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From the Field: Snow Algal Science

ABOUT THE BLOG AUTHORS: The Kodner Lab is an enigmatic group studying alpine snow algae in the Washington area. Dr. Robin Kodner, our intrepid leader, has a passion for algae surpassing previously known bounds, bringing joy and genius to the mountainous algae. Our seaweed physiologist and roof rack expert, Dr. Dan Van Hees, brings humor and height to the otherwise all women  crew. Maya Matsumoto, our live-in lab goddess and NSF REPS Fellow, graduated from Western Washington University in 2021 and works full time toiling away at the microscope and preventing organizational disaster. This summer, our lab has three undergraduate researchers. First up is AG Camara, a marine biology major and sailor from California that we dragged into the cold and snow of our Mt Baker field site. Clare Hanneman majors in marine biology and studio art, and always has a fresh perspective. Honu Pata, the last member rounding out our team, is an organismal biology major and our field work car DJ. Together, we are working to characterize the dynamics of an annual algae bloom that appears on a lake near the Mount Baker Ski Area.



From the Baker Ski Area parking lot, it’s a few miles of trekking up and over some hills to a snow-covered lake. This makes Bagley Lake the perfect site for our yearly field study – it’s much more accessible than some of the other trips we make to hunt for pink snow. It is here, on Bagley Lake in the North Cascades, that we return to every week in the summer wearing our fanny packs and matching pink hats to observe and collect samples of an annual snow algal bloom that causes patches of snow on the lake to turn a vibrant pink.

4 red cells in the center of the microscope image in a diamond shape, each with a glowing yellow-gold envelope around it

“Snow algae” encompass a range of algae which live and grow in the snow, of which three genera are known to produce red or pink blooms in alpine snow annually. Chlainomonas is one such genus and the main alga that reappears every year on Bagley Lake. Although you might expect that we do most of our field work in the winter, Chlainomonas requires that the snow be slightly melted with water available in the snowpack to bloom, meaning these pink bursts across the snow occur during the spring and summer months (Hoham 2000).

In summer months, the bright sunlight reflects off the white snow and creates intense rays, which the algae shield themselves from by producing a red pigment called astaxanthin. This sunscreen is a significant portion of our interest, as it lowers the albedo of the snow, increasing the rate of snowmelt by up to 17% (Oregon Field Guide 2020). These warmer spots on the snow change the snowpack and the characteristics of the melt season after season. We hope that by better understanding snow algal blooms and the way that they interact with their surroundings, we will better be able to predict the ways in which the snow will melt in the coming years. In a world where climate change is vastly shifting these snowy areas, accounting for every factor is a necessity to understand where these ecosystems are headed in the future.

To do this, every week we pack up our bags with many, many 50ml tubes, drive up the mountain, strap on our snowshoes, and head out to the lake. Some days it’s so sunny that the snow seems blindingly white and you could take a dip in the lake if you really wanted to. On other days, it’s constant rain and crossing our fingers that we can spot the pink amongst the slush.

An image of a woman in navy blue with a pink trucker hat kneeling in the snow next to a a small yellow flag, scooping snow into a 50 mL falcon tube

The vibrancy and hue of the bloom varies throughout the season, sometimes brighter and sometimes paler, though we can’t say why, as much of the snow algal life cycle and growth processes are still unknown. The funding from NSF that is supporting our work this summer helps us move closer to understanding these processes. From there, we pull out the many tubes that determine the destiny of these algae, whether for microscopy, lugols fixing, or for DNA extraction and sequencing. We walk all over the snow-covered lake scooping snow into our tubes patch by patch, sometimes even using our field microscope to check out what the algae look like on the spot. The tubes are packed into thermoses to keep them cold during the sweaty trek back to the cars and down the mountain, until we return to the lab with our pink bounty in tow.

An image of a man in a blue sweatshirt and pink trucker hat holding a handheld field microscope to his eye. The microscope is approximately the size of a hoagie

Upon our return to the lab, we place our samples in the fridge and get started on imaging. Snow algae have not successfully been cultured in a lab setting which means we can only observe them in their natural habitat or in the samples we bring back from the field. As a result of these incompatibilities with a lab life, we get microscopy done quickly so the species will retain as much of their natural state as possible. Traits such as flagella can be sensitive to changes in temperature, so time is of the essence. Examining the morphology of these cells is an important part of the research we do because understanding what they look like throughout the season can tell us about major shifts in their life history and how these cells age in their most populous season.

Because one project is never enough, we also run a citizen science initiative in addition to our work at Bagley Lake. The Living Snow Project aims to mobilize volunteers to head to the mountains in search of pink snow in their region. This allows us to build a large-scale database of snow algae distribution and biodiversity. We try to make participation simple and convenient for mountain travel, and each volunteer is given a sandwich bag kit containing gloves, an instruction sheet, a mailing address, and two tubes containing preservatives. Since starting the project in 2017, we’ve received hundreds upon hundreds of samples, from as near as our own Mt. Baker, to as far north as Barrow, Alaska, and even from France and Peru! You can follow the project on Instagram, @Living_Snow_Project, or find our website.  In addition, our Living Snow Project app allows volunteers log coordinates, date, photos, etc. of an algal sighting or sample collection.

An image of snow algae, which is a red cell on a dark grey background, the center is teardrop shaped with a round glowing envelope around it

Like our Bagley samples, Living Snow samples are also imaged under a microscope, where we identify key features of the algae. They are then filtered, and their DNA extracted so we can better understand the geographic distributions of these algal species. This citizen science project, however, does far more than just gather data for our own purposes. It also spreads awareness to the greater public about what snow algae are, where they can be found, and how they relate to their environment. By creating the opportunity for all people to participate in our project, volunteers get to connect with scientific discovery on a personal level and experience science outside of the classroom. Through the hundreds of volunteers who have participated in this project, and the outreach opportunities we’ve been so lucky to participate in, we have been able to increase public interest and understanding of alpine ecosystems. This project gives people the chance to get outside in the name of science, and creates a wonderful, open-ended data set, which we hope will inform our knowledge of species distribution and diversity on a wider scale.



Hoham, R.W. 2000. Snow Algae: The Effects of Chemical and Physical Factors on Their Life Cycles and Populations. In Journey to Diverse Microbial Worlds. 2: 131-45

Oregon Field Guide. (2020). What Makes Snow Pink. Facebook. Retrieved August 22, 2022

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