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Microbial Diversity in the Indian Ocean Sediments: An Insight into the Distribution and Associated Factors. Curr Microbiol 2022; 79:115. [PMID: 35195780 DOI: 10.1007/s00284-022-02801-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2021] [Accepted: 11/23/2021] [Indexed: 11/03/2022]
Abstract
Indian Ocean is the third largest oceanic division of the world and shelter to a huge microbial diversity. These microbes play an important role in the metabolism of carbon, sulfur, nitrogen, and phosphorus in the ocean water. They are also major contributors of carbon fixing and sequestration, as much as terrestrial plants to achieve CO2 emissions reduction. The prokaryotic community in the East Indian Ocean primarily comprises of heterotrophic bacteria like Alphaproteobacteria and Gammaproteobacteria, followed by Firmicutes and Actinobacteria. The Arabian Sea and the Bay of Bengal are typically characterized by presence of vast areas of oxygen minimum zones (OMZs) and have been witnessing a shift in the microbial diversity due to the changing conditions in the ocean water. Several canonical correspondence analyses reveal temperature, salinity, and phosphate levels as crucial environmental factors in propelling the distribution of diazotrophs. The viral consortia are dominated by the Caudovirales, an order of tailed bacteriophages. Due to the rapid change in the environmental factors such as topography, temperature, and sunlight contributing toward climate change, their role in sustaining the chemical composition of the ocean can be drastically affected especially with the evidence of several bacterial and fungal communities responding to latitudinal and temperature change. Therefore, we aim to critically review the status of microbial diversity in Indian Ocean to predict their response toward climate change as they are the sentinels of change in marine life and to understand the dynamics of microbial communities in the various locations of Indian Ocean.
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Microbial Abundance and Diversity in Subsurface Lower Oceanic Crust at Atlantis Bank, Southwest Indian Ridge. Appl Environ Microbiol 2021; 87:e0151921. [PMID: 34469194 DOI: 10.1128/aem.01519-21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
International Ocean Discovery Program Expedition 360 drilled Hole U1473A at Atlantis Bank, an oceanic core complex on the Southwest Indian Ridge, with the aim of recovering representative samples of the lower oceanic crust. Recovered cores were primarily gabbro and olivine gabbro. These mineralogies may host serpentinization reactions that have the potential to support microbial life within the recovered rocks or at greater depths beneath Atlantis Bank. We quantified prokaryotic cells and analyzed microbial community composition for rock samples obtained from Hole U1473A and conducted nutrient addition experiments to assess if nutrient supply influences the composition of microbial communities. Microbial abundance was low (≤104 cells cm-3) but positively correlated with the presence of veins in rocks within some depth ranges. Due to the heterogeneous nature of the rocks downhole (alternating stretches of relatively unaltered gabbros and more significantly altered and fractured rocks), the strength of the positive correlations between rock characteristics and microbial abundances was weaker when all depths were considered. Microbial community diversity varied at each depth analyzed. Surprisingly, addition of simple organic acids, ammonium, phosphate, or ammonium plus phosphate in nutrient addition experiments did not affect microbial diversity or methane production in nutrient addition incubation cultures over 60 weeks. The work presented here from Site U1473A, which is representative of basement rock samples at ultraslow spreading ridges and the usually inaccessible lower oceanic crust, increases our understanding of microbial life present in this rarely studied environment and provides an analog for basement below ocean world systems such as Enceladus. IMPORTANCE The lower oceanic crust below the seafloor is one of the most poorly explored habitats on Earth. The rocks from the Southwest Indian Ridge (SWIR) are similar to rock environments on other ocean-bearing planets and moons. Studying this environment helps us increase our understanding of life in other subsurface rocky environments in our solar system that we do not yet have the capability to access. During an expedition to the SWIR, we drilled 780 m into lower oceanic crust and collected over 50 rock samples to count the number of resident microbes and determine who they are. We also selected some of these rocks for an experiment where we provided them with different nutrients to explore energy and carbon sources preferred for growth. We found that the number of resident microbes and community structure varied with depth. Additionally, added nutrients did not shape the microbial diversity in a predictable manner.
