Inference on Paleoclimate Change Using Microbial Habitat Preference in Arctic Holocene Sediments

Area of Science:

• Marine geology
• Microbiology
• Paleoceanography

Background:

• Microbial communities play a crucial role in marine biogeochemical cycles.
• Understanding past microbial habitats provides insights into climate change impacts.
• The sulphate-methane transition zone (SMTZ) is a key environment for microbial activity.

Purpose of the Study:

• To investigate the relationship between microbial assemblages and paleoclimate records in the Chukchi Sea.
• To identify geological, geochemical, and microbiological evidence for the SMTZ in Core GC1.
• To assess the distribution of microbial groups and lipid biomarkers in relation to the SMTZ.

Main Methods:

• Analysis of microbial assemblages from sediment Core GC1.
• High-resolution paleoceanographic and geochemical analyses.
• Identification and localization of the sulphate-methane transition zone (SMTZ).

Main Results:

• Microbial habitat preferences were found to be closely linked to Holocene paleoclimate records.
• Geological, geochemical, and microbiological evidence confirmed the presence of the SMTZ in the Chukchi Sea.
• The distribution of Gammaproteobacteria and Marine Group II Euryarchaeota (MG-II) aligned with known SMTZ patterns. Crenarchaeol concentration was highest around the SMTZ.

Conclusions:

• Microbiological profiles integrated with geological records are effective for tracking microbial habitat preferences.
• These preferences reflect climate-triggered changes in the paleodepositional environment.
• The distribution of specific archaeal groups (MG-I, MG-II) and the interpretation of crenarchaeol require careful consideration for paleoclimate proxy development.