Mason
Olivia U.
Mason
Olivia U.
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ArticleDiversity at single nucleotide to pangenome scales among sulfur cycling bacteria in salt marshes(American Society for Microbiology, 2023-10-26) Perez Castro, Sherlynette ; Peredo, Elena L. ; Mason, Olivia U. ; Vineis, Joseph H. ; Bowen, Jennifer L. ; Mortazavi, Behzad ; Ganesh, Anakha ; Ruff, S. Emil ; Paul, Blair G. ; Giblin, Anne E. ; Cardon, Zoe G.Sulfur-cycling microbial communities in salt marsh rhizosphere sediments mediate a recycling and detoxification system central to plant productivity. Despite the importance of sulfur-cycling microbes, their biogeographic, phylogenetic, and functional diversity remain poorly understood. Here, we use metagenomic data sets from Massachusetts (MA) and Alabama (AL) salt marshes to examine the distribution and genomic diversity of sulfur-cycling plant-associated microbes. Samples were collected from sediments under Sporobolus alterniflorus and Sporobolus pumilus in separate MA vegetation zones, and under S. alterniflorus and Juncus roemerianus co-occuring in AL. We grouped metagenomic data by plant species and site and identified 38 MAGs that included pathways for sulfate reduction or sulfur oxidation. Phylogenetic analyses indicated that 29 of the 38 were affiliated with uncultivated lineages. We showed differentiation in the distribution of MAGs between AL and MA, between S. alterniflorus and S. pumilus vegetation zones in MA, but no differentiation between S. alterniflorus and J. roemerianus in AL. Pangenomic analyses of eight ubiquitous MAGs also detected site- and vegetation-specific genomic features, including varied sulfur-cycling operons, carbon fixation pathways, fixed single-nucleotide variants, and active diversity-generating retroelements. This genetic diversity, detected at multiple scales, suggests evolutionary relationships affected by distance and local environment, and demonstrates differential microbial capacities for sulfur and carbon cycling in salt marsh sediments.
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ArticleDrilling constraints on lithospheric accretion and evolution at Atlantis Massif, Mid-Atlantic Ridge 30°N(American Geophysical Union, 2011-07-19) Blackman, Donna K. ; Ildefonse, Benoit ; John, Barbara E. ; Ohara, Y. ; Miller, D. J. ; Abe, Natsue ; Abratis, M. ; Andal, E. S. ; Andreani, Muriel ; Awaji, S. ; Beard, J. S. ; Brunelli, Daniele ; Charney, A. B. ; Christie, D. M. ; Collins, John A. ; Delacour, A. G. ; Delius, H. ; Drouin, M. ; Einaudi, F. ; Escartin, Javier E. ; Frost, B. R. ; Fruh-Green, Gretchen L. ; Fryer, P. B. ; Gee, Jeffrey S. ; Grimes, C. B. ; Halfpenny, A. ; Hansen, H.-E. ; Harris, Amber C. ; Tamura, A. ; Hayman, Nicholas W. ; Hellebrand, Eric ; Hirose, T. ; Hirth, Greg ; Ishimaru, S. ; Johnson, Kevin T. M. ; Karner, G. D. ; Linek, M. ; MacLeod, Christopher J. ; Maeda, J. ; Mason, Olivia U. ; McCaig, A. M. ; Michibayashi, K. ; Morris, Antony ; Nakagawa, T. ; Nozaka, Toshio ; Rosner, Martin ; Searle, Roger C. ; Suhr, G. ; Tominaga, Masako ; von der Handt, A. ; Yamasaki, T. ; Zhao, XixiExpeditions 304 and 305 of the Integrated Ocean Drilling Program cored and logged a 1.4 km section of the domal core of Atlantis Massif. Postdrilling research results summarized here constrain the structure and lithology of the Central Dome of this oceanic core complex. The dominantly gabbroic sequence recovered contrasts with predrilling predictions; application of the ground truth in subsequent geophysical processing has produced self-consistent models for the Central Dome. The presence of many thin interfingered petrologic units indicates that the intrusions forming the domal core were emplaced over a minimum of 100–220 kyr, and not as a single magma pulse. Isotopic and mineralogical alteration is intense in the upper 100 m but decreases in intensity with depth. Below 800 m, alteration is restricted to narrow zones surrounding faults, veins, igneous contacts, and to an interval of locally intense serpentinization in olivine-rich troctolite. Hydration of the lithosphere occurred over the complete range of temperature conditions from granulite to zeolite facies, but was predominantly in the amphibolite and greenschist range. Deformation of the sequence was remarkably localized, despite paleomagnetic indications that the dome has undergone at least 45° rotation, presumably during unroofing via detachment faulting. Both the deformation pattern and the lithology contrast with what is known from seafloor studies on the adjacent Southern Ridge of the massif. There, the detachment capping the domal core deformed a 100 m thick zone and serpentinized peridotite comprises ∼70% of recovered samples. We develop a working model of the evolution of Atlantis Massif over the past 2 Myr, outlining several stages that could explain the observed similarities and differences between the Central Dome and the Southern Ridge.