Volume 16 Issue 10, October 2023

Recording 4.3 billion years of Earth’s history, Jesse Reimink explores the many ways that zircon allows geologists to keep track of the past.

Glacier ice contains high-pressure air bubbles, which burst into seawater as ice melts at tidewater glacier termini. Laboratory measurements found that these bubbles double the rate of ice melt. Theoretically, this effect could be even larger in a real glacier. However, bursting bubbles are currently neglected in models projecting sea level rise.

Analysis of mineral inclusions in magmas that crystallized before and after the Great Oxidation Event reveals marked changes in the oxidation state of sulfur — owing to the recycling into the mantle of sediments that had been geochemically altered at the surface by atmospheric events.

From a stalagmite that grew 14,000–8,500 years ago, isotopic data provide a detailed history of groundwater infiltration associated with a strengthening North American monsoon, as the climate transitioned from a cool dry late-glacial period into a warmer and wetter Early Holocene.

Phosphorus from intensive agriculture contributes to increased algal blooms, threatening ecosystems and drinking water sources. We found increasing dissolved phosphorus concentrations in more than 170 Great Lakes Basin streams, despite stable or decreasing total phosphorus levels. Higher latitudes experienced greater relative increases, potentially due to warmer winters and altered flow pathways.

Accurate estimates of the land carbon sink are vital for informing climate projections and net-zero policies. Application of a strict filtering method to microwave satellite data enabled the evaluation of global vegetation biomass carbon dynamics for 2010–2019. The results highlight the role of demography in driving forest carbon gains and losses.

Exoenzymes produced by heterotrophic microorganisms early in Earth history helped unlock previously unavailable organic matter and transformed ocean geochemistry.

The widespread occurrence of young grabens associated with larger compressional structures on Mercury’s surface suggests contractional tectonism has continued on the planet into geologically recent times.

Flat microplastic fibres have much longer residence times and travel further in the atmosphere than previously appreciated, according to simulations of the settling of microplastics with different shapes.

Laboratory experiments suggest that bursting bubbles enhance ice melt from tidewater glaciers, and consequently, glacier-ice structure needs to be accounted for in projections of ice loss and sea-level rise.

Oceanographic observations indicate sustained warming and enhanced basal melt since 2016 below the Fimbulisen ice sheet in East Antarctica, associated with increased subpolar westerlies and reduced sea ice.

A decade of satellite observations suggests that old, degraded and deforested tropical forests are almost carbon neutral whereas northern young forests are the biggest contributor to the rising amount of carbon stored globally in vegetation.

Analyses of phosphorus concentrations in more than 370 watersheds of the Great Lakes Basin from 2003 to 2019 suggest widespread increases in soluble reactive phosphorus concentrations, despite often decreasing or non-significant trends in total phosphorus.

The Earth may become inhospitable to land mammals in about 250 Myr owing to climate warming and drying associated with the assembly of the next supercontinent, Pangaea-Ultima, according to combined tectonic, climate and mammal habitability modelling.

Enhanced soil carbon mineralization due to additional organic matter inputs, a phenomenon called priming, diminishes within a few years as soils adapt to the higher carbon inputs.

Early Holocene groundwater recharge rates were higher than modern in the Grand Canyon region, probably due to an expanded North American Monsoon, according to a speleothem record and isotope-enabled palaeoclimate modelling.

Subduction of sediments shaped geochemically by an increasingly oxidized atmosphere shifted the redox state of the mantle during the early Proterozoic, according to an analysis of sulfur speciation in apatites from ancient igneous zircons.