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Gladkov GV, Kimeklis AK, Tembotov RK, Ivanov MN, Andronov EE, Abakumov EV. Linking the composition of cryoconite prokaryotic communities in the Arctic, Antarctic, and Central Caucasus with their chemical characteristics. Sci Rep 2024; 14:15838. [PMID: 38982048 PMCID: PMC11233692 DOI: 10.1038/s41598-024-64452-3] [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: 08/31/2023] [Accepted: 06/10/2024] [Indexed: 07/11/2024] Open
Abstract
Cryoconites are the deposits on the surface of glaciers that create specific ecological niches for the development of microorganism communities. The sediment material can vary in origin, structure, and nutrient content, creating local variations in the growth conditions. An additional factor of variability is the location of the glaciers, as they are found in different climatic zones in the high mountain regions and closer to the poles. Here, using the analysis of amplicon sequencing of the 16S rRNA gene, we studied the taxonomic composition of the prokaryotic communities from glaciers from remote regions, including the Arctic (Mushketova on the Severnaya Zemlya, IGAN in Polar Ural), Antarctic (Pimpirev on the Livingstone Island) and Central Caucasus (Skhelda and Garabashi) and connected it with the variation of the physicochemical characteristics of the substrate: pH, carbon, nitrogen, macro- and microelements. The cryoconite microbiomes were comprised of specific for this environment phyla (mostly Pseudomonadota, Cyanobacteria, Bacteroidota, Acidobacteriota, and Actinobacteriota), but each glacier had a unique taxonomic imprint. The core microbiome between regions was composed of only a few ASVs, among which the most likely globally distributed ones attributed to Polaromonas sp., Rhodoferax sp., Cryobacterium sp., and Hymenobacter frigidus. The WGSNA defined clusters of co-occurring ASVs between microbiomes, that significantly change their abundance corresponding with the variation of chemical parameters of cryoconites, but do not fully coincide with their regional separation. Thus, our work demonstrates that the chemical characteristics of the sediment material can explain the variation in the cryoconite prokaryotic community which is not always linked to geographic isolation.
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Affiliation(s)
- Grigory V Gladkov
- Department of Applied Ecology, St. Petersburg State University, Saint-Petersburg, Russia, 199034
- Laboratory of Microbiological Monitoring and Bioremediation of Soils, All-Russian Research Institute for Agricultural Microbiology, Pushkin, Russia, 196608
| | - Anastasiia K Kimeklis
- Department of Applied Ecology, St. Petersburg State University, Saint-Petersburg, Russia, 199034
- Laboratory of Microbiological Monitoring and Bioremediation of Soils, All-Russian Research Institute for Agricultural Microbiology, Pushkin, Russia, 196608
| | - Rustam Kh Tembotov
- Department of Applied Ecology, St. Petersburg State University, Saint-Petersburg, Russia, 199034
- Tembotov Institute of Ecology of Mountain Territories, Russian Academy of Sciences, Nalchik, Russia, 360051
| | - Mikhail N Ivanov
- Department of Cryolithology and Glaciology, Lomonosov Moscow State University, GSP-1, Leninskie Gory, Moscow, Russia, 119991
| | - Evgeny E Andronov
- Laboratory of Microbiological Monitoring and Bioremediation of Soils, All-Russian Research Institute for Agricultural Microbiology, Pushkin, Russia, 196608
- V.V. Dokuchaev Soil Science Institute, Moscow, Russia, 119017
| | - Evgeny V Abakumov
- Department of Applied Ecology, St. Petersburg State University, Saint-Petersburg, Russia, 199034.
- Laboratory of Microbiological Monitoring and Bioremediation of Soils, All-Russian Research Institute for Agricultural Microbiology, Pushkin, Russia, 196608.
