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Oceanic crust from the Panorama district in the Pilbara Craton of Western Australia is a time capsule of early Earth.Planet Observer/Universal Images Group via Getty

Early Earth might have been covered with ocean and almost devoid of land. Researchers examined the ratio of oxygen isotopes in a 3.2-billion-year-old slab of the planet’s crust that is exposed in Western Australia. High levels of oxygen-18 in the oldest rock suggest that continents (which absorb that isotope) might not have emerged until between 3 billion and 2.5 billion years ago.

The Guardian | 5 min read

Reference: Nature Geoscience paper

Features & opinion

“Someone I admire retracted a very important paper when I was a young scientist,” says Nobel-prizewinning chemist Frances Arnold, who retracted a paper in January. “I wanted to pay that lesson forward.” Arnold and three other senior scientists share what they learnt from the experience of retracting flawed papers.

Nature Index | 4 min read

When ecologist Matthias Rillig welcomed artist Karine Bonneval into his lab, he saw some benefits he had not expected. In the end, a new research question was born, which resulted in a paper listing Bonneval as a co-author. Rillig offers his advice for scientists on how to make the most of an artist-in-residence.

Nature | 8 min read

Reference: Soil Systems paper

News & views

Around one-third of the global human population is infected with the single-celled organism Toxoplasma gondii, which in some cases causes the incurable disease toxoplasmosis. Researchers have found a single gene that controls the conversion of the parasite into a form that chronically infects the human brain. Targeting the gene, BFD1, shows real potential for making progress in the development of drugs or vaccines, writes biochemist Eva-Maria Frickel.

Nature | 6 min read

Reference: Cell paper

Image of the week

In a 340-litre aquarium, researchers smashed vortices of coloured fluid together to study turbulence. They discovered a cascading cycle of propagating, ever-smaller vortices — “a Russian nesting doll of disorder”. (Harvard John A. Paulson School of Engineering and Applied Sciences press release)