Sugars in Snow, Their Sources, and Fate Related to Microbial Metabolism: A Review

Abstract

Snowpacks play a key role in local and regional biogeochemical cycles and impact surrounding ecosystems during snowmelt. While they do not serve as long-term carbon sinks like glaciers or permafrost, snowpacks temporarily store nutrients, pollutants, and microorganisms that can be released into surrounding ecosystems through meltwater. Active snow microorganisms within temporary snowpacks can contribute to carbon cycling through processes such as carbon fixation, respiration, and carbohydrate metabolism. In addition, snowpacks continuously receive atmospheric inputs, including carbohydrates from plants and microbes. These carbohydrates serve as indicators of biological and human activities. Factors like season, altitude, and location affect the carbohydrate composition, with sugars like glucose, sucrose, and mannitol linked to vegetation and microbial activity, while others, such as levoglucosan, mannosan, and galactosan, trace biomass burning events. Over time, snowpacks transform into firn and eventually ice, trapping airborne particles like carbohydrates. These preserved compounds in ice cores provide insights into past environmental conditions, including vegetation patterns and fire events. However, the current situation of rapid climate change threatens to disrupt these snowpack systems, underscoring the need for urgent investigation into the dynamics of carbohydrates and microbial activity. Thus, further research is crucial to unravel the biochemical processes within snowpacks and their implications for ecosystem dynamics. Field studies and experimental approaches will be fundamental in advancing our understanding of these complex and evolving systems.