Snow Algae Thrives in Some of Earth’s Most Extreme Conditions

A new study found snow algae on Nieves Penitentes at high elevations in the Chilean Andes.

“The expedition was an epic and very arduous trip to a remote mountain,” Steven Schmidt, a University of Colorado, Boulder professor and one of the paper’s authors, told Glacierhub. “[The] original goal was to sample a lake below a remnant glacier high on the mountain, but the lake was frozen solid and the winds were horrendous,” Schmidt explained, “so we worked lower on the mountain and carried out the first ever search for life on Nieves Penitentes.”

Nieves Penitentes are elongated ice structures. They form when windblown snow banks build up and melt due to a combination of high radiation, low humidity, and dry winds. The snow melts into the pinnacle-shape which earned Penitentes their name—they are said to resemble monks in white robes paying penance. Penitentes are important to the dry, high-altitude areas where they are found because they can be a periodic source of meltwater for the rocky ground.

Nieves Penitentes at the research site
(Source: Steven Schimdt)

Schimdt described how the researchers were surprised to find patches of red ice on the sides of some of the penitentes. “We took samples from these patches and later found that they contained some unique snow algae and a thriving community of other microbes,” he told GlacierHub.

The study was published the journal of Arctic, Antarctic, and Alpine Research

“Snow algae are microscopic plant-like organisms that are able to live on and within the snowpack,” plant and algal physiologist Matthew Davey, who was not involved in the study, told GlacierHub. Snow algae is also known as watermelon snow because of the color it creates on the surface of snow and ice. The snow’s watermelon hue is caused by an abundance of natural reddish pigments called carotenoids which also shield the algae from ultraviolet light, drought, and cold, contributing to their ability to survive in extreme environments. 

Red snow algae on Nieves Penitentes 
(Source: Steven Schmidt)

Researchers don’t entirely understand how the algae bloom in high density given the low temperatures and high light levels they live with. “There is evidence that they can be deposited by wind, they could already be in the rock surface from previous years or they could be brought by animals,” Davey explained. “Once the snow has melted slightly, so there is liquid water, the algae can reproduce and bloom within days or weeks. During this time they can start green, then turn red, or stay green or stay red—it depends on the algal species,” he said of their formation process. 

The samples of snow algae were collected from Penitentes on the Chilean side of Volcán Llullaillaco. It is the second tallest active volcano in the world after Ojos del Salado and it sits on Chile’s border with Argentina. The Penitentes were between 1-1.5 meters tall. The presence of snow algae on Penitentes is notable because the algae can change the albedo of ice and increase melting rates.

Lara Vimercati and Jack Darcy, two members of the research team, on Volcán Llullaillaco. 
(Source: Steven Schmidt )

The study describes the environment that the samples were collected in as “perhaps the best earthly analog for surface and near-surface soils on Mars,” opening the door for implications in astrobiological research. The high elevation where the snow algae was found is responsible for the conditions that create an almost extraterrestrial environment; there are very high levels of ultraviolet radiation, intense daily freeze-thaw cycles, and one of the driest climates on the planet. 

Penitente-like structures were recently found on Pluto and possibly on Europa, one of Jupiter’s moons. In the context of these discoveries, Schmidt said that “penitentes and the harsh environment that surrounds them provide a new terrestrial analog for astrobiological studies of life beyond Earth.” The finding in the new study that “penitentes are oases of life in the otherwise barren expanses” pushes the boundaries of the current understanding of the cold-dry limits of life. 

The surface of Pluto’s Tartarus Dorsa region, where penitentes were found.

Lead author Lara Vimercati reflected on the study’s broader implications. “Our study shows how no matter how challenging the environmental conditions, life finds a way when there is availability of liquid water,” she said.

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What Snow Algae in the Pacific Northwest Could Reveal About Life on Mars

Recently published research by the University of Minnesota’s Trinity Hamilton and Jeff Havig reveals how increasing atmospheric carbon dioxide levels promote the growth of snow algae blooms on glaciers in the Pacific Northwest. 

But the two researchers also report that snow algae dynamics on the surface lead to subglacial conditions that provide a refuge for biodiversity, which could have implications for the search for life on Mars.

Read on to find out how.

