Sea plankton have been found on the International Space Station – but how did they get there?

If the science side of Tumblr can’t explain it, read this

Photo highlights of the day: A hummingbird flies in a garden in Pereira, Colombia. (Luis Acosta/AFP/Getty Images)

More of today’s best photos

A family taking a trip around Australia were treated to more than they bargained for when crocodilian crowd favourite ‘Brutus’ took on a bull shark in the muddy mangroves. The result? Dinner for Brutus, curtains for the shark.

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Photo: Andrew Paice/Getty

An explorer injured at the bottom of Germany’s deepest cave 12 days ago has re-emerged after a rescue operation involving 728 people from five countries and estimated to have cost several million euros. The Riesending cave complex being closed for good. Read more here

Photo: Markus Leitner/AP

An ashcloud has grounded flights between Australia and south-east Asia, and all domestic flights from Darwin airport in the north of the country.

The cloud, which was caused by the eruption of Sangeang Api in southern Indonesia on Friday evening, has drifted across central Australia, according to Reuters. Full story here

Photo: Sofyan Efend / HKV / Barcroft

The week in wildlife: A goldsmith beetle (Cetonia aurata) files over stone-breaker (Saxifraga) flowers in a garden outside Moscow. (Yuri Kadobnov/AFP/Getty Images)

Photos of the day: Sulo Karjalainen, known to many as the “bearman” is affectionately licked by one of his bears, in Kuusamo, Finland. The 73-year-old runs Kuusamo Large Carnivore Centre with his brother Jalo, which has been home to more than 20 orphaned brown bears. Photograph: Pasi Jantti/Barcroft Media

Next month, scientists will meet to mark the 150th anniversary of the discovery of the La Madeleine mammoth – an engraving on ivory that proves man had lived alongside these prehistoric creatures. More of this story

Photograph: Matt Dunham/AP