On his first night tent-camping in Antarctica, Pablo Almela fell asleep to the guttural sounds of elephant seals. “It was like Jurassic Park,” he laughs, noting how remarkable it was to be zipped up safely in a tent in one of the most remote locations on the planet. Thankfully, it was summer. When he woke up the next morning it was cold, grey, and drizzling, but “warmer than [Minnesota].”
Almela was far from his hometown in the Spanish countryside. He had little field experience when the Universidad Autónoma de Madrid offered to send him to Antarctica in order to investigate the microbes that tolerate the cold Antarctic landscape. He claims the offer was a “right time, right place, kind of thing,” and accepted it without hesitation. But after several weeks of collecting samples in the freezing rain, Almela made a sudden self-discovery.
“I realized that fieldwork was my work. It's where I really enjoy myself the most,” he says. “And it’s really fulfilling when you start understanding what’s happening, in my case, with [cold-tolerant microbes].” In Antarctica, he learned that the presence of penguin poop can drastically alter the composition of microbial communities on a landscape, that time makes a difference in what kind of life lives in exposed soils, and more.
Now, as a postdoctoral associate in Trinity Hamilton’s “Fringe” lab, Almela uses his expertise to study “snow algae,” a colorful phenomenon that often occurs in icy environments. In the past few months, Almela has co-authored three publications about the snow algae in prominent scientific journals, painting a picture of what these odd microbes could mean for our planet’s environmental trajectory.
In search of watermelon snow
Trinity Hamilton’s lab is studying snow algae as part of a collaborative National Science Foundation (NSF) award with Jim Elser from the University of Montana. Also called watermelon snow, snow algae pigments can be bright red, pink, orange, and green, and are visible to the naked eye. These pigments absorb light and retain heat. In large numbers, snow algae “blooms” can contribute to increasing rates of snow and ice melt.
Snow algae blooms may have existed in nature for a long time, but the increasing prevalence of pink snow may signal more rapid change. “There was one study in Alaska where they actually linked 11% of loss of glacier ice and snow to the impact of darkening from snow algae,” says Jeff Havig, a geochemist and a contributor in Hamilton’s research project. Scientists are concerned that environmental changes could cause a boom in blooms, further exacerbating stress on the fragile ecosystems of Earth’s iciest places. The problem? No one knows much about snow algae, including what its “ideal” conditions are and how these conditions might change over time.
“Something like one-sixth of the world's population depend on alpine systems for their water, and algae live in these systems,” says Hamilton. “So it's really important to understand the role they are playing in generating melt and other dynamics we don't understand.”
Hamilton, Almela, and other contributors make regular trips to the Rocky and Cascade mountains to sample the algae and measure how much light gets reflected from the colorful patches of snow. The hikes to their locations are generally manageable. But the timing is always a little tricky. “We can’t predict when the algae is going to bloom,” says Almela.
Members of the Fringe Lab, as Hamilton’s research group is known, often depend on internet sources like Reddit and AllTrails to identify patches of pink snow where algae blooms are sure to be found. “Sometimes we even use Instagram’s [location features] to look into the background of pictures to see if there's red snow,” says Hamilton. For the past three summers, the team booked flights based on expected bloom times and sampled snow algae at sites all across the United States.
A pollution problem
A main objective of the lab’s NSF-funded research is to identify the nutrient limitations of snow algae. These kinds of questions are important in a world where excess nutrient loads are becoming increasingly prevalent. Excess nutrients from fertilizer run-off and other causes can cause algae blooms in lakes. In mountainous regions where snow algae grows, excess nutrients may be in the air – literally.
“Since the Industrial Revolution and fossil fuel burning, [people have] been pumping oxidized nitrogen into the atmosphere, and that comes back down with precipitation,” says Hamilton. We can also get nitrogen deposition from dust. “Based on the way that the Rockies are positioned, there’s kind of a sweet spot for nitrogen deposition in northern Utah.” The dust blows in from the Great Salt Lake basin to the west. Hamilton hypothesized that because there are high rates of nitrogen deposition in the Rockies, they might potentially find more snow algae there than field sites on the Cascade Range.
To test their hypothesis, Hamilton’s team had to sample algae and snow samples from their prospective field sites. Their lodging was minimal – but as long as they had access to refrigerator space and electricity for processing samples, they were set.
The team hikes to the field site, collects a few gallons of snow from their sample areas, and processes the samples back at their lodgings. “Pablo filters a lot of biomass for DNA for carbon and nitrogen isotopes and for various other different analyses,” says Havig. “And then there's water that's collected for water chemistry. It’s a big process.” Their set-up allows them to process samples quickly the same day of sampling.
Cold conclusions
The team still has a lot of work to do to wrap up their research, but Almela is especially excited to see the years of work add up to a few exciting conclusions. The researchers recently published a paper describing how an increase in environmental phosphorus, not nitrogen, may play a bigger role in encouraging snow algae growth than previously thought.
In another paper, the researchers shared their findings about how snow algae can reduce albedo, or “light reflected from a surface” – increasing rates of snow melt even when the algae is growing under the snow’s surface. “We know the impact of the algae when it’s growing on the surface, but we know almost nothing about the blooms happening underneath,” says Almela.
That’s what he’s trying to understand next. Their field protocols recently expanded to include algae samples from under the surface. And Almela is ready, always happy to head back out to do fieldwork in cooler temps. – Adara Taylor