Global warming significantly affects Arctic tundra, including permafrost thaw and soluble C release that may differentially affect tundra microbial growth. Using laboratory experiments, we report some of the first evidence for the effects of soluble glucose C enrichment on tundra soil prokaryotes (bacteria and archaea) and fungi, with comparisons to microbial eukaryotes. Fungal increase in C biomass was equivalent to ten % (w/w) of the added glucose-C, and for prokaryote biomass 2% (w/w), the latter comparable to prior published results. The C-gain after 14 days was 1.3 mg/g soil for fungi, and ~200 µg/g for prokaryotes. This article is protected by copyright. All rights reserved.