What is snow algae?

Interest in snow algae goes back to at least the days of Aristotle, who speculated in The History of Animals about the reasons for its color.

Snow algae are photosynthetic green algae that appear as strips or patches of red or watermelon-colored snow on the surface of glaciers. Snow algae, according to some, can also emit a watermelon-like smell.

Carotenoids are responsible for the red or pinkish color of snow algae and help protect it from the ultraviolet light, drought, and cold that are characteristic of glacier environments.

But the darker color of snow algae means its proliferation can lower albedo, which triggers melting—as much as 13 percent, according to a 2016 study.

Snow algae blankets the Southeast Glacier on Mount Ritter in California. (Source: US Forest Service/Flickr)

Snow algae gets a boost from a warming world

Hamilton and Havig, writing in The ISME Journal, report a positive feedback between increased atmospheric carbon dioxide concentrations and snow-algae blooms.

“Not only is increasing CO2 leading to increased melting of glaciers from heating the atmosphere but also from increasing snow algae blooms, which darken glacial surfaces, lowering the albedo and thus increasing the heating and melting of the surfaces,” Havig told GlacierHub.

The duo conducted their research on Gotchen Glacier on Mt. Adams in Washington, Eliot Glacier on Mt. Hood in Oregon, and Collier Glacier on North Sister, also in Oregon.

The findings could help improve the accuracy of climate models.

Trinity Hamilton collects ice worms on Collier Glacier, North Sister, Oregon. (Source: Jeff Havig)

Below the glacial surface

Their research on the glaciers of the Pacific Northwest shows that snow algae dynamics on the surface of glaciers impacts subglacier conditions too.

In an article published in the journal Geochimica et Cosmochimica Acta, they describe how snow algae cycles carbon and nitrogen through the glacier and feeds subglacial microbial communities and weathering of the bedrock below glaciers.

“The presence of heterotrophic microorganisms in the subglacial system is a potential driver of CO2 generation as they break down organic carbon coming from the supraglacial system and convert it into CO2, which can then combine with water to form carbonic acid, a key driver of mineral breakdown and dissolution,” Harvig said.

Carbonic acid, in other words, breaks down the silicate rocks that characterize the volcanic-rock formations on top of which the glaciers formed.

Life on Mars

Considering that life thrives within the volcanic rock-hosted glaciers on Earth, might the stratovolcanoes and cryosphere of Mars also provide a refuge for biodiversity?

An artist’s rendering of glaciers on the surface of Mars. (Source: NASA/Jet Propulsion Laboratory)

Hamilton and Havig are collaborating with researchers at Purdue University and Northern Arizona University to explore that very question.

“Mars is currently a glaciated planet, and so glacier-associated life may have developed there, and we are interested in looking for refugia where life could still be present or learning how to look for evidence of past life.”

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Roundup: Snow Algae, Dams in Ecuador, and Patagonia’s Cashmere

Snow Algae and Atmospheric Carbon Dioxide

From Science Direct: “Most of what is known about snow algae communities has been learned from studies centered on glaciers and snowfields located on sedimentary or metamorphic bedrock, but little is known about snow algae systems hosted in volcanic bedrock (Hamilton and Havig, 2017). Recent work has quantified primary productivity as predominantly phototrophically mediated, and demonstrated inorganic carbon limitation of primary productivity by snow algae communities on PNW glaciers (Hamilton and Havig, 2017Hamilton and Havig, 2018) suggesting increasing productivity with increasing atmospheric CO2 concentrations.”

Read more about the study here.

Pink Snow Algae (Source: James St John /Flickr)


From the New York Times: “This giant dam in the jungle, financed and built by China, was supposed to christen Ecuador’s vast ambitions, solve its energy needs, and help lift the small South American country out of poverty. Instead, it has become part of a national scandal engulfing the country in corruption, perilous amounts of debt—and a future tethered to China. Nearly every top Ecuadorean official involved in the dam’s construction is either imprisoned or sentenced on bribery charges. That includes a former vice president, a former electricity minister and even the former anti-corruption official monitoring the project, who was caught on tape talking about Chinese bribes.”

Read more about China’s role in Ecuadorian dam construction here.