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Yang Y, Zhou GJ, Li Z, Sun J, Wong AST, Ko VCC, Wu RSS, Lai KP. Effects of benzophenone-3 and its metabolites on the marine diatom Chaetoceros neogracilis: Underlying mechanisms and environmental implications. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 923:171371. [PMID: 38432364 DOI: 10.1016/j.scitotenv.2024.171371] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2023] [Revised: 02/19/2024] [Accepted: 02/27/2024] [Indexed: 03/05/2024]
Abstract
The wide application of benzophenones (BPs), such as benzophenone-3 (BP3), as an ingredient in sunscreens, cosmetics, coatings, and plastics, has led to their global contamination in aquatic environments. Using the marine diatom Chaetoceros neogracilis as a model, this study assessed the toxic effects and mechanisms of BP3 and its two major metabolites (BP8 and BP1). The results showed that BP3 exhibited higher toxicity on C. neogracilis than BP8 and BP1, with their 72-h median effective concentrations being 0.4, 0.8 and 4 mg/L, respectively. Photosynthesis efficiencies were significantly reduced after exposure to environmentally relevant concentrations of the three benzophenones, while cell viability, membrane integrity, membrane potential, and metabolic activities could be further impaired at their higher concentrations. Comparative transcriptomic analysis, followed by gene ontology and KEGG pathway enrichment analyses unraveled that all the three tested benzophenones disrupted photosynthesis and nitrogen metabolism of the diatom through alteration of similar pathways. The toxic effect of BP3 was also attributable to its unique inhibitory effects on eukaryotic ribosome biosynthesis and DNA replication. Taken together, our findings underscore that benzophenones may pose a significant threat to photosynthesis, oxygen production, primary productivity, carbon fixation, and the nitrogen cycle of diatom in coastal waters worldwide.
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Affiliation(s)
- Yi Yang
- State Key Laboratory of Marine Pollution and Department of Chemistry, City University of Hong Kong, Hong Kong
| | - Guang-Jie Zhou
- Department of Ecology and Institute of Hydrobiology, Jinan University, Guangzhou 510632, PR China
| | - Ziying Li
- State Key Laboratory of Chemical Oncogenomics, Key Laboratory of Chemical Biology, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, PR China; Shenzhen Academy of Metrology & Quality Inspection, Shenzhen 518055, PR China
| | - Jiaji Sun
- School of Energy and Environment and State Key Laboratory of Marine Pollution, City University of Hong Kong, Kowloon, Hong Kong
| | | | - Vincent Chi Chiu Ko
- State Key Laboratory of Marine Pollution and Department of Chemistry, City University of Hong Kong, Hong Kong
| | - Rudolf Shiu Sun Wu
- State Key Laboratory of Marine Pollution and Department of Chemistry, City University of Hong Kong, Hong Kong; Department of Science and Environmental Studies, The Education University of Hong Kong, Hong Kong
| | - Keng Po Lai
- Key Laboratory of Environmental Pollution and Integrative Omics, Education Department of Guangxi Zhuang Autonomous Region, Guilin Medical University, Guilin, PR China; State Key Laboratory of Marine Pollution and Department of Chemistry, City University of Hong Kong, Hong Kong.
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Lumian J, Sumner DY, Grettenberger CL, Jungblut AD, Irber L, Pierce-Ward NT, Brown CT. Biogeographic distribution of five Antarctic cyanobacteria using large-scale k-mer searching with sourmash branchwater. Front Microbiol 2024; 15:1328083. [PMID: 38440141 PMCID: PMC10909832 DOI: 10.3389/fmicb.2024.1328083] [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: 10/26/2023] [Accepted: 02/06/2024] [Indexed: 03/06/2024] Open
Abstract
Cyanobacteria form diverse communities and are important primary producers in Antarctic freshwater environments, but their geographic distribution patterns in Antarctica and globally are still unresolved. There are however few genomes of cultured cyanobacteria from Antarctica available and therefore metagenome-assembled genomes (MAGs) from Antarctic cyanobacteria microbial mats provide an opportunity to explore distribution of uncultured taxa. These MAGs also allow comparison with metagenomes of cyanobacteria enriched communities from a range of habitats, geographic locations, and climates. However, most MAGs do not contain 16S rRNA gene sequences, making a 16S rRNA gene-based biogeography comparison difficult. An alternative technique is to use large-scale k-mer searching to find genomes of interest in public metagenomes. This paper presents the results of k-mer based searches for 5 Antarctic cyanobacteria MAGs from Lake Fryxell and Lake Vanda, assigned the names Phormidium pseudopriestleyi FRX01, Microcoleus sp. MP8IB2.171, Leptolyngbya sp. BulkMat.35, Pseudanabaenaceae cyanobacterium MP8IB2.15, and Leptolyngbyaceae cyanobacterium MP9P1.79 in 498,942 unassembled metagenomes from the National Center for Biotechnology Information (NCBI) Sequence Read Archive (SRA). The Microcoleus sp. MP8IB2.171 MAG was found in a wide variety of environments, the P. pseudopriestleyi MAG was found in environments with challenging conditions, the Leptolyngbyaceae cyanobacterium MP9P1.79 MAG was only found in Antarctica, and the Leptolyngbya sp. BulkMat.35 and Pseudanabaenaceae cyanobacterium MP8IB2.15 MAGs were found in Antarctic and other cold environments. The findings based on metagenome matches and global comparisons suggest that these Antarctic cyanobacteria have distinct distribution patterns ranging from locally restricted to global distribution across the cold biosphere and other climatic zones.
