Mapping carbon dioxide soil diffuse emissions and temperature at Deception Island volcano, South Shetland, Antarctica

LAMBERTI, M.C.; FORTE, P.; AGUSTO, M.; MASSENZIO, A.; GUERRIERO, L.

Conferencia; SCAR Open Science Conference 2022; 2022

Deception Island is amongst the most active volcanoes in Antarctica. Located in the southeast margin of the South Shetlands archipelago in the Bransfield Strait, this volcano has erupted at least twenty times in the last two centuries. The volcanic edifice emerges forming a horseshoe-shaped island with several hydrothermal sites and monogenetic cones scattered around its surface.In this work, we report the results of a carbon dioxide (CO2) soil diffuse degassing survey carried out in February – March, 2022. In total, we took 857 CO2 soil diffuse flux and 1011 soil temperature measurements in seven hydrothermal sites: Primero de Mayo Bay, Whalers Bay, Pendulum Cove, Carlos Salvador –a previously unnamed beach between Cross Hill and Wensleydale Beacon–, Cerro Caliente, Mount Pond, and a site located on the outer slope of Stonethrow Ridge. Soil CO2 fluxes and temperatures were obtained by means of a West Systems portable flow-meter and a Hanna HI 935005N thermometer, respectively. All surveyed sites presented anomalous CO2 fluxes and/or soil temperatures. Measurements of CO2 soil diffuse flux show values up to ⁓13400 g m-2d-1. Soil temperatures range between -3 and ⁓50°C. A preliminary statistical analysis suggests soil CO2 is fed by a combination of sources. Most hydrothermal sites present well defined diffuse degassing structures that release as much as 1.3 t d-1 of volcanic CO2 into the atmosphere.The findings of this survey will allow discriminating different sources of CO2, estimating the total output of CO2 and calculating the thermal energy release of Deception Island.