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Louca S, Taylor GT, Astor YM, Buck KN, Muller-Karger FE. Transport-limited reactions in microbial systems. Environ Microbiol 2023; 25:268-282. [PMID: 36345893 DOI: 10.1111/1462-2920.16275] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2022] [Accepted: 10/29/2022] [Indexed: 11/11/2022]
Abstract
Predicting microbial metabolic rates and emergent biogeochemical fluxes remains challenging due to the many unknown population dynamical, physiological and reaction-kinetic parameters and uncertainties in species composition. Here, we show that the need for these parameters can be eliminated when population dynamics and reaction kinetics operate at much shorter time scales than physical mixing processes. Such scenarios are widespread in poorly mixed water columns and sediments. In this 'fast-reaction-transport' (FRT) limit, all that is required for predictions are chemical boundary conditions, the physical mixing processes and reaction stoichiometries, while no knowledge of species composition, physiology or population/reaction kinetic parameters is needed. Using time-series data spanning years 2001-2014 and depths 180-900 m across the permanently anoxic Cariaco Basin, we demonstrate that the FRT approach can accurately predict the dynamics of major electron donors and acceptors (Pearson r ≥ 0.9 in all cases). Hence, many microbial processes in this system are largely transport limited and thus predictable regardless of species composition, population dynamics and kinetics. Our approach enables predictions for many systems in which microbial community dynamics and kinetics are unknown. Our findings also reveal a mechanism for the frequently observed decoupling between function and taxonomy in microbial systems.
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Affiliation(s)
- Stilianos Louca
- Department of Biology, University of Oregon, Oregon, USA
- Institute of Ecology and Evolution, University of Oregon, Oregon, USA
| | - Gordon T Taylor
- School of Marine and Atmospheric Sciences, Stony Brook University, New York, New York, USA
| | - Yrene M Astor
- Estación de Investigaciones Marinas de Margarita, Fundación La Salle de Ciencias Naturales, Punta de Piedras, Estado Nueva Esparta, Venezuela
| | - Kristen N Buck
- College of Marine Science, University of South Florida, Florida, USA
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Flow cytometric sorting of loricate choanoflagellates from the oligotrophic ocean. Eur J Protistol 2022; 86:125914. [PMID: 36137332 DOI: 10.1016/j.ejop.2022.125914] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Revised: 08/11/2022] [Accepted: 08/17/2022] [Indexed: 11/23/2022]
Abstract
It is challenging to study protists with extensive, loosely-associated extracellular structures because of the problems with keeping specimens intact. Here we have tested the suitability of high-speed flow cytometric sorting as a tool for studying such protists using oceanic loricate choanoflagellates as a model. We chose choanoflagellates because their lorica-to-cell volume ratio is > 10 and the voluminous loricae, i.e., the siliceous cell baskets essential for taxonomic identification, only loosely enclose the cells. Besides, owing to low concentrations, choanoflagellates are grossly under-sampled in the oligotrophic ocean. On four research cruises the small heterotrophic protists from samples collected in the photic layer of the South Atlantic and South Pacific oligotrophic (sub)tropical gyres and adjacent mesotrophic waters were flow sorted at sea for electron microscopy ashore. Among the flow-sorted protozoa we were able to select loricate choanoflagellates to assess their species diversity and concentrations. The well-preserved loricae of flow-sorted choanoflagellates made identification of 29 species from 14 genera possible. In the oligotrophic waters, we found neither endemic species nor evident morphological adaptations other than a tendency for lighter silicification of loricae. Common sightings of specimens storing extra costae in preparation for division, indicate choanoflagellates thriving in oligotrophic waters rather than enduring them. Thus, this case study demonstrates that high-speed flow sorting can assist in studying protists with extracellular structures 16-78× bigger than the enclosed cell.
