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Heyerhoff B, Engelen B, Bunse C. Auxiliary Metabolic Gene Functions in Pelagic and Benthic Viruses of the Baltic Sea. Front Microbiol 2022; 13:863620. [PMID: 35875520 PMCID: PMC9301287 DOI: 10.3389/fmicb.2022.863620] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Accepted: 06/02/2022] [Indexed: 11/13/2022] Open
Abstract
Marine microbial communities are facing various ecosystem fluctuations (e.g., temperature, organic matter concentration, salinity, or redox regimes) and thus have to be highly adaptive. This might be supported by the acquisition of auxiliary metabolic genes (AMGs) originating from virus infections. Marine bacteriophages frequently contain AMGs, which allow them to augment their host’s metabolism or enhance virus fitness. These genes encode proteins for the same metabolic functions as their highly similar host homologs. In the present study, we analyzed the diversity, distribution, and composition of marine viruses, focusing on AMGs to identify their putative ecologic role. We analyzed viruses and assemblies of 212 publicly available metagenomes obtained from sediment and water samples across the Baltic Sea. In general, the virus composition in both compartments differed compositionally. While the predominant viral lifestyle was found to be lytic, lysogeny was more prevalent in sediments than in the pelagic samples. The highest proportion of AMGs was identified in the genomes of Myoviridae. Overall, the most abundantly occurring AMGs are encoded for functions that protect viruses from degradation by their hosts, such as methylases. Additionally, some detected AMGs are known to be involved in photosynthesis, 7-cyano-7-deazaguanine synthesis, and cobalamin biosynthesis among other functions. Several AMGs that were identified in this study were previously detected in a large-scale analysis including metagenomes from various origins, i.e., different marine sites, wastewater, and the human gut. This supports the theory of globally conserved core AMGs that are spread over virus genomes, regardless of host or environment.
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2
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Xie L, Zhang R, Luo YW. Assessment of Explicit Representation of Dynamic Viral Processes in Regional Marine Ecological Models. Viruses 2022; 14:v14071448. [PMID: 35891428 PMCID: PMC9324674 DOI: 10.3390/v14071448] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2022] [Revised: 06/25/2022] [Accepted: 06/26/2022] [Indexed: 01/27/2023] Open
Abstract
Viruses, the most abundant microorganisms in the ocean, play important roles in marine ecosystems, mainly by killing their hosts and contributing to nutrient recycling. However, in models simulating ecosystems in real marine environments, the virus-mediated mortality (VMM) rates of their hosts are implicitly represented by constant parameters, thus ignoring the dynamics caused by interactions between viruses and hosts. Here, we construct a model explicitly representing marine viruses and the VMM rates of major hosts, heterotrophic bacteria, and apply it to two sites in the oligotrophic North Pacific and the more productive Arabian Sea. The impacts of the viral processes were assessed by comparing model results with the viral processes enabled and disabled. For reliable assessments, a data assimilation method was used to objectively optimize the model parameters in each run. The model generated spatiotemporally variable VMM rates, generally decreasing in the subsurface but increasing at the surface. Although the dynamics introduced by viruses could be partly stabilized by the ecosystems, they still caused substantial changes to the bacterial abundance, primary production and carbon export, with the changes greater at the more productive site. Our modeling experiments reveal the importance of explicitly simulating dynamic viral processes in marine ecological models.
