Antarctic permafrost degassing in Taylor Valley by extensive soil gas investigation

• Published in: Science of The Total Environment
• Main Authors: Ruggiero, Livio, Sciarra, Alessandra, Mazzini, Adriano, Florindo, Fabio, Wilson, Gary, Tartarello, Maria Chiara, Mazzoli, Claudio, Anderson, Jacob, Romano, Valentina, Worthington, Rachel, Bigi, Sabina, Sassi, Raffaele, Ciotoli, Giancarlo
• Other Authors: Istituto Nazionale di Geofisica e Vulcanologia (INGV), Sezione Roma1, Roma, Italia, Center of Earth Evolution and Dynamics, University of Oslo, Sem Sælandsvei 2A, 0371 Oslo, Norway, Istituto Nazionale di Geofisica e Vulcanologia (INGV), Sezione AC, Roma, Italia, GNS Science, 30-368, Lower Hutt 5040, New Zealand, Earth Science Department, “Sapienza” University of Rome, Piazzale Aldo Moro 5, 00185 Roma, Italy, Department of Geosciences, University of Padua, Via Gradenigo 6, 35131 Padova, Italy, Department of Marine Science, University of Otago, 56, Dunedin 9054, New Zealand, National Research Council, Institute of Environmental Geology and Geoengineering, CNR-IGAG, Area della Ricerca di Roma 1- Strada Provinciale, 5d, 9 – 00010, Montelibretti, Rome, Italy
• Format: Article in Journal/Newspaper
• Language: English
• Published: Elsevier 2023
• Subjects: Antarctica; CO(2) output; McMurdo Dry Valleys; Permafrost; Soil gas survey; 02.01. Permafrost; Antarctic; Arctic; Austral; Taylor Valley; The Antarctic; Antarc*; Ice; Ice Sheet; permafrost
• Online Access: http://hdl.handle.net/2122/16180; https://doi.org/10.1016/j.scitotenv.2022.161345

Ongoing studies conducted in northern polar regions reveal that permafrost stability plays a key role in the modern carbon cycle as it potentially stores considerable quantities of greenhouse gases. Rapid and recent warming of the Arctic permafrost is resulting in significant greenhouse gas emissions, both from physical and microbial processes. The potential impact of greenhouse gas release from the Antarctic region has not, to date, been investigated. In Antarctica, the McMurdo Dry Valleys comprise 10 % of the ice-free soil surface areas in Antarctica and like the northern polar regions are also warming albeit at a slower rate. The work presented herein examines a comprehensive sample suite of soil gas (e.g., CO2, CH4 and He) concentrations and CO2 flux measurements conducted in Taylor Valley during austral summer 2019/2020. Analytical results reveal the presence of significant concentrations of CO2, CH4 and He (up to 3.44 vol%, 18,447 ppmv and 6.49 ppmv, respectively) at the base of the active layer. When compared with the few previously obtained measurements, we observe increased CO2 flux rates (estimated CO2 emissions in the study area of 21.6 km2 ≈ 15 tons day-1). We suggest that the gas source is connected with the deep brines migrating from inland (potentially from beneath the Antarctic Ice Sheet) towards the coast beneath the permafrost layer. These data provide a baseline for future investigations aimed at monitoring the changing rate of greenhouse gas emissions from Antarctic permafrost, and the potential origin of gases, as the southern polar region warms. Published 161345 6A. Geochimica per l'ambiente e geologia medica JCR Journal