丁香园AV

In alpine and polar snow fields swaths of orange, green, or watermelon-red can appear across the icy landscape. Caused by microscopic single-cell algae, algal blooms like 鈥渨atermelon snow鈥� darken the snow surface and accelerate seasonal snowmelt, raising many questions for scientists. How does it photosynthesize in low-light and freezing conditions? To what extent is snow melt accelerating? Is climate change affecting the occurrence of algal blooms?

丁香园AV (丁香园AV) molecular biology and biochemistry (MBB) professor Lynne Quarmby studies the microbiome of snow algae using genomics, bioinformatics, ecology and cell biology to understand what drives this cellular life. For over two decades, the Quarmby Lab studied fundamental cell biology and advanced our understanding of disease mechanisms. Her new interest in snow algae arises from a deep engagement with the climate crises.

The research group鈥檚 interdisciplinary project on watermelon snow combines the disciplines of cell biology and ecology, which has resulted in groundbreaking findings. For example, they have documented a , and most recently the lab sequenced the genome of Sanguina aurantia鈥攖he microscopic cell that causes watermelon-red snow. 

The paper,  with 丁香园AV PhD student Breanna Raymond, Pierre Guenzi-Tiberi and Eric Mar茅chal (Universit茅 Grenoble Alpes), describes the challenge of isolating the elusive red algae鈥攁nd the innovative methods used to sequence its genome.

We spoke with Professor Quarmby about her research. 
 

Where does watermelon snow occur and why is it important to study and understand?

Watermelon snow occurs in mountains all over the world and on Arctic and Antarctic snow. It appears in historical records including in Captain John Ross鈥� report of the 1818 expedition in search of the Northwest Passage, and in Charles Darwin鈥檚 report of his 1835 hike over the Andes. If you hike in the mountains of British Columbia, you have likely seen swaths of watermelon-red across the snow fields 鈥� Northwestern North America is a hot spot for this phenomenon.

Because algal blooms reduce the albedo of snow, they accelerate seasonal snow melt. And alpine snow fields provide an important store of water for cities around the world. We want to understand the blooms and learn whether they are increasing in scope, duration, and intensity with global warming.

Why was it challenging to isolate the red algae and how did you work around that?  

First, we had to collect samples from the mountain snow fields. For this project, I was fortunate to recruit three graduate students, Kurt Yakimovich, Casey Engstrom, and Breanna Raymond, all of whom enjoy spending time in the mountains. Watermelon snow is a rich and complex microbiome, including many species of algae, fungi, bacteria, and a wide array of protists. Back in the lab we took two approaches to isolating the the snow algae cells鈥攇rowing them in culture and sitting at the microscope, painstakingly aspirating one cell at time.

What can scientists learn from sequencing the genome of snow algae?

Until now, the lack of a high-quality snow algal genome has limited our understanding of the cellular adaptations that allow snow algae to thrive at low temperatures and high light鈥攊ncluding ultraviolet conditions. We have made the DNA and RNA sequencing data of the red-snow-populating genus Sanguina available to facilitate future analyses, and we hope the content presented in this study will set the foundation for future research. We also outline a reproducible bioinformatic pipeline to assemble highly contiguous and complete green algal genomes, so ideally this information can contribute a novel perspective on approaching de novo assemblies.

Have you determined how watermelon snow is contributing to snow melt? Is the occurrence of watermelon snow increasing?

The research team and other scientists have established that watermelon snow acelerates snow melt. However, in the context of global warming, watermelon snow is more victim than culprit鈥攄uring the 2021 heat dome in southern BC, the snow melted out before the blooms could form.

As a scientist, , author and , you have demonstrated a passion for scientific discovery as well as sharing and mobilizing knowledge. What advice do you have for emerging scientist-activists?

The urgency of the climate crises demands our attention, whatever our career path or stage. I urge everyone to talk about it more, and to consider what we believe and why. It is by now well-established that fossil fuel interests are highly skilled at using our cognitive biases and tendancies for magical thinking to turn us away from climate action. We all need to be more politically engaged and insist on meaningful and prompt climate action, which must at its foundation include no new fossil fuel infrastructure and serious transitions away from fossil fuel use. In addition to talking about climate and being politically engaged, it is important to fly less and eat less meat, especially ruminants.

 

To learn more about Quarmby鈥檚 work as a microbiologist and activist experiencing climate change in the High Arctic check out her book: .

And read: Knowledge Mobilizers: Weaving art, activism and science to brave the realities of a changing climate.