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Geng L, Yang L, Liu T, Zhang S, Sun X, Wang W, Pan H, Yan L. Higher diversity of sulfur-oxidizing bacteria based on soxB gene sequencing in surface water than in spring in Wudalianchi volcanic group, NE China. Int Microbiol 2024:10.1007/s10123-024-00526-6. [PMID: 38740654 DOI: 10.1007/s10123-024-00526-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2023] [Revised: 04/26/2024] [Accepted: 05/03/2024] [Indexed: 05/16/2024]
Abstract
INTRODUCTION Sulfur-oxidizing bacteria (SOB) play a key role in the biogeochemical cycling of sulfur. OBJECTIVES To explore SOB diversity, distribution, and physicochemical drivers in five volcanic lakes and two springs in the Wudalianchi volcanic field, China. METHODS This study analyzed microbial communities in samples via high-throughput sequencing of the soxB gene. Physical-chemical parameters were measured, and QIIME 2 (v2019.4), R, Vsearch, MEGA7, and Mothur processed the data. Alpha diversity indices and UPGMA clustering assessed community differences, while heat maps visualized intra-sample variations. Canoco 5.0 analyzed community-environment correlations, and NMDS, Adonis, and PcoA explored sample dissimilarities and environmental factor correlations. SPSS v.18.0 tested for statistical significance. RESULTS The diversity of SOB in surface water was higher than in springs (more than 7.27 times). We detected SOB affiliated to β-proteobacteria (72.3 %), α-proteobacteria (22.8 %), and γ-proteobacteria (4.2 %) distributed widely in these lakes and springs. Rhodoferax and Cupriavidus were most frequent in all water samples, while Rhodoferax and Bradyrhizobium are dominant in surface waters but rare in springs. SOB genera in both habitats were positively correlated. Co-occurrence analysis identified Bradyrhizobium, Blastochloris, Methylibium, and Metyhlobacterium as potential keystone taxa. Redundancy analysis (RDA) revealed positive correlations between SOB diversity and total carbon (TC), Fe2+, and total nitrogen (TN) in all water samples. CONCLUSION The diversity and community structure of SOB in volcanic lakes and springs in the Wudalianchi volcanic group were clarified. Moreover, the diversity and abundance of SOB decreased with the variation of water openness, from open lakes to semi-enclosed lakes and enclosed lakes.
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Affiliation(s)
- Lirong Geng
- Heilongjiang Provincial Key Laboratory of Environmental Microbiology and Recycling of Argo-Waste in Cold Region, College of Life Science and Biotechnology, Heilongjiang Bayi Agricultural University, Daqing, 163319, Heilongjiang, China
| | - Lei Yang
- Heilongjiang Provincial Key Laboratory of Environmental Microbiology and Recycling of Argo-Waste in Cold Region, College of Life Science and Biotechnology, Heilongjiang Bayi Agricultural University, Daqing, 163319, Heilongjiang, China
| | - Tao Liu
- Heilongjiang Provincial Key Laboratory of Environmental Microbiology and Recycling of Argo-Waste in Cold Region, College of Life Science and Biotechnology, Heilongjiang Bayi Agricultural University, Daqing, 163319, Heilongjiang, China
| | - Shuang Zhang
- Heilongjiang Provincial Key Laboratory of Environmental Microbiology and Recycling of Argo-Waste in Cold Region, College of Life Science and Biotechnology, Heilongjiang Bayi Agricultural University, Daqing, 163319, Heilongjiang, China
| | - Xindi Sun
- Heilongjiang Provincial Key Laboratory of Environmental Microbiology and Recycling of Argo-Waste in Cold Region, College of Life Science and Biotechnology, Heilongjiang Bayi Agricultural University, Daqing, 163319, Heilongjiang, China
| | - Weidong Wang
- Heilongjiang Provincial Key Laboratory of Environmental Microbiology and Recycling of Argo-Waste in Cold Region, College of Life Science and Biotechnology, Heilongjiang Bayi Agricultural University, Daqing, 163319, Heilongjiang, China
- Key Laboratory of Low‑carbon Green Agriculture in Northeastern China, Ministry of Agriculture and Rural Affairs P. R. China, Heilongjiang Bayi Agricultural University, Daqing, 163319, China
| | - Hong Pan
- Institute of Natural Resources and Ecology, Heilongjiang Academy of Science, Harbin, 150090, Heilongjiang, China
| | - Lei Yan
- Heilongjiang Provincial Key Laboratory of Environmental Microbiology and Recycling of Argo-Waste in Cold Region, College of Life Science and Biotechnology, Heilongjiang Bayi Agricultural University, Daqing, 163319, Heilongjiang, China.
