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Zhao Z, Zhao Y, Marotta F, Xamxidin M, Li H, Xu J, Hu B, Wu M. The microbial community structure and nitrogen cycle of high-altitude pristine saline lakes on the Qinghai-Tibetan plateau. Front Microbiol 2024; 15:1424368. [PMID: 39132143 PMCID: PMC11312105 DOI: 10.3389/fmicb.2024.1424368] [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: 04/27/2024] [Accepted: 06/18/2024] [Indexed: 08/13/2024] Open
Abstract
The nitrogen (N) cycle is the foundation of the biogeochemistry on Earth and plays a crucial role in global climate stability. It is one of the most important nutrient cycles in high-altitude lakes. The biogeochemistry of nitrogen is almost entirely dependent on redox reactions mediated by microorganisms. However, the nitrogen cycling of microbial communities in the high-altitude saline lakes of the Qinghai-Tibet Plateau (QTP), the world's "third pole" has not been investigated extensively. In this study, we used a metagenomic approach to investigate the microbial communities in four high-altitude pristine saline lakes in the Altun mountain on the QTP. We observed that Proteobacteria, Bacteroidota, and Actinobacteriota were dominant in these lakes. We reconstructed 1,593 bacterial MAGs and 8 archaeal MAGs, 1,060 of which were found to contain nitrogen cycle related genes. Our analysis revealed that nitrite reduction, nitrogen fixation, and assimilatory nitrate reduction processes might be active in the lakes. Denitrification might be a major mechanism driving the potential nitrogen loss, while nitrification might be inactive. A wide variety of microorganisms in the lake, dominated by Proteobacteria, participate together in the nitrogen cycle. The prevalence of the dominant taxon Yoonia in these lakes may be attributed to its well-established nitrogen functions and the coupled proton dynamics. This study is the first to systematically investigate the structure and nitrogen function of the microbial community in the high-altitude pristine saline lakes in the Altun mountain on the QTP. As such, it contributes to a better comprehension of biogeochemistry of high-altitude saline lakes.
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Affiliation(s)
- Zhe Zhao
- College of Life Sciences, Zhejiang University, Hangzhou, China
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Yuxiang Zhao
- Environmental Microbiome Engineering and Biotechnology Laboratory, Center for Environmental Engineering Research, Department of Civil Engineering, The University of Hong Kong, Pokfulam, Hong Kong SAR, China
- College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, China
| | - Federico Marotta
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | | | - Huan Li
- Lab of Plateau Ecology and Nature Conservation, The Altun Mountain National Nature Reserve, Xinjiang, China
| | - Junquan Xu
- Lab of Plateau Ecology and Nature Conservation, The Altun Mountain National Nature Reserve, Xinjiang, China
| | - Baolan Hu
- College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, China
- Zhejiang Province Key Laboratory for Water Pollution Control and Environmental Safety, Hangzhou, China
- Key Laboratory of Environment Remediation and Ecological Health, Ministry of Education, College of Environmental Resource Sciences, Zhejiang University, Hangzhou, China
| | - Min Wu
- College of Life Sciences, Zhejiang University, Hangzhou, China
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Handler ER, Andersen SDJ, Gradinger R, McGovern M, Vader A, Poste AE. Seasonality in land-ocean connectivity and local processes control sediment bacterial community structure and function in a High Arctic tidal flat. FEMS Microbiol Ecol 2024; 100:fiad162. [PMID: 38111220 PMCID: PMC10799726 DOI: 10.1093/femsec/fiad162] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Revised: 10/26/2023] [Accepted: 12/14/2023] [Indexed: 12/20/2023] Open
Abstract
Climate change is altering patterns of precipitation, cryosphere thaw, and land-ocean influxes, affecting understudied Arctic estuarine tidal flats. These transitional zones between terrestrial and marine systems are hotspots for biogeochemical cycling, often driven by microbial processes. We investigated surface sediment bacterial community composition and function from May to September along a river-intertidal-subtidal-fjord gradient. We paired metabarcoding of in situ communities with in vitro carbon-source utilization assays. Bacterial communities differed in space and time, alongside varying environmental conditions driven by local seasonal processes and riverine inputs, with salinity emerging as the dominant structuring factor. Terrestrial and riverine taxa were found throughout the system, likely transported with runoff. In vitro assays revealed sediment bacteria utilized a broader range of organic matter substrates when incubated in fresh and brackish water compared to marine water. These results highlight the importance of salinity for ecosystem processes in these dynamic tidal flats, with the highest potential for utilization of terrestrially derived organic matter likely limited to tidal flat areas (and times) where sediments are permeated by freshwater. Our results demonstrate that intertidal flats must be included in future studies on impacts of increased riverine discharge and transport of terrestrial organic matter on coastal carbon cycling in a warming Arctic.
