Orphan Lab

Characterizing sediment microbial communities and investigating the impact of the physicochemical environment on methane cycling across methane seeps in the Gulf of Alaska

• Aim to analyze microbial ecology using DNA sequencing techniques and explore potential relationships between microbial communities and geochemical data

• Responsibilities include extracting DNA from environmental samples, running PCR reactions for 16S rRNA, analyzing microbial diversity based on sequence data, analyzing geochemical data paired with microbial diversity data (to look for relationships between the two), and sample microscopy

Abstract

Ocean floor methane seeps are essential to global methane cycling and climate control. However, the environmental factors impacting anaerobic oxidation of methane (AOM) powered by anaerobic methanotrophic archaea (ANME) and sulfate-reducing bacteria (SRB) consortia at these seeps remains largely understudied. By investigating the sediment microbial communities and geochemical conditions from varying depths and habitats (e.g. clams, frenulates), we explored the composition and function of ANME-SRB consortia at methane seeps in the Gulf of Alaska. Sediment samples were collected via a deep-sea research submersible and studied using DNA extraction, 16S rRNA PCR amplification, and FISH microscopy to profile microbial communities and their distribution. Porewater was geochemically analyzed to grasp the environmental conditions influencing AOM. Our results reveal variability in microbial community composition and activity, particularly at depths of  6 to 15 cm below the seafloor, where high DNA concentrations and microbial aggregates were observed, suggesting active AOM processes. This study enhances our understanding of microbial interactions at oceanic methane seeps, offering insights into the relationship between AOM consortia and marine ecosystems. Further research on the ecological implications of ANME-SRB consortia will prove instrumental to understanding the role of seafloor carbon cycling on climate change.