- Key Laboratory of Low‑carbon Green Agriculture in Northeastern China, Ministry of Agriculture and Rural Affairs P. R. China, Heilongjiang Bayi Agricultural University, Daqing, 163319, China.
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Astorch-Cardona A, Odin GP, Chavagnac V, Dolla A, Gaussier H, Rommevaux C. Linking Zetaproteobacterial diversity and substratum type in iron-rich microbial mats from the Lucky Strike hydrothermal field (EMSO-Azores observatory). Appl Environ Microbiol 2024; 90:e0204123. [PMID: 38193671 PMCID: PMC10880625 DOI: 10.1128/aem.02041-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2023] [Accepted: 12/01/2023] [Indexed: 01/10/2024] Open
Abstract
Zetaproteobacteria have been reported in different marine and terrestrial environments all over the globe. They play an essential role in marine iron-rich microbial mats, as one of their autotrophic primary producers, oxidizing Fe(II) and producing Fe-oxyhydroxides with different morphologies. Here, we study and compare the Zetaproteobacterial communities of iron-rich microbial mats from six different sites of the Lucky Strike Hydrothermal Field through the use of the Zetaproteobacterial operational taxonomic unit (ZetaOTU) classification. We report for the first time the Zetaproteobacterial core microbiome of these iron-rich microbial mats, which is composed of four ZetaOTUs that are cosmopolitan and essential for the development of the mats. The study of the presence and abundance of different ZetaOTUs among sites reveals two clusters, which are related to the lithology and permeability of the substratum on which they develop. The Zetaproteobacterial communities of cluster 1 are characteristic of poorly permeable substrata, with little evidence of diffuse venting, while those of cluster 2 develop on hydrothermal slabs or deposits that allow the percolation and outflow of diffuse hydrothermal fluids. In addition, two NewZetaOTUs 1 and 2 were identified, which could be characteristic of anthropic iron and unsedimented basalt, respectively. We also report significant correlations between the abundance of certain ZetaOTUs and that of iron oxide morphologies, indicating that their formation could be taxonomically and/or environmentally driven. We identified a new morphology of Fe(III)-oxyhydroxides that we named "corals." Overall, our work contributes to the knowledge of the biogeography of this bacterial class by providing additional data from the Atlantic Ocean, a lesser-studied ocean in terms of Zetaproteobacterial diversity.IMPORTANCEUp until now, Zetaproteobacterial diversity studies have revealed possible links between Zetaproteobacteria taxa, habitats, and niches. Here, we report for the first time the Zetaproteobacterial core microbiome of iron-rich mats from the Lucky Strike Hydrothermal Field (LSHF), as well as two new Zetaproteobacterial operational taxonomic units (NewZetaOTUs) that could be substratum specific. We highlight that the substratum on which iron-rich microbial mats develop, especially because of its permeability to diffuse hydrothermal venting, has an influence on their Zetaproteobacterial communities. Moreover, our work adds to the knowledge of the biogeography of this bacterial class by providing additional data from the hydrothermal vent sites along the Mid-Atlantic Ridge. In addition to the already described iron oxide morphologies, we identify in our iron-rich mats a new morphology that we named corals. Finally, we argue for significant correlations between the relative abundance of certain ZetaOTUs and that of iron oxide morphologies, contributing to the understanding of the drivers of iron oxide production in iron-oxidizing bacteria.
