Hu
Sarah K
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Sarah K
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ArticleDaily dynamics of contrasting spring algal blooms in Santa Monica Bay (central Southern California Bight)(Society for Applied Microbiology, 2022-07-26) Ollison, Gerid A. ; Hu, Sarah K. ; Hopper, Julie V. ; Stewart, Brittany P. ; Smith, Jayme ; Beatty, Jennifer L. ; Rink, Laura K. ; Caron, David A.Protistan algae (phytoplankton) dominate coastal upwelling ecosystems where they form massive blooms that support the world's most important fisheries and constitute an important sink for atmospheric CO2. Bloom initiation is well understood, but the biotic and abiotic forces that shape short-term dynamics in community composition are still poorly characterized. Here, high-frequency (daily) changes in relative abundance dynamics of the metabolically active protistan community were followed via expressed 18S V4 rRNA genes (RNA) throughout two algal blooms during the spring of 2018 and 2019 in Santa Monica Bay (central Southern California Bight). A diatom bloom formed after wind-driven, nutrient upwelling events in both years, but different taxa dominated each year. Whereas diatoms bloomed following elevated nutrients and declined after depletion each year, a massive dinoflagellate bloom manifested under relatively low inorganic nitrogen conditions following diatom bloom senescence in 2019 but not 2018. Network analysis revealed associations between diatoms and cercozoan putative parasitic taxa and syndinean parasites during 2019 that may have influenced the demise of the diatoms, and the transition to a dinoflagellate-dominated bloom.
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DatasetHigh throughput tag-sequencing data from Gorda Ridge Hydrothermal vent field, including 16S and 18S rRNA gene sequences, and environmental metadata from Gorda Ridge Seamount, May/June 2019(Biological and Chemical Oceanography Data Management Office (BCO-DMO). Contact: bco-dmo-data@whoi.edu, 2021-01-06) Hu, Sarah K. ; Huber, Julie ; Smith, Amy R.High throughput tag-sequencing data from Gorda Ridge Hydrothermal vent field, including 16S and 18S rRNA gene sequences, and environmental metadata from Gorda Ridge Seamount, May/June 2019. For a complete list of measurements, refer to the full dataset description in the supplemental file 'Dataset_description.pdf'. The most current version of this dataset is available at: https://www.bco-dmo.org/dataset/828392
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DatasetNCBI accession metadata for 18S rRNA gene tag sequences from DNA and RNA from samples collected in coastal California in 2013 and 2014(Biological and Chemical Oceanography Data Management Office (BCO-DMO). Contact: bco-dmo-data@whoi.edu, 2019-07-24) Caron, David ; Hu, Sarah KRaw DNA and RNA V4 tag sequences include spatially and temporally distinct samples from coastal California. Samples were collected in Niskin bottles with a CTD rosette at the San Pedro Ocean Time-series (SPOT) between April of 2013 and January of 2014. This dataset contains sequence data accession numbers and metadata for the National Center for Biotechnology Information (NCBI) Sequence Read Archive (SRA) database (SRA Study ID: SRP070577, BioProject: PRJNA311248). For a complete list of measurements, refer to the full dataset description in the supplemental file 'Dataset_description.pdf'. The most current version of this dataset is available at: https://www.bco-dmo.org/dataset/745527
