The world is full of microorganisms, and there are still many out there that we know nothing about. Scientists have embarked on a study of the microbes in streams that are fed by glaciers, in an effort to learn more not only about their biology and complexity, but also about how they may be affected by climate change. The findings have been reported in two studies, in Nature Microbiology and in Nature.
In this work, the researchers collected and assessed the microbial content of samples that were taken from over 170 glacier-fed streams in locations around the world, including Alaska, the Chilean and Ecuadorian Andes, the European Alps, the Himalayas, Greenland, New Zealand, the Tien Shan and Pamir Mountains in Asia, and the Rwenzori Mountains in Uganda. These areas may be far apart, but the environmental conditions are similar and include freezing temperatures, low nutrient availability, powerful summer UV radiation, and little sunlight in winter.
These similarities led the researchers to expect low levels of microbial diversity, and not many differences from one place to another, noted first Nature author Leïla Ezzat, PhD. “But our analyses proved the contrary; there’s a remarkable amount of microbial biodiversity and biogeography across the world’s glacier-fed streams.”
The data from this work was used to create a global atlas of the glacier-fed stream microbiome. These microbiomes are also significantly different from those in other frozen regions. About half of the bacteria in any sample was local to the mountain range. This was especially notable in New Zealand and Ecuador, which are already known to host many unique plants and animals. The researchers suggested that this is due to their relative geographical isolation, and the natural selection that is already a powerful force in extreme regions like streams that are fed by melting glaciers.
The glacier-fed microbiome was shown to be very complex, and includes many algae, archaea, bacteria, fungi, and viruses.
“It's fascinating to see the broad range of adaptive strategies that microorganisms have developed to survive in this extreme environment,” said first Nature Microbiology study author Grégoire Michoud.
Some microorganisms are able to utilize many different substances including carbon, UV rays, minerals, and maybe gases as well, so they can take energy from different, variable sources. They seem to be well-suited to conditions that can quickly change, and many may easily adapt to climate change.
Sources: EPFL, Nature, Nature Microbiology
