The cold volcano: the active layer thermal regime of Deception Island, Maritime Antarctica

Abstract

Permafrost monitoring is a key approach to assess soil responses in paraglacial environments under current climate change. This study investigates the active layer thermal regime of Deception Island by analyzing a seven-year dataset of soil temperature and moisture collected at two contrasting sites: (i) a Haplic Cryosol at Fumarole Bay (FB) and (ii) a Turbic Cryosol at Telefon Bay (TB). Temperature and moisture probes were installed at multiple depths (10–70 cm) and continuously monitored between 2010 and 2016. Statistical analyses included correlation among soil layers and multivariable regression. Results reveal a periglacial soil thermal regime with a shallow active layer, and maximum thaw depths of 86 cm (FB) and 109 cm (TB). At FB, sedimentary discontinuities and marine deposits promoted buffering of the permafrost table, while at TB the uniform volcanic matrix allowed stronger coupling with air temperatures, making permafrost more vulnerable. Although permafrost at FB was warmer, the TB site exhibited greater fragility due to stronger air–soil interactions. No evidence of geothermal heat influence was detected during the monitoring period. These findings provide new insights into permafrost dynamics in volcanic islands of Maritime Antarctica, highlighting the influence of geomorphological and sedimentary settings on active layer variability.