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Parsons RJ, Liu S, Longnecker K, Yongblah K, Johnson C, Bolaños LM, Comstock J, Opalk K, Kido Soule MC, Garley R, Carlson CA, Temperton B, Bates NR. Suboxic DOM is bioavailable to surface prokaryotes in a simulated overturn of an oxygen minimum zone, Devil's Hole, Bermuda. Front Microbiol 2023; 14:1287477. [PMID: 38179459 PMCID: PMC10765504 DOI: 10.3389/fmicb.2023.1287477] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2023] [Accepted: 11/17/2023] [Indexed: 01/06/2024] Open
Abstract
Oxygen minimum zones (OMZs) are expanding due to increased sea surface temperatures, subsequent increased oxygen demand through respiration, reduced oxygen solubility, and thermal stratification driven in part by anthropogenic climate change. Devil's Hole, Bermuda is a model ecosystem to study OMZ microbial biogeochemistry because the formation and subsequent overturn of the suboxic zone occur annually. During thermally driven stratification, suboxic conditions develop, with organic matter and nutrients accumulating at depth. In this study, the bioavailability of the accumulated dissolved organic carbon (DOC) and the microbial community response to reoxygenation of suboxic waters was assessed using a simulated overturn experiment. The surface inoculated prokaryotic community responded to the deep (formerly suboxic) 0.2 μm filtrate with cell densities increasing 2.5-fold over 6 days while removing 5 μmol L-1 of DOC. After 12 days, the surface community began to shift, and DOC quality became less diagenetically altered along with an increase in SAR202, a Chloroflexi that can degrade recalcitrant dissolved organic matter (DOM). Labile DOC production after 12 days coincided with an increase of Nitrosopumilales, a chemoautotrophic ammonia oxidizing archaea (AOA) that converts ammonia to nitrite based on the ammonia monooxygenase (amoA) gene copy number and nutrient data. In comparison, the inoculation of the deep anaerobic prokaryotic community into surface 0.2 μm filtrate demonstrated a die-off of 25.5% of the initial inoculum community followed by a 1.5-fold increase in cell densities over 6 days. Within 2 days, the prokaryotic community shifted from a Chlorobiales dominated assemblage to a surface-like heterotrophic community devoid of Chlorobiales. The DOM quality changed to less diagenetically altered material and coincided with an increase in the ribulose-1,5-bisphosphate carboxylase/oxygenase form I (cbbL) gene number followed by an influx of labile DOM. Upon reoxygenation, the deep DOM that accumulated under suboxic conditions is bioavailable to surface prokaryotes that utilize the accumulated DOC initially before switching to a community that can both produce labile DOM via chemoautotrophy and degrade the more recalcitrant DOM.
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Affiliation(s)
- Rachel J. Parsons
- Microbial Ecology Laboratory, Bermuda Institute of Ocean Sciences, St. George’s, Bermuda
- Julie Ann Wrigley Global Futures Laboratory, School of Ocean Futures, Arizona State University, Tempe, AZ, United States
| | - Shuting Liu
- Department of Ecology, Evolution and Marine Biology, Marine Science Institute, University of California, Santa Barbara, California, CA, United States
- Department of Environmental and Sustainability Sciences, Kean University, Union, NJ, United States
| | - Krista Longnecker
- Department of Marine Chemistry and Geochemistry, Woods Hole Oceanographic Institution, Woods Hole, MA, United States
| | - Kevin Yongblah
- Microbial Ecology Laboratory, Bermuda Institute of Ocean Sciences, St. George’s, Bermuda
- Department of Biology, University of Syracuse, Syracuse, NY, United States
| | - Carys Johnson
- Microbial Ecology Laboratory, Bermuda Institute of Ocean Sciences, St. George’s, Bermuda
| | - Luis M. Bolaños
- School of Biosciences, University of Exeter, Exeter, United Kingdom
| | - Jacqueline Comstock
- Department of Ecology, Evolution and Marine Biology, Marine Science Institute, University of California, Santa Barbara, California, CA, United States
| | - Keri Opalk
- Department of Ecology, Evolution and Marine Biology, Marine Science Institute, University of California, Santa Barbara, California, CA, United States
| | - Melissa C. Kido Soule
- Department of Marine Chemistry and Geochemistry, Woods Hole Oceanographic Institution, Woods Hole, MA, United States
| | - Rebecca Garley
- Microbial Ecology Laboratory, Bermuda Institute of Ocean Sciences, St. George’s, Bermuda
- Julie Ann Wrigley Global Futures Laboratory, School of Ocean Futures, Arizona State University, Tempe, AZ, United States
| | - Craig A. Carlson
- Department of Ecology, Evolution and Marine Biology, Marine Science Institute, University of California, Santa Barbara, California, CA, United States
| | - Ben Temperton
- School of Biosciences, University of Exeter, Exeter, United Kingdom
| | - Nicholas R. Bates
- Microbial Ecology Laboratory, Bermuda Institute of Ocean Sciences, St. George’s, Bermuda
- Julie Ann Wrigley Global Futures Laboratory, School of Ocean Futures, Arizona State University, Tempe, AZ, United States
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Vipindas PV, Jabir T, Venkatachalam S, Yang EJ, Jain A, Krishnan KP. Vertical segregation and phylogenetic characterization of archaea and archaeal ammonia monooxygenase gene in the water column of the western Arctic Ocean. Extremophiles 2023; 27:24. [PMID: 37668803 DOI: 10.1007/s00792-023-01310-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Accepted: 08/21/2023] [Indexed: 09/06/2023]
Abstract
Archaea constitute a substantial fraction of marine microbial biomass and play critical roles in the biogeochemistry of oceans. However, studies on their distribution and ecology in the Arctic Ocean are relatively scarce. Here, we studied the distributions of archaea and archaeal ammonia monooxygenase (amoA) gene in the western Arctic Ocean, using the amplicon sequencing approach from the sea surface to deep waters up to 3040 m depth. A total of five archaeal phyla, Nitrososphaerota, "Euryarchaeota", "Halobacteriota," "Nanoarchaeota", and Candidatus Thermoplasmatota, were detected. We observed a clear, depth-dependent vertical segregation among archaeal communities. Ca. Thermoplasmatota (66.8%) was the most dominant phylum in the surface waters. At the same time, Nitrososphaerota (55.9%) was dominant in the deep waters. Most of the amoA gene OTUs (99%) belonged to the Nitrosopumilales and were further clustered into five subclades ("NP-Alpha", "NP-Delta", "NP-Epsilon", "NP-Gamma", and "NP-Theta"). "NP-Epsilon" was the most dominant clade throughout the water column and "NP_Alpha" showed higher abundance only in the deeper water. Salinity and inorganic nutrient concentrations were the major factors that determined the vertical segregation of archaea. We anticipate that the observed differences in the vertical distribution of archaea might contribute to the compartmentalization of dark carbon fixation and nitrification in deeper water and organic matter degradation in surface waters of the Arctic Ocean.
