Metagenomic Insight into Environmentally Challenged Methane-Fed Microbial Communities

Area of Science:

• Microbiology
• Environmental Science
• Biogeochemistry

Background:

• Methane-consuming microbial communities are crucial for carbon cycling.
• Prior research suggests complex interactions and carbon transfer among functional guilds feeding on methane.
• Understanding these communities is vital for predicting methane's role in ecosystems.

Purpose of the Study:

• To investigate microbial community composition and dynamics in methane-fed microcosms over 14 weeks.
• To analyze community responses to different dioxygen partial pressures.
• To elucidate functional guild interactions and metabolic pathways involved in methane oxidation.

Main Methods:

• High-resolution metagenomics and metatranscriptomics were employed.
• Laboratory incubation of natural microbial samples fed exclusively with methane.
• Simulated low and high dioxygen partial pressures were applied to assess community trajectories.

Main Results:

• Community trajectories differed significantly between low and high dioxygen conditions, with notable replicate variability.
• Four major functional guilds dominated: Methylococcaceae, Methylophilaceae, Burkholderiales, and Bacteroidetes.
• Metatranscriptomics revealed co-expression of methanol dehydrogenases and stress response genes, suggesting dioxygen competition.

Conclusions:

• Dioxygen availability profoundly influences methane-oxidizing microbial community structure and function.
• Complex trophic interactions exist, with Burkholderiales and Bacteroidetes likely utilizing byproducts from methanotrophs.
• The study highlights the intricate metabolic and competitive strategies within methane-consuming microbial ecosystems.