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Kamennaya NA, Kennaway G, Sleigh MA, Zubkov MV. Notable predominant morphology of the smallest most abundant protozoa of the open ocean revealed by electron microscopy. JOURNAL OF PLANKTON RESEARCH 2022; 44:542-558. [PMID: 35898814 PMCID: PMC9310263 DOI: 10.1093/plankt/fbac031] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Accepted: 05/18/2022] [Indexed: 06/15/2023]
Abstract
In the microbe-driven ecosystems of the open ocean, the small heterotrophic flagellates (sHF) are the chief microbial predators and recyclers of essential nutrients to phototrophic microbes. Even with intensive molecular phylogenetic studies of the sHF, the origins of their feeding success remain obscure because of limited understanding of their morphological adaptations to feeding. Here, we examined the sHF morphologies in the largest, most oligotrophic South Pacific and Atlantic (sub)tropical gyres and adjacent mesotrophic waters. On four research cruises, the sHF cells were flow cytometrically sorted from bacterioplankton and phytoplankton for electron microscopy. The sorted sHF comprised chiefly heterokont (HK) biflagellates and unikont choanoflagellates numerically at around 10-to-1 ratio. Of the four differentiated morphological types of HK omnipresent in the open ocean, the short-tinsel heterokont (stHK), whose tinsel flagellum is too short to propagate a complete wave, is predominant and a likely candidate to be the most abundant predator on Earth. Modeling shows that the described stHK propulsion is effective in feeding on bacterioplankton cells at low concentrations; however, owing to general prey scarcity in the oligotrophic ocean, selective feeding is unsustainable and omnivory is equally obligatory for the seven examined sHF types irrespective of their mode of propulsion.
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Affiliation(s)
- Nina A Kamennaya
- French Associates Institute for Agriculture and Biotechnology of Drylands, The Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Campus Sede Boqer, Be'er Sheva 8499000, Israel
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Louca S, Scranton MI, Taylor GT, Astor YM, Crowe SA, Doebeli M. Circumventing kinetics in biogeochemical modeling. Proc Natl Acad Sci U S A 2019; 116:11329-11338. [PMID: 31097587 PMCID: PMC6561284 DOI: 10.1073/pnas.1819883116] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Microbial metabolism drives biogeochemical fluxes in virtually every ecosystem. Modeling these fluxes is challenged by the incredible diversity of microorganisms, whose kinetic parameters are largely unknown. In poorly mixed systems, such as stagnant water columns or sediments, however, long-term bulk microbial metabolism may become limited by physical transport rates of substrates across space. Here we mathematically show that under these conditions, biogeochemical fluxes are largely predictable based on the system's transport properties, chemical boundary conditions, and the stoichiometry of metabolic pathways, regardless of the precise kinetics of the resident microorganisms. We formalize these considerations into a predictive modeling framework and demonstrate its use for the Cariaco Basin subeuphotic zone, one of the largest anoxic marine basins worldwide. Using chemical concentration data solely from the upper boundary (depth 180 m) and lower boundary (depth 900 m), but without a priori knowledge of metabolite fluxes, chemical depth profiles, kinetic parameters, or microbial species composition, we predict the concentrations and vertical fluxes of biologically important substances, including oxygen, nitrate, hydrogen sulfide, and ammonium, across the entire considered depth range (180-900 m). Our predictions largely agree with concentration measurements over a period of 14 years ([Formula: see text] = 0.78-0.92) and become particularly accurate during a period where the system was near biogeochemical steady state (years 2007-2009, [Formula: see text] = 0.86-0.95). Our work enables geobiological predictions for a large class of ecosystems without knowledge of kinetic parameters or geochemical depth profiles. Conceptually, our work provides a possible explanation for the decoupling between microbial species composition and bulk metabolic function, observed in various ecosystems.