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Affiliation(s)
- Puthiya Veettil Vipindas
- Arctic Ecology and Biogeochemistry Division, Ministry of Earth Sciences, National Centre for Polar and Ocean Research, Vasco-da-Gama, Goa, 403 804, India.
| | - Thajudeen Jabir
- Arctic Ecology and Biogeochemistry Division, Ministry of Earth Sciences, National Centre for Polar and Ocean Research, Vasco-da-Gama, Goa, 403 804, India
| | - Siddarthan Venkatachalam
- Arctic Ecology and Biogeochemistry Division, Ministry of Earth Sciences, National Centre for Polar and Ocean Research, Vasco-da-Gama, Goa, 403 804, India
| | - Eun Jin Yang
- Division of Ocean Sciences, Korea Polar Research Institute, 26 Songdo-dong, Yeonsu-gu, Incheon, 21990, Republic of Korea
| | - Anand Jain
- Arctic Ecology and Biogeochemistry Division, Ministry of Earth Sciences, National Centre for Polar and Ocean Research, Vasco-da-Gama, Goa, 403 804, India
| | - Kottekkatu Padinchati Krishnan
- Arctic Ecology and Biogeochemistry Division, Ministry of Earth Sciences, National Centre for Polar and Ocean Research, Vasco-da-Gama, Goa, 403 804, India
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3
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Bayer B, McBeain K, Carlson CA, Santoro AE. Carbon content, carbon fixation yield and dissolved organic carbon release from diverse marine nitrifiers. LIMNOLOGY AND OCEANOGRAPHY 2023; 68:84-96. [PMID: 37064272 PMCID: PMC10092583 DOI: 10.1002/lno.12252] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Revised: 09/27/2022] [Accepted: 10/12/2022] [Indexed: 06/19/2023]
Abstract
Nitrifying microorganisms, including ammonia-oxidizing archaea, ammonia-oxidizing bacteria, and nitrite-oxidizing bacteria, are the most abundant chemoautotrophs in the ocean and play an important role in the global carbon cycle by fixing dissolved inorganic carbon (DIC) into biomass. The release of organic compounds by these microbes is not well quantified, but may represent an as-yet unaccounted source of dissolved organic carbon (DOC) available to marine food webs. Here, we provide measurements of cellular carbon and nitrogen quotas, DIC fixation yields and DOC release of 10 phylogenetically diverse marine nitrifiers. All investigated strains released DOC during growth, representing on average 5-15% of the fixed DIC. Changes in substrate concentration and temperature did not affect the proportion of fixed DIC released as DOC, but release rates varied between closely related species. Our results also indicate previous studies may have underestimated DIC fixation yields of marine nitrite oxidizers due to partial decoupling of nitrite oxidation from CO2 fixation, and due to lower observed yields in artificial compared to natural seawater medium. The results of this study provide critical values for biogeochemical models of the global carbon cycle, and help to further constrain the implications of nitrification-fueled chemoautotrophy for marine food-web functioning and the biological sequestration of carbon in the ocean.
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Affiliation(s)
- Barbara Bayer
- Department of Ecology, Evolution and Marine BiologyUniversity of CaliforniaSanta BarbaraCalifornia
- Present address:
Department of Microbiology and Ecosystem ScienceUniversity of ViennaViennaAustria
| | - Kelsey McBeain
- Department of Ecology, Evolution and Marine BiologyUniversity of CaliforniaSanta BarbaraCalifornia
- Present address:
Department of OceanographyUniversity of Hawai'i at ManoaHonoluluHawaii
| | - Craig A. Carlson
- Department of Ecology, Evolution and Marine BiologyUniversity of CaliforniaSanta BarbaraCalifornia
| | - Alyson E. Santoro
- Department of Ecology, Evolution and Marine BiologyUniversity of CaliforniaSanta BarbaraCalifornia
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4
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Woo Y, Cruz MC, Wuertz S. Selective Enrichment of Nitrososphaera viennensis-Like Ammonia-Oxidizing Archaea over Ammonia-Oxidizing Bacteria from Drinking Water Biofilms. Microbiol Spectr 2022; 10:e0184522. [PMID: 36445127 PMCID: PMC9769795 DOI: 10.1128/spectrum.01845-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Accepted: 11/08/2022] [Indexed: 12/03/2022] Open
Abstract
Ammonia-oxidizing archaea (AOA) can oxidize ammonia to nitrite for energy gain. They have been detected in chloraminated drinking water distribution systems (DWDS) along with the more common ammonia-oxidizing bacteria (AOB) and nitrite-oxidizing bacteria (NOB). To date, no members of the AOA have been isolated or enriched from drinking water environments. To begin the investigation of the role of AOA in chloraminated DWDS, we developed a selective approach using biofilm samples from a full-scale operational network as inoculum. A Nitrososphaera viennensis-like AOA taxon was enriched from a mixed community that also included Nitrosomonas-like AOB while gradually scaling up the culture volume. Dimethylthiourea (DMTU) and pyruvate at 100 μM were added to promote the growth of AOA while inhibiting AOB. This resulted in the eventual washout of AOB, while NOB were absent after 2 or 3 rounds of amendment with 24 μM sodium azide. The relative abundance of AOA in the enrichment increased from 0.2% to 39.5% after adding DMTU and pyruvate, and further to 51.6% after filtration through a 0.45-μm pore size membrane, within a period of approximately 6 months. IMPORTANCE Chloramination has been known to increase the risk of nitrification episodes in DWDS due to the presence of ammonia-oxidizing microorganisms. Among them, AOB are more frequently detected than AOA. All publicly available cultures of AOA have been isolated from soil, marine or surface water environments, meaning they are allochthonous to DWDS. Hence, monochloramine exposure studies involving these strains may not accurately reflect their role in DWDS. The described method allows for the rapid enrichment of autochthonous AOA from drinking water nitrifying communities. The high relative abundance of AOA in the resulting enrichment culture reduces any confounding effects of co-existing heterotrophic bacteria when investigating the response of AOA to varied levels of monochloramine in drinking water.
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Affiliation(s)
- Yissue Woo
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
- Singapore Centre for Environmental Life Sciences Engineering, Interdisciplinary Graduate Programme, Nanyang Technological University, Singapore, Singapore
- School of Civil and Environmental Engineering, Nanyang Technological University, Singapore, Singapore
| | - Mercedes Cecilia Cruz
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
| | - Stefan Wuertz
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
- School of Civil and Environmental Engineering, Nanyang Technological University, Singapore, Singapore
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5
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LaBrie R, Péquin B, Fortin St-Gelais N, Yashayaev I, Cherrier J, Gélinas Y, Guillemette F, Podgorski DC, Spencer RGM, Tremblay L, Maranger R. Deep ocean microbial communities produce more stable dissolved organic matter through the succession of rare prokaryotes. SCIENCE ADVANCES 2022; 8:eabn0035. [PMID: 35857452 DOI: 10.1126/sciadv.abn0035] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
The microbial carbon pump (MCP) hypothesis suggests that successive transformation of labile dissolved organic carbon (DOC) by prokaryotes produces refractory DOC (RDOC) and contributes to the long-term stability of the deep ocean DOC reservoir. We tested the MCP by exposing surface water from a deep convective region of the ocean to epipelagic, mesopelagic, and bathypelagic prokaryotic communities and tracked changes in dissolved organic matter concentration, composition, and prokaryotic taxa over time. Prokaryotic taxa from the deep ocean were more efficient at consuming DOC and producing RDOC as evidenced by greater abundance of highly oxygenated molecules and fluorescent components associated with recalcitrant molecules. This first empirical evidence of the MCP in natural waters shows that carbon sequestration is more efficient in deeper waters and suggests that the higher diversity of prokaryotes from the rare biosphere holds a greater metabolic potential in creating these stable dissolved organic compounds.