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Yang Y, Nagata T. Viral Production in Seawater Filtered Through 0.2-μm Pore-Size Filters: A Hidden Biogeochemical Cycle in a Neglected Realm. Front Microbiol 2021; 12:774849. [PMID: 34867916 PMCID: PMC8637275 DOI: 10.3389/fmicb.2021.774849] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Accepted: 10/25/2021] [Indexed: 11/20/2022] Open
Abstract
Viral production is a key parameter for assessing virus-mediated biogeochemical cycles. One widely used method for the determination of viral production, called the virus reduction assay, reduces viral abundance, while maintaining bacterial abundance, using 0.2-μm pore-size filters. Viral production is estimated from the increase of viral abundance during incubation. We hypothesized that small-cell-sized bacterial communities can pass through 0.2-μm filters and drive viral production, representing a missing fraction of viral production that is missed by the virus reduction assay. Coastal seawater was filtered through 0.2-μm filters and diluted with virus-free seawater. Viral production in the <0.2-μm filtrate was estimated from changes in viral abundance determined through flow cytometry. We found that viruses were produced in the <0.2-μm communities, which were strongly enriched with low nucleic acid content bacteria. Estimated viral production in the <0.2-μm filtrates accounted for up to 43% of total viral production and 10% of dissolved organic carbon production mediated by viral lysis of bacterial cells. By not considering viral production in these <0.2-μm communities, the virus reduction assay may underestimate viral production. Virus–bacteria interactions in <0.2-μm communities may represent a significant and overlooked role of viruses in marine food webs and carbon fluxes.
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Affiliation(s)
- Yanhui Yang
- Atmosphere and Ocean Research Institute, The University of Tokyo, Kashiwa, Japan
| | - Toshi Nagata
- Atmosphere and Ocean Research Institute, The University of Tokyo, Kashiwa, Japan
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Pascoal F, Costa R, Magalhães C. The microbial rare biosphere: current concepts, methods and ecological principles. FEMS Microbiol Ecol 2021; 97:5974270. [PMID: 33175111 DOI: 10.1093/femsec/fiaa227] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Accepted: 11/06/2020] [Indexed: 01/04/2023] Open
Abstract
Our ability to describe the highly diverse pool of low abundance populations present in natural microbial communities is increasing at an unprecedented pace. Yet we currently lack an integrative view of the key taxa, functions and metabolic activity which make-up this communal pool, usually referred to as the 'rare biosphere', across the domains of life. In this context, this review examines the microbial rare biosphere in its broader sense, providing an historical perspective on representative studies which enabled to bridge the concept from macroecology to microbial ecology. It then addresses our current knowledge of the prokaryotic rare biosphere, and covers emerging insights into the ecology, taxonomy and evolution of low abundance microeukaryotic, viral and host-associated communities. We also review recent methodological advances and provide a synthetic overview on how the rare biosphere fits into different conceptual models used to explain microbial community assembly mechanisms, composition and function.
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Affiliation(s)
- Francisco Pascoal
- Interdisciplinary Centre of Marine and Environmental Research (CIIMAR), University of Porto, Terminal de Cruzeiros do Porto de Leixoes, Avenida General Norton de Matos, S/N, 4450-208 Matosinhos, Portugal
| | - Rodrigo Costa
- Department of Bioengineering, Institute for Bioengineering and Biosciences (iBB), Instituto Superior Técnico, University of Lisbon, Av. Rovisco Pais 1049-001, Lisbon, Portugal.,Centre of Marine Sciences (CCMAR), University of Algarve, Campus de Gambelas, 8005-139, Faro, Portugal.,U.S. Department of Energy Joint Genome Institute, 1 Cyclotron Road, CA 94720, USA.,Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, CA 94720 Berkeley, USA
| | - Catarina Magalhães
- Interdisciplinary Centre of Marine and Environmental Research (CIIMAR), University of Porto, Terminal de Cruzeiros do Porto de Leixoes, Avenida General Norton de Matos, S/N, 4450-208 Matosinhos, Portugal.,Faculty of Sciences, University of Porto, Rua do Campo Alegre s/n, 4169-007, Porto, Portugal.,School of Science, University of Waikato, Gate 1, Knighton Road 3240, Hamilton, New Zealand.,Ocean Frontier Institute, Dalhousie University, Steele Ocean Sciences Building, Dalhousie University 1355 Oxford St., B3H4R2 Halifax, NS, Canada