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Affiliation(s)
- Stilianos Louca
- Institute of Ecology and Evolution, University of Oregon, Eugene, OR 97403;
- Department of Biology, University of Oregon, Eugene, OR 97403
| | - Mary I Scranton
- School of Marine and Atmospheric Sciences, Stony Brook University, Stony Brook, NY 11794
| | - Gordon T Taylor
- School of Marine and Atmospheric Sciences, Stony Brook University, Stony Brook, NY 11794
| | - Yrene M Astor
- Estación de Investigaciones Marinas de Margarita, Fundación La Salle de Ciencias Naturales, Punta de Piedras, Estado Nueva Esparta, Venezuela
- Institute for Marine Remote Sensing, University of South Florida, Tampa, FL 33701
| | - Sean A Crowe
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
- Department of Earth, Ocean, and Atmospheric Sciences, University of British Columbia, Vancouver, BC V6T 1Z4, Canada
| | - Michael Doebeli
- Biodiversity Research Centre, University of British Columbia, Vancouver, BC V6T 1Z4, Canada
- Department of Mathematics, University of British Columbia, Vancouver, BC V6T 1Z2, Canada
- Department of Zoology, University of British Columbia, Vancouver, BC V6T 1Z4, Canada
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Louca S, Hawley AK, Katsev S, Torres-Beltran M, Bhatia MP, Kheirandish S, Michiels CC, Capelle D, Lavik G, Doebeli M, Crowe SA, Hallam SJ. Integrating biogeochemistry with multiomic sequence information in a model oxygen minimum zone. Proc Natl Acad Sci U S A 2016; 113:E5925-E5933. [PMID: 27655888 PMCID: PMC5056048 DOI: 10.1073/pnas.1602897113] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Microorganisms are the most abundant lifeform on Earth, mediating global fluxes of matter and energy. Over the past decade, high-throughput molecular techniques generating multiomic sequence information (DNA, mRNA, and protein) have transformed our perception of this microcosmos, conceptually linking microorganisms at the individual, population, and community levels to a wide range of ecosystem functions and services. Here, we develop a biogeochemical model that describes metabolic coupling along the redox gradient in Saanich Inlet-a seasonally anoxic fjord with biogeochemistry analogous to oxygen minimum zones (OMZs). The model reproduces measured biogeochemical process rates as well as DNA, mRNA, and protein concentration profiles across the redox gradient. Simulations make predictions about the role of ubiquitous OMZ microorganisms in mediating carbon, nitrogen, and sulfur cycling. For example, nitrite "leakage" during incomplete sulfide-driven denitrification by SUP05 Gammaproteobacteria is predicted to support inorganic carbon fixation and intense nitrogen loss via anaerobic ammonium oxidation. This coupling creates a metabolic niche for nitrous oxide reduction that completes denitrification by currently unidentified community members. These results quantitatively improve previous conceptual models describing microbial metabolic networks in OMZs. Beyond OMZ-specific predictions, model results indicate that geochemical fluxes are robust indicators of microbial community structure and reciprocally, that gene abundances and geochemical conditions largely determine gene expression patterns. The integration of real observational data, including geochemical profiles and process rate measurements as well as metagenomic, metatranscriptomic and metaproteomic sequence data, into a biogeochemical model, as shown here, enables holistic insight into the microbial metabolic network driving nutrient and energy flow at ecosystem scales.