Ecuador’s Coca Codo Sinclair Dam (Source: Ministerio de Turismo Ecuador/Flickr)

Recycled Cashmere Sweaters by Patagonia

From Business Insider: “The process of creating cashmere is so inherently detrimental—requiring lots of resources and incurring lots of environmental degradation—that any claim of sustainability is pretty much moot. It may make us happy to have, but it sure isn’t preserving the grasslands of Mongolia. Patagonia’s cashmere line is the best no-compromise option I’ve found. Each piece is made out of 95 percent cashmere scraps collected from European garment factories, plus 5 percent virgin wool for strength. Altogether, it’s a line of durable, warm, guilt-free cashmere sweaters, hats, and scarves with way less ecological impact, plus the added benefit of Patagonia-level quality and design. You can also view “The Footprint Chronicles” to learn about their supply chain and the sewing factory that made your sweater.”

Read more about Patagonia’s cashmere sweaters here

Patagonia Logo (Source: /Wikimedia)


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On Russian Glaciers, Algae Imitate Goldilocks

Setting up research camp on glacier in Suntar-Khayata Mountains (source: Melnikov Permafrost Institute)
Setting up research camp on glacier in Suntar-Khayata Mountains (source: Melnikov Permafrost Institute)

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.

Microscopic photographs of impurities (A) and pigmented ice algae, Ancylonema nordenskioldii (B) (source: Polar Biology)
Microscopic photographs of impurities (A) and pigmented ice algae, Ancylonema nordenskioldii (B) (source: Frontiers in Earth Science)

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.

Glacier 31 in Suntar Khayata Mountains (source: Melnikov Permafrost Institute)
Glacier 31 in Suntar Khayata Mountains (source: Melnikov Permafrost Institute)

Roundup: Yaks, Snow Algae, and Slime Molds

How do wild yaks respond to glacier melt and past exploitation?

Yak at Yundrok Yumtso Lake

“To explore how mammals of extreme elevation respond to glacial recession and past harvest, we combined our fieldwork with remote sensing and used analyses of ~60 expeditions from 1850–1925 to represent baseline conditions for wildlife before heavy exploitation on the Tibetan Plateau. Focusing on endangered wild yaks (Bos mutus), we document female changes in habitat use across time whereupon they increasingly relied on steeper post-glacial terrain, and currently have a 20x greater dependence on winter snow patches than males. Our twin findings—that the sexes of a cold-adapted species respond differently to modern climate forcing and long-past exploitation—indicate that effective conservation planning will require knowledge of the interplay between past and future if we will assure persistence of the region’s biodiversity.”

Read more about the article here.


Snow algae grows on glacier surface annually.

Snow Algae

“Snow algae in shallow ice cores (7 m long) from Yala Glacier in the Lang-tang region of Nepal were examined for potential use in ice-core dating. Ice-core samples taken at 5350 m a.s.l. in 1994 contained more than seven species of snow algae. In a vertical profile of the algal biomass, 11 distinct algal layers were observed. Seasonal observation in 1996 at the coring site indicated most algal growth occurred from late spring to late summer. Pit observation in 1991, 1992 and 1994 indicated that algal layer formation takes place annually.”

Read more about the article here.


Slime mold preys on bacterium under snow.

Slime Molds

“Abundance and habitat requirements of nivicolous myxomycetes were surveyed over 4 yr at the northwestern Greater Caucasus ridge (Russia). An elevational transect spanning 3.66 km from 1 700 to 3 000 m a.s.l. was established at the summit Malaya Khatipara situated within the Teberda State Biosphere reserve. Between 2010 and 2013 1177 fructifications of nivicolous myxomycetes were recorded, with 700 of these determined to 44 species, varieties, and forms. Virtually all fructifications developed near or at the margin of a snow field. Abundance of myxomycete fructifications varied extremely between years, ranging from near zero to hundreds of colonies. At sites with known myxomycete occurrences 16 data loggers were installed in the years 2011 and 2012, measuring relative humidity and temperature at the soil surface. Together with weather data recorded on the nearby Klukhor pass and experiments with myxamoebae cultured on agar, these data explain the observed extreme fluctuations in myxomycete abundance.”

Read more about the article here.