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

Abstract

The present study combines data of microbial assemblages with high-resolution paleoceanographic records from Core GC1 recovered in the Chukchi Sea. For the first time, we have demonstrated that microbial habitat preferences are closely linked to Holocene paleoclimate records, and found geological, geochemical, and microbiological evidence for the inference of the sulphate-methane transition zone (SMTZ) in the Chukchi Sea. In Core GC1, the layer of maximum crenarchaeol concentration was localized surrounding the SMTZ. The vertically distributed predominant populations of Gammaproteobacteria and Marine Group II Euryarchaeota (MG-II) were consistent with patterns of the known global SMTZs. MG-II was the most prominent archaeal group, even within the layer of elevated concentrations of crenarchaeol, an archaeal lipid biomarker most commonly used for Marine Group I Thaumarchaeota (MG-I). The distribution of MG-I and MG-II in Core GC1, as opposed to the potential contribution of MG-I to the marine tetraether lipid pool, suggests that the application of glycerol dibiphytanyl glycerol tetraethers (GDGT)-based proxies needs to be carefully considered in the subsurface sediments owing to the many unknowns of crenarchaeol. In conclusion, microbiological profiles integrated with geological records seem to be useful for tracking microbial habitat preference, which reflect climate-triggered changes from the paleodepositional environment.

Metabolomic Profile of the Fungus Cryomyces antarcticus Under Simulated Martian and Space Conditions as Support for Life-Detection Missions on Mars

“…These mechanisms involve the glutathione redox system, which is well known to be present also in black fungi ( Jürgensen et al, 2001 ). Under stress conditions, glutathione reduced (GSH) is utilised to scavenge the ROS directly by donating a reducing equivalent (H + + e – ) from its thiol group of cysteine to other unstable ROS ( Han et al, 2017 ). High levels of glutathione detected in the S-MRS samples, therefore, suggest a sustained and efficient ROS scavenging response of the fungus.…”

Biolocomotion and Premelting in Ice

“…Finally, we describe settings to which our analysis is applicable. It is of general interest to understand how particles in ice migrate in response to environmental forcing, as they are used as proxy to infer past climate [14,127,128]. Moreover, bioparticles in ice migrate in response to environmental forcing, and microorganisms play an important role in climate change [129][130][131].…”

Biolocomotion and premelting in ice

“…Finally, we describe settings to which our analysis is applicable. It is of general interest to understand how particles in ice migrate in response to environmental forcing, as they are used as proxy to infer past climate [5,98,99]. Moreover, bioparticles in ice migrate in response to environmental forcing, and micro-organisms play an important role in climate change [100][101][102].…”