• 24,000-year-old organisms found frozen in Siberia can still reproduce | Zoology | The Guardian
    http://www.theguardian.com/science/2021/jun/07/24000-year-old-organisms-found-frozen-in-siberia-can-still-reproduce
    https://i.guim.co.uk/img/media/08183f5e6abfb902c69271deed6de5a69b3df986/0_122_1440_864/master/1440.jpg?width=1200&height=630&quality=85&auto=format&fit=crop&overlay-ali
    Bdelloid rotifers are solely female and procreate by cloning themselves.
    Photograph: Michael Plewka/AFP/Getty Images

    Russian scientists find bdelloid rotifers deep in remote permafrost

    A microscopic worm-like creature, labelled an “evolutionary scandal” by biologists for having thrived for millions of years without having sex, has now been shown to persist for at least 24,000 years in Siberian permafrost and then reproduce, researchers have found.

    Multicellular invertebrates that are solely female, bdelloid rotifers are already renowned for their resistance to radiation and ability to withstand rather inhospitable environments: drying, starvation and low oxygen. They’ve also existed for at least 35m years – and can be found today in freshwater lakes, ponds, streams and moist terrestrial habitats such as moss, lichen, tree bark and soil.

    These tough little critters – which have a complete digestive tract that includes a mouth and an anus – are able to survive hostile environments by halting all activity and almost entirely arresting their metabolism.

    This is called cryptobiosis, which means “hidden life”, said Stas Malavin, a researcher at the Soil Cryology Laboratory at the Institute of Physicochemical and Biological Problems in Soil Science in Pushchino, Russia. “It’s a state, kind of, between life and death.

    The Soil Cryology Lab has previously isolated other microscopic organisms – including a 30,000-year-old nematode worm – from permafrost. But in this study, Malavin and his colleagues used radiocarbon-dating to determine that the rotifers, recovered from samples salvaged from remote Arctic locations via a drilling rig, were about 24,000 years old. Earlier evidence had shown the creatures could survive for up to a decade when frozen.