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Affiliation(s)
- Richard LaBrie
- Département des sciences biologiques, Université de Montréal, Pavillon MIL C. P. 6128, succ. Centre-ville, Montréal, QC H3C 3J7, Canada
- Groupe de recherche interuniversitaire en limnologie et environnement aquatique (GRIL), Université de Montréal, C. P. 6128, succ. Centre-ville, Montréal, QC H3C 3J7, Canada
| | - Bérangère Péquin
- Département des sciences biologiques, Université de Montréal, Pavillon MIL C. P. 6128, succ. Centre-ville, Montréal, QC H3C 3J7, Canada
- Groupe de recherche interuniversitaire en limnologie et environnement aquatique (GRIL), Université de Montréal, C. P. 6128, succ. Centre-ville, Montréal, QC H3C 3J7, Canada
| | - Nicolas Fortin St-Gelais
- Département des sciences biologiques, Université de Montréal, Pavillon MIL C. P. 6128, succ. Centre-ville, Montréal, QC H3C 3J7, Canada
- Groupe de recherche interuniversitaire en limnologie et environnement aquatique (GRIL), Université de Montréal, C. P. 6128, succ. Centre-ville, Montréal, QC H3C 3J7, Canada
| | - Igor Yashayaev
- Department of Fisheries and Ocean Canada, Bedford Institute of Oceanography, 1 Challenger Dr., Dartmouth, NS B2Y 4A2, Canada
| | - Jennifer Cherrier
- Department of Earth and Environmental Sciences, Brooklyn College-The City University of New York, 2900 Bedford Avenue, Brooklyn, NY 11210, USA
| | - Yves Gélinas
- Geotop and Department of Chemistry and Biochemistry, Concordia University, 7141 Sherbrooke W., Montréal, QC H4B 1R6, Canada
| | - François Guillemette
- Groupe de recherche interuniversitaire en limnologie et environnement aquatique (GRIL), Université de Montréal, C. P. 6128, succ. Centre-ville, Montréal, QC H3C 3J7, Canada
- Département des sciences de l'environnement, Université du Québec à Trois-Rivières, 3351 Boulevard des Forges, Trois-Rivières, QC G8Z 4M3, Canada
| | - David C Podgorski
- Pontchartrain Institute for Environmental Sciences, Department of Chemistry, The University of New Orleans, 2000 Lakeshore Dr., New Orleans, LA 70148, USA
| | - Robert G M Spencer
- National High Magnetic Field Laboratory, Geochemistry Group, Department of Earth, Ocean and Atmospheric Science, Florida State University, Tallahassee, FL 32306, USA
| | - Luc Tremblay
- Département de chimie et biochimie, Université de Moncton, 18, avenue Antonine-Maillet, Moncton, NB E1A 3E9, Canada
| | - Roxane Maranger
- Département des sciences biologiques, Université de Montréal, Pavillon MIL C. P. 6128, succ. Centre-ville, Montréal, QC H3C 3J7, Canada
- Groupe de recherche interuniversitaire en limnologie et environnement aquatique (GRIL), Université de Montréal, C. P. 6128, succ. Centre-ville, Montréal, QC H3C 3J7, Canada
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6
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Cathalot C, Roussel EG, Perhirin A, Creff V, Donval JP, Guyader V, Roullet G, Gula J, Tamburini C, Garel M, Godfroy A, Sarradin PM. Hydrothermal plumes as hotspots for deep-ocean heterotrophic microbial biomass production. Nat Commun 2021; 12:6861. [PMID: 34824206 PMCID: PMC8617075 DOI: 10.1038/s41467-021-26877-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Accepted: 10/19/2021] [Indexed: 11/09/2022] Open
Abstract
Carbon budgets of hydrothermal plumes result from the balance between carbon sinks through plume chemoautotrophic processes and carbon release via microbial respiration. However, the lack of comprehensive analysis of the metabolic processes and biomass production rates hinders an accurate estimate of their contribution to the deep ocean carbon cycle. Here, we use a biogeochemical model to estimate the autotrophic and heterotrophic production rates of microbial communities in hydrothermal plumes and validate it with in situ data. We show how substrate limitation might prevent net chemolithoautotrophic production in hydrothermal plumes. Elevated prokaryotic heterotrophic production rates (up to 0.9 gCm-2y-1) compared to the surrounding seawater could lead to 0.05 GtCy-1 of C-biomass produced through chemoorganotrophy within hydrothermal plumes, similar to the Particulate Organic Carbon (POC) export fluxes reported in the deep ocean. We conclude that hydrothermal plumes must be accounted for as significant deep sources of POC in ocean carbon budgets.
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Affiliation(s)
- Cécile Cathalot
- Laboratoire Cycles Géochimiques et ressources - LCG/GM/REM, Ifremer, Plouzané, France.
| | - Erwan G. Roussel
- grid.4825.b0000 0004 0641 9240Laboratoire de Microbiologie des Environnements Extrêmes – LMEE/EEP/REM, Ifremer, Plouzané, France
| | - Antoine Perhirin
- grid.4825.b0000 0004 0641 9240Laboratoire Environnement Profond – LEP/EEP/REM, IFREMER, Plouzané, France
| | - Vanessa Creff
- grid.4825.b0000 0004 0641 9240Laboratoire de Microbiologie des Environnements Extrêmes – LMEE/EEP/REM, Ifremer, Plouzané, France
| | - Jean-Pierre Donval
- grid.4825.b0000 0004 0641 9240Laboratoire Cycles Géochimiques et ressources – LCG/GM/REM, Ifremer, Plouzané, France
| | - Vivien Guyader
- grid.4825.b0000 0004 0641 9240Laboratoire Cycles Géochimiques et ressources – LCG/GM/REM, Ifremer, Plouzané, France
| | - Guillaume Roullet
- Univ Brest, CNRS, IRD, Ifremer, Laboratoire d’Océanographie Physique et Spatiale (LOPS), IUEM, Plouzané, France
| | - Jonathan Gula
- Univ Brest, CNRS, IRD, Ifremer, Laboratoire d’Océanographie Physique et Spatiale (LOPS), IUEM, Plouzané, France ,grid.440891.00000 0001 1931 4817Institut Universitaire de France (IUF), Paris, France
| | - Christian Tamburini
- Aix-Marseille Univ, Université de Toulon, CNRS, IRD, MIO UM110 Marseille, France
| | - Marc Garel
- Aix-Marseille Univ, Université de Toulon, CNRS, IRD, MIO UM110 Marseille, France
| | - Anne Godfroy
- grid.4825.b0000 0004 0641 9240Laboratoire de Microbiologie des Environnements Extrêmes – LMEE/EEP/REM, Ifremer, Plouzané, France
| | - Pierre-Marie Sarradin
- grid.4825.b0000 0004 0641 9240Laboratoire Environnement Profond – LEP/EEP/REM, IFREMER, Plouzané, France
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7
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Genderjahn S, Lewin S, Horn F, Schleicher AM, Mangelsdorf K, Wagner D. Living Lithic and Sublithic Bacterial Communities in Namibian Drylands. Microorganisms 2021; 9:235. [PMID: 33498742 PMCID: PMC7911874 DOI: 10.3390/microorganisms9020235] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2020] [Revised: 01/17/2021] [Accepted: 01/20/2021] [Indexed: 12/26/2022] Open
Abstract
Dryland xeric conditions exert a deterministic effect on microbial communities, forcing life into refuge niches. Deposited rocks can form a lithic niche for microorganisms in desert regions. Mineral weathering is a key process in soil formation and the importance of microbial-driven mineral weathering for nutrient extraction is increasingly accepted. Advances in geobiology provide insight into the interactions between microorganisms and minerals that play an important role in weathering processes. In this study, we present the examination of the microbial diversity in dryland rocks from the Tsauchab River banks in Namibia. We paired culture-independent 16S rRNA gene amplicon sequencing with culture-dependent (isolation of bacteria) techniques to assess the community structure and diversity patterns. Bacteria isolated from dryland rocks are typical of xeric environments and are described as being involved in rock weathering processes. For the first time, we extracted extra- and intracellular DNA from rocks to enhance our understanding of potentially rock-weathering microorganisms. We compared the microbial community structure in different rock types (limestone, quartz-rich sandstone and quartz-rich shale) with adjacent soils below the rocks. Our results indicate differences in the living lithic and sublithic microbial communities.