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Affiliation(s)
- Stilianos Louca
- Institute of Applied Mathematics, University of British Columbia, Vancouver, BC, Canada V6T1Z2
| | - Alyse K Hawley
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC, Canada V6T1Z3
| | - Sergei Katsev
- Large Lakes Observatory, University of Minnesota Duluth, Duluth, MN 55812; Department of Physics and Astronomy, University of Minnesota Duluth, Duluth, MN 55812
| | - Monica Torres-Beltran
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC, Canada V6T1Z3
| | - Maya P Bhatia
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC, Canada V6T1Z3; Canadian Institute for Advanced Research Program in Integrated Microbial Biodiversity, Canadian Institute for Advanced Research, Toronto, ON, Canada M5G1Z8
| | - Sam Kheirandish
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC, Canada V6T1Z3
| | - Céline C Michiels
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC, Canada V6T1Z3
| | - David Capelle
- Department of Earth, Ocean, and Atmospheric Sciences, University of British Columbia, Vancouver, BC, Canada V6T1Z4
| | - Gaute Lavik
- Biogeochemistry Group, Max Planck Institute for Marine Microbiology, Bremen D-28359, Germany
| | - Michael Doebeli
- Department of Zoology, University of British Columbia, Vancouver, BC, Canada V6T1Z4; Department of Mathematics, University of British Columbia, Vancouver, BC, Canada V6T1Z4
| | - Sean A Crowe
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC, Canada V6T1Z3; Department of Earth, Ocean, and Atmospheric Sciences, University of British Columbia, Vancouver, BC, Canada V6T1Z4; Ecosystem Services, Commercialization Platforms, and Entrepreneurship (ECOSCOPE) Training Program, University of British Columbia, Vancouver, BC, Canada V6T1Z3;
| | - Steven J Hallam
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC, Canada V6T1Z3; Canadian Institute for Advanced Research Program in Integrated Microbial Biodiversity, Canadian Institute for Advanced Research, Toronto, ON, Canada M5G1Z8; Ecosystem Services, Commercialization Platforms, and Entrepreneurship (ECOSCOPE) Training Program, University of British Columbia, Vancouver, BC, Canada V6T1Z3; Graduate Program in Bioinformatics, University of British Columbia, Vancouver, BC, Canada V6T1Z3; Peter Wall Institute for Advanced Studies, University of British Columbia, Vancouver, BC, Canada V6T1Z2
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Edgcomb VP, Pachiadaki M. Ciliates along Oxyclines of Permanently Stratified Marine Water Columns. J Eukaryot Microbiol 2014; 61:434-45. [DOI: 10.1111/jeu.12122] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2014] [Revised: 02/28/2014] [Accepted: 02/28/2014] [Indexed: 11/30/2022]
Affiliation(s)
- Virginia P. Edgcomb
- Department of Geology and Geophysics; Woods Hole Oceanographic Institution; Woods Hole Massachusetts 02543
| | - Maria Pachiadaki
- Department of Geology and Geophysics; Woods Hole Oceanographic Institution; Woods Hole Massachusetts 02543
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Oikonomou A, Pachiadaki M, Stoeck T. Protistan grazing in a meromictic freshwater lake with anoxic bottom water. FEMS Microbiol Ecol 2013; 87:691-703. [DOI: 10.1111/1574-6941.12257] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2013] [Revised: 10/29/2013] [Accepted: 11/13/2013] [Indexed: 01/26/2023] Open
Affiliation(s)
- Andreas Oikonomou
- Department of Ecology; University of Kaiserslautern; Kaiserslautern Germany
| | - Maria Pachiadaki
- Department of Ecology; University of Kaiserslautern; Kaiserslautern Germany
| | - Thorsten Stoeck
- Department of Ecology; University of Kaiserslautern; Kaiserslautern Germany
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Anderson R, Wylezich C, Glaubitz S, Labrenz M, Jürgens K. Impact of protist grazing on a key bacterial group for biogeochemical cycling in Baltic Sea pelagic oxic/anoxic interfaces. Environ Microbiol 2013; 15:1580-94. [PMID: 23368413 DOI: 10.1111/1462-2920.12078] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2012] [Revised: 12/17/2012] [Accepted: 12/20/2012] [Indexed: 11/27/2022]
Abstract
Barrier zones between oxic and anoxic water masses (redoxclines) host highly active prokaryotic communities with important roles in biogeochemical cycling. In Baltic Sea pelagic redoxclines, Epsilonproteobacteria of the genus Sulfurimonas (subgroup GD17) have been shown to dominate chemoautotrophic denitrification. However, little is known on the loss processes affecting this prokaryotic group. In the present study, the protist grazing impact on the Sulfurimonas subgroup GD17 was determined for suboxic and oxygen/hydrogen sulphide interface depths of Baltic Sea redoxclines, using predator exclusion assays and bacterial amendment with the cultured representative 'Sulfurimonas gotlandica' strain GD1. Additionally, the principal bacterivores were identified by RNA-Stable Isotope Probing (RNA-SIP). The natural Sulfurimonas subgroup GD17 population grew strongly under oxygen/hydrogen sulphide interface conditions (doubling time: 1-1.5 days), but protist grazing could consume the complete new cell production per day. In suboxic samples, little or no growth of Sulfurimonas subgroup GD17 was observed. RNA-SIP identified five active grazers, belonging to typical redoxcline ciliates (Oligohymenophorea, Prostomatea) and globally widespread marine flagellate groups (MAST-4, Chrysophyta, Cercozoa). Overall, we demonstrate for the first time that protist grazing can control the growth, and potentially the vertical distribution, of a chemolithoautotrophic key-player of oxic/anoxic interfaces.