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5
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Zheng L, Liang X, Shi R, Li P, Zhao J, Li G, Wang S, Han S, Radosevich M, Zhang Y. Viral Abundance and Diversity of Production Fluids in Oil Reservoirs. Microorganisms 2020; 8:microorganisms8091429. [PMID: 32957569 PMCID: PMC7563284 DOI: 10.3390/microorganisms8091429] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Revised: 09/11/2020] [Accepted: 09/15/2020] [Indexed: 11/16/2022] Open
Abstract
Viruses are widely distributed in various ecosystems and have important impacts on microbial evolution, community structure and function and nutrient cycling in the environment. Viral abundance, diversity and distribution are important for a better understanding of ecosystem functioning and have often been investigated in marine, soil, and other environments. Though microbes have proven useful in oil recovery under extreme conditions, little is known about virus community dynamics in such systems. In this study, injection water and production fluids were sampled in two blocks of the Daqing oilfield limited company where water flooding and microbial flooding were continuously used to improve oil recovery. Virus-like particles (VLPs) and bacteria in these samples were extracted and enumerated with epifluorescence microscopy, and viromes of these samples were also sequenced with Illumina Hiseq PE150. The results showed that a large number of viruses existed in the oil reservoir, and VLPs abundance of production wells was 3.9 ± 0.7 × 108 mL-1 and virus to bacteria ratio (VBR) was 6.6 ± 1.1 during water flooding. Compared with water flooding, the production wells of microbial flooding had relative lower VLPs abundance (3.3 ± 0.3 × 108 mL-1) but higher VBR (7.9 ± 2.2). Assembled viral contigs were mapped to an in-house virus reference data separate from the GenBank non-redundant nucleotide (NT) database, and the sequences annotated as virus accounted for 35.34 and 55.04% of total sequences in samples of water flooding and microbial flooding, respectively. In water flooding, 7 and 6 viral families were identified in the injection and production wells, respectively. In microbial flooding, 6 viral families were identified in the injection and production wells. The total number of identified viral species in the injection well was higher than that in the production wells for both water flooding and microbial flooding. The Shannon diversity index was higher in the production well of water flooding than in the production well of microbial flooding. These results show that viruses are very abundant and diverse in the oil reservoir's ecosystem, and future efforts are needed to reveal the potential function of viral communities in this extreme environment.
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Affiliation(s)
- Liangcan Zheng
- Key Laboratory of Pollution Ecology and Environmental Engineering, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, China; (L.Z.); (R.S.); (P.L.); (S.W.); (S.H.)
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xiaolong Liang
- Department of Biosystems Engineering and Soil Science, The University of Tennessee, Knoxville, TN 37996, USA; (X.L.); (M.R.)
| | - Rongjiu Shi
- Key Laboratory of Pollution Ecology and Environmental Engineering, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, China; (L.Z.); (R.S.); (P.L.); (S.W.); (S.H.)
| | - Ping Li
- Key Laboratory of Pollution Ecology and Environmental Engineering, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, China; (L.Z.); (R.S.); (P.L.); (S.W.); (S.H.)
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jinyi Zhao
- No. 2 Oil Production Company, Daqing Oilfield Limited Company, Daqing 163414, China; (J.Z.); (G.L.)
| | - Guoqiao Li
- No. 2 Oil Production Company, Daqing Oilfield Limited Company, Daqing 163414, China; (J.Z.); (G.L.)
| | - Shuang Wang
- Key Laboratory of Pollution Ecology and Environmental Engineering, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, China; (L.Z.); (R.S.); (P.L.); (S.W.); (S.H.)
| | - Siqin Han
- Key Laboratory of Pollution Ecology and Environmental Engineering, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, China; (L.Z.); (R.S.); (P.L.); (S.W.); (S.H.)
| | - Mark Radosevich
- Department of Biosystems Engineering and Soil Science, The University of Tennessee, Knoxville, TN 37996, USA; (X.L.); (M.R.)
| | - Ying Zhang
- Key Laboratory of Pollution Ecology and Environmental Engineering, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, China; (L.Z.); (R.S.); (P.L.); (S.W.); (S.H.)
