Carbonate bedrock may not alleviate DIC limitation of snow algae — a test of hypothesis in the Medicine Bow Mountains, WY, USA

ABSTRACT

Snow is a critical component of the Earth system. High elevation snow can persist into the melt season and hosts a diverse array of life including snow algae. Due in part to the presence of pigments, snow algae lower albedo and accelerate snow melt which has led to increasing interest in identifying and quantifying the environmental factors that constrain their distribution. Dissolved inorganic carbon (DIC) concentration is low in supraglacial snow on Cascade stratovolcanoes and snow algae primary productivity can be stimulated through DIC addition. Here we asked if CO₂ would still be a limiting nutrient for snow hosted on glacially eroded carbonate bedrock (which could provide an additional source of DIC). We assayed snow algae communities for nutrient and DIC limitation on two seasonal snowfields on glacially eroded carbonate bedrock in the Snowy Range of the Medicine Bow Mountains, Wyoming, USA. DIC stimulated snow algae primary productivity in snow with lower DIC concentration despite the presence of carbonate bedrock, which alleviated DIC limitation in the other site. Our results support the hypothesis that increased atmospheric CO₂ concentrations may lead to larger and more robust snow algae blooms globally, even for sites with carbonate bedrock.