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Affiliation(s)
- Aina Astorch-Cardona
- Aix-Marseille University, Université de Toulon, CNRS, IRD, MIO, Marseille, France
| | - Giliane P. Odin
- Laboratoire Géomatériaux et Environnement, Université Gustave Eiffel, Marne-la-Vallée, France
| | - Valérie Chavagnac
- Géosciences Environnement Toulouse, CNRS UMR 5563 (CNRS/UPS/IRD/CNES), Université de Toulouse, Observatoire Midi-Pyrénées, Toulouse, France
| | - Alain Dolla
- Aix-Marseille University, Université de Toulon, CNRS, IRD, MIO, Marseille, France
| | - Hélène Gaussier
- Aix-Marseille University, Université de Toulon, CNRS, IRD, MIO, Marseille, France
| | - Céline Rommevaux
- Aix-Marseille University, Université de Toulon, CNRS, IRD, MIO, Marseille, France
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Hribovšek P, Olesin Denny E, Dahle H, Mall A, Øfstegaard Viflot T, Boonnawa C, Reeves EP, Steen IH, Stokke R. Putative novel hydrogen- and iron-oxidizing sheath-producing Zetaproteobacteria thrive at the Fåvne deep-sea hydrothermal vent field. mSystems 2023; 8:e0054323. [PMID: 37921472 PMCID: PMC10734525 DOI: 10.1128/msystems.00543-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2023] [Accepted: 10/02/2023] [Indexed: 11/04/2023] Open
Abstract
IMPORTANCE Knowledge on microbial iron oxidation is important for understanding the cycling of iron, carbon, nitrogen, nutrients, and metals. The current study yields important insights into the niche sharing, diversification, and Fe(III) oxyhydroxide morphology of Ghiorsea, an iron- and hydrogen-oxidizing Zetaproteobacteria representative belonging to Zetaproteobacteria operational taxonomic unit 9. The study proposes that Ghiorsea exhibits a more extensive morphology of Fe(III) oxyhydroxide than previously observed. Overall, the results increase our knowledge on potential drivers of Zetaproteobacteria diversity in iron microbial mats and can eventually be used to develop strategies for the cultivation of sheath-forming Zetaproteobacteria.
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Affiliation(s)
- Petra Hribovšek
- Centre for Deep Sea Research, University of Bergen, Bergen, Norway
- Department of Earth Science, University of Bergen, Bergen, Norway
| | - Emily Olesin Denny
- Centre for Deep Sea Research, University of Bergen, Bergen, Norway
- Department of Biological Sciences, University of Bergen, Bergen, Norway
- Computational Biology Unit, University of Berge, Bergen, Norway
| | - Håkon Dahle
- Centre for Deep Sea Research, University of Bergen, Bergen, Norway
- Department of Biological Sciences, University of Bergen, Bergen, Norway
- Computational Biology Unit, University of Berge, Bergen, Norway
| | - Achim Mall
- Centre for Deep Sea Research, University of Bergen, Bergen, Norway
- Department of Biological Sciences, University of Bergen, Bergen, Norway
| | - Thomas Øfstegaard Viflot
- Centre for Deep Sea Research, University of Bergen, Bergen, Norway
- Department of Earth Science, University of Bergen, Bergen, Norway
| | - Chanakan Boonnawa
- Centre for Deep Sea Research, University of Bergen, Bergen, Norway
- Department of Earth Science, University of Bergen, Bergen, Norway
| | - Eoghan P. Reeves
- Centre for Deep Sea Research, University of Bergen, Bergen, Norway
- Department of Earth Science, University of Bergen, Bergen, Norway
| | - Ida Helene Steen
- Centre for Deep Sea Research, University of Bergen, Bergen, Norway
- Department of Biological Sciences, University of Bergen, Bergen, Norway
| | - Runar Stokke
- Centre for Deep Sea Research, University of Bergen, Bergen, Norway
- Department of Biological Sciences, University of Bergen, Bergen, Norway
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Demaret L, Hutchinson IB, Ingley R, Edwards HGM, Fagel N, Compere P, Javaux EJ, Eppe G, Malherbe C. Fe-Rich Fossil Vents as Mars Analog Samples: Identification of Extinct Chimneys in Miocene Marine Sediments Using Raman Spectroscopy, X-Ray Diffraction, and Scanning Electron Microscopy-Energy Dispersive X-Ray Spectroscopy. ASTROBIOLOGY 2022; 22:1081-1098. [PMID: 35704291 DOI: 10.1089/ast.2021.0128] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
