Brazelton William

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Brazelton
First Name
William
ORCID
0000-0003-0933-0148

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  • Preprint
    Archaea and bacteria with surprising microdiversity show shifts in dominance over 1,000-year time scales in hydrothermal chimneys
    ( 2009-12-06) Brazelton, William J. ; Ludwig, Kristin A. ; Sogin, Mitchell L. ; Andreishcheva, Ekaterina N. ; Kelley, Deborah S. ; Shen, Chuan-Chou ; Edwards, R. Lawrence ; Baross, John A.
    The Lost City Hydrothermal Field, an ultramafic-hosted system located 15 km west of the Mid-Atlantic Ridge, has experienced at least 30,000 years of hydrothermal activity. Previous studies have shown that its carbonate chimneys form by mixing of ~90ºC, pH 9-11 hydrothermal fluids and cold seawater. Flow of methane and hydrogen-rich hydrothermal fluids in the porous interior chimney walls supports archaeal biofilm communities dominated by a single phylotype of Methanosarcinales. In this study, we have extensively sampled the carbonate-hosted archaeal and bacterial communities by obtaining sequences of >200,000 amplicons of the 16S rRNA V6 region and correlated the results with isotopic (230Th) ages of the chimneys over a 1200 year period. Rare sequences in young chimneys were often more abundant in older chimneys, indicating that members of the rare biosphere can become dominant members of the ecosystem when environmental conditions change. These results suggest that a long history of selection over many cycles of chimney growth has resulted in numerous closely related species at Lost City, each of which is pre-adapted to a particular set of re-occurring environmental conditions. Due to the unique characteristics of the Lost City Hydrothermal Field, these data offer an unprecedented opportunity to study the dynamics of a microbial ecosystem's rare biosphere over a thousand-year time scale.
  • Article
    Metabolic strategies shared by basement residents of the lost city hydrothermal field
    (American Society for Microbiology, 2022-09-13) Brazelton, William J. ; McGonigle, Julia M. ; Motamedi, Shahrzad ; Pendleton, H. Lizethe ; Twing, Katrina I. ; Miller, Briggs C. ; Lowe, William J. ; Hoffman, Alessandrina M. ; Prator, Cecilia A. ; Chadwick, Grayson L. ; Anderson, Rika E. ; Thomas, Elaina ; Butterfield, David A. ; Aquino, Karmina A. ; Fruh-Green, Gretchen L. ; Schrenk, Matthew O. ; Lang, Susan Q.
    Alkaline fluids venting from chimneys of the Lost City hydrothermal field flow from a potentially vast microbial habitat within the seafloor where energy and organic molecules are released by chemical reactions within rocks uplifted from Earth’s mantle. In this study, we investigated hydrothermal fluids venting from Lost City chimneys as windows into subseafloor environments where the products of geochemical reactions, such as molecular hydrogen (H2), formate, and methane, may be the only available sources of energy for biological activity. Our deep sequencing of metagenomes and metatranscriptomes from these hydrothermal fluids revealed a few key species of archaea and bacteria that are likely to play critical roles in the subseafloor microbial ecosystem. We identified a population of Thermodesulfovibrionales (belonging to phylum Nitrospirota) as a prevalent sulfate-reducing bacterium that may be responsible for much of the consumption of H2 and sulfate in Lost City fluids. Metagenome-assembled genomes (MAGs) classified as Methanosarcinaceae and Candidatus Bipolaricaulota were also recovered from venting fluids and represent potential methanogenic and acetogenic members of the subseafloor ecosystem. These genomes share novel hydrogenases and formate dehydrogenase-like sequences that may be unique to hydrothermal environments where H2 and formate are much more abundant than carbon dioxide. The results of this study include multiple examples of metabolic strategies that appear to be advantageous in hydrothermal and subsurface alkaline environments where energy and carbon are provided by geochemical reactions.
  • Dataset
    Samples collected and their associated temperatures on an expedition to the Lost City hydrothermal field on R/V Atlantis cruise AT42-01 in September 2018
    (Biological and Chemical Oceanography Data Management Office (BCO-DMO). Contact: bco-dmo-data@whoi.edu, 2020-03-30) Lang, Susan Q. ; Brazelton, William ; Fruh-Green, Gretchen ; Kelley, Deborah ; Lilley, Marvin
    Summary of samples collected by the Hydrothermal Organic Geochemistry (HOG) sampler on AT-4201 with ROV Jason, on dives J2_1107 through J2_1111, during R/V Atlantic cruise AT42-01, September 9 - October 1, 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/782197
  • Preprint
    Multiple scales of diversification within natural populations of archaea in hydrothermal chimney biofilms
    ( 2009-06-17) Brazelton, William J. ; Sogin, Mitchell L. ; Baross, John A.
