How Hypersaline Brines Drive Microbial Transitions and Carbon Metabolism Plasticity

Microbial communities shift with salinity and K⁺, altering succession & carbon‑use strategies across evaporation stages.



Microbial community transition and carbon metabolism plasticity under continuous evaporative salinization in hypersaline brines


HIGHLIGHT

  • •
    Microbial dominance shifted from Euryarchaeota to Proteobacteria, with increasing α-diversity.
  • •
    Potassium ion was a key driver, negatively regulating overall carbon metabolism but promoting amino acid utilization.
  • •
    Carbon metabolic capacity showed plasticity, initially inhibited then recovered along the salinization gradient.
  • •
    Microbial adaptive strategies mediating carbon cycling under extreme and fluctuating salinity.


Abstract

Saline lakes are critical yet fragile ecosystems where microbial communities drive biogeochemical cycles under extreme salinity gradients, yet their adaptive mechanisms to evaporative salinization remain poorly understood. This study investigated microbial community dynamics and carbon source utilization strategies across five distinct evaporation stages (from original brine to residue brine) in salt reservoirs of the Charkhan Salt Lake, Tibetan Plateau. High-throughput 16S rRNA sequencing revealed a transition from archaeal dominance (Euryarchaeota) in early stages to bacterial dominance (Proteobacteria) as salinity increased, accompanied by a significant rise in α-diversity (146 to 711 OTUs). Biolog-ECO analysis, which measures metabolic potential under standardized conditions, revealed that microbial carbon utilization capacity initially declined but later recovered, among which potassium ion (K+) concentration showed the strongest negative correlation with both metabolic intensity and carbon source diversity. Further analysis of experimental data indicated that, elevated K+ levels suppressed carbohydrate utilization while promoting amino acid metabolism in later stages. These findings suggest the adaptive resilience of microbial communities to salinity fluctuations in hypersaline environments and indicate their core role in regulating carbon cycling, demonstrating that the patterns of microbial community succession and carbon source utilization are jointly shaped by salinity and potassium ions dynamics.

Read full article for free (open access):
https://www.sciencedirect.com/science/article/pii/S2666517426001100




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