Effects of warming and enhanced snow deposition on soil moisture and soil temperature in High Arctic ecosystems

Abstract

Warming has an especially significant effect on High Arctic soils because these systems are carbon-rich and are closely linked with permafrost processes. Fluctuations in soil temperature and moisture in the High Arctic influence rates of permafrost thaw and microbial activity, leading to increased soil carbon release and loss of critical nutrients.This project aims to understand the effects of atmospheric warming by examining how elevated temperature and snow deposition influenced soil moisture and soil temperature trends from 2015 to 2024 in soils at the International Tundra Experiment (ITEX) site on Melville Island, Nunavut at the Cape Bounty Arctic Watershed Observatory (CBAWO). ITEX is a long-term, global experiment, investigating the effects of climate warming on tundra ecosystems through standardized experimental warming methods, such as open-top chambers. At the CBAWO, snow fences allow us to examine the interactive effects of elevated temperature and snowfall. Hourly soil measurements were collected from three of eight replicates under four treatments: Control, Warm, Snow, and Snow + Warm combination. Measurements included volumetric water content (m³/m³ VWC) and temperature at 5cm depth (℃), and temperature at thaw depth (~60 cm below the soil surface). Spring months showed the greatest change in temperature and moisture across all years and between all treatments. A significant interaction between years and treatments when observing the effects on temperature (F(3,291039) = 12.92, P < 0.0001) indicates that the effect of each treatment varied annually, suggesting legacy effects on soil warming. Across all years, Control plots were consistently the coldest, while the combined Snow + Warm treatment produced the greatest warming, demonstrating synergistic effects.