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Affiliation(s)
- Steffi Genderjahn
- GFZ German Research Centre for Geosciences, Section Geomicrobiology, Telegrafenberg, 14473 Potsdam, Germany; (S.L.); (F.H.); (D.W.)
| | - Simon Lewin
- GFZ German Research Centre for Geosciences, Section Geomicrobiology, Telegrafenberg, 14473 Potsdam, Germany; (S.L.); (F.H.); (D.W.)
| | - Fabian Horn
- GFZ German Research Centre for Geosciences, Section Geomicrobiology, Telegrafenberg, 14473 Potsdam, Germany; (S.L.); (F.H.); (D.W.)
| | - Anja M. Schleicher
- GFZ German Research Centre for Geosciences, Section Organic Geochemistry, Telegrafenberg, 14473 Potsdam, Germany;
| | - Kai Mangelsdorf
- GFZ German Research Centre for Geosciences, Section Anorganic Chemistry, Telegrafenberg, 14473 Potsdam, Germany;
| | - Dirk Wagner
- GFZ German Research Centre for Geosciences, Section Geomicrobiology, Telegrafenberg, 14473 Potsdam, Germany; (S.L.); (F.H.); (D.W.)
- Institute of Geosciences, University of Potsdam, 14476 Potsdam, Germany
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8
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Adyasari D, Hassenrück C, Montiel D, Dimova N. Microbial community composition across a coastal hydrological system affected by submarine groundwater discharge (SGD). PLoS One 2020; 15:e0235235. [PMID: 32598345 PMCID: PMC7323985 DOI: 10.1371/journal.pone.0235235] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Accepted: 06/10/2020] [Indexed: 11/18/2022] Open
Abstract
Mobile Bay, the fourth largest estuary in the USA located in the northern Gulf of Mexico, is known for extreme hypoxia in the water column during dry season caused by NH4+-rich and anoxic submarine groundwater discharge (SGD). Nutrient dynamics in the coastal ecosystem point to potentially elevated microbial activities; however, little is known about microbial community composition and their functional roles in this area. In this study, we investigated microbial community composition, distribution, and metabolic prediction along the coastal hydrological compartment of Mobile Bay using 16S rRNA gene sequencing. We collected microbial samples from surface (river and bay water) and subsurface water (groundwater and coastal pore water from two SGD sites with peat and sandy lithology, respectively). Salinity was identified as the primary factor affecting the distribution of microbial communities across surface water samples, while DON and PO43- were the major predictor of community shift within subsurface water samples. Higher microbial diversity was found in coastal pore water in comparison to surface water samples. Gammaproteobacteria, Bacteroidia, and Oxyphotobacteria dominated the bacterial community. Among the archaea, methanogens were prevalent in the peat-dominated SGD site, while the sandy SGD site was characterized by a higher proportion of ammonia-oxidizing archaea. Cyanobium PCC-6307 and unclassified Thermodesulfovibrionia were identified as dominant taxa strongly associated with trends in environmental parameters in surface and subsurface samples, respectively. Microbial communities found in the groundwater and peat layer consisted of taxa known for denitrification and dissimilatory nitrate reduction to ammonium (DNRA). This finding suggested that microbial communities might also play a significant role in mediating nitrogen transformation in the SGD flow path and in affecting the chemical composition of SGD discharging to the water column. Given the ecological importance of microorganisms, further studies at higher taxonomic and functional resolution are needed to accurately predict chemical biotransformation processes along the coastal hydrological continuum, which influence water quality and environmental condition in Mobile Bay.
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Affiliation(s)
- Dini Adyasari
- Department of Biogeochemistry and Geology, Leibniz Centre for Tropical Marine Research, Bremen, Germany
| | - Christiane Hassenrück
- Department of Biogeochemistry and Geology, Leibniz Centre for Tropical Marine Research, Bremen, Germany
| | - Daniel Montiel
- Department of Geological Sciences, Coastal Hydrogeology Laboratory, University of Alabama, Alabama, AL, United States of America
- Geosyntec Consultants, Clearwater, FL, United States of America
| | - Natasha Dimova
- Department of Geological Sciences, Coastal Hydrogeology Laboratory, University of Alabama, Alabama, AL, United States of America
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9
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Sun Y, Liu Y, Pan J, Wang F, Li M. Perspectives on Cultivation Strategies of Archaea. MICROBIAL ECOLOGY 2020; 79:770-784. [PMID: 31432245 DOI: 10.1007/s00248-019-01422-7] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Accepted: 08/01/2019] [Indexed: 06/10/2023]
Abstract
Archaea have been recognized as a major domain of life since the 1970s and occupy a key position in the tree of life. Recent advances in culture-independent approaches have greatly accelerated the research son Archaea. However, many hypotheses concerning the diversity, physiology, and evolution of archaea are waiting to be confirmed by culture-base experiments. Consequently, archaeal isolates are in great demand. On the other hand, traditional approaches of archaeal cultivation are rarely successful and require urgent improvement. Here, we review the current practices and applicable microbial cultivation techniques, to inform on potential strategies that could improve archaeal cultivation in the future. We first summarize the current knowledge on archaeal diversity, with an emphasis on cultivated and uncultivated lineages pertinent to future research. Possible causes for the low success rate of the current cultivation practices are then discussed to propose future improvements. Finally, innovative insights for archaeal cultivation are described, including (1) medium refinement for selective cultivation based on the genetic and transcriptional information; (2) consideration of the up-to-date archaeal culturing skills; and (3) application of multiple cultivation techniques, such as co-culture, direct interspecies electron transfer (DIET), single-cell isolation, high-throughput culturing (HTC), and simulation of the natural habitat. Improved cultivation efforts should allow successful isolation of as yet uncultured archaea, contributing to the much-needed physiological investigation of archaea.
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Affiliation(s)
- Yihua Sun
- Institute for Advanced Study, Shenzhen University, Shenzhen, Guangdong, People's Republic of China
- Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Optoelectronic Engineering, Shenzhen University, Shenzhen, Guangdong, People's Republic of China
| | - Yang Liu
- Institute for Advanced Study, Shenzhen University, Shenzhen, Guangdong, People's Republic of China
| | - Jie Pan
- Institute for Advanced Study, Shenzhen University, Shenzhen, Guangdong, People's Republic of China
| | - Fengping Wang
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, People's Republic of China
- State Key Laboratory of Ocean Engineering, Shanghai Jiao Tong University, Shanghai, People's Republic of China
| | - Meng Li
- Institute for Advanced Study, Shenzhen University, Shenzhen, Guangdong, People's Republic of China.
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10
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Single cell analyses reveal contrasting life strategies of the two main nitrifiers in the ocean. Nat Commun 2020; 11:767. [PMID: 32034151 PMCID: PMC7005884 DOI: 10.1038/s41467-020-14542-3] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2019] [Accepted: 01/17/2020] [Indexed: 11/11/2022] Open
Abstract
Nitrification, the oxidation of ammonia via nitrite to nitrate, is a key process in marine nitrogen (N) cycling. Although oceanic ammonia and nitrite oxidation are balanced, ammonia-oxidizing archaea (AOA) vastly outnumber the main nitrite oxidizers, the bacterial Nitrospinae. The ecophysiological reasons for this discrepancy in abundance are unclear. Here, we compare substrate utilization and growth of Nitrospinae to AOA in the Gulf of Mexico. Based on our results, more than half of the Nitrospinae cellular N-demand is met by the organic-N compounds urea and cyanate, while AOA mainly assimilate ammonium. Nitrospinae have, under in situ conditions, around four-times higher biomass yield and five-times higher growth rates than AOA, despite their ten-fold lower abundance. Our combined results indicate that differences in mortality between Nitrospinae and AOA, rather than thermodynamics, biomass yield and cell size, determine the abundances of these main marine nitrifiers. Furthermore, there is no need to invoke yet undiscovered, abundant nitrite oxidizers to explain nitrification rates in the ocean. Ammonia oxidizing archaea and Nitrospinae are the main known nitrifiers in the ocean, but the much greater abundance of the former is puzzling. Here, the authors show that differences in mortality, rather than thermodynamics, cell size or biomass yield, explain the discrepancy, without the need to invoke yet undiscovered, abundant nitrite oxidizers.