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Garlapati D, Kumar BC, Muthukumar C, Madeswaran P, Ramu K, Murthy MVR. Assessing the in situ bacterial diversity and composition at anthropogenically active sites using the environmental DNA (eDNA). MARINE POLLUTION BULLETIN 2021; 170:112593. [PMID: 34126444 DOI: 10.1016/j.marpolbul.2021.112593] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2020] [Revised: 05/28/2021] [Accepted: 05/30/2021] [Indexed: 06/12/2023]
Abstract
In this study, we identified the in situ bacterial groups and their community structure in coastal waters influenced by anthropogenic inputs. The use of environmental DNA (eDNA) and high throughput sequencing (HTS) were employed to derive accurate and reliable information on bacterial abundance. The V3 and V4 hypervariable regions of the 16S rRNA gene were amplified and the sequences were clustered into operational taxonomic units to analyze the site-specific variations in community composition. The percentage composition within the bacterial orders varied significantly among nearshore anthropogenic hotspots and offshore (5 km) samples. The microbial network constructed taking the bacterial abundance as nodes displayed strong positive and negative correlations within the bacterial families. Overall, the use of eDNA coupled with HTS is an incredible means for monitoring and assessing the abundance of bacterial communities and also serves as a biomonitoring tool to understand the degree of anthropogenic contamination in coastal waters.
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Affiliation(s)
- Deviram Garlapati
- National Centre for Coastal Research, Ministry of Earth Sciences (MoES), Government of India, Chennai 600100, India.
| | - B Charan Kumar
- National Centre for Coastal Research, Ministry of Earth Sciences (MoES), Government of India, Chennai 600100, India
| | - C Muthukumar
- National Centre for Coastal Research, Ministry of Earth Sciences (MoES), Government of India, Chennai 600100, India
| | - P Madeswaran
- National Centre for Coastal Research, Ministry of Earth Sciences (MoES), Government of India, Chennai 600100, India
| | - K Ramu
- National Centre for Coastal Research, Ministry of Earth Sciences (MoES), Government of India, Chennai 600100, India
| | - M V Ramana Murthy
- National Centre for Coastal Research, Ministry of Earth Sciences (MoES), Government of India, Chennai 600100, India
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Baumas CMJ, Le Moigne FAC, Garel M, Bhairy N, Guasco S, Riou V, Armougom F, Grossart HP, Tamburini C. Mesopelagic microbial carbon production correlates with diversity across different marine particle fractions. THE ISME JOURNAL 2021; 15:1695-1708. [PMID: 33452475 PMCID: PMC8163737 DOI: 10.1038/s41396-020-00880-z] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Revised: 12/02/2020] [Accepted: 12/09/2020] [Indexed: 01/29/2023]
Abstract
The vertical flux of marine snow particles significantly reduces atmospheric carbon dioxide concentration. In the mesopelagic zone, a large proportion of the organic carbon carried by sinking particles dissipates thereby escaping long term sequestration. Particle associated prokaryotes are largely responsible for such organic carbon loss. However, links between this important ecosystem flux and ecological processes such as community development of prokaryotes on different particle fractions (sinking vs. non-sinking) are yet virtually unknown. This prevents accurate predictions of mesopelagic organic carbon loss in response to changing ocean dynamics. Using combined measurements of prokaryotic heterotrophic production rates and species richness in the North Atlantic, we reveal that carbon loss rates and associated microbial richness are drastically different with particle fractions. Our results demonstrate a strong negative correlation between prokaryotic carbon losses and species richness. Such a trend may be related to prokaryotes detaching from fast-sinking particles constantly enriching non-sinking associated communities in the mesopelagic zone. Existing global scale data suggest this negative correlation is a widespread feature of mesopelagic microbes.