- Correspondence:
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Köstner N, Jürgens K, Labrenz M, Herndl GJ, Winter C. Uneven host cell growth causes lysogenic virus induction in the Baltic Sea. PLoS One 2019; 14:e0220716. [PMID: 31386696 PMCID: PMC6684075 DOI: 10.1371/journal.pone.0220716] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2019] [Accepted: 07/22/2019] [Indexed: 12/04/2022] Open
Abstract
In the Baltic Sea redoxcline, lysogenic viruses infecting prokaryotes have rarely been detected using the commonly used inducing agent mitomycin C. However, it is well known that not all viruses are induceable by mitomycin C and growing evidence suggests that changes in trophic conditions may trigger the induction of lysogenic viruses. We hypothesized that using antibiotics to simulate a strong change in trophic conditions for antibiotica-resistant cells due to reduced competition for resources might lead to the induction of lysogenic viruses into the lytic cycle within these cells. This hypothesis was tested by incubating prokaryotes obtained throughout the Baltic Sea redoxcline in seawater with substantially reduced numbers of viruses. We used a mixture of the protein synthesis-inhibiting antibiotics streptomycin and erythromycin to induce the desired changes in trophic conditions for resistant cells and at the same time ensuring that no progeny viruses were formed in sensitive cells. No inducible lysogenic viruses could be detected in incubations amended with mitomycin C. Yet, the presence of streptomycin and erythromycin increased virus-induced mortality of prokaryotes by 56–930% compared to controls, resulting in the induction of lysogenic viruses equivalent to 2–14% of in situ prokaryotic abundance. The results indicate the existence of a previously unrecognized induction mechanism for lysogenic viruses in the Baltic Sea redoxcline, as the mode of action distinctly differs between the used antibiotics (no virus production within affected cells) and mitomycin C (lysogenic viruses are produced within affected cells). Obtaining accurate experimental data on levels of lysogeny in prokaryotic host cells remains challenging, as relying on mitomycin C alone may severely underestimate lysogeny.
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Affiliation(s)
- Nicole Köstner
- Department of Limnology and Bio-Oceanography, Center of Functional Ecology, University of Vienna, Vienna, Austria
| | - Klaus Jürgens
- Department of Biological Oceanography, Leibniz Institute for Baltic Sea Research (IOW), Rostock-Warnemünde, Germany
| | - Matthias Labrenz
- Department of Biological Oceanography, Leibniz Institute for Baltic Sea Research (IOW), Rostock-Warnemünde, Germany
| | - Gerhard J. Herndl
- Department of Limnology and Bio-Oceanography, Center of Functional Ecology, University of Vienna, Vienna, Austria
- NIOZ, Department of Marine Microbiology and Biogeochemistry, Royal Netherlands Institute for Sea Research, Utrecht University, AB Den Burg, The Netherlands
| | - Christian Winter
- Department of Limnology and Bio-Oceanography, Center of Functional Ecology, University of Vienna, Vienna, Austria
- * E-mail:
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Roux S, Brum JR. A viral reckoning: viruses emerge as essential manipulators of global ecosystems. ENVIRONMENTAL MICROBIOLOGY REPORTS 2019; 11:3-8. [PMID: 30298570 DOI: 10.1111/1758-2229.12700] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2018] [Accepted: 09/30/2018] [Indexed: 06/08/2023]
Affiliation(s)
- Simon Roux
- US DOE Joint Genome Institute, Lawrence Berkeley National Laboratory, Walnut Creek, CA, 94598, USA
| | - Jennifer R Brum
- Department of Oceanography and Coastal Sciences, Louisiana State University, Baton Rouge, LA, 70808, USA
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Parvathi A, Jasna V, Aparna S, Pradeep Ram AS, Aswathy VK, Balachandran KK, Muraleedharan KR, Mathew D, Sime-Ngando T. High Incidence of Lysogeny in the Oxygen Minimum Zones of the Arabian Sea (Southwest Coast of India). Viruses 2018; 10:v10110588. [PMID: 30373217 PMCID: PMC6267222 DOI: 10.3390/v10110588] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2018] [Revised: 09/19/2018] [Accepted: 09/20/2018] [Indexed: 12/24/2022] Open
Abstract