    Corroborative data collected from 16S rRNA clone libraries, intergenic transcribed spacer (ITS) region clone libraries, and 16S rRNA hypervariable region tag pyrosequencing demonstrate microdiversity within single-species archaeal biofilms of the Lost City Hydrothermal Field. Both 16S rRNA clone libraries and pyrosequencing of the V6 hypervariable region show that Lost City Methanosarcinales (LCMS) biofilms are dominated by a single sequence, but the pyrosequencing dataset also reveals the presence of an additional 1654 rare sequences. Clone libraries constructed with DNA spanning the V6 hypervariable region and ITS show that multiple ITS sequences are associated with the same dominant V6 sequence. Furthermore, ITS variability differed among three chimney samples, and the sample with the highest ITS diversity also contained the highest V6 diversity as measured by clone libraries as well as tag pyrosequencing. These results indicate that the extensive microdiversity detected in V6 tag sequences is an underestimate of genetic diversity within the archaeal biofilms.
  • Article
    Carbon assimilation strategies in ultrabasic groundwater: clues from the integrated study of a serpentinization-influenced aquifer
    (American Society for Microbiology, 2020-03-10) Seyler, Lauren M. ; Brazelton, William J. ; McLean, Craig ; Putman, Lindsay I. ; Hyer, Alex ; Kubo, Michael D. Y. ; Hoehler, Tori M. ; Cardace, Dawn ; Schrenk, Matthew O.
    Serpentinization is a low-temperature metamorphic process by which ultramafic rock chemically reacts with water. Such reactions provide energy and materials that may be harnessed by chemosynthetic microbial communities at hydrothermal springs and in the subsurface. However, the biogeochemistry mediated by microbial populations that inhabit these environments is understudied and complicated by overlapping biotic and abiotic processes. We applied metagenomics, metatranscriptomics, and untargeted metabolomics techniques to environmental samples taken from the Coast Range Ophiolite Microbial Observatory (CROMO), a subsurface observatory consisting of 12 wells drilled into the ultramafic and serpentinite mélange of the Coast Range Ophiolite in California. Using a combination of DNA and RNA sequence data and mass spectrometry data, we found evidence for several carbon fixation and assimilation strategies, including the Calvin-Benson-Bassham cycle, the reverse tricarboxylic acid cycle, the reductive acetyl coenzyme A (acetyl-CoA) pathway, and methylotrophy, in the microbial communities inhabiting the serpentinite-hosted aquifer. Our data also suggest that the microbial inhabitants of CROMO use products of the serpentinization process, including methane and formate, as carbon sources in a hyperalkaline environment where dissolved inorganic carbon is unavailable.
  • Article
    Impacts of deep-sea mining on microbial ecosystem services
    (Association for the Sciences of Limnology and Oceanography, 2020-01-13) Orcutt, Beth N. ; Bradley, James ; Brazelton, William J. ; Estes, Emily R. ; Goordial, Jacqueline M. ; Huber, Julie A. ; Jones, Rose M. ; Mahmoudi, Nagissa ; Marlow, Jeffrey ; Murdock, Sheryl ; Pachiadaki, Maria G.
    Interest in extracting mineral resources from the seafloor through deep‐sea mining has accelerated in the past decade, driven by consumer demand for various metals like zinc, cobalt, and rare earth elements. While there are ongoing studies evaluating potential environmental impacts of deep‐sea mining activities, these focus primarily on impacts to animal biodiversity. The microscopic spectrum of seafloor life and the services that this life provides in the deep sea are rarely considered explicitly. In April 2018, scientists met to define the microbial ecosystem services that should be considered when assessing potential impacts of deep‐sea mining, and to provide recommendations for how to evaluate and safeguard these services. Here, we indicate that the potential impacts of mining on microbial ecosystem services in the deep sea vary substantially, from minimal expected impact to loss of services that cannot be remedied by protected area offsets. For example, we (1) describe potential major losses of microbial ecosystem services at active hydrothermal vent habitats impacted by mining, (2) speculate that there could be major ecosystem service degradation at inactive massive sulfide deposits without extensive mitigation efforts, (3) suggest minor impacts to carbon sequestration within manganese nodule fields coupled with potentially important impacts to primary production capacity, and (4) surmise that assessment of impacts to microbial ecosystem services at seamounts with ferromanganese crusts is too poorly understood to be definitive. We conclude by recommending that baseline assessments of microbial diversity, biomass, and, importantly, biogeochemical function need to be considered in environmental impact assessments of deep‐sea mining.