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Affiliation(s)
- Chloé M. J. Baumas
- grid.500499.10000 0004 1758 6271Aix-Marseille Université, Université de Toulon, CNRS, IRD, Mediterranean Institute of Oceanography (MIO, UM 110), Marseille, France
| | - Frédéric A. C. Le Moigne
- grid.500499.10000 0004 1758 6271Aix-Marseille Université, Université de Toulon, CNRS, IRD, Mediterranean Institute of Oceanography (MIO, UM 110), Marseille, France
| | - Marc Garel
- grid.500499.10000 0004 1758 6271Aix-Marseille Université, Université de Toulon, CNRS, IRD, Mediterranean Institute of Oceanography (MIO, UM 110), Marseille, France
| | - Nagib Bhairy
- grid.500499.10000 0004 1758 6271Aix-Marseille Université, Université de Toulon, CNRS, IRD, Mediterranean Institute of Oceanography (MIO, UM 110), Marseille, France
| | - Sophie Guasco
- grid.500499.10000 0004 1758 6271Aix-Marseille Université, Université de Toulon, CNRS, IRD, Mediterranean Institute of Oceanography (MIO, UM 110), Marseille, France
| | - Virginie Riou
- grid.500499.10000 0004 1758 6271Aix-Marseille Université, Université de Toulon, CNRS, IRD, Mediterranean Institute of Oceanography (MIO, UM 110), Marseille, France
| | - Fabrice Armougom
- grid.500499.10000 0004 1758 6271Aix-Marseille Université, Université de Toulon, CNRS, IRD, Mediterranean Institute of Oceanography (MIO, UM 110), Marseille, France
| | - Hans-Peter Grossart
- grid.419247.d0000 0001 2108 8097Department of Experimental Limnology, Leibniz Institute of Freshwater Ecology and Inland Fisheries, Stechlin, Germany ,grid.11348.3f0000 0001 0942 1117Institute of Biochemistry and Biology, Postdam University, 14469 Potsdam, Germany
| | - Christian Tamburini
- grid.500499.10000 0004 1758 6271Aix-Marseille Université, Université de Toulon, CNRS, IRD, Mediterranean Institute of Oceanography (MIO, UM 110), Marseille, France
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Yang SH, Park MJ, Kwon KK. Oricola thermophila sp. nov., a marine bacterium isolated from tidal flat sediment and emended description of the genus Oricola Hameed et al. 2015. Int J Syst Evol Microbiol 2020; 71. [PMID: 33263513 DOI: 10.1099/ijsem.0.004574] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
A Gram-stain-negative, facultatively anaerobic, rod-shaped (1.8-4.4×0.5-0.7 µm) and motile marine bacterium, designated as MEBiC13590T, was isolated from tidal flat sediment sampled at Incheon City, on the west coast of the Republic of Korea. The 16S rRNA gene sequence analysis revealed that strain MEBiC13590T showed high similarity to Oricola cellulosilytica CC-AMH-0T (98.2 %), followed by Oceaniradius stylonematis StC1T (97.5 %); however, it clustered with Oricola cellulosilytica. The phylogenomic tree inferred by the up-to-date bacterial core gene set suggested that strain MEBiC13590T shared a phyletic line with Oricola cellulosilytica. Average nucleotide identity and digital DNA-DNA hybridization values (75.0 and 19.3 %, respectively) between strain MEBiC13590T and Oricola cellulosilytica CC-AMH-0T were below the respective species delineation cutoffs. Growth was observed at 22-50 °C (optimum, 45 °C), at pH 5-9 (optimum, pH 7) and with 1-6 % (optimum, 3 %) NaCl. The predominant cellular fatty acids were C16 : 0 (7.6 %), C18 : 0 (12.2 %), 11-methyl C18 : 1 ω7c (5.7 %), C19 : 0 cyclo ω6c and summed feature 8 (comprising C18 : 1 ω7c and/or C18 : 1 ω6c; 38 %). The DNA G+C content was 63.5 mol%. The major respiratory quinone was Q-10. Several phenotypic characteristics such as growth temperature, oxygen requirement, enzyme activities of urease, gelatinase, lipase (C14), α-chymotrypsin, acid phosphatase, β-galactosidase, β-glucosidase etc. differentiate strain MEBiC13590T from Oricola cellulosilytica CC-AMH-0T. Based on this polyphasic taxonomic data, strain MEBiC13590T should be classified as representing a novel species in the genus Oricola for which the name Oricola thermophila sp. nov. is proposed . The type strain is MEBiC13590T (=KCCM 43313T=JCM 33661T).