On Earth, the circulation of Fe-rich fluids in hydrothermal environments leads to characteristic iron mineral deposits, reflecting the pH and redox chemical conditions of the hydrothermal system, and is often associated with chemotroph microorganisms capable of deriving energy from chemical gradients. On Mars, iron-rich hydrothermal sites are considered to be potentially important astrobiological targets for searching evidence of life during exploration missions, such as the Mars 2020 and the ExoMars 2022 missions. In this study, an extinct hydrothermal chimney from the Jaroso hydrothermal system (SE Spain), considered an interesting geodynamic and mineralogical terrestrial analog for Mars, was analyzed using Raman spectroscopy, X-ray diffraction, and scanning electron microscopy coupled with energy dispersive X-ray spectroscopy. The sample consists of a fossil vent in a Miocene shallow-marine sedimentary deposit composed of a marl substrate, an iron-rich chimney pipe, and a central space filled with backfilling deposits and vent condensates. The iron crust is particularly striking due to the combined presence of molecular and morphological indications of a microbial colonization, including mineral microstructures (e.g., stalks, filaments), iron oxyhydroxide phases (altered goethite, ferrihydrite), and organic signatures (carotenoids, organopolymers). The clear identification of pigments by resonance Raman spectroscopy and the preservation of organics in association with iron oxyhydroxides by Raman microimaging demonstrate that the iron crust was indeed colonized by microbial communities. These analyses confirm that Raman spectroscopy is a powerful tool for documenting the habitability of such historical hydrothermal environments. Finally, based on the results obtained, we propose that the ancient iron-rich hydrothermal pipes should be recognized as singular terrestrial Mars analog specimens to support the preparatory work for robotic in situ exploration missions to Mars, as well as during the subsequent interpretation of data returned by those missions.
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Affiliation(s)
- Lucas Demaret
- Mass Spectrometry Laboratory, MolSys Research Unit, University of Liege, Liege, Belgium
- Early Life Traces & Evolution-Astrobiology, UR Astrobiology, University of Liege, Liege, Belgium
| | - Ian B Hutchinson
- Department of Physics and Astronomy, University of Leicester, Leicester, United Kingdom
| | - Richard Ingley
- Department of Physics and Astronomy, University of Leicester, Leicester, United Kingdom
| | - Howell G M Edwards
- Department of Physics and Astronomy, University of Leicester, Leicester, United Kingdom
| | - Nathalie Fagel
- Laboratory Argiles, Géochimie et Environnements Sédimentaires, University of Liege, Liege, Belgium
| | - Philippe Compere
- Laboratory of Functional and Evolutionary Morphology, UR FOCUS, and Centre for Applied Research and Education in Microscopy (CAREM), University of Liege, Liege, Belgium
| | - Emmanuelle J Javaux
- Early Life Traces & Evolution-Astrobiology, UR Astrobiology, University of Liege, Liege, Belgium
| | - Gauthier Eppe
- Mass Spectrometry Laboratory, MolSys Research Unit, University of Liege, Liege, Belgium
| | - Cédric Malherbe
- Mass Spectrometry Laboratory, MolSys Research Unit, University of Liege, Liege, Belgium
- Early Life Traces & Evolution-Astrobiology, UR Astrobiology, University of Liege, Liege, Belgium
- Department of Physics and Astronomy, University of Leicester, Leicester, United Kingdom
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Little CTS, Johannessen KC, Bengtson S, Chan CS, Ivarsson M, Slack JF, Broman C, Thorseth IH, Grenne T, Rouxel OJ, Bekker A. A late Paleoproterozoic (1.74 Ga) deep-sea, low-temperature, iron-oxidizing microbial hydrothermal vent community from Arizona, USA. GEOBIOLOGY 2021; 19:228-249. [PMID: 33594795 DOI: 10.1111/gbi.12434] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2020] [Revised: 01/18/2021] [Accepted: 02/01/2021] [Indexed: 06/12/2023]
Abstract
Modern marine hydrothermal vents occur in a wide variety of tectonic settings and are characterized by seafloor emission of fluids rich in dissolved chemicals and rapid mineral precipitation. Some hydrothermal systems vent only low-temperature Fe-rich fluids, which precipitate deposits dominated by iron oxyhydroxides, in places together with Mn-oxyhydroxides and amorphous silica. While a proportion of this mineralization is abiogenic, most is the result of the metabolic activities of benthic, Fe-oxidizing bacteria (FeOB), principally belonging to the Zetaproteobacteria. These micro-organisms secrete micrometer-scale stalks, sheaths, and tubes with a variety of morphologies, composed largely of ferrihydrite that act as sacrificial structures, preventing encrustation of the cells that produce them. Cultivated