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DatasetMicrobial eukaryotic focused metatranscriptome data from seawater collected in coastal California in May of 2015(Biological and Chemical Oceanography Data Management Office (BCO-DMO). Contact: bco-dmo-data@whoi.edu, 2020-05-11) Caron, David ; Hu, Sarah KSeawater was collected via Niskin bottles mounted with a CTD from the San Pedro Ocean Time-series (SPOT) station off the coast of Southern California near the surface (5 m), 150 and 890 m, in late May 2015. Raw sequence data was generated as part of a metatranscriptome study targeting the protistan community. Raw sequences are available at the National Center for Biotechnology Information (NCBI) Sequence Read Archive (SRA) database (SRA Study ID: SRP110974, BioProject: PRJNA391503). Sequences for BioProject PRJNA608423 will be available at NCBI on Jan 1st, 2021. These data were published in Hu et al. (2018). For a complete list of measurements, refer to the full dataset description in the supplemental file 'Dataset_description.pdf'. The most current version of this dataset is available at: https://www.bco-dmo.org/dataset/745518
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ArticleA primer for microbiome time-series analysis(Frontiers Media, 2020-04-21) Coenen, Ashley R. ; Hu, Sarah K. ; Luo, Elaine ; Muratore, Daniel ; Weitz, Joshua S.Time-series can provide critical insights into the structure and function of microbial communities. The analysis of temporal data warrants statistical considerations, distinct from comparative microbiome studies, to address ecological questions. This primer identifies unique challenges and approaches for analyzing microbiome time-series. In doing so, we focus on (1) identifying compositionally similar samples, (2) inferring putative interactions among populations, and (3) detecting periodic signals. We connect theory, code and data via a series of hands-on modules with a motivating biological question centered on marine microbial ecology. The topics of the modules include characterizing shifts in community structure and activity, identifying expression levels with a diel periodic signal, and identifying putative interactions within a complex community. Modules are presented as self-contained, open-access, interactive tutorials in R and Matlab. Throughout, we highlight statistical considerations for dealing with autocorrelated and compositional data, with an eye to improving the robustness of inferences from microbiome time-series. In doing so, we hope that this primer helps to broaden the use of time-series analytic methods within the microbial ecology research community.
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ArticleMarine microeukaryotem metatranscriptomics: sample processing and bioinformatic workflow recommendations for ecological applications(Frontiers Media, 2022-06-28) Cohen, Natalie R. ; Alexander, Harriet ; Krinos, Arianna I. ; Hu, Sarah K. ; Lampe, Robert H.Microeukaryotes (protists) serve fundamental roles in the marine environment as contributors to biogeochemical nutrient cycling and ecosystem function. Their activities can be inferred through metatranscriptomic investigations, which provide a detailed view into cellular processes, chemical-biological interactions in the environment, and ecological relationships among taxonomic groups. Established workflows have been individually put forth describing biomass collection at sea, laboratory RNA extraction protocols, and bioinformatic processing and computational approaches. Here, we present a compilation of current practices and lessons learned in carrying out metatranscriptomics of marine pelagic protistan communities, highlighting effective strategies and tools used by practitioners over the past decade. We anticipate that these guidelines will serve as a roadmap for new marine scientists beginning in the realms of molecular biology and/or bioinformatics, and will equip readers with foundational principles needed to delve into protistan metatranscriptomics.
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ArticleDiel transcriptional oscillations of light-sensitive regulatory elements in open-ocean eukaryotic plankton communities(National Academy of Sciences, 2021-02-09) Coesel, Sacha N. ; Durham, Bryndan P. ; Groussman, Ryan D. ; Hu, Sarah K. ; Caron, David A. ; Morales, Rhonda L. ; Ribalet, François ; Armbrust, E. VirginiaThe 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.