Though microbial processes in the oxygen minimum zones (OMZs) of the Arabian Sea (AS) are well documented, prokaryote-virus interactions are less known. The present study was carried out to determine the potential physico-chemical factors influencing viral abundances and their life strategies (lytic and lysogenic) along the vertical gradient in the OMZ of the AS (southwest coast of India). Water samples were collected during the southwest monsoon (SWM) season in two consecutive years (2015 and 2016) from different depths, namely, the surface layer, secondary chlorophyll a maxima (~30–40 m), oxycline (~70–80 m), and hypoxic/suboxic layers (~200–350 m). The high viral abundances observed in oxygenated surface waters (mean ± SD = 6.1 ± 3.4 × 106 viral-like particles (VLPs) mL−1), drastically decreased with depth in the oxycline region (1.2 ± 0.5 × 106 VLPs mL−1) and hypoxic/suboxic waters (0.3 ± 0.3 × 106 VLPs mL−1). Virus to prokaryote ratio fluctuated in the mixed layer (~10) and declined significantly (p < 0.001) to 1 in the hypoxic layer. Viral production (VP) and frequency of virus infected cells (FIC) were maximum in the surface and minimum in the oxycline layer, whereas the viral lysis was undetectable in the suboxic/hypoxic layer. The detection of a high percentage of lysogeny in suboxic (48%) and oxycline zones (9–24%), accompanied by undetectable rates of lytic viral infection support the hypothesis that lysogeny may represent the major survival strategy for viruses in unproductive or harsh nutrient/host conditions in deoxygenated waters.
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Affiliation(s)
- Ammini Parvathi
- CSIR-National Institute of Oceanography, Regional Centre (CSIR), Kochi 682 018, India.
| | - Vijayan Jasna
- CSIR-National Institute of Oceanography, Regional Centre (CSIR), Kochi 682 018, India.
| | - Sreekumar Aparna
- CSIR-National Institute of Oceanography, Regional Centre (CSIR), Kochi 682 018, India.
| | - Angia Sriram Pradeep Ram
- Laboratoire Microorganismes, Génome et Environnement, UMR CNRS 6023, Université Clermont-Auvergne, 1 Impasse Amélie Murat, 63178 Aubière CEDEX, France.
| | | | | | | | - Dayana Mathew
- CSIR-National Institute of Oceanography, Regional Centre (CSIR), Kochi 682 018, India.
| | - Telesphore Sime-Ngando
- Laboratoire Microorganismes, Génome et Environnement, UMR CNRS 6023, Université Clermont-Auvergne, 1 Impasse Amélie Murat, 63178 Aubière CEDEX, France.
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Hewson I, Bistolas KSI, Button JB, Jackson EW. Occurrence and seasonal dynamics of RNA viral genotypes in three contrasting temperate lakes. PLoS One 2018; 13:e0194419. [PMID: 29543885 PMCID: PMC5854377 DOI: 10.1371/journal.pone.0194419] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2017] [Accepted: 03/04/2018] [Indexed: 11/18/2022] Open
Abstract
Decades of research have demonstrated the crucial importance of viruses in freshwater ecosystems. However, few studies have focused on the seasonal dynamics and potential hosts of RNA viruses. We surveyed microbial-sized (i.e. 5-0.2 μm) mixed community plankton transcriptomes for RNA viral genomes and investigated their distribution between microbial and macrobial plankton over a seasonal cycle across three temperate lakes by quantitative reverse transcriptase PCR (qRT-PCR). A total of 30 contigs bearing similarity to RNA viral genomes were recovered from a global assembly of 30 plankton RNA libraries. Of these, only 13 were found in >2 libraries and recruited >100 reads (of 9.13 x 107 total reads), representing several picornaviruses, two tobamoviruses and a reovirus. We quantified the abundance of four picornaviruses and the reovirus monthly from August 2014 to May 2015. Patterns of viral abundance in the >5 μm size fraction and representation in microbial-sized community RNA libraries over time suggest that one picornavirus genotype (TS24835) and the reovirus (TS148892) may infect small (<5 μm) eukaryotic microorganisms, while two other picornaviruses (TS24641 and TS4340) may infect larger (>5 μm) eukaryotic microorganisms or metazoa. Our data also suggest that picornavirus TS152062 may originate from an allochthonous host. All five viral genotypes were present in at least one size fraction across all 3 lakes during the year, suggesting that RNA viruses may easily disperse between adjacent aquatic habitats. Our data therefore demonstrate that RNA viruses are widespread in temperate lacustrine ecosystems, and may provide evidence of viral infection in larger eukaryotes (including metazoa) inhabiting the lakes.