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Affiliation(s)
- Ruth Anderson
- Department of Biological Oceanography, Leibniz Institute for Baltic Sea Research, Seestrasse 15, 18119, Rostock-Warnemünde, Germany.
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Wylezich C, Jürgens K. Protist diversity in suboxic and sulfidic waters of the Black Sea. Environ Microbiol 2011; 13:2939-56. [DOI: 10.1111/j.1462-2920.2011.02569.x] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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10
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La Cono V, Smedile F, Bortoluzzi G, Arcadi E, Maimone G, Messina E, Borghini M, Oliveri E, Mazzola S, L'Haridon S, Toffin L, Genovese L, Ferrer M, Giuliano L, Golyshin PN, Yakimov MM. Unveiling microbial life in new deep-sea hypersaline Lake Thetis. Part I: Prokaryotes and environmental settings. Environ Microbiol 2011; 13:2250-68. [PMID: 21518212 DOI: 10.1111/j.1462-2920.2011.02478.x] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
In September 2008, an expedition of the RV Urania was devoted to exploration of the genomic richness of deep hypersaline anoxic lakes (DHALs) located in the Western part of the Mediterranean Ridge. Approximately 40 nautical miles SE from Urania Lake, the presence of anoxic hypersaline lake, which we named Thetis, was confirmed by swath bathymetry profiling and through immediate sampling casts. The brine surface of the Thetis Lake is located at a depth of 3258 m with a thickness of ≈ 157 m. Brine composition was found to be thalassohaline, saturated by NaCl with a total salinity of 348‰, which is one of highest value reported for DHALs. Similarly to other Mediterranean DHALs, seawater-brine interface of Thetis represents a steep pycno- and chemocline with gradients of salinity, electron donors and acceptors and posseses a remarkable stratification of prokaryotic communities, observed to be more metabolically active in the upper interface where redox gradient was sharper. [(14) C]-bicarbonate fixation analysis revealed that microbial communities are sustained by sulfur-oxidizing chemolithoautotrophic primary producers that thrive within upper interface. Besides microaerophilic autotrophy, heterotrophic sulfate reduction, methanogenesis and anaerobic methane oxidation are likely the predominant processes driving the ecosystem of Thetis Lake.
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Affiliation(s)
- Violetta La Cono
- Institute for Coastal Marine Environment, CNR, Spianata S.Raineri 86, 98122 Messina, Italy
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Madrid VM, Taylor GT, Scranton MI, Chistoserdov AY. Phylogenetic diversity of bacterial and archaeal communities in the anoxic zone of the Cariaco Basin. Appl Environ Microbiol 2001; 67:1663-74. [PMID: 11282619 PMCID: PMC92783 DOI: 10.1128/aem.67.4.1663-1674.2001] [Citation(s) in RCA: 120] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Microbial community samples were collected from the anoxic zone of the Cariaco Basin at depths of 320, 500, and 1,310 m on a November 1996 cruise and were used to construct 16S ribosomal DNA libraries. Of 60 nonchimeric sequences in the 320-m library, 56 belonged to the epsilon subdivision of the Proteobacteria (epsilon-Proteobacteria) and 53 were closely related to ectosymbionts of Rimicaris exoculata and Alvinella pompejana, which are referred to here as epsilon symbiont relatives (ESR). The 500-m library contained sequences affiliated with the fibrobacteria, the Flexibacter-Cytophaga-Bacteroides division, the division Verrucomicrobia, the division Proteobacteria, and the OP3 candidate division. The Proteobacteria included members of the gamma, delta, epsilon and new candidate subdivisions, and gamma-proteobacterial sequences were dominant (25.6%) among the proteobacterial sequences. As in the 320-m library, the majority of the epsilon-proteobacteria belonged to the ESR group. The genus Fibrobacter and its relatives were the second largest group in the library (23.6%), followed by the delta-proteobacteria and the epsilon-proteobacteria. The 1,310-m library had the greatest diversity; 59 nonchimeric clones in the library contained 30 unique sequences belonging to the planctomycetes, the fibrobacteria, the Flexibacter-Cytophaga-Bacteroides division, the Proteobacteria, and the OP3 and OP8 candidate divisions. The proteobacteria included members of new candidate subdivisions and the beta, gamma, delta, and epsilon-subdivisions. ESR sequences were still present in the 1,310-m library but in a much lower proportion (8.5%). One archaeal sequence was present in the 500-m library (2% of all microorganisms in the library), and eight archaeal sequences were present in the 1,310-m library (13.6%). All archaeal sequences fell into two