Volcanoes that typically erupt effusively can generate highly explosive eruptions of basaltic lava under specific temperature and viscosity conditions, suggest crystallization experiments combined with numerical models of magma fragmentation. The image shows volume rendering of plagioclase crystals with swallow-tailed morphologies.

See Arzilli et al.

Hot and dry climate extremes in Australia are linked to stratospheric polar vortex weakening, with potential implications for their predictability, according to statistical analyses of observational data from the past 40 years. The image shows an oil colour painting inspired by the satellite images of weather patterns over Australia.

See Lim et al.

Glaciers in the Andes have lost about 23 Gt of mass per year between 2000 and 2018, with the fastest loss in Patagonia, according to time series of digital elevation models that are based on ASTER stereo images. The image shows the calving front of Perito Moreno Glacier in Patagonia, Argentina in January 2013.

See Dussaillant et al.

Phosphorus limitation can significantly reduce the response of the Amazon forest to CO2 fertilization, according to analyses of a free-air CO2 enrichment (FACE) experiment combined with terrestrial ecosystem models. The image shows fine roots of trees for taking available phosphorus at the FACE experimental site in Central Amazonia.

See Fleischer et al..

Large volcanic eruptions in the first half of the 19th century blurred the transition from the Little Ice Age to anthropogenic warming, and led to sustained cooling, drought in Africa and weakened monsoons, suggests a combination of observations and model simulations. The image shows the Rosenlaui Glacier in the Bernese Alps between Engelhörner and Wellhorn in June 1828, in a pen and watercolour drawing by the Swiss artist Samuel Birmann.

See Brönnimann et al. and Editorial.

Banded iron formations could not have formed by post-depositional oxidation, according to four million hydrogeological box model iterations that failed to reproduce secondary oxidation on reasonable timescales. The image shows Joffre Gorge in Karijini National Park, Western Australia. This gorge cuts through the largest known banded iron formation in the world: the 2.46-billion-year-old, 300-m-thick Joffre Member of the Brockman Iron Formation.

See Robbins et al. and Stüeken News & Views.

Shallow moonquakes detected at four Apollo landing sites between 1969 and 1976 occurred during maximum stress and in close proximity to young faults, suggesting that the Moon is tectonically active, according to reanalyses of the seismic data and tidal force modelling. The image shows Taurus–Littrow Valley on the eastern edge of Mare Serenitatis, as seen in an oblique Lunar Reconnaissance Orbiter Camera image. A prominent landslide from South Massif that may have been triggered by fault-related moonquakes spreads across the valley floor and the scarp.

See Watters et al.

Geomagnetic jerks in the Earth’s magnetic field are caused by the arrival of hydromagnetic waves and could be generated by sudden releases of buoyancy in the Earth’s core, suggest geodynamic numerical model simulations. The image shows a visualization of the interior of Earth's core as modelled in a numerical geodynamo simulation, with lines of force of the magnetic field (orange) stretched, twisted and folded by the turbulent convective flow of electrically conducting fluid (red and blue).

See Aubert and Finlay

Many lakes that currently mix once or twice a year may become permanently stratified or mix only once in a warming climate, suggest numerical simulations of lake mixing regimes. Mixing regimes are most affected by ice-cover duration and surface temperatures. The image shows an early summer sunset at the Lake Erken laboratory and field station, Sweden.

See Woolway and Merchant

The shape and internal structure of bilobate comet 67P is controlled by mechanically driven erosion of shear fracture networks, according to a three-dimensional analysis of images from the Rosetta mission. The image shows the Jupiter-family comet 67P/Churyumov–Gerasimenko.

See Matonti et al. and News & Views by Keane

Prescribed burning has far less impact on peat growth and carbon sequestration than previously thought, according to a long-term experiment in fire-managed peat moorlands in England. Managed burning may be a viable strategy for making peatlands more resilient to devastating wildfire. The image shows prescribed burning of moorland in upland Britain.

See Marrs et al. and News & Views by Cochrane

Glacial meltwater from the Greenland Ice Sheet causes buoyancy-driven upwelling of nutrient-rich, subtropical waters from depth to the continental shelf. This nutrient transport may exceed the direct ice-sheet inputs, according to geochemical analyses of transect samples from Sermilik Fjord. The image shows the inner Sermilik Fjord, Southeast Greenland, in August 2015.

See Cape et al.