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Affiliation(s)
- Ian Hewson
- Department of Microbiology, Cornell University, Ithaca, NY United States of America
| | - Kalia S. I. Bistolas
- Department of Microbiology, Cornell University, Ithaca, NY United States of America
| | - Jason B. Button
- Department of Microbiology, Cornell University, Ithaca, NY United States of America
| | - Elliot W. Jackson
- Department of Microbiology, Cornell University, Ithaca, NY United States of America
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Winter C, Köstner N, Kruspe C, Urban D, Muck S, Reinthaler T, Herndl GJ. Mixing alters the lytic activity of viruses in the dark ocean. Ecology 2018; 99:700-713. [PMID: 29315529 PMCID: PMC5905300 DOI: 10.1002/ecy.2135] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/05/2017] [Revised: 10/17/2017] [Accepted: 12/18/2017] [Indexed: 11/11/2022]
Abstract
In aquatic habitats, viral lysis of prokaryotic cells lowers the overall efficiency of the microbial loop, by which dissolved organic carbon is transfered to higher trophic levels. Mixing of water masses in the dark ocean occurs on a global scale and may have far reaching consequences for the different prokaryotic and virus communities found in these waters by altering the environmental conditions these communities experience. We hypothesize that mixing of deep ocean water masses enhances the lytic activity of viruses infecting prokaryotes. To address this hypothesis, major deep-sea water masses of the Atlantic Ocean such as North Atlantic Deep Water, Mediterranean Sea Overflow Water, Antarctic Intermediate Water, and Antarctic Bottom Water were sampled at five locations. Prokaryotic cells from these samples were collected by filtration and subsequently incubated in virus-reduced water from either the same (control) or a different water mass (transplantation treatment). Additionally, mixtures of prokaryotes obtained from two different water masses were incubated in a mixture of virus-reduced water from the same water masses (control) or in virus-reduced water from the source water masses separately (mixing treatments). Pronounced differences in productivity-related parameters (prokaryotic leucine incorporation, prokaryotic and viral abundance) between water masses caused strong changes in viral lysis of prokaryotes. Often, mixing of water masses increased viral lysis of prokaryotes, indicating that lysogenic viruses were induced into the lytic cycle. Mixing-induced changes in viral lysis had a strong effect on the community composition of prokaryotes and viruses. Our data show that mixing of deep-sea water masses alters levels of viral lysis of prokaryotes and in many cases weakens the efficiency of the microbial loop by enhancing the recycling of organic carbon in the deep ocean.
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Affiliation(s)
- Christian Winter
- Department of Limnology and Bio‐OceanographyCenter of EcologyUniversity of ViennaAlthanstrasse 14Vienna1090Austria
| | - Nicole Köstner
- Department of Limnology and Bio‐OceanographyCenter of EcologyUniversity of ViennaAlthanstrasse 14Vienna1090Austria
| | - Carl‐Philip Kruspe
- Department of Limnology and Bio‐OceanographyCenter of EcologyUniversity of ViennaAlthanstrasse 14Vienna1090Austria
| | - Damaris Urban
- Department of Limnology and Bio‐OceanographyCenter of EcologyUniversity of ViennaAlthanstrasse 14Vienna1090Austria
| | - Simone Muck
- Department of Limnology and Bio‐OceanographyCenter of EcologyUniversity of ViennaAlthanstrasse 14Vienna1090Austria
| | - Thomas Reinthaler
- Department of Limnology and Bio‐OceanographyCenter of EcologyUniversity of ViennaAlthanstrasse 14Vienna1090Austria
| | - Gerhard J. Herndl
- Department of Limnology and Bio‐OceanographyCenter of EcologyUniversity of ViennaAlthanstrasse 14Vienna1090Austria
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