Melting glaciers release tons of unknown bacteria  

Trapped for millions of years

Rapidly melting glaciers are releasing massive amounts of bacteria into lakes and rivers, transforming frozen ecosystems. Studying waters from the melting ice of 10 locations in the northern hemisphere, researchers estimate that over the next 80 years, continued global warming will release hundreds of thousands of tons of bacteria into the environment.

Glaciers are masses of ice that move slowly towards the sea. Along with water, they also hide minerals, gases and organic materials that have been trapped for thousands or millions of years. Studying the contents of a glacier is like opening a door to history. Trapped microbes could be a source of new antibiotics, but scientists point out that the bacteria are being released faster than they can record.

They find an average of tens of thousands of microbes per millimeter of water and estimate that over a hundred thousand tons of bacteria will be released in 80 years.

The number of microbes released is closely related to how quickly the glaciers melt and, by extension, how much we continue to warm the planet. But the mass of microbes released is enormous, even with conservative heating.

The scientists did not study specific bacteria, they simply estimated their combined biomass, so they could not identify species that might pose a threat to human health, nor determine whether the microbes were active or dead. Without further studies we cannot know whether this sudden influx of bacteria will contribute to further environmental change. However, the researchers expect that it will have unprecedented effects on the production and biodiversity of microbial communities and biochemical cycles.

We need a better picture to predict the effects of climate change on glacier surfaces and biogeochemistry.

The research was published in Communications Earth & Environment .