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11
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Dekas AE, Parada AE, Mayali X, Fuhrman JA, Wollard J, Weber PK, Pett-Ridge J. Characterizing Chemoautotrophy and Heterotrophy in Marine Archaea and Bacteria With Single-Cell Multi-isotope NanoSIP. Front Microbiol 2019; 10:2682. [PMID: 31920997 PMCID: PMC6927911 DOI: 10.3389/fmicb.2019.02682] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2019] [Accepted: 11/05/2019] [Indexed: 11/28/2022] Open
Abstract
Characterizing and quantifying in situ metabolisms remains both a central goal and challenge for environmental microbiology. Here, we used a single-cell, multi-isotope approach to investigate the anabolic activity of marine microorganisms, with an emphasis on natural populations of Thaumarchaeota. After incubating coastal Pacific Ocean water with 13C-bicarbonate and 15N-amino acids, we used nanoscale secondary ion mass spectrometry (nanoSIMS) to isotopically screen 1,501 individual cells, and 16S rRNA amplicon sequencing to assess community composition. We established isotopic enrichment thresholds for activity and metabolic classification, and with these determined the percentage of anabolically active cells, the distribution of activity across the whole community, and the metabolic lifestyle—chemoautotrophic or heterotrophic—of each cell. Most cells (>90%) were anabolically active during the incubation, and 4–17% were chemoautotrophic. When we inhibited bacteria with antibiotics, the fraction of chemoautotrophic cells detected via nanoSIMS increased, suggesting archaea dominated chemoautotrophy. With fluorescence in situ hybridization coupled to nanoSIMS (FISH-nanoSIMS), we confirmed that most Thaumarchaeota were living chemoautotrophically, while bacteria were not. FISH-nanoSIMS analysis of cells incubated with dual-labeled (13C,15N-) amino acids revealed that most Thaumarchaeota cells assimilated amino-acid-derived nitrogen but not carbon, while bacteria assimilated both. This indicates that some Thaumarchaeota do not assimilate intact amino acids, suggesting intra-phylum heterogeneity in organic carbon utilization, and potentially their use of amino acids for nitrification. Together, our results demonstrate the utility of multi-isotope nanoSIMS analysis for high-throughput metabolic screening, and shed light on the activity and metabolism of uncultured marine archaea and bacteria.
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Affiliation(s)
- Anne E Dekas
- Department of Earth System Science, Stanford University, Stanford, CA, United States.,Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, CA, United States
| | - Alma E Parada
- Department of Earth System Science, Stanford University, Stanford, CA, United States.,Department of Biological Sciences, University of Southern California, Los Angeles, CA, United States
| | - Xavier Mayali
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, CA, United States
| | - Jed A Fuhrman
- Department of Biological Sciences, University of Southern California, Los Angeles, CA, United States
| | - Jessica Wollard
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, CA, United States
| | - Peter K Weber
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, CA, United States
| | - Jennifer Pett-Ridge
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, CA, United States
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12
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Wang S, Zheng X, Xia H, Shi D, Fan J, Wang P, Yan Z. Archaeal community variation in the Qinhuangdao coastal aquaculture zone revealed by high-throughput sequencing. PLoS One 2019; 14:e0218611. [PMID: 31226149 PMCID: PMC6588238 DOI: 10.1371/journal.pone.0218611] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2019] [Accepted: 06/05/2019] [Indexed: 11/18/2022] Open
Abstract
The differences in archaeal diversity and community composition in the sediments and waters of the Qinhuangdao coastal aquaculture zone were investigated. Furthermore, the associations between dominant archaeal taxa with geographic and environmental variables were evaluated. High-throughput sequencing of archaeal 16S rRNA genes yielded a total of 176,211 quality-filtered reads and 1,178 operational taxonomic units (OTUs) overall. The most abundant phylum and class among all communities were Thaumarchaeota and Nitrososphaeria, respectively. Beta diversity analysis indicated that community composition was divided into two groups according to the habitat type (i.e., sediments or waters). Only 9.8% OTUs were shared by communities from the two habitats, while 73.9% and 16.3% of the OTUs were unique to sediment or water communities, respectively. Furthermore, the relative abundances of the dominant OTUs differed with habitat type. Investigations of relationships between dominant OTUs and environmental variables indicated that some dominant OTUs were more sensitive to variation in environmental factors, which could be due to individual taxonomic differences in lifestyles and biological processes. Overall, the investigation of archaeal community variation within the Qinhuangdao coastal aquaculture zone provides an important baseline understanding of the microbial ecology in this important ecosystem.
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Affiliation(s)
- Shuping Wang
- State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing, China
| | - Xin Zheng
- State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing, China
| | - Huijuan Xia
- State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing, China
| | - Di Shi
- State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing, China
| | - Juntao Fan
- State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing, China
| | - Pengyuan Wang
- State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing, China
| | - Zhenguang Yan
- State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing, China
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13
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Abstract
Archaea are ubiquitous and abundant members of the marine plankton. Once thought of as rare organisms found in exotic extremes of temperature, pressure, or salinity, archaea are now known in nearly every marine environment. Though frequently referred to collectively, the planktonic archaea actually comprise four major phylogenetic groups, each with its own distinct physiology and ecology. Only one group-the marine Thaumarchaeota-has cultivated representatives, making marine archaea an attractive focus point for the latest developments in cultivation-independent molecular methods. Here, we review the ecology, physiology, and biogeochemical impact of the four archaeal groups using recent insights from cultures and large-scale environmental sequencing studies. We highlight key gaps in our knowledge about the ecological roles of marine archaea in carbon flow and food web interactions. We emphasize the incredible uncultivated diversity within each of the four groups, suggesting there is much more to be done.
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Affiliation(s)
- Alyson E Santoro
- Department of Ecology, Evolution, and Marine Biology, University of California, Santa Barbara, California 93106, USA;
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14
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Kitzinger K, Padilla CC, Marchant HK, Hach PF, Herbold CW, Kidane AT, Könneke M, Littmann S, Mooshammer M, Niggemann J, Petrov S, Richter A, Stewart FJ, Wagner M, Kuypers MMM, Bristow LA. Cyanate and urea are substrates for nitrification by Thaumarchaeota in the marine environment. Nat Microbiol 2018; 4:234-243. [PMID: 30531977 DOI: 10.1038/s41564-018-0316-2] [Citation(s) in RCA: 61] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2017] [Accepted: 10/30/2018] [Indexed: 02/01/2023]
Abstract
Ammonia-oxidizing archaea of the phylum Thaumarchaeota are among the most abundant marine microorganisms1. These organisms thrive in the oceans despite ammonium being present at low nanomolar concentrations2,3. Some Thaumarchaeota isolates have been shown to utilize urea and cyanate as energy and N sources through intracellular conversion to ammonium4-6. Yet, it is unclear whether patterns observed in culture extend to marine Thaumarchaeota, and whether Thaumarchaeota in the ocean directly utilize urea and cyanate or rely on co-occurring microorganisms to break these substrates down to ammonium. Urea utilization has been reported for marine ammonia-oxidizing communities7-10, but no evidence of cyanate utilization exists for marine ammonia oxidizers. Here, we demonstrate that in the Gulf of Mexico, Thaumarchaeota use urea and cyanate both directly and indirectly as energy and N sources. We observed substantial and linear rates of nitrite production from urea and cyanate additions, which often persisted even when ammonium was added to micromolar concentrations. Furthermore, single-cell analysis revealed that the Thaumarchaeota incorporated ammonium-, urea- and cyanate-derived N at significantly higher rates than most other microorganisms. Yet, no cyanases were detected in thaumarchaeal genomic data from the Gulf of Mexico. Therefore, we tested cyanate utilization in Nitrosopumilus maritimus, which also lacks a canonical cyanase, and showed that cyanate was oxidized to nitrite. Our findings demonstrate that marine Thaumarchaeota can use urea and cyanate as both an energy and N source. On the basis of these results, we hypothesize that urea and cyanate are substrates for ammonia-oxidizing Thaumarchaeota throughout the ocean.