groups; two clones in the 1,310-m library belonged to the kingdom Crenarchaeota and the remaining sequences in both libraries belonged to the kingdom Euryarchaeota. The latter group appears to be related to the Eel-TA1f2 sequence, which belongs to an archaeon suggested to be able to oxidize methane anaerobically. Based on phylogenetic inferences and measurements of dark CO(2) fixation, we hypothesized that (i) the ESR are autotrophic anaerobic sulfide oxidizers, (ii) sulfate reduction and fermentative metabolism may be carried out by a large number of bacteria in the 500- and 1,310-m libraries, and (iii) members of the Euryarchaeota found in relatively large numbers in the 1,310-m library may be involved in anaerobic methane oxidation. Overall, the composition of microbial communities from the Cariaco Basin resembles the compositions of communities from several anaerobic sediments, supporting the hypothesis that the Cariaco Basin water column is similar to anaerobic sediments.
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Affiliation(s)
- V M Madrid
- Marine Sciences Research Center, State University of New York at Stony Brook, Stony Brook, NY 11794-5000, USA
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Fenchel T, Bernard C, Esteban G, Finlay BJ, Hansen PJ, Iversen N. Microbial diversity and activity in a Danish Fjord with anoxic deep water. ACTA ACUST UNITED AC 1995. [DOI: 10.1080/00785326.1995.10430576] [Citation(s) in RCA: 86] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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Kenig F, Damsté JS, Frewin NL, Hayes JM, De Leeuw JW. Molecular indicators for palaeoenvironmental change in a Messinian evaporitic sequence (Vena del Gesso, Italy). II: High-resolution variations in abundances and 13C contents of free and sulphur-bound carbon skeletons in a single marl bed. ORGANIC GEOCHEMISTRY 1995; 23:485-526. [PMID: 11539140 DOI: 10.1016/0146-6380(95)00049-k] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The extractable organic matter of 10 immature samples from a marl bed of one evaporitic cycle of the Vena del Gesso sediments (Gessoso-solfifera Fm., Messinian, Italy) was analyzed quantitatively for free hydrocarbons and organic sulphur compounds. Nickel boride was used as a desulphurizing agent to recover sulphur-bound lipids from the polar and asphaltene fractions. Carbon isotopic compositions (delta vs PDB) of free hydrocarbons and of S-bound hydrocarbons were also measured. Relationships between these carbon skeletons, precursor biolipids, and the organisms producing them could then be examined. Concentrations of S-bound lipids and free hydrocarbons and their delta values were plotted vs depth in the marl bed and the profiles were interpreted in terms of variations in source organisms, 13 C contents of the carbon source, and environmentally induced changes in isotopic fractionation. The overall range of delta values measured was 24.7%, from -11.6% for a component derived from green sulphur bacteria (Chlorobiaceae) to -36.3% for a lipid derived from purple sulphur bacteria (Chromatiaceae). Deconvolution of mixtures of components deriving from multiple sources (green and purple sulphur bacteria, coccolithophorids, microalgae and higher plants) was sometimes possible because both quantitative and isotopic data were available and because either the free or S-bound pool sometimes appeared to contain material from a single source. Several free n-alkanes and S-bound lipids appeared to be specific products of upper-water-column primary producers (i.e. algae and cyanobacteria). Others derived from anaerobic photoautotrophs and from heterotrophic protozoa (ciliates), which apparently fed partly on Chlorobiaceae. Four groups of n-alkanes produced by algae or cyanobacteria were also recognized based on systematic variations of abundance and isotopic composition with depth. For hydrocarbons probably derived from microalgae, isotopic variations are well correlated with those of total organic carbon. A resistant aliphatic biomacromolecule produced by microalgae is, therefore, probably an important component of the kerogen. These variations reflect changes in the depositional environment and early diagenetic transformations. Changes in the concentrations of S-bound lipids induced by variations in conditions favourable for sulphurization were discriminated from those related to variations in primary producer assemblages. The water column of the lagoonal basin was stratified and photic zone anoxia occurred during the early and middle stages of marl deposition. During the last stage of the marl deposition the stratification collapsed due to a significant shallowing of the water column. Contributions from anaerobic photoautotrophs were apparently associated with variations in depth of the chemocline.
