Microbial Mat Compositional and Functional Sensitivity to Environmental Disturbance.

Area of Science:

• Microbial ecology
• Ecosystem dynamics
• Environmental microbiology

Background:

• Ecosystem resilience to perturbations relies on biodiversity.
• Rare microbial taxa may offer long-term stability, but their response to environmental changes is poorly understood.
• Microbial mat ecosystems provide models for studying these dynamics.

Purpose of the Study:

• To investigate how environmental disturbance affects the protein synthesis potential (PSP) of rare and abundant microbial communities.
• To assess the impact of these changes on potential biogeochemical processes.
• To model the relationship between disturbance, biodiversity, and ecosystem function.

Main Methods:

• Utilized a microbial mat ecosystem on San Salvador Island, The Bahamas, as a model system.
• Analyzed 16S rRNA and rRNA gene sequencing before and after a major salinity shift caused by Hurricane Irene.
• Employed quantitative PCR to examine genes and transcripts involved in nitrogen and sulfur cycling.

Main Results:

• Significant shifts in the diversity and PSP of both abundant and rare archaeal and bacterial taxa were observed post-disturbance.
• Overall community PSP increased after the disturbance, with notable changes in specific phyla like Halobacteria, Crenarchaeota, Thaumarchaeota, Thermoplasmata, Cyanobacteria, and Proteobacteria.
• Expression of genes related to nitrogen fixation, nitrification, denitrification, and sulfate reduction increased post-disturbance.

Conclusions:

• Microbial communities exhibit complex adaptation to environmental change, with both rare and abundant taxa contributing to functional shifts.
• Disturbance-induced changes in microbial community structure and PSP directly influence potential biogeochemical cycling.
• Findings enhance understanding of the links between biodiversity, disturbance, and ecosystem function, aiding in the development of improved ecosystem models.