Volume 14 Issue 11, November 2021

The fate of sedimentary carbon in rivers is determined by a combination of mineral protection and transit time. Along the fluvial journey from headwaters to sea, biogeochemical transformations control whether carbon is buried or returned to the atmosphere as CO₂.

Evaporative loss of sulfur from molten planetesimals can explain the sub-chondritic sulfur isotope composition of the bulk silicate mantle, suggesting an important role for planetesimal evaporation in establishing Earth’s volatile budget.

Earth’s volatile element content was established largely by volatile evaporation from molten planetesimals before Earth’s formation, according to first-principles calculations and examination of sulfur isotope fractionation.

Orbital forcing consistently influenced the magnitude of millennial-scale climate variability through the Pleistocene, according to an analysis of four high-resolution Northern Hemisphere proxy records covering the past 1.5 Myr.

Millennial-scale climate oscillations can arise from orbital forcing alone during relatively stable glacial climate states, according to an analysis of high- and low-latitude climate proxy records as well as climate modelling.

The oxygenation of Earth may have been delayed due to high late Archaean extraterrestrial impact rates, which acted as a fluctuating sink of atmospheric oxygen, according to a reassessment of past impactor fluxes and atmospheric chemistry modelling.

Recent strengthening of the snow/ice albedo feedback is due to Antarctic sea-ice loss, according to satellite observations of surface albedo.

Climate change warms extreme hot days over tropical land more strongly than the mean temperature as hot days are dry, according to a new theory and analysis of global climate models.

Particulate organic carbon oxidation in rivers is regulated by both transit time and mineral protection, according to modelling and analysis of organic matter transported nearly 1,300 km through a lowland river.

Anthropogenic climate change is impacting the temperature and ice cover of lakes across the globe, according to an attribution analysis based on hindcasts and projections from lake models.

Much of the nutrient transport from the deep ocean into the ocean’s upper water column occurs through the Southern Ocean, with mixing and advection playing complementary roles, according to a box model analysis of the isotopic composition of ocean nitrate.

Warming-enhanced microbial respiration can explain marine anoxia patterns across depth, a key driver of the end-Permian mass extinction, according to biogeochemical modelling and geochemical proxy records.

Reorganized ocean circulation during Late Ordovician cooling altered oxygenation through the water column, provoking a new look at the extinction mechanism, according to anoxia reconstructions using the I/Ca proxy and Earth system modelling.