marine FeOB generally require neutral pH and microaerobic conditions to grow. Here, we describe the morphology and mineralogy of filamentous microstructures from a late Paleoproterozoic (1.74 Ga) jasper (Fe-oxide-silica) deposit from the Jerome area of the Verde mining district in central Arizona, USA, that resemble the branching tubes formed by some modern marine FeOB. On the basis of this comparison, we interpret the Jerome area filaments as having formed by FeOB on the deep seafloor, at the interface of weakly oxygenated seawater and low-temperature Fe-rich hydrothermal fluids. We compare the Jerome area filaments with other purported examples of Precambrian FeOB and discuss the implications of their presence for existing redox models of Paleoproterozoic oceans during the "Boring Billion."
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Affiliation(s)
| | | | - Stefan Bengtson
- Department of Palaeobiology, Swedish Museum of Natural History, Stockholm, Sweden
| | - Clara S Chan
- Department of Earth Sciences, University of Delaware, Newark, USA
| | - Magnus Ivarsson
- Department of Palaeobiology, Swedish Museum of Natural History, Stockholm, Sweden
- Department of Biology, University of Southern Denmark, Odense M, Denmark
| | - John F Slack
- U.S. Geological Survey (Emeritus), National Center, Reston, USA
| | - Curt Broman
- Department of Geological Sciences, Stockholm University, Stockholm, Sweden
| | | | - Tor Grenne
- Geological Survey of Norway, Trondheim, Norway
| | | | - Andrey Bekker
- Department of Earth and Planetary Sciences, University of California, Riverside, USA
- Department of Geology, University of Johannesburg, Johannesburg, South Africa
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Muturi SM, Muthui LW, Njogu PM, Onguso JM, Wachira FN, Opiyo SO, Pelle R. Metagenomics survey unravels diversity of biogas microbiomes with potential to enhance productivity in Kenya. PLoS One 2021; 16:e0244755. [PMID: 33395690 PMCID: PMC7781671 DOI: 10.1371/journal.pone.0244755] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Accepted: 12/16/2020] [Indexed: 12/27/2022] Open
Abstract
The obstacle to optimal utilization of biogas technology is poor understanding of biogas microbiomes diversities over a wide geographical coverage. We performed random shotgun sequencing on twelve environmental samples. Randomized complete block design was utilized to assign the twelve treatments to four blocks, within eastern and central regions of Kenya. We obtained 42 million paired-end reads that were annotated against sixteen reference databases using two ENVO ontologies, prior to β-diversity studies. We identified 37 phyla, 65 classes and 132 orders. Bacteria dominated and comprised 28 phyla, 42 classes and 92 orders, conveying substrate's versatility in the treatments. Though, Fungi and Archaea comprised 5 phyla, the Fungi were richer; suggesting the importance of hydrolysis and fermentation in biogas production. High β-diversity within the taxa was largely linked to communities' metabolic capabilities. Clostridiales and Bacteroidales, the most prevalent guilds, metabolize organic macromolecules. The identified Cytophagales, Alteromonadales, Flavobacteriales, Fusobacteriales, Deferribacterales, Elusimicrobiales, Chlamydiales, Synergistales to mention but few, also catabolize macromolecules into smaller substrates to conserve energy. Furthermore, δ-Proteobacteria, Gloeobacteria and Clostridia affiliates syntrophically regulate PH2 and reduce metal to provide reducing equivalents. Methanomicrobiales and other Methanomicrobia species were the most prevalence Archaea, converting formate, CO2(g), acetate and methylated substrates into CH4(g). Thermococci, Thermoplasmata and Thermoprotei were among the sulfur and other metal reducing Archaea that contributed to redox balancing and other metabolism within treatments. Eukaryotes, mainly fungi were the least abundant guild, comprising largely Ascomycota and Basidiomycota species. Chytridiomycetes, Blastocladiomycetes and Mortierellomycetes were among the rare species, suggesting their metabolic and substrates limitations. Generally, we observed that environmental and treatment perturbations influenced communities' abundance, β-diversity and reactor performance largely through stochastic effect. Understanding diversity of biogas microbiomes over wide environmental variables and its' productivity provided insights into better management strategies that ameliorate biochemical limitations to effective biogas production.
