show Abstracthide AbstractNorthern-latitude tundra soils harbor substantial carbon (C) stocks that are highly susceptible to microbial degradation with rising global temperatures. Understanding the magnitude and direction, e.g., C release or sequestration, of the microbial responses to warming is necessary to accurately model climate change. In this study, Alaskan tundra soils were subjected to experimental in-situ warming by ~1.1 °C above ambient temperature, and the microbial responses were evaluated using metagenomics after 1.5 and 4.5 years, at two depths: 15-25 cm (pre-existing active layer) and 45-55 cm (recently-thawed permafrost boundary layer).