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Affiliation(s)
- Jessica Lumian
- Department of Earth and Planetary Sciences, Microbiology Graduate Group, University of California Davis, Davis, CA, United States
| | - Dawn Y. Sumner
- Department of Earth and Planetary Sciences, University of California Davis, Davis, CA, United States
| | - Christen L. Grettenberger
- Department of Earth and Planetary Sciences, University of California Davis, Davis, CA, United States
- Department of Environmental Toxicology, University of California Davis, Davis, CA, United States
| | - Anne D. Jungblut
- Department of Science, The Natural History Museum, London, United Kingdom
| | - Luiz Irber
- Population Health and Reproduction, University of California Davis, Davis, CA, United States
| | - N. Tessa Pierce-Ward
- Population Health and Reproduction, University of California Davis, Davis, CA, United States
| | - C. Titus Brown
- Population Health and Reproduction, University of California Davis, Davis, CA, United States
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Lumian J, Grettenberger C, Jungblut AD, Mackey TJ, Hawes I, Alatorre-Acevedo E, Sumner DY. Genomic profiles of four novel cyanobacteria MAGs from Lake Vanda, Antarctica: insights into photosynthesis, cold tolerance, and the circadian clock. Front Microbiol 2024; 14:1330602. [PMID: 38282730 PMCID: PMC10812107 DOI: 10.3389/fmicb.2023.1330602] [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: 10/31/2023] [Accepted: 11/29/2023] [Indexed: 01/30/2024] Open
Abstract
Cyanobacteria in polar environments face environmental challenges, including cold temperatures and extreme light seasonality with small diurnal variation, which has implications for polar circadian clocks. However, polar cyanobacteria remain underrepresented in available genomic data, and there are limited opportunities to study their genetic adaptations to these challenges. This paper presents four new Antarctic cyanobacteria metagenome-assembled genomes (MAGs) from microbial mats in Lake Vanda in the McMurdo Dry Valleys in Antarctica. The four MAGs were classified as Leptolyngbya sp. BulkMat.35, Pseudanabaenaceae cyanobacterium MP8IB2.15, Microcoleus sp. MP8IB2.171, and Leptolyngbyaceae cyanobacterium MP9P1.79. The MAGs contain 2.76 Mbp - 6.07 Mbp, and the bin completion ranges from 74.2-92.57%. Furthermore, the four cyanobacteria MAGs have average nucleotide identities (ANIs) under 90% with each other and under 77% with six existing polar cyanobacteria MAGs and genomes. This suggests that they are novel cyanobacteria and demonstrates that polar cyanobacteria genomes are underrepresented in reference databases and there is continued need for genome sequencing of polar cyanobacteria. Analyses of the four novel and six existing polar cyanobacteria MAGs and genomes demonstrate they have genes coding for various cold tolerance mechanisms and most standard circadian rhythm genes with the Leptolyngbya sp. BulkMat.35 and Leptolyngbyaceae cyanobacterium MP9P1.79 contained kaiB3, a divergent homolog of kaiB.
