Volume 18 Issue 5, May 2025

The rise of oxygen in the early Earth’s atmosphere remains enigmatic in its timing and extent. Insights from thallium isotopes in Archean shales suggest that it may have experienced flips in oxygenation on a global scale prior to 2.5 billion years ago.

Ancient metamorphosed basalts show a sulfur isotopic fingerprint of surface sediment, suggesting volatile cycling by a subduction-like process was occurring more than 3.8 billion years ago.

Presolar moissanite grains are stellar fossils that act as messengers from the cosmos. Nan Liu explores the ways moissanite enables cosmochemists to investigate the origin and evolution of our Solar System and beyond.

Atmospheric oxygen, supplied from the oceans, dramatically rose during the Great Oxidation Event. Our examination of the preceding evolution of seawater oxygenation revealed that the redox state in seawater oscillated between oxic and anoxic conditions before oceanic oxygenation again increased towards the dawn of the Great Oxidation Event.

The Indian summer monsoon plays a key part in influencing marine life in the Bay of Bengal. Palaeoceanographic records reveal that both extremely weak and strong monsoon phases led to declines in marine productivity. Future monsoon shifts pose a disruptive threat to the stability of regional ecosystems and fisheries.

Warming-induced changes in extreme precipitation intensity that exceed the Clausius–Clapeyron scaling rate can be explained by a statistical shift from stratiform to convective precipitation, according to an analysis of lightning records across Europe.

Observations from a borehole in the Kamb Ice Stream suggest that discrete subglacial discharge events dominate channel melt and sediment transport.

The morphological complexity that develops on suspended sediment surfaces due to microbial colonization substantially increases drag, according to high-resolution microscopic imaging and fluid dynamics simulations.

Dissolved inorganic carbon can be a limiting factor for organic nitrogen production in rivers, and so bedrock composition may influence river chemistry, according to geochemical analysis of rivers in Asia and statistical analysis of global datasets.

North Atlantic Deep Water formation was only moderately weaker than it is now during the last glacial period, even when freshwater inputs were high, according to an analysis of independent proxy records.

Deep marine shelf environments experienced fluctuating levels of seawater oxygenation before the Great Oxidation Event, as reflected by oscillations between nitrogen fixation and denitrification recorded by nitrogen isotopes in banded iron formations.

Oxygenated bottom water existed transiently on continental shelves with O₂ penetrating into underlying marine sediments by about 2.65 billion years ago, according to a study of thallium isotopes in Archaean shales.

Periods with enhanced iron and sulfide availability that promoted recycling of bioavailable phosphorus from sediments contributed to episodic development of oxygen oases in the Archaean ocean, according to analysis of trace metals, phosphorus and iron from 2.9-billion-year-old sediments.

Combined sulfur and neodymium isotopes suggest that volatile cycling at subduction zones began 3.8 Gyr ago or earlier, according to a study of Eoarchaean mantle-derived rocks with arc-lava characteristics.

Changes in terrestrial runoff into the Bay of Bengal during both extremely weak and strong Indian summer monsoon phases since the Last Glacial Maximum caused a collapse in marine primary production linked to increased stratification, according to proxy records from a marine sediment core.