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Affiliation(s)
- Samuel Mwangangi Muturi
- Department of Biological Sciences, University of Eldoret, Eldoret, Kenya
- Institute for Bioteschnology Research, Jomo Kenyatta University of Agriculture and Technology, Juja, Kenya
| | - Lucy Wangui Muthui
- Biosciences Eastern and Central Africa—International Livestock Research Institute (BecA-ILRI) Hub, Nairobi, Kenya
| | - Paul Mwangi Njogu
- Institute for Energy and Environmental Technology, Jomo Kenyatta University of Agriculture and Technology, Juja, Kenya
| | - Justus Mong’are Onguso
- Institute for Bioteschnology Research, Jomo Kenyatta University of Agriculture and Technology, Juja, Kenya
| | | | - Stephen Obol Opiyo
- OARDC, Molecular and Cellular Imaging Center-Columbus, Ohio State University, Columbus, Ohio, United States of America
- The University of Sacread Heart, Gulu, Uganda
| | - Roger Pelle
- Biosciences Eastern and Central Africa—International Livestock Research Institute (BecA-ILRI) Hub, Nairobi, Kenya
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McAllister SM, Polson SW, Butterfield DA, Glazer BT, Sylvan JB, Chan CS. Validating the Cyc2 Neutrophilic Iron Oxidation Pathway Using Meta-omics of Zetaproteobacteria Iron Mats at Marine Hydrothermal Vents. mSystems 2020; 5:e00553-19. [PMID: 32071158 PMCID: PMC7029218 DOI: 10.1128/msystems.00553-19] [Citation(s) in RCA: 51] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2019] [Accepted: 01/22/2020] [Indexed: 01/04/2023] Open
Abstract
Zetaproteobacteria create extensive iron (Fe) oxide mats at marine hydrothermal vents, making them an ideal model for microbial Fe oxidation at circumneutral pH. Comparison of neutrophilic Fe oxidizer isolate genomes has revealed a hypothetical Fe oxidation pathway, featuring a homolog of the Fe oxidase Cyc2 from Acidithiobacillus ferrooxidans However, Cyc2 function is not well verified in neutrophilic Fe oxidizers, particularly in Fe-oxidizing environments. Toward this, we analyzed genomes and metatranscriptomes of Zetaproteobacteria, using 53 new high-quality metagenome-assembled genomes reconstructed from Fe mats at Mid-Atlantic Ridge, Mariana Backarc, and Loihi Seamount (Hawaii) hydrothermal vents. Phylogenetic analysis demonstrated conservation of Cyc2 sequences among most neutrophilic Fe oxidizers, suggesting a common function. We confirmed the widespread distribution of cyc2 and other model Fe oxidation pathway genes across all represented Zetaproteobacteria lineages. High expression of these genes was observed in diverse Zetaproteobacteria under multiple environmental conditions and in incubations. The putative Fe oxidase gene cyc2 was highly expressed in situ, often as the top expressed gene. The cyc2 gene showed increased expression in Fe(II)-amended incubations, with corresponding increases in carbon fixation and central metabolism gene expression. These results substantiate the Cyc2-based Fe oxidation pathway in neutrophiles and demonstrate its significance in marine Fe-mineralizing environments.IMPORTANCE Iron oxides are important components of our soil, water supplies, and ecosystems, as they sequester nutrients, carbon, and metals. Microorganisms can form iron oxides, but it is unclear whether this is a significant mechanism in the environment. Unlike other major microbial energy metabolisms, there is no marker gene for iron oxidation, hindering our ability to track these microbes. Here, we investigate a promising possible iron oxidation gene, cyc2, in iron-rich hydrothermal vents, where iron-oxidizing microbes dominate. We pieced together diverse Zetaproteobacteria genomes, compared these genomes, and analyzed expression of cyc2 and other hypothetical iron oxidation genes. We show that cyc2 is widespread among iron oxidizers and is highly expressed and potentially regulated, making it a good marker for the capacity for iron oxidation and potentially a marker for activity. These findings will help us understand and potentially quantify the impacts of neutrophilic iron oxidizers in a wide variety of marine and terrestrial environments.
