Next generation of geobiology

A directional long-distance ET chain from reduced to oxidized zones occurs in the subsurface, which reaches the distance of over centimeter scale. This implicates an overlooked contribution of “remote” electron sources/sinks for local biogeochemical processes.

Several groups of archaea, such as the order Methanocellales, are characterised by their ability to produce methane. Here, Suzuki et al. identify a Methanocellales archaeon that lacks essential methanogenesis genes and seems to be instead a CO₂-reducing, electron-fueled acetogen.

High altitude blue ice areas in Antarctica support diverse microbial life in highly abundant cryoconite holes and are also hotspots of subsurface melting, nutrients and dissolved carbon, according to field mapping and ice core analyses

Phosphorus is an essential nutrient which may have influenced Earth’s early biosphere. This study interrogates genomic records, finding potentially phosphate depleted conditions toward the end of the Archean when enzymes for scavenging reduced phosphorus compounds spread throughout the tree of life.

Three previously undocumented tsunamis on the East coast of Korea are revealed by biological signatures in bacterial taxa that are associated with submarine volcanism, suggesting these biomarkers can be used as a proxy to understand past tsunamis caused by volcanic activity.

Plasticity and evolutionary changes in phytoplankton phenotypes in the ocean can be better represented by integrating statistical and multi-trait-based numerical models which will help improve predictions of future ecosystem states and ocean carbon cycling.

A novel phylum of bacteria widespread in oligotrophic marine sediments are capable of oxidizing nitrite to nitrate and could resolve the apparent abundance mismatch between ammonia- and nitrite-oxidizers.

Analysis of the virus community associated with red algal mats in Yellowstone National Park shows it to be dominated by Megaviricetes, with resident virus lineages being of ancient origin and encoding genomic footprints of adaptation to thermophily.

The marine clamworm Perineresis vancaurica fragments expanded polystyrene foam and its gut bacteria, dominated by Acinetobacter and Ruegeria, enhance polystyrene degradation, according to analyses and incubation experiments conducted on samples collected around Xiamen Island, China.

The transition from a glacier-covered to a sub-aerial lake in Antarctica between 4900 and 1070 years ago increased the richness and diversity of prokaryotes, according to an analysis of ancient DNA metabarcodes and geochemical data from a sediment core from Lake Profound.

The absence of phosphate precipitation and nitrogen-limited biological uptake explains the high phosphate concentrations in an origin-of-life analogue, according to the geochemical results from a phosphate-rich soda lake, Last Chance Lake, Canada.

Active vent fields composed of iron-oxyhydroxide mounds hosting thriving microbial mat communities at the Hatiba Mons in the Red Sea may be analogous to Precambrian environments, suggests an underwater survey accompanied by geochemical and genetic analysis.

Microbial communities can be incubated and grown in sawdust from a martian meteorite under terrestrial conditions, which suggests that martian regolith could be used for cultivation in human habitats on Mars under the appropriate conditions.

It can be challenging to identify extinct organisms with morphology alone. Here, the authors use non-destructive Fourier Transform Infrared Spectroscopy to determine the molecular fingerprints of eukaryotes and prokaryotes from the 407 Ma Rhynie chert fossil assemblage of Aberdeenshire, Scotland.

Detection of material preserved in a mineralized fracture likely indicate microbial remains and dubiofossils and suggests serpentinizing environments can preserve morphological evidence of rock-hosted microbial life, according to analyses of drill core samples from the Samail Ophiolite in Oman.

The authors report nickel-porphyrins derivatives of chlorophyll in ~1 Gyr-old multicellular eukaryotes, preserved in low-grade metamorphic rocks. This brand new approach permits to identify early phototrophic organisms through the geological record.

Cenozoic signatures of life in calcite and pyrite deposits suggest deep biosphere activity throughout the Fennoscandian Shield, as revealed by isotopic, molecular and morphological analyses of mineral specimens.

Present et al. examine the processes controlling lithification of microbial mats in a Caribbean peritidal carbonate environment. The authors present sedimentological and geochemical evidence of a surprising bias against preserving the most robust, widespread microbial ecosystems in the sedimentary record.

Microbial sulfate reduction is active in high pH serpentinization fluids and may be a potential microbial metabolism on other rocky bodies in the solar system, according to analyses of fluids from boreholes in Omani and Californian ophiolites.

It is widely hypothesised that primeval life utilized small organic molecules as sources of carbon and energy, however, the presence of such primordial ingredients in early Earth habitats has not yet been demonstrated. Here the authors report the existence of indigenous organic molecules and gases in primary fluid inclusions in c. 3.5- billion-year-old rocks from Western Australia.

Terrestrial chemolithotrophic microbes living on Martian crustal material produce distinct biosignatures which could be detected by future missions searching for evidence of past life, according to experiments on a Noachian Martian meteorite.