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Affiliation(s)
- Katharina Kitzinger
- Max Planck Institute for Marine Microbiology, Bremen, Germany.,Department of Microbiology and Ecosystem Science, University of Vienna, Vienna, Austria
| | - Cory C Padilla
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA, USA
| | | | - Philipp F Hach
- Max Planck Institute for Marine Microbiology, Bremen, Germany
| | - Craig W Herbold
- Department of Microbiology and Ecosystem Science, University of Vienna, Vienna, Austria
| | - Abiel T Kidane
- Max Planck Institute for Marine Microbiology, Bremen, Germany
| | - Martin Könneke
- Marine Archaea Group, MARUM - Center for Marine Environmental Sciences & Department of Geosciences, University of Bremen, Bremen, Germany
| | - Sten Littmann
- Max Planck Institute for Marine Microbiology, Bremen, Germany
| | - Maria Mooshammer
- Department of Microbiology and Ecosystem Science, University of Vienna, Vienna, Austria
| | - Jutta Niggemann
- Research Group for Marine Geochemistry (ICBM-MPI Bridging Group), Institute for Chemistry and Biology of the Marine Environment, Carl von Ossietzky University Oldenburg, Oldenburg, Germany
| | - Sandra Petrov
- Marine Archaea Group, MARUM - Center for Marine Environmental Sciences & Department of Geosciences, University of Bremen, Bremen, Germany
| | - Andreas Richter
- Department of Microbiology and Ecosystem Science, University of Vienna, Vienna, Austria
| | - Frank J Stewart
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA, USA
| | - Michael Wagner
- Department of Microbiology and Ecosystem Science, University of Vienna, Vienna, Austria
| | | | - Laura A Bristow
- Max Planck Institute for Marine Microbiology, Bremen, Germany.,Department of Biology and Nordic Center for Earth Evolution (NordCEE), University of Southern Denmark, Odense, Denmark
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15
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Daebeler A, Herbold CW, Vierheilig J, Sedlacek CJ, Pjevac P, Albertsen M, Kirkegaard RH, de la Torre JR, Daims H, Wagner M. Cultivation and Genomic Analysis of " Candidatus Nitrosocaldus islandicus," an Obligately Thermophilic, Ammonia-Oxidizing Thaumarchaeon from a Hot Spring Biofilm in Graendalur Valley, Iceland. Front Microbiol 2018; 9:193. [PMID: 29491853 PMCID: PMC5817080 DOI: 10.3389/fmicb.2018.00193] [Citation(s) in RCA: 61] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2017] [Accepted: 01/29/2018] [Indexed: 11/21/2022] Open
Abstract
Ammonia-oxidizing archaea (AOA) within the phylum Thaumarchaeota are the only known aerobic ammonia oxidizers in geothermal environments. Although molecular data indicate the presence of phylogenetically diverse AOA from the Nitrosocaldus clade, group 1.1b and group 1.1a Thaumarchaeota in terrestrial high-temperature habitats, only one enrichment culture of an AOA thriving above 50°C has been reported and functionally analyzed. In this study, we physiologically and genomically characterized a newly discovered thaumarchaeon from the deep-branching Nitrosocaldaceae family of which we have obtained a high (∼85%) enrichment from biofilm of an Icelandic hot spring (73°C). This AOA, which we provisionally refer to as "Candidatus Nitrosocaldus islandicus," is an obligately thermophilic, aerobic chemolithoautotrophic ammonia oxidizer, which stoichiometrically converts ammonia to nitrite at temperatures between 50 and 70°C. "Ca. N. islandicus" encodes the expected repertoire of enzymes proposed to be required for archaeal ammonia oxidation, but unexpectedly lacks a nirK gene and also possesses no identifiable other enzyme for nitric oxide (NO) generation. Nevertheless, ammonia oxidation by this AOA appears to be NO-dependent as "Ca. N. islandicus" is, like all other tested AOA, inhibited by the addition of an NO scavenger. Furthermore, comparative genomics revealed that "Ca. N. islandicus" has the potential for aromatic amino acid fermentation as its genome encodes an indolepyruvate oxidoreductase (iorAB) as well as a type 3b hydrogenase, which are not present in any other sequenced AOA. A further surprising genomic feature of this thermophilic ammonia oxidizer is the absence of DNA polymerase D genes - one of the predominant replicative DNA polymerases in all other ammonia-oxidizing Thaumarchaeota. Collectively, our findings suggest that metabolic versatility and DNA replication might differ substantially between obligately thermophilic and other AOA.
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Affiliation(s)
- Anne Daebeler
- Division of Microbial Ecology, Department of Microbiology and Ecosystem Science, Research Network “Chemistry meets Microbiology”, University of Vienna, Vienna, Austria
| | - Craig W. Herbold
- Division of Microbial Ecology, Department of Microbiology and Ecosystem Science, Research Network “Chemistry meets Microbiology”, University of Vienna, Vienna, Austria
| | - Julia Vierheilig
- Division of Microbial Ecology, Department of Microbiology and Ecosystem Science, Research Network “Chemistry meets Microbiology”, University of Vienna, Vienna, Austria
| | - Christopher J. Sedlacek
- Division of Microbial Ecology, Department of Microbiology and Ecosystem Science, Research Network “Chemistry meets Microbiology”, University of Vienna, Vienna, Austria
| | - Petra Pjevac
- Division of Microbial Ecology, Department of Microbiology and Ecosystem Science, Research Network “Chemistry meets Microbiology”, University of Vienna, Vienna, Austria
| | - Mads Albertsen
- Department of Chemistry and Bioscience, Center for Microbial Communities, Aalborg University, Aalborg, Denmark
| | - Rasmus H. Kirkegaard
- Department of Chemistry and Bioscience, Center for Microbial Communities, Aalborg University, Aalborg, Denmark
| | - José R. de la Torre
- Department of Biology, San Francisco State University, San Francisco, CA, United States
| | - Holger Daims
- Division of Microbial Ecology, Department of Microbiology and Ecosystem Science, Research Network “Chemistry meets Microbiology”, University of Vienna, Vienna, Austria
| | - Michael Wagner
- Division of Microbial Ecology, Department of Microbiology and Ecosystem Science, Research Network “Chemistry meets Microbiology”, University of Vienna, Vienna, Austria
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16
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Dang H, Chen CTA. Ecological Energetic Perspectives on Responses of Nitrogen-Transforming Chemolithoautotrophic Microbiota to Changes in the Marine Environment. Front Microbiol 2017; 8:1246. [PMID: 28769878 PMCID: PMC5509916 DOI: 10.3389/fmicb.2017.01246] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2016] [Accepted: 06/20/2017] [Indexed: 11/15/2022] Open
Abstract
Transformation and mobilization of bioessential elements in the biosphere, lithosphere, atmosphere, and hydrosphere constitute the Earth’s biogeochemical cycles, which are driven mainly by microorganisms through their energy and material metabolic processes. Without microbial energy harvesting from sources of light and inorganic chemical bonds for autotrophic fixation of inorganic carbon, there would not be sustainable ecosystems in the vast ocean. Although ecological energetics (eco-energetics) has been emphasized as a core aspect of ecosystem analyses and microorganisms largely control the flow of matter and energy in marine ecosystems, marine microbial communities are rarely studied from the eco-energetic perspective. The diverse bioenergetic pathways and eco-energetic strategies of the microorganisms are essentially the outcome of biosphere-geosphere interactions over evolutionary times. The biogeochemical cycles are intimately interconnected with energy fluxes across the biosphere and the capacity of the ocean to fix inorganic carbon is generally constrained by the availability of nutrients and energy. The understanding of how microbial eco-energetic processes influence the structure and function of marine ecosystems and how they interact with the changing environment is thus fundamental to a mechanistic and predictive understanding of the marine carbon and nitrogen cycles and the trends in global change. By using major groups of chemolithoautotrophic microorganisms that participate in the marine nitrogen cycle as examples, this article examines their eco-energetic strategies, contributions to carbon cycling, and putative responses to and impacts on the various global change processes associated with global warming, ocean acidification, eutrophication, deoxygenation, and pollution. We conclude that knowledge gaps remain despite decades of tremendous research efforts. The advent of new techniques may bring the dawn to scientific breakthroughs that necessitate the multidisciplinary combination of eco-energetic, biogeochemical and “omics” studies in this field.