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Affiliation(s)
- F Kenig
- Division of Marine Biogeochemistry, Netherlands Institute for Sea Research, Texel, The Netherlands
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Sinninghe Damste JS, Kenig F, Koopmans MP, Koster J, Schouten S, Hayes JM, de Leeuw JW. Evidence for gammacerane as an indicator of water column stratification. GEOCHIMICA ET COSMOCHIMICA ACTA 1995; 59:1895-1900. [PMID: 11540109 DOI: 10.1016/0016-7037(95)00073-9] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
A new route for the formation of gammacerane from tetrahymanol is proposed; in addition to dehydration and hydrogenation, sulphurisation and early C-S cleavage are shown to be important in the pathway of formation, especially in marine sediments. Evidence is twofold. First, relatively large amounts of the gammacerane skeleton are sequestered in S-rich macromolecular aggregates formed by natural sulphurisation of functionalised lipids. Selective cleavage of polysulphide linkages with MeLi/MeI led to formation of 3-methylthiogammacerane, indicating that the gammacerane skeleton is primarily bound via sulphur at position 3, consistent with the idea that tetrahymanol (or the corresponding ketone) is the precursor for gammacerane. Second, upon mild artificial maturation of two sediments using hydrous pyrolysis, gammacerane is released from S-rich macromolecular aggregates by cleavage of the relatively weak C-S bonds. The stable carbon isotopic compositions of gammacerane and lipids derived from primary producers and green sulphur bacteria in both the Miocene Gessoso-solfifera and Upper Jurassic Allgau Formations indicate that gammacerane is derived from bacterivorous ciliates which were partially feeding on green sulphur bacteria. This demonstrates that anaerobic ciliates living at or below the chemocline are important sources for gammacerane, consistent with the fact that ciliates only biosynthesize tetrahymanol if their diet is deprived of sterols. This leads to the conclusion that gammacerane is an indicator for water column stratification, which solves two current enigmas in gammacerane geochemistry. Firstly, it explains why gammacerane is often found in sediments deposited under hypersaline conditions but is not necessarily restricted to this type of deposits. Secondly, it explains why lacustrine deposits may contain abundant gammacerane since most lakes in the temperate climatic zones are stratified during summer.
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Affiliation(s)
- J S Sinninghe Damste
- Netherlands Institute for Sea Research (NIOZ), Department of Marine Biogeochemistry, Den Burg, The Netherlands
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15
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Guhl BE, Finlay BJ, Schink B. Seasonal development of hypolimnetic ciliate communities in a eutrophic pond. FEMS Microbiol Ecol 1994. [DOI: 10.1111/j.1574-6941.1994.tb00115.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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Guhl BE, Finlay BJ. Anaerobic predatory ciliates track seasonal migrations of planktonic photosynthetic bacteria. FEMS Microbiol Lett 1993. [DOI: 10.1111/j.1574-6968.1993.tb06049.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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