Salinization influences the biodiversity-ecosystem functioning relationship more strongly at high salinity.

Area of Science:

• Microbial ecology
• Ecosystem science
• Environmental microbiology

Background:

• Salinization poses a significant threat to ecosystem stability by altering microbial communities.
• The influence of salinity on biodiversity-ecosystem functioning (BEF) relationships is not well understood.

Purpose of the Study:

• To investigate how varying salinity levels impact BEF relationships in artificial microbial communities.
• To understand the mechanisms driving these changes under hypersaline conditions.

Main Methods:

• Construction of artificial microbial communities with diverse salt tolerance and phylogeny (5-40 strains).
• Culturing communities across a wide salinity gradient (0.9%–20%).
• Analysis of ecosystem yield, community composition, and metabolic functions (e.g., glycosyl hydrolase activity).

Main Results:

• Low-to-moderate salinity (0.9%–7%) had minimal impact on BEF relationships.
• High salinity (15%–20%) amplified the negative effects of biodiversity loss on ecosystem yield.
• Hypersaline conditions promoted halophile dominance (e.g., *Halomonas*) and inhibited metabolic functions.
• Selection effects predominated over complementarity effects under high salinity.

Conclusions:

• Microbial biodiversity plays a critical role in mitigating hypersaline stress.
• High salinity exacerbates biodiversity loss impacts, threatening ecosystem stability.
• Targeted strategies are needed to enhance ecosystem resilience to global salinization.