Scientists have discovered nearly 1,000 new species of bacteria in samples of snow and ice from Tibetan glaciers, raising concerns about disease spread as polar ice caps melt with global warming.

Researchers evaluated whether bacteria species trapped in glaciers in Tibet could reach other areas as snow and ice melt, says the new study published last week in the journal. nature biotechnology.

Ice samples were collected from 21 glaciers in Tibet between 2010 and 2016 by researchers – including those at the Chinese Academy of Sciences – who melted them to analyze what remained.

They found 968 unique types of bacteria, 98% of which were previously unknown to science.

The new findings come nearly a year after scientists discovered ancient viruses trapped in glaciers – some over 15,000 years old – on the Tibetan Plateau.

Ice sheets and glaciers make up nearly a tenth of the Earth’s surface cover, and a growing number of studies have also shown that they are melting due to the climate crisis.

Scientists believe that some of the trapped bacteria may be infectious to plants, animals and modern humans, who particularly lack immunity to these ancient microbes.

“These microorganisms can carry new virulence factors that make plants, animals and humans vulnerable,” the scientists wrote in the study.

The researchers warn that modern and ancient pathogens trapped in glaciers “can lead to localized and even epidemics”.

The newly discovered bacteria in the current study also come from a region of particular interest in the world – where melting ice and snow feeds many rivers that lead to densely populated parts of China and India.

The researchers wrote: “The Tibetan Plateau, known as the water tower of Asia, is the source of many of the world’s largest rivers, including the Yangtze River, Yellow River, Ganges River, and Yarlung Tsangpo (Brahmaputra River)”.

“The release of potentially dangerous bacteria could affect the two most populous countries in the world: China and India,” they added.

In future studies, scientists hope to assess whether microbes released from melting glaciers around the world pose a threat to plants and animals downstream.