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DatasetHigh throughput tag-sequencing accessions (18S rRNA gene region) and environmental metadata from Axial Seamount, 2013-2015(Biological and Chemical Oceanography Data Management Office (BCO-DMO). Contact: bco-dmo-data@whoi.edu, 2021-01-06) Hu, Sarah K. ; Huber, JulieHigh throughput tag-sequencing accessions (18S rRNA gene region) and environmental metadata from Axial Seamount, 2013-2015. For a complete list of measurements, refer to the full dataset description in the supplemental file 'Dataset_description.pdf'. The most current version of this dataset is available at: https://www.bco-dmo.org/dataset/828345
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DatasetOperational taxonomic unit (OTU) table for 18S rRNA gene tag sequences from DNA and RNA from samples collected in coastal California in 2013 and 2014(Biological and Chemical Oceanography Data Management Office (BCO-DMO). Contact: bco-dmo-data@whoi.edu, 2020-05-06) Caron, David ; Hu, Sarah KThis dataset is a raw output operational taxonomic unit (OTU) table generated by processing and clustering raw 18S rRNA gene tag sequences from extracted DNA and RNA. Columns represent samples, including month sampled, material (either extracted RNA or DNA), and depth (in meters); thus values in each column represent the number of sequences in that sample that belong to a given OTU (OTUs by row). Each row represents a single OTU. The last column lists the taxonomic identifier assigned to each OTU. The raw sequence data can be found in the NCBI SRA database under accession number SRP070577 with the associated BioProject PRJNA311248. For a complete list of measurements, refer to the full dataset description in the supplemental file 'Dataset_description.pdf'. The most current version of this dataset is available at: https://www.bco-dmo.org/dataset/748064
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ArticleEukaryotic genomes from a global metagenomic data set illuminate trophic modes and biogeography of ocean plankton(American Society for Microbiology, 2023-11-10) Alexander, Harriet ; Hu, Sarah K. ; Krinos, Arianna I. ; Pachiadaki, Maria G. ; Tully, Benjamin J. ; Neely, Christopher J. ; Reiter, TaylorMetagenomics is a powerful method for interpreting the ecological roles and physiological capabilities of mixed microbial communities. Yet, many tools for processing metagenomic data are neither designed to consider eukaryotes nor are they built for an increasing amount of sequence data. EukHeist is an automated pipeline to retrieve eukaryotic and prokaryotic metagenome-assembled genomes (MAGs) from large-scale metagenomic sequence data sets. We developed the EukHeist workflow to specifically process large amounts of both metagenomic and/or metatranscriptomic sequence data in an automated and reproducible fashion. Here, we applied EukHeist to the large-size fraction data (0.8–2,000 µm) from Tara Oceans to recover both eukaryotic and prokaryotic MAGs, which we refer to as TOPAZ (Tara Oceans Particle-Associated MAGs). The TOPAZ MAGs consisted of >900 environmentally relevant eukaryotic MAGs and >4,000 bacterial and archaeal MAGs. The bacterial and archaeal TOPAZ MAGs expand upon the phylogenetic diversity of likely particle- and host-associated taxa. We use these MAGs to demonstrate an approach to infer the putative trophic mode of the recovered eukaryotic MAGs. We also identify ecological cohorts of co-occurring MAGs, which are driven by specific environmental factors and putative host-microbe associations. These data together add to a number of growing resources of environmentally relevant eukaryotic genomic information. Complementary and expanded databases of MAGs, such as those provided through scalable pipelines like EukHeist, stand to advance our understanding of eukaryotic diversity through increased coverage of genomic representatives across the tree of life.
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ArticleProtistan community composition and metabolism in the North Pacific Subtropical Gyre: influences of mesoscale eddies and depth(Wiley, 2023-12-11) Gleich, Samantha J. ; Hu, Sarah K. ; Krinos, Arianna I. ; Caron, David A.Marine protists and their metabolic activities are intricately tied to the cycling of nutrients and the flow of energy through microbial food webs. Physiochemical changes in the environment, such as those that result from mesoscale eddies, may impact protistan communities, but the effects that such changes have on protists are poorly known. A metatranscriptomic study was conducted to investigate how eddies affected protists at adjacent cyclonic and anticyclonic eddy sites in the oligotrophic ocean at four depths from 25 to 250 m. Eddy polarity impacted protists at all depths sampled, although the effects of eddy polarity were secondary to the impact of depth across the depth range. Eddy-induced vertical shifts in the water column yielded differences in the cyclonic and anticyclonic eddy protistan communities, and these differences were the most pronounced at and just below the deep chlorophyll maximum. An analysis of transcripts associated with protistan nutritional physiology at 150 m revealed that cyclonic eddies may support a more heterotrophic community, while anticyclonic eddies promote a more phototrophic community. The results of this study indicate that eddies alter the metabolism of protists particularly in the lower euphotic zone and may therefore impact carbon export from the euphotic zone.