Glaciers might seem like places that are hostile to life, but it turns out that microorganisms like algae and photosynthesizing bacteria (known as cyanobacteria) can flourish on them. A team of researchers recently investigated these life forms on four glaciers in the Suntar-Khayata Mountains in eastern Siberia, a range that’s home to nearly 200 glaciers. After three research expeditions during melt seasons, two of which relied on a helicopter for transport, they discovered that the snow algae followed a Goldilocks approach: they were most abundant in the middle of the glaciers.
According to the study, published online in March in the journal Polar Science, the researchers took samples from the glaciers with a stainless steel scoop, then later analyzed them at a laboratory at Chiba University in Japan, the home institution of four of the scientists. They found that there were two main taxa of the green algae on the glaciers: a species with a round shape called Chloromonas sp, and a filament-like species called Ancylonema nordenskioldii. The found that the first species prospered more in the snowy areas of the glaciers, and the second, on ice.
What’s more, they found that algae had more biomass— in other words, were more abundant— in the middle of the glaciers. The top part? Too snowy. The bottom part? Too much water runoff.
“The decrease in biomass in the upper part of the glaciers can be explained by an increase in the snow-cover frequency with altitude reducing the light intensity of the algal habitats,” the researchers posit. “On the other hand, the decrease in biomass in the lower area has been explained by the amount of running meltwater on the glacier surface.” In other words, the upper portions remain snow-covered the longest, so the algae there have the shortest period of sunlight required for growth. The lower portions receive the largest amount of meltwater, so the algae there are more likely to be washed off the glacier surface.
The authors report that these findings are similar to those from research that’s been carried out on the Arctic. And while they found the same types of green algae and cyanobacteria each year they did research, they did find that the total amount of biomass of the algae changed over the years. For example, on one glacier, 2012 saw the largest amount of algal biomass, which the authors attribute to the weather— it was hotter that year, so the melt season was longer.
The authors conclude by acknowledging that the connection between the algae’s abundance and the temperature should be researched more, and nod towards the future impacts of climate change. “Further studies are necessary to evaluate the impact of expected climate warming in the Arctic region in the coming century on the microbial community on the glaciers,” they write. And the study may also serve more generally as a reminder of the complexity of ecosystems, even in habitats as harsh as glaciers. Though the lowest portions of glaciers are typically the warmest, they are not necessarily the ones that are most hospitable to life. Instead, each glacier is a complex ecosystem, with distinctive spatial patterns that merit close attention.