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Affiliation(s)
- Eleanor R Handler
- Department of Arctic and Marine Biology, UiT – The Arctic University of Norway, Framstredet 39, 9019 Tromsø, Norway
- Department of Arctic Biology, The University Centre in Svalbard, P.O. Box 156, 9171 Longyearbyen, Norway
- Norwegian Institute for Water Research, Fram Centre for High North Research, Hjalmar Johansensgate 14, 9007 Tromsø, Norway
| | - Sebastian D J Andersen
- Department of Arctic and Marine Biology, UiT – The Arctic University of Norway, Framstredet 39, 9019 Tromsø, Norway
- Department of Arctic Biology, The University Centre in Svalbard, P.O. Box 156, 9171 Longyearbyen, Norway
- Norwegian Institute for Water Research, Fram Centre for High North Research, Hjalmar Johansensgate 14, 9007 Tromsø, Norway
| | - Rolf Gradinger
- Department of Arctic and Marine Biology, UiT – The Arctic University of Norway, Framstredet 39, 9019 Tromsø, Norway
| | - Maeve McGovern
- Department of Arctic and Marine Biology, UiT – The Arctic University of Norway, Framstredet 39, 9019 Tromsø, Norway
- Norwegian Institute for Water Research, Fram Centre for High North Research, Hjalmar Johansensgate 14, 9007 Tromsø, Norway
| | - Anna Vader
- Department of Arctic Biology, The University Centre in Svalbard, P.O. Box 156, 9171 Longyearbyen, Norway
| | - Amanda E Poste
- Department of Arctic and Marine Biology, UiT – The Arctic University of Norway, Framstredet 39, 9019 Tromsø, Norway
- Norwegian Institute for Water Research, Fram Centre for High North Research, Hjalmar Johansensgate 14, 9007 Tromsø, Norway
- Norwegian Institute for Nature Research, Fram Centre for High North Research, Hjalmar Johansensgate 14, 9007 Tromsø, Norway
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Hwang K, Choe H, Kim KM. Complete genome of Polaribacter huanghezhanensis KCTC 32516 T isolated from glaciomarine fjord sediment of Svalbard. Mar Genomics 2023; 72:101068. [PMID: 38008528 DOI: 10.1016/j.margen.2023.101068] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Revised: 08/17/2023] [Accepted: 08/18/2023] [Indexed: 11/28/2023]
Abstract
Polaribacter huanghezhanensis KCTC 32516T is an aerobic, non-flagellated, Gram-negative, orange-colony-forming bacterium that was isolated from the surficial glaciomarine sediment of inner basin of Kongsfjorden, Svalbard. The sampling site is characterized by a sedimentation of organic depleted lithogenous particles from the nearby glaciers, resulting in reduction of organic matter concentration. In order to understand microbial adaptation to the oligotrophic environment, we here sequenced the complete genome of the P. huanghezhanensis KCTC 32516T. The genome consists of 2,587,874 bp (G + C content of 31.5%) with a single chromosome, 2391 protein-coding genes, 39 tRNAs, and 2 rRNA operons. Our comparative analysis revealed that the P. huanghezhanensis possess the smallest genome in fifteen Polaribacter species with genome. The streamlined genome of this species, required less resource in replication, could evolved by the nutrient deficiency in surrounding environment. Simultaneously, the 15 KOs involved in amino acid biosynthesis and anaplerotic carbon fixation is uniquely absent in the P. huanghezhanensis. In addition, although the advantage of small genome, other 15 KOs involved in resource recycling and stress resistance is uniquely present in sequenced genome. This result demonstrates that the sequenced genome serves as a valuable model for further studies aimed at elucidating the molecular mechanisms associated with adaptation to oligotrophic habitat.
