California Grassland Precipitation Legacy Soil Community

Community ID CommunityMech:000215

Ecological State PERTURBED

Environment California Mediterranean-climate grassland soil
ENVO:00005750

A semiarid California Mediterranean-climate grassland soil microbial community studied under two field-imposed precipitation regimes (100 percent versus 50 percent of mean annual precipitation) and assayed during the first autumn rewet. Quantitative H2-18O stable-isotope-probing, 16S rRNA amplicon sequencing, metagenomics, and metatranscriptomics revealed that reduced winter precipitation imposed a lasting legacy on community turnover: microbial growth declined by about one order of magnitude and mortality by about two orders of magnitude relative to ambient plots, lowering community growth efficiency (new biomass growth divided by respiration). Soil organic carbon shifted from microbial-necromass-derived lipid-, amino-sugar-, and protein-like compounds toward more oxidized lignin- and tannin-like plant detritus compounds. Meta-omics linked high-CGE communities to N-rich necromass consumption with elevated amino acid and peptidoglycan biosynthesis and aromatic compound degradation, while low-CGE communities had elevated carbohydrate metabolism and lipid turnover consistent with plant-detritus processing and membrane maintenance.

Taxonomy

Taxon	Ontology ID	Functional Roles	Abundance
grassland soil bacteria	NCBITaxon:2	PRIMARY_DEGRADER SECONDARY_FERMENTER	DOMINANT
PMID:41964077 - SUPPORT (IN_VIVO) "measured microbial growth and mortality via quantitative 18O stable isotope probing and 16S rRNA gene amplicon sequencing"

Ecological Interactions

Taxon

Cross-feeding

Mutualism

Syntrophy

Competition

Commensalism

Niche partitioning

Colonization facilitation

Strain competition

Predation

Necromass Cross-Feeding at High Community Growth Efficiency

CROSS_FEEDING

Metabolites: amino acid (CHEBI:33709), peptidoglycan (CHEBI:8005)

Biological Processes:

aromatic compound catabolic process (GO:0019439)
amino acid biosynthetic process (GO:0008652)
peptidoglycan biosynthetic process (GO:0009252)

Evidence

PMID:41964077 - SUPPORT (IN_VIVO)

"microbes appeared to consume more energetically favorable N-rich necromass"
PMID:41964077 - SUPPORT (IN_VIVO)

"increased amino acids and peptidoglycan biosynthesis and greater aromatic compound degradation"

Plant Detritus Degradation at Low Community Growth Efficiency

COMPETITION

Biological Processes:

carbohydrate metabolic process (GO:0005975)
lipid metabolic process (GO:0006629)

Evidence

PMID:41964077 - SUPPORT (IN_VIVO)

"communities had elevated carbohydrate metabolism and lipid turnover"
PMID:41964077 - SUPPORT (IN_VIVO)

"increased investment in plant detritus degradation and membrane repair and maintenance rather than growth"

Precipitation-Legacy Turnover Suppression

NICHE_PARTITIONING

Evidence

PMID:41964077 - SUPPORT (IN_VIVO)

"microbial growth declined by ~1 order of magnitude, yielding decreased community growth efficiency"
PMID:41964077 - SUPPORT (IN_VIVO)

"microbial mortality declined by ~2 orders of magnitude"

External Resources

Name	Repository	Resource ID
Primary publication for the California grassland precipitation legacy community PubMed record for the Hernandez et al. 2026 Microbiome paper on precipitation-legacy effects on grassland soil microbial community growth efficiency.	OTHER	PMID:41964077
PMID:41964077 - SUPPORT (IN_VIVO) "reduced winter rainfall decreases microbial turnover following rewetting without a concurrent reduction in CO2 emissions"
DOI landing page DOI link to the Microbiome paper.	OTHER	doi:10.1186/s40168-026-02395-9

Environmental Factors

Factor	Value	Unit
Imposed precipitation regime	100 percent vs 50 percent mean annual precipitation	N/A
PMID:41964077 - SUPPORT (IN_VIVO) "two precipitation regimes (100% vs. 50% mean annual precipitation)"
Autumn rewetting with H2-18O	laboratory rewet with isotopically labeled water	N/A
PMID:41964077 - SUPPORT (IN_VIVO) "soils were rewetted in the laboratory with H218O and sampled at 0 h, 3 h, 24 h, 48 h, 72 h, and 168 h post rewet"
Soil organic carbon composition shift	necromass-like to plant-detritus-like compounds	N/A
PMID:41964077 - SUPPORT (IN_VIVO) "shifted from lipid-like, amino-sugar-like, and protein-like compounds (indicative of microbial necromass) to more oxidized lignin-like and tannin-like compounds (indicative of decomposing plant-derived compounds)"