Scientists have warned that melting glaciers could transform frozen ecosystems due to the large amounts of bacteria they have released into rivers and streams. Scientists estimate that over the next 80 years, there could be hundreds of thousands of tons of bacteria released into the environments beneath glaciers as a result of global warming.
Studying glaciers
Earlier this year, scientists began to realize that Arctic ice is shrinking faster and faster, and past research suggests that some glaciers have passed a tipping point where meltwater is shrinking as glacial runoff decreases.
Glaciers are masses of ice that slowly creep seaward and carve mountain valleys. However, in these flows there is more than just frozen water, there are also minerals, gases, and organic materials trapped in a unidirectional slide that could take more than millions of years to complete.
“We think of glaciers as a huge reservoir of frozen water, but the key lesson from this research is that they are also ecosystems in their own right,” said Arwyn Edwards, a microbiologist and author of the study.
Microbes buried in ice bodies could be a source of useful new compounds, such as antibiotics. Now, however, glacier melt is generating the release of bacteria in tons, much faster than scientists can catalog.
Consequences of glacier melting
For this research, the team, led by hydrologist Ian Stevens, sampled glacial meltwater from ten northern hemisphere ice bodies in the European Alps, Greenland, Svalbard, and the Canadian Arctic.
They found an average of tens of thousands of microbes in every millimeter of water, so they estimate that more than a hundred thousand tons of bacteria could be ejected into the waters, not including glaciers in the Asian Hindu Kush Himalayan region.
The quantities of bacteria that have been released are equivalent to 650,000 tons of carbon released annually into rivers, lakes, fjords, and oceans in the northern hemisphere. Although it all depends on the speed of glacier melting and the rate at which emissions are curbed. If the global temperature continues to rise by 2° to 3 °C, the masses of bacteria in the water would peak in just a few decades. The number of microbes released depends on the rate at which glaciers melt, but the mass of microbes released is very large, even with moderate warming.
These microbes in glacial meltwater can fertilize the ecosystems below, but these may be sensitive environments or catchments used by communities that rely on glacial runoff as a water source.
The researchers were unable to identify any species of bacteria that might be any threat to human health or to determine whether or not the microbes are active. “The risk is probably very small, but it requires careful assessment,” Edwards said.
It is anticipated that they could have a profound effect on the productivity and biodiversity of microbial communities, as well as on biogeochemical cycles. However, more research is still needed to assess the downstream effects of microbe-laden meltwater.
Story originally published in Spanish in Ecoosfera