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Affiliation(s)
- Kyuin Hwang
- Division of Polar Life Sciences, Korea Polar Research Institute, 26 Songdomirae-ro, Yeonsu-gu, Incheon 21990, Republic of Korea.
| | - Hanna Choe
- Biological Resource Center, Korea Research Institute of Bioscience and Biotechnology, 181 Ipsin-gil, Jeongeup 56212, Republic of Korea
| | - Kyung Mo Kim
- Division of Polar Life Sciences, Korea Polar Research Institute, 26 Songdomirae-ro, Yeonsu-gu, Incheon 21990, Republic of Korea
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Amiour S, Chekroud K, Font-Verdera F, Anver S, Liébana R, Hafdi O, Viver T. Overview of the Diversity of Extremely Saline Soils from a Semi-Arid Region Using 16S rRNA Gene Sequencing: A Case Study of the Sebkhas in Algerian High Plateaus. Microbiology (Reading) 2022. [DOI: 10.1134/s0026261722100472] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
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Jain A, Krishnan KP. Marine Group-II archaea dominate particle-attached as well as free-living archaeal assemblages in the surface waters of Kongsfjorden, Svalbard, Arctic Ocean. Antonie van Leeuwenhoek 2021; 114:633-647. [PMID: 33694023 PMCID: PMC7945612 DOI: 10.1007/s10482-021-01547-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/07/2020] [Accepted: 02/16/2021] [Indexed: 01/23/2023]
Abstract
Marine archaea are a significant component of the global oceanic ecosystems, including the polar oceans. However, only a few attempts have been made to study archaea in the high Arctic fjords. Given the importance of Archaea in carbon and nitrogen cycling, it is imperative to explore their diversity and community composition in the high Arctic fjords, such as Kongsfjorden (Svalbard). In the present study, we evaluated archaeal diversity and community composition in the size-fractionated microbial population, viz-a-viz free-living (FL; 0.2-3 μm) and particle-attached (PA; > 3 μm) using archaeal V3-V4 16S rRNA gene amplicon sequencing. Our results indicate that the overall archaeal community in the surface water of Kongsfjorden was dominated by the members of the marine group-II (MGII) archaea, followed by the MGI group members, including Nitrosopumilaceae and Nitrososphaeraceae. Although a clear niche partitioning between PA and FL archaeal communities was not observed, 2 OTUs among 682 OTUs, and 3 ASVs out of 1932 ASVs were differentially abundant among the fractions. OTU001/ASV0002, classified as MGIIa, was differentially abundant in the PA fraction. OTU006/ASV0006/ASV0010 affiliated with MGIIb were differentially abundant in the FL fraction. Particulate organic nitrogen and C:N ratio were the most significant variables (P < 0.05) explaining the observed variation in the FL and PA archaeal communities, respectively. These results indicate an exchange between archaeal communities or a generalist lifestyle switching between FL and PA fractions. Besides, the particles' elemental composition (carbon and nitrogen) seems to play an essential role in shaping the PA archaeal communities in the surface waters of Kongsfjorden.
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Affiliation(s)
- Anand Jain
- Arctic Division, National Centre for Polar and Ocean Research, Ministry of Earth Sciences, Vasco-da-Gama, Goa, India.
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