Stoichiometric imbalance drives predictable microbial response to enhanced methane flux in marine sediments
ID：736
Oral Presentation
2027-01-13 14:15 （China Standard Time）
Session：Session 14 - Microbial connectivity at the deep-sea floor: sediment–water interactions, particles, and benthic–pelagic coupling
Abstract
Deep-sea sediments are dynamic interfaces that link upward methane supply from subseafloor reservoirs with microbial carbon and nutrient cycling across the sediment-water boundary. Yet the ecological principles governing microbial responses to abrupt methane supply remain poorly constrained. We investigated a newly activated methane leakage site at 1,766 m water depth in the Qiongdongnan Basin, South China Sea, where gas-hydrate exploration triggered enhanced methane release. Annual in situ observations from 2022 to 2025, together with adjacent non-seep and mature seep references, allowed us to resolve microbial succession across an early-stage seep-development chronosequence.
By integrating high-resolution sediment geochemistry, metagenomics, community-aggregated trait analysis, genome-scale metabolic modeling and machine learning, we found that methane leakage produced a transient stoichiometric imbalance characterized by elevated dissolved inorganic nitrogen relative to dissolved inorganic carbon. Metagenomic reconstruction of 3,080 species-level representative genomes showed that this shift was accompanied by rapid restructuring of benthic microbial communities: early leakage-impacted sediments were enriched in larger-genome, faster-growing copiotrophs, higher biosynthetic and nitrogen-metabolism potential, and intensified metabolic competition. Over subsequent years, communities progressively moved toward mature seep-like assemblages dominated by slower-growing, more streamlined taxa and stronger metabolic complementarity. Pairwise metabolic modeling further suggested that phylogenetically and genomically divergent taxa formed the strongest cross-feeding relationships, with larger-genome organisms tending to act as metabolite donors and streamlined taxa as recipients.
Resource stoichiometry, particularly the DIN:DIC ratio, emerged as a key predictor of community-weighted genome size, microbial life-history axes and interspecies interaction structure. These trait axes further predicted methane-derived carbon allocation into organic and inorganic carbon pools. Our results reveal a stoichiometry-trait-function framework linking subsurface methane input, sediment biogeochemistry and microbial connectivity at the deep-sea floor, providing a mechanistic basis for forecasting benthic microbial succession and carbon transformation under changing methane fluxes.
By integrating high-resolution sediment geochemistry, metagenomics, community-aggregated trait analysis, genome-scale metabolic modeling and machine learning, we found that methane leakage produced a transient stoichiometric imbalance characterized by elevated dissolved inorganic nitrogen relative to dissolved inorganic carbon. Metagenomic reconstruction of 3,080 species-level representative genomes showed that this shift was accompanied by rapid restructuring of benthic microbial communities: early leakage-impacted sediments were enriched in larger-genome, faster-growing copiotrophs, higher biosynthetic and nitrogen-metabolism potential, and intensified metabolic competition. Over subsequent years, communities progressively moved toward mature seep-like assemblages dominated by slower-growing, more streamlined taxa and stronger metabolic complementarity. Pairwise metabolic modeling further suggested that phylogenetically and genomically divergent taxa formed the strongest cross-feeding relationships, with larger-genome organisms tending to act as metabolite donors and streamlined taxa as recipients.
Resource stoichiometry, particularly the DIN:DIC ratio, emerged as a key predictor of community-weighted genome size, microbial life-history axes and interspecies interaction structure. These trait axes further predicted methane-derived carbon allocation into organic and inorganic carbon pools. Our results reveal a stoichiometry-trait-function framework linking subsurface methane input, sediment biogeochemistry and microbial connectivity at the deep-sea floor, providing a mechanistic basis for forecasting benthic microbial succession and carbon transformation under changing methane fluxes.
Speaker
Author
Important Dates
-
Jan 30
2026
Session / Event proposals open
-
Mar 31
2026
Session / Event proposals close
（Extended to April 7） -
Apr 30
2026
Session acceptance notifications
-
Apr 30
2026
Abstract submissions & registration open
-
Jun 30
2026
Abstract submissions close
（Extended to July 21） -
Aug 31
2026
Abstract acceptance notifications
-
Sep 15
2026
Scientific program released
-
Oct 15
2026
Early bird registration closes
-
Jan 12–15
2027
XMAS 2027