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Affiliation(s)
- Sean M McAllister
- School of Marine Science and Policy, University of Delaware, Newark, Delaware, USA
| | - Shawn W Polson
- Center for Bioinformatics and Computational Biology, University of Delaware, Newark, Delaware, USA
| | - David A Butterfield
- Joint Institute for the Study of Atmosphere and Ocean, University of Washington, Seattle, Washington, USA
- Pacific Marine Environmental Laboratory, National Oceanic and Atmospheric Administration, Seattle, Washington, USA
| | - Brian T Glazer
- Department of Oceanography, University of Hawai'i, Honolulu, Hawai'i, USA
| | - Jason B Sylvan
- Department of Oceanography, Texas A&M University, College Station, Texas, USA
| | - Clara S Chan
- School of Marine Science and Policy, University of Delaware, Newark, Delaware, USA
- Department of Earth Sciences, University of Delaware, Newark, Delaware, USA
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Tobias-Hünefeldt SP, Wing SR, Espinel-Velasco N, Baltar F, Morales SE. Depth and location influence prokaryotic and eukaryotic microbial community structure in New Zealand fjords. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 693:133507. [PMID: 31377366 DOI: 10.1016/j.scitotenv.2019.07.313] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2019] [Revised: 07/19/2019] [Accepted: 07/19/2019] [Indexed: 06/10/2023]
Abstract
Systems with strong horizontal and vertical gradients, such as fjords, are useful models for studying environmental forcing. Here we examine microbial (prokaryotic and eukaryotic) community changes associated with the surface low salinity layer (LSL) and underlying seawater in multiple fjords in Fiordland National Park (New Zealand). High rainfall (1200-8000 mm annually) and linked runoff from native forested catchments results in surface LSLs with high tannin concentrations within each fjord. These gradients are expected to drive changes in microbial communities. We used amplicon sequencing (16S and 18S) to assess the impact of these gradients on microbial communities and identified depth linked changes in diversity and community structure. With increasing depth, we observed significant increases in Proteobacteria (15%) and SAR (37%), decreases in Opisthokonta (35%), and transiently increased Bacteroidetes (3% increase from 0 to 40 m, decreasing by 8% at 200 m). Community structure differences were observed along a transect from the head to the mouth, specifically 25% mean relative abundance decreases in Opisthokonta and Bacteroidetes, and increases in SAR (25%) and Proteobacteria (>5%) at the surface, indicating changes based on distance from the ocean. This provides the first in-depth view into the ecological drivers of microbial communities within New Zealand fjords.
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Affiliation(s)
- Sven P Tobias-Hünefeldt
- Department of Microbiology and Immunology, University of Otago, PO Box 56, Dunedin 9054, New Zealand
| | - Stephen R Wing
- Department of Marine Science, University of Otago, PO Box 56, Dunedin 9054, New Zealand
| | | | - Federico Baltar
- Department of Marine Science, University of Otago, PO Box 56, Dunedin 9054, New Zealand; Department of Limnology and Oceanography, Division of Bio-Oceanography, University of Vienna, Althanstrasse 14, A-1090 Vienna, Austria.
| | - Sergio E Morales
- Department of Microbiology and Immunology, University of Otago, PO Box 56, Dunedin 9054, New Zealand.
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