctive biogeographies. Phosphorus and ammonia availabilities as well as hydrostatic pressure were identified as selective forces driving marine AOA genotypic and gene content variability in different oceanic regions. Notably, AOA methylphosphonate biosynthetic genes span diverse oceanic provinces, reinforcing their importance for methane production in the ocean. Together, our combined comparative physiological, genomic, and metagenomic analyses provide a comprehensive view of the biogeography of globally abundant AOA and their adaptive radiation into a vast range of marine and terrestrial habitats.
Assessing community metabolism and flexibility: metabolomics and microbial diversity across the North Pacific Transition Zone and in response to nutrient amendments
2020
- Political Science
- Ecology
- Biology
Frequent coauthors
- 6 shared
BW Frost
University of Washington
- 6 shared
Albert Calbet
- 6 shared
Seth G. John
University of Southern California
- 4 shared
W. Lampert
Max Planck Society
- 4 shared
Thomas Wichard
Friedrich Schiller University Jena
- 4 shared
Giuliana d’Ippolito
- 4 shared
C. Guisande
Universidade de Vigo
- 4 shared
Nicholas J. Hawco
University of Hawaiʻi at Mānoa
Awards & honors
- Fellow of the American Association for the Advancement of Sc…
- Fellow of the American Academy of Microbiology
- Fellow of the Washington State Academy of Science
- twice been named a Gordon and Betty Moore Foundation Marine…
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