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Affiliation(s)
- Jessica Lumian
- Department of Earth and Planetary Sciences, Microbiology Graduate Group, University of California Davis, Davis, CA, United States
| | - Christen Grettenberger
- Department of Earth and Planetary Sciences, University of California Davis, Davis, CA, United States
- Department of Environmental Toxicology, University of California Davis, Davis, CA, United States
| | - Anne D. Jungblut
- Department of Sciences, The Natural History Museum, London, United Kingdom
| | - Tyler J. Mackey
- Department of Earth and Planetary Sciences, University of New Mexico, Albuquerque, NM, United States
| | - Ian Hawes
- Coastal Marine Field Station, University of Waikato, Tauranga, New Zealand
| | - Eduardo Alatorre-Acevedo
- Department of Earth and Planetary Sciences, University of California Davis, Davis, CA, United States
| | - Dawn Y. Sumner
- Department of Earth and Planetary Sciences, University of California Davis, Davis, CA, United States
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Mashamaite L, Lebre PH, Varliero G, Maphosa S, Ortiz M, Hogg ID, Cowan DA. Microbial diversity in Antarctic Dry Valley soils across an altitudinal gradient. Front Microbiol 2023; 14:1203216. [PMID: 37555066 PMCID: PMC10406297 DOI: 10.3389/fmicb.2023.1203216] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2023] [Accepted: 06/23/2023] [Indexed: 08/10/2023] Open
Abstract
INTRODUCTION The Antarctic McMurdo Dry Valleys are geologically diverse, encompassing a wide variety of soil habitats. These environments are largely dominated by microorganisms, which drive the ecosystem services of the region. While altitude is a well-established driver of eukaryotic biodiversity in these Antarctic ice-free areas (and many non-Antarctic environments), little is known of the relationship between altitude and microbial community structure and functionality in continental Antarctica. METHODS We analysed prokaryotic and lower eukaryotic diversity from soil samples across a 684 m altitudinal transect in the lower Taylor Valley, Antarctica and performed a phylogenic characterization of soil microbial communities using short-read sequencing of the 16S rRNA and ITS marker gene amplicons. RESULTS AND DISCUSSION Phylogenetic analysis showed clear altitudinal trends in soil microbial composition and structure. Cyanobacteria were more prevalent in higher altitude samples, while the highly stress resistant Chloroflexota and Deinococcota were more prevalent in lower altitude samples. We also detected a shift from Basidiomycota to Chytridiomycota with increasing altitude. Several genera associated with trace gas chemotrophy, including Rubrobacter and Ornithinicoccus, were widely distributed across the entire transect, suggesting that trace-gas chemotrophy may be an important trophic strategy for microbial survival in oligotrophic environments. The ratio of trace-gas chemotrophs to photoautotrophs was significantly higher in lower altitude samples. Co-occurrence network analysis of prokaryotic communities showed some significant differences in connectivity within the communities from different altitudinal zones, with cyanobacterial and trace-gas chemotrophy-associated taxa being identified as potential keystone taxa for soil communities at higher altitudes. By contrast, the prokaryotic network at low altitudes was dominated by heterotrophic keystone taxa, thus suggesting a clear trophic distinction between soil prokaryotic communities at different altitudes. Based on these results, we conclude that altitude is an important driver of microbial ecology in Antarctic ice-free soil habitats.
