Rising Temperatures Increase Algae Growth, Glacier Loss Across North Cascades

Nature Communications, 8 May 2023

Dark red algae on snow can increase spring snowmelt by 20% in the US Pacific Northwest, jeopardizing downstream species such as salmon that depend on the stability of these frozen mountain regions for their survival. Increasingly early spring weather allows dense algae blooms to spread across the snow. Algae absorbs heat from the sun and intensifies melting, stripping glaciers of their protective snow covers. Along with water resources, snow and ice help regulate downstream river temperatures by sending cold meltwater down the mountain slopes every spring, supporting salmon spawning during the late summer dry season. This cold meltwater has become even more important as heatwaves intensify across the Western US. Over the past century, spring snowpack in the North Cascades has declined by one-third, and glacier area by nearly two-thirds.

https://www.nature.com/articles/s43247-023-00768-8