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Affiliation(s)
- Sung-Hyun Yang
- Marine Biotechnology Research Center, Korea Institute of Ocean Science & Technology, 385, Haeyang-ro, Yeongdo-gu, Busan, Republic of Korea
| | - Mi-Jeong Park
- KIOST School, University of Science and Technology, Daejeon, Republic of Korea
- Marine Biotechnology Research Center, Korea Institute of Ocean Science & Technology, 385, Haeyang-ro, Yeongdo-gu, Busan, Republic of Korea
| | - Kae Kyoung Kwon
- KIOST School, University of Science and Technology, Daejeon, Republic of Korea
- Marine Biotechnology Research Center, Korea Institute of Ocean Science & Technology, 385, Haeyang-ro, Yeongdo-gu, Busan, Republic of Korea
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Li S, Luo Z, Ji G. Seasonal function succession and biogeographic zonation of assimilatory and dissimilatory nitrate-reducing bacterioplankton. THE SCIENCE OF THE TOTAL ENVIRONMENT 2018; 637-638:1518-1525. [PMID: 29801245 DOI: 10.1016/j.scitotenv.2018.05.020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Revised: 05/01/2018] [Accepted: 05/02/2018] [Indexed: 06/08/2023]
Abstract
The dominance of different nitrate-reducing pathways determines nitrogen cycling patterns. Denitrification (DNF) has been widely studied, but assimilatory nitrate reduction (ANR) and dissimilatory nitrate reduction to ammonium (DNRA) have received much less attention. Their ecological patterns and responsible microbes are poorly understood. Here, we studied the structure and function succession of the three functional groups in the middle route of the South-to-North Water Diversion Project, which is a 1230 km canal spanning 8 degrees of latitude. The results reflected a nitrogen-removing pattern dominated by DNF in the summer and a nitrogen-retaining pattern dominated by ANR and DNRA in the winter. Stenotrophomonas, a typical denitrifier, was the keystone species in the summer and contributed to N2O production. Clostridium, a genus able to conduct ANR and DNRA, was the keystone species in the winter. Notably, a significant zonation pattern was discovered. According to the community structure, the system could be separated into two biogeographic zones, and the Yellow River (about latitude 35°N) is an important cut-off line. This bacterial biogeography followed different water characteristics and ecological processes. ANR was found to be an important process and seasonally transformed its habitat from the northern zone to the southern zone. DNRA bacteria were acclimated to the northern zone and favored at this region in both seasons. The generation of N2O, a strong greenhouse gas, also exhibited this zonation pattern. This is the first study to consider assimilatory and dissimilatory nitrate reducers together at a molecular level, and provides new insights into the underlying patterns of a nitrate-reducing bacterioplankton community.
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Affiliation(s)
- Shengjie Li
- Key Laboratory of Water and Sediment Sciences, Ministry of Education, Department of Environmental Engineering, Peking University, Beijing 100871, China
| | - Zhongxin Luo
- Key Laboratory of Water and Sediment Sciences, Ministry of Education, Department of Environmental Engineering, Peking University, Beijing 100871, China
| | - Guodong Ji
- Key Laboratory of Water and Sediment Sciences, Ministry of Education, Department of Environmental Engineering, Peking University, Beijing 100871, China.
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