Results provide critical insights into the ecological succession from an anaerobic, chemolithotrophy-rich preharvest microbial community to an aerobic, photosynthetically driven postharvest assemblage, advancing the understanding of microbial biogeochemistry in managed hypersaline ecosystems.
Abstract
Solar salt pans are extreme hypersaline environments that represent functionally specialised microbial communities mediating essential biogeochemical transformation. Vedaranyam, a coastal region of the Bay of Bengal containing artificially constructed solar salterns for salt production. There is limited information available on the metagenome diversity and functional profiling of this saltpan, which prompted us to investigate it. Here, we report the first whole metagenome sequencing to explore the dynamics of the functional structure of microbial communities in saltpan during the preharvest and postharvest phases of salt production. Methanobacteriota and Pseudomonadota dominated both phases at the phylum level, while Halobacteria comprised the most abundant class (53.2% preharvest; 48% postharvest). A notable bloom of Dactylococcopsis salina was observed during postharvest (4.28% to 12.67%) and flock doubling of Cyanobacterota relative abundance (5.5% to 10.6%), reflecting photosynthetic primary production following salt removal. Conversely, during postharvest phase sulfur oxidising Guyparkeria halophila reduced 23 fold, while the DMSP accumulating osmolyte producer Salinibaculum marinum dominated preharvest (6.98%). However, functional classification of the metagenome revealed active participation of the microbial community across five major biogeochemical cycles. Encompassing carbon fixation by cyanobacteria and diverse haloarchaea, nitrogen cycling through diazotrophy and denitrification, a cryptic preharvest sulfur cycle coupling sulfate reduction and sulphide oxidation, phase shifted DMSP catabolism, and light driven bacteriorhodopsin through archaeal energy conservation. Metagenomic assembly yielded ten metagenomic assembled genomes (MAGs), revealing the taxonomic diversity and metabolic potential of the dominant halophilic community across biogeochemical cycles. These results provide critical insights into the ecological succession from an anaerobic, chemolithotrophy-rich preharvest microbial community to an aerobic, photosynthetically driven postharvest assemblage, advancing our understanding of microbial biogeochemistry in managed hypersaline ecosystems.
An extensive culturomics study of 549 isolates from the hypersaline soils of the Odiel Saltmarshes Natural Area and compared the results with previously generated shotgun metagenomic datasets demonstrate the complementarity of culturomics and metagenomics and provide an insight into the microbial communities inhabiting the hypersaline soils of the Odiel Saltmarshes.
Analysis of microbiome samples collected from hadal seawaters via in situ filtration during 12 human-occupied vehicle dives identifies 135,073 non-redundant active proteins, with over 95% being hadal-specific.
Wei-Jia Zhang, Aoran Hu, Ziheng Wu et al.· Cell Host and Microbe· 0 citations
The plastisphere is an emerging anthropogenic ecosystem hosting complex microbial assemblages. While heterotrophic colonizers are well studied, the role of primary producers such as cyanobacteria remains underexplored. Here, we reanalyzed 16S rRNA gene amplicon data from 3160 plastisphere samples across 62 aquatic studies to assess their role in community assembly at a global scale. Substrate type explained a significant but relatively small fraction of variation (R2 = 0.048), whereas β-diversity showed clear separation between marine and freshwater communities. Among all substrate types (plastic, microplastic, natural polymer, and nonplastic), plastic-associated communities exhibited the highest estimated contribution of deterministic assembly processes in both freshwater and marine ecosystems. Co-occurrence networks showed low modularity and high clustering, revealing recurrent community association patterns across plastisphere data sets, while several topologically central taxa exhibited frequent associations with cyanobacteria. Notably, Xenococcaceae and Phormidesmiaceae were consistently enriched on plastics relative to surrounding environments. Independent metagenomic analyses corroborate enrichment of Phormidesmiaceae. These results demonstrate recurrent cyanobacterial enrichment in plastisphere communities and identify co-occurrence patterns between cyanobacteria and heterotrophic taxa. These associations generate hypotheses regarding possible phototroph-heterotroph linkages on plastic surfaces that warrant experimental investigation.
Saesha Verma, Sakcham Bairoliya, Ya-Fen Wang et al.· Environmental Science and Te...· 0 citations
A comprehensive genome‑resolved assessment of the taxonomic and functional diversity of the Lake Karum microbiome is provided and microbial taxa with the potential to drive key carbon, nitrogen, and sulfur cycling processes in a hypersaline lake are identified.
M. Macey, Velislava Ilieva, B. Stephens et al.· Environmental Microbiome· 0 citations
ABSTRACT The shallow hydrothermal system of the Tagoro submarine volcano (Canary Islands, Spain) has been discharging low‐temperature, nutrient‐rich, acidic fluids high in CO2 and H2S since March 2012. Despite influencing local microbial communities, the effects of these hydrothermal fluids on community structure and diversity across spatial gradients remain poorly understood. Using 16S rRNA gene sequencing, we observed significant differences in prokaryotic community structure from epipelagic waters to benthic habitats affected by hydrothermal activity. Prokaryotic richness and diversity decreased closer to hydrothermal sources, yet novel taxa were prevalent across all hydrothermally influenced habitats. Archaeal diversity was low and dominated by ammonia‐oxidising Nitrosopumilaceae, while bacterial communities were more diverse, including iron‐oxidising Mariprofundaceae, methane‐oxidising Methylomonadaceae and metabolically versatile Rhodobacteraceae. Molecular analyses revealed microbial specialisation within these families, complementing scanning electron microscopy observations of active bacterial biomineralization in chimney fragments linked to Mariprofundaceae members. Together, these findings offer new insights into the ecology and functional potential of microbial assemblages in the Tagoro hydrothermal system, suggesting their involvement in nitrogen, iron, sulphur and methane cycling. This study advances our understanding of microbial distribution patterns in shallow‐sea hydrothermal fields and highlights the high prevalence of novel taxa with potential biotechnological relevance.
Clàudia Pérez-Barrancos, E. Fraile-Nuez, J. A. Lozano-Rodríguez et al.· Environmental Microbiology· 0 citations
It is demonstrated that environmental filtering shapes both the taxonomic and functional organization of Antarctic microbiomes and highlight polar ecosystems as reservoirs of unexplored biosynthetic diversity with potential biotechnological relevance.
William B. Medeiros, Kelly Hidalgo-Martinez, D. D. P. S. Penna et al.· World Journal of Microbiolog...· 0 citations
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