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Affiliation(s)
- Lefentse Mashamaite
- Department of Biochemistry, Genetics and Microbiology, Centre for Microbial Ecology and Genomics, University of Pretoria, Pretoria, South Africa
| | - Pedro H. Lebre
- Department of Biochemistry, Genetics and Microbiology, Centre for Microbial Ecology and Genomics, University of Pretoria, Pretoria, South Africa
| | - Gilda Varliero
- Department of Biochemistry, Genetics and Microbiology, Centre for Microbial Ecology and Genomics, University of Pretoria, Pretoria, South Africa
- Rhizosphere Processes Group, Swiss Federal Research Institute WSL, Birmensdorf, Switzerland
| | - Silindile Maphosa
- Department of Biochemistry, Genetics and Microbiology, Centre for Microbial Ecology and Genomics, University of Pretoria, Pretoria, South Africa
| | - Max Ortiz
- Department of Biochemistry, Genetics and Microbiology, Centre for Microbial Ecology and Genomics, University of Pretoria, Pretoria, South Africa
- Clemson University Genomics & Bioinformatics Facility, Clemson University, Clemson, SC, United States
| | - Ian D. Hogg
- Department of Biochemistry, Genetics and Microbiology, Centre for Microbial Ecology and Genomics, University of Pretoria, Pretoria, South Africa
- School of Science, University of Waikato, Hamilton, New Zealand
- Canadian High Arctic Research Station, Polar Knowledge Canada, Cambridge Bay, NU, Canada
| | - Don A. Cowan
- Department of Biochemistry, Genetics and Microbiology, Centre for Microbial Ecology and Genomics, University of Pretoria, Pretoria, South Africa
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Pessi IS, Popin RV, Durieu B, Lara Y, Tytgat B, Savaglia V, Roncero-Ramos B, Hultman J, Verleyen E, Vyverman W, Wilmotte A. Novel diversity of polar Cyanobacteria revealed by genome-resolved metagenomics. Microb Genom 2023; 9:mgen001056. [PMID: 37417735 PMCID: PMC10438808 DOI: 10.1099/mgen.0.001056] [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: 02/03/2023] [Accepted: 05/30/2023] [Indexed: 07/08/2023] Open
Abstract
Benthic microbial mats dominated by Cyanobacteria are important features of polar lakes. Although culture-independent studies have provided important insights into the diversity of polar Cyanobacteria, only a handful of genomes have been sequenced to date. Here, we applied a genome-resolved metagenomics approach to data obtained from Arctic, sub-Antarctic and Antarctic microbial mats. We recovered 37 metagenome-assembled genomes (MAGs) of Cyanobacteria representing 17 distinct species, most of which are only distantly related to genomes that have been sequenced so far. These include (i) lineages that are common in polar microbial mats such as the filamentous taxa Pseudanabaena, Leptolyngbya, Microcoleus/Tychonema and Phormidium; (ii) the less common taxa Crinalium and Chamaesiphon; (iii) an enigmatic Chroococcales lineage only distantly related to Microcystis; and (iv) an early branching lineage in the order Gloeobacterales that is distributed across the cold biosphere, for which we propose the name Candidatus Sivonenia alaskensis. Our results show that genome-resolved metagenomics is a powerful tool for expanding our understanding of the diversity of Cyanobacteria, especially in understudied remote and extreme environments.
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Affiliation(s)
- Igor S. Pessi
- Department of Microbiology, University of Helsinki, Helsinki, Finland
- Helsinki Institute of Sustainability Science (HELSUS), Helsinki, Finland
| | - Rafael V. Popin
- Department of Microbiology, University of Helsinki, Helsinki, Finland
| | - Benoit Durieu
- InBioS – Centre for Protein Engineering, University of Liège, Liège, Belgium
| | - Yannick Lara
- Early Life Traces & Evolution-Astrobiology, UR-Astrobiology, University of Liège, Liège, Belgium
| | - Bjorn Tytgat
- Laboratory of Protistology & Aquatic Ecology, Ghent University, Ghent, Belgium
| | - Valentina Savaglia
- InBioS – Centre for Protein Engineering, University of Liège, Liège, Belgium
- Laboratory of Protistology & Aquatic Ecology, Ghent University, Ghent, Belgium
| | - Beatriz Roncero-Ramos
- InBioS – Centre for Protein Engineering, University of Liège, Liège, Belgium
- Department of Plant Biology and Ecology, University of Sevilla, Sevilla, Spain
| | - Jenni Hultman
- Department of Microbiology, University of Helsinki, Helsinki, Finland
- Helsinki Institute of Sustainability Science (HELSUS), Helsinki, Finland
- Natural Resources Institute Finland (LUKE), Helsinki, Finland
| | - Elie Verleyen
- Laboratory of Protistology & Aquatic Ecology, Ghent University, Ghent, Belgium
| | - Wim Vyverman
- Laboratory of Protistology & Aquatic Ecology, Ghent University, Ghent, Belgium
| | - Annick Wilmotte
- InBioS – Centre for Protein Engineering, University of Liège, Liège, Belgium