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Affiliation(s)
- Hongyue Dang
- State Key Laboratory of Marine Environmental Science, Institute of Marine Microbes and Ecospheres, College of Ocean and Earth Sciences, Xiamen UniversityXiamen, China
| | - Chen-Tung A Chen
- Department of Oceanography, National Sun Yat-sen UniversityKaohsiung, Taiwan
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17
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Global-Scale Structure of the Eelgrass Microbiome. Appl Environ Microbiol 2017; 83:AEM.03391-16. [PMID: 28411219 PMCID: PMC5452814 DOI: 10.1128/aem.03391-16] [Citation(s) in RCA: 74] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2016] [Accepted: 04/05/2017] [Indexed: 02/06/2023] Open
Abstract
Plant-associated microorganisms are essential for their hosts' survival and performance. Yet, most plant microbiome studies to date have focused on terrestrial species sampled across relatively small spatial scales. Here, we report the results of a global-scale analysis of microbial communities associated with leaf and root surfaces of the marine eelgrass Zostera marina throughout its range in the Northern Hemisphere. By contrasting host microbiomes with those of surrounding seawater and sediment, we uncovered the structure, composition, and variability of microbial communities associated with eelgrass. We also investigated hypotheses about the assembly of the eelgrass microbiome using a metabolic modeling approach. Our results reveal leaf communities displaying high variability and spatial turnover that mirror their adjacent coastal seawater microbiomes. By contrast, roots showed relatively low compositional turnover and were distinct from surrounding sediment communities, a result driven by the enrichment of predicted sulfur-oxidizing bacterial taxa on root surfaces. Predictions from metabolic modeling of enriched taxa were consistent with a habitat-filtering community assembly mechanism whereby similarity in resource use drives taxonomic cooccurrence patterns on belowground, but not aboveground, host tissues. Our work provides evidence for a core eelgrass root microbiome with putative functional roles and highlights potentially disparate processes influencing microbial community assembly on different plant compartments. IMPORTANCE Plants depend critically on their associated microbiome, yet the structure of microbial communities found on marine plants remains poorly understood in comparison to that for terrestrial species. Seagrasses are the only flowering plants that live entirely in marine environments. The return of terrestrial seagrass ancestors to oceans is among the most extreme habitat shifts documented in plants, making them an ideal testbed for the study of microbial symbioses with plants that experience relatively harsh abiotic conditions. In this study, we report the results of a global sampling effort to extensively characterize the structure of microbial communities associated with the widespread seagrass species Zostera marina, or eelgrass, across its geographic range. Our results reveal major differences in the structure and composition of above- versus belowground microbial communities on eelgrass surfaces, as well as their relationships with the environment and host.
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18
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Lakshmanan V, Ray P, Craven KD. Toward a Resilient, Functional Microbiome: Drought Tolerance-Alleviating Microbes for Sustainable Agriculture. Methods Mol Biol 2017; 1631:69-84. [PMID: 28735391 DOI: 10.1007/978-1-4939-7136-7_4] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
In recent years, the utilization of novel sequencing techniques opened a new field of research into plant microbiota and was used to explore a wide diversity of microorganisms both inside and outside of plant host tissues, i.e., the endosphere and rhizosphere, respectively. An early realization from such research was that species richness and diversity of the plant microbiome are both greater than believed even a few years ago, and soil is likely home to the most abundant and diverse microbial habitats known. In most ecosystems sampled thus far, overall microbial complexity is determined by the combined influences of plant genotype, soil structure and chemistry, and prevailing environmental conditions, as well as the native "bulk soil" microbial populations from which membership is drawn. Beneficial microorganisms, traditionally referring primarily to nitrogen-fixing bacteria, plant growth-promoting rhizobacteria, and mycorrhizal fungi, play a key role in major functions such as plant nutrition acquisition and plant resistance to biotic and abiotic stresses . Utilization of plant-associated microbes in food production is likely to be critical for twenty-first century agriculture, where arable cropland is limited and food, fiber, and feed productivity must be sustained or even improved with fewer chemical inputs and less irrigation.
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Affiliation(s)
- Venkatachalam Lakshmanan
- Plant Biology Division, The Samuel Roberts Noble Foundation, 2510 Sam Noble Parkway, Ardmore, OK, 73401, USA
| | - Prasun Ray
- Plant Biology Division, The Samuel Roberts Noble Foundation, 2510 Sam Noble Parkway, Ardmore, OK, 73401, USA
| | - Kelly D Craven
- Plant Biology Division, The Samuel Roberts Noble Foundation, 2510 Sam Noble Parkway, Ardmore, OK, 73401, USA.
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19
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Vick-Majors TJ, Mitchell AC, Achberger AM, Christner BC, Dore JE, Michaud AB, Mikucki JA, Purcell AM, Skidmore ML, Priscu JC. Physiological Ecology of Microorganisms in Subglacial Lake Whillans. Front Microbiol 2016; 7:1705. [PMID: 27833599 PMCID: PMC5081474 DOI: 10.3389/fmicb.2016.01705] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2016] [Accepted: 10/12/2016] [Indexed: 11/13/2022] Open
Abstract
Subglacial microbial habitats are widespread in glaciated regions of our planet. Some of these environments have been isolated from the atmosphere and from sunlight for many thousands of years. Consequently, ecosystem processes must rely on energy gained from the oxidation of inorganic substrates or detrital organic matter. Subglacial Lake Whillans (SLW) is one of more than 400 subglacial lakes known to exist under the Antarctic ice sheet; however, little is known about microbial physiology and energetics in these systems. When it was sampled through its 800 m thick ice cover in 2013, the SLW water column was shallow (~2 m deep), oxygenated, and possessed sufficient concentrations of C, N, and P substrates to support microbial growth. Here, we use a combination of physiological assays and models to assess the energetics of microbial life in SLW. In general, SLW microorganisms grew slowly in this energy-limited environment. Heterotrophic cellular carbon turnover times, calculated from 3H-thymidine and 3H-leucine incorporation rates, were long (60 to 500 days) while cellular doubling times averaged 196 days. Inferred growth rates (average ~0.006 d-1) obtained from the same incubations were at least an order of magnitude lower than those measured in Antarctic surface lakes and oligotrophic areas of the ocean. Low growth efficiency (8%) indicated that heterotrophic populations in SLW partition a majority of their carbon demand to cellular maintenance rather than growth. Chemoautotrophic CO2-fixation exceeded heterotrophic organic C-demand by a factor of ~1.5. Aerobic respiratory activity associated with heterotrophic and chemoautotrophic metabolism surpassed the estimated supply of oxygen to SLW, implying that microbial activity could deplete the oxygenated waters, resulting in anoxia. We used thermodynamic calculations to examine the biogeochemical and energetic consequences of environmentally imposed switching between aerobic and anaerobic metabolisms in the SLW water column. Heterotrophic metabolisms utilizing acetate and formate as electron donors yielded less energy than chemolithotrophic metabolisms when calculated in terms of energy density, which supports experimental results that showed chemoautotrophic activity in excess of heterotrophic activity. The microbial communities of subglacial lake ecosystems provide important natural laboratories to study the physiological and biogeochemical behavior of microorganisms inhabiting cold, dark environments.