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Trivedi CB, Keuschnig C, Larose C, Rissi DV, Mourot R, Bradley JA, Winkel M, Benning LG. DNA/RNA Preservation in Glacial Snow and Ice Samples. Front Microbiol 2022; 13:894893. [PMID: 35677909 PMCID: PMC9168539 DOI: 10.3389/fmicb.2022.894893] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2022] [Accepted: 04/29/2022] [Indexed: 11/13/2022] Open
Abstract
The preservation of nucleic acids for high-throughput sequencing is an ongoing challenge for field scientists. In particular, samples that are low biomass, or that have to be collected and preserved in logistically challenging environments (such as remote sites or during long sampling campaigns) can pose exceptional difficulties. With this work, we compare and assess the effectiveness of three preservation methods for DNA and RNA extracted from microbial communities of glacial snow and ice samples. Snow and ice samples were melted and filtered upon collection in Iceland, and filters were preserved using: (i) liquid nitrogen flash freezing, (ii) storage in RNAlater, or (iii) storage in Zymo DNA/RNA Shield. Comparative statistics covering nucleic acid recovery, sequencing library preparation, genome assembly, and taxonomic diversity were used to determine best practices for the preservation of DNA and RNA samples from these environments. Our results reveal that microbial community composition based on DNA was comparable at the class level across preservation types. Based on extracted RNA, the taxonomic composition of the active community was primarily driven by the filtered sample volume (i.e., biomass content). In low biomass samples (where <200 ml of sample volume was filtered) the taxonomic and functional signatures trend toward the composition of the control samples, while in samples where a larger volume (more biomass) was filtered our data showed comparable results independent of preservation type. Based on all comparisons our data suggests that flash freezing of filters containing low biomass is the preferred method for preserving DNA and RNA (notwithstanding the difficulties of accessing liquid nitrogen in remote glacial field sites). Generally, RNAlater and Zymo DNA/RNA Shield solutions work comparably well, especially for DNA from high biomass samples, but Zymo DNA/RNA Shield is favored due to its higher yield of preserved RNA. Biomass quantity from snow and ice samples appears to be the most important factor in regards to the collection and preservation of samples from glacial environments.
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Affiliation(s)
- Christopher B Trivedi
- Interface Geochemistry, GFZ German Research Centre for Geosciences, Potsdam, Germany
| | | | - Catherine Larose
- Environmental Microbial Genomics, Université de Lyon, Ecully Cedex, France
| | | | - Rey Mourot
- Interface Geochemistry, GFZ German Research Centre for Geosciences, Potsdam, Germany.,Department of Earth Sciences, Freie Universität Berlin, Berlin, Germany
| | - James A Bradley
- Interface Geochemistry, GFZ German Research Centre for Geosciences, Potsdam, Germany.,School of Geography, Queen Mary University of London, London, United Kingdom
| | - Matthias Winkel
- Interface Geochemistry, GFZ German Research Centre for Geosciences, Potsdam, Germany
| | - Liane G Benning
- Interface Geochemistry, GFZ German Research Centre for Geosciences, Potsdam, Germany.,Department of Earth Sciences, Freie Universität Berlin, Berlin, Germany
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Emerging Ecotone and Microbial Community of a Sulfidic Spring in the Reka River near Škocjanske Jame, Slovenia. DIVERSITY 2021. [DOI: 10.3390/d13120655] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
During long periods with no precipitation, a sulfidic spring (Smrdljivec) appears in the dry bed of the Reka River before sinking into the karst underground. The study characterizes the area’s geological setting, development of microbial communities and an ecotone, and impact on the vulnerable karst ecosystem. Geological mapping of the area, stable isotopic analyses, field measurements, and physico-chemical and toxicity analyses were applied to elucidate the environmental conditions. The spring’s microbial diversity was assessed using cultivation methods, microscopy, and metagenomics. Sulfur compounds in the spring probably originate from coal layers in the vicinity. Metagenomic analyses revealed 175 distinct operational taxonomic units in spring water and biofilms. Proteobacteria predominated in developed biofilms, and a “core” microbiome was represented by methylotrophs, including Methylobacter, Methylomonas, and Methylotenera. Diatoms represented an important component of biofilm biomass. A combination of environmental factors and climatic conditions allows the formation and accessibility of emerging biodiversity hotspots and ecotones. Details of their dynamic nature, global impact, and distribution should be highlighted further and given more protection.
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