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Affiliation(s)
- Trista J Vick-Majors
- Department of Land Resources and Environmental Sciences, Montana State University Bozeman, MT, USA
| | - Andrew C Mitchell
- Department of Geography and Earth Sciences, Aberystwyth University Aberystwyth, UK
| | - Amanda M Achberger
- Department of Biological Sciences, Louisiana State University Baton Rouge, LA, USA
| | - Brent C Christner
- Department of Microbiology and Cell Science, University of FloridaGainesville, FL, USA; Biodiversity Institute, University of FloridaGainesville, FL, USA
| | - John E Dore
- Department of Land Resources and Environmental Sciences, Montana State University Bozeman, MT, USA
| | - Alexander B Michaud
- Department of Land Resources and Environmental Sciences, Montana State University Bozeman, MT, USA
| | - Jill A Mikucki
- Department of Microbiology, University of Tennessee Knoxville, TN, USA
| | - Alicia M Purcell
- Department of Microbiology, University of Tennessee Knoxville, TN, USA
| | - Mark L Skidmore
- Department of Earth Sciences, Montana State University Bozeman, MT, USA
| | - John C Priscu
- Department of Land Resources and Environmental Sciences, Montana State University Bozeman, MT, USA
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20
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Evidence for the Existence of Autotrophic Nitrate-Reducing Fe(II)-Oxidizing Bacteria in Marine Coastal Sediment. Appl Environ Microbiol 2016; 82:6120-6131. [PMID: 27496777 PMCID: PMC5068159 DOI: 10.1128/aem.01570-16] [Citation(s) in RCA: 58] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2016] [Accepted: 08/02/2016] [Indexed: 11/23/2022] Open
Abstract
Nitrate-reducing Fe(II)-oxidizing microorganisms were described for the first time ca. 20 years ago. Most pure cultures of nitrate-reducing Fe(II) oxidizers can oxidize Fe(II) only under mixotrophic conditions, i.e., when an organic cosubstrate is provided. A small number of nitrate-reducing Fe(II)-oxidizing cultures have been proposed to grow autotrophically, but unambiguous evidence for autotrophy has not always been provided. Thus, it is still unclear whether or to what extent Fe(II) oxidation coupled to nitrate reduction is an enzymatically catalyzed and energy-yielding autotrophic process or whether Fe(II) is abiotically oxidized by nitrite from heterotrophic nitrate reduction. The aim of the present study was to find evidence for the existence of autotrophic nitrate-reducing Fe(II) oxidizers in coastal marine sediments. Microcosm incubations showed that with increasing incubation times, the stoichiometric ratio of reduced nitrate/oxidized Fe(II) [NO3−reduced/Fe(II)oxidized] decreased, indicating a decreasing contribution of heterotrophic denitrification and/or an increasing contribution of autotrophic nitrate-reducing Fe(II) oxidation over time. After incubations of sediment slurries for >10 weeks, nitrate-reducing activity ceased, although nitrate was still present. This suggests that heterotrophic nitrate reduction had ceased due to the depletion of readily available organic carbon. However, after the addition of Fe(II) to these batch incubation mixtures, the nitrate-reducing activity resumed, and Fe(II) was oxidized, indicating the activity of autotrophic nitrate-reducing Fe(II) oxidizers. The concurrent reduction of 14C-labeled bicarbonate concentrations unambiguously proved that autotrophic C fixation occurred during Fe(II) oxidation and nitrate reduction. Our results clearly demonstrated that autotrophic nitrate-reducing Fe(II)-oxidizing bacteria were present in the investigated coastal marine sediments.
IMPORTANCE Twenty years after the discovery of nitrate-reducing Fe(II) oxidizers, it is still controversially discussed whether autotrophic nitrate-reducing Fe(II)-oxidizing microorganisms exist and to what extent Fe(II) oxidation in this reduction/oxidation process is enzymatically catalyzed or which role abiotic side reactions of Fe(II) with reactive N species play. Most pure cultures of nitrate-reducing Fe(II) oxidizers are mixotrophic; i.e., they need an organic cosubstrate to maintain their activity over several cultural transfers. For the few existing autotrophic isolates and enrichment cultures, either the mechanism of nitrate-reducing Fe(II) oxidation is not known or evidence for their autotrophic lifestyle is controversial. In the present study, we provide evidence for the existence of autotrophic nitrate-reducing Fe(II) oxidizers in coastal marine sediments. The evidence is based on stoichiometries of nitrate reduction and Fe(II) oxidation determined in microcosm incubations and the incorporation of carbon from CO2 under conditions that favor the activity of nitrate-reducing Fe(II) oxidizers.
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Contribution of ammonia oxidation to chemoautotrophy in Antarctic coastal waters. ISME JOURNAL 2016; 10:2605-2619. [PMID: 27187795 PMCID: PMC5113851 DOI: 10.1038/ismej.2016.61] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/25/2015] [Revised: 02/04/2016] [Accepted: 03/22/2016] [Indexed: 11/09/2022]
Abstract
There are few measurements of nitrification in polar regions, yet geochemical evidence suggests that it is significant, and chemoautotrophy supported by nitrification has been suggested as an important contribution to prokaryotic production during the polar winter. This study reports seasonal ammonia oxidation (AO) rates, gene and transcript abundance in continental shelf waters west of the Antarctic Peninsula, where Thaumarchaeota strongly dominate populations of ammonia-oxidizing organisms. Higher AO rates were observed in the late winter surface mixed layer compared with the same water mass sampled during summer (mean±s.e.: 62±16 versus 13±2.8 nm per day, t-test P<0.0005). AO rates in the circumpolar deep water did not differ between seasons (21±5.7 versus 24±6.6 nm per day; P=0.83), despite 5- to 20-fold greater Thaumarchaeota abundance during summer. AO rates correlated with concentrations of Archaea ammonia monooxygenase (amoA) genes during summer, but not with concentrations of Archaea amoA transcripts, or with ratios of Archaea amoA transcripts per gene, or with concentrations of Betaproteobacterial amoA genes or transcripts. The AO rates we report (<0.1–220 nm per day) are ~10-fold greater than reported previously for Antarctic waters and suggest that inclusion of Antarctic coastal waters in global estimates of oceanic nitrification could increase global rate estimates by ~9%. Chemoautotrophic carbon fixation supported by AO was 3–6% of annualized phytoplankton primary production and production of Thaumarchaeota biomass supported by AO could account for ~9% of the bacterioplankton production measured in winter. Growth rates of thaumarchaeote populations inferred from AO rates averaged 0.3 per day and ranged from 0.01 to 2.1 per day.
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