Active layer thermal regime in two climatically contrasted sites of the Antarctic Peninsula region

Hrbáček, Filip; Oliva, Marc; Láska, Kamil; Fernández, Jesús Ruíz; Pablo, Miguel Ángel de; Vieira, Gonçalo; Ramos, Miguel; Nývlt, Daniel

doi:10.18172/cig.2915

Cited by 15 publications

(10 citation statements)

References 22 publications

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“…In other localities of the Antarctic Peninsula region, the ALT showed also a high variability, such as on Signy Island, where ALT ranged between 0.8 and 1.8 m influenced by vegetation (Guglielmin et al, 2012), or on James Ross Island where the ALT reached 0.5 to 0.8 m at sites with different lithological properties under colder climate conditions (Hrbáček et al, 2016).…”

Section: Thaw Depthmentioning

confidence: 98%

Recent shallowing of the thaw depth at Crater Lake, Deception Island, Antarctica (2006–2014)

Ramos

Vieira

Pablo

et al. 2017

CATENA

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The Western Antarctic Peninsula region is one of the hot spots of climate change and one of the most ecologically sensitive regions of Antarctica, where permafrost is near its climatic limits. The research was conducted in Deception Island, an active stratovolcano in the South Shetlands archipelago off the northern tip of the Antarctic Peninsula. The climate is polar oceanic, with high precipitation and mean annual air temperatures (MAAT) close to − 3°C. The soils are composed by ashes and pyroclasts with high porosity and high water content, with icerich permafrost at −0.8°C at the depth of zero annual amplitude, with an active layer of about 30 cm. Results from thaw depth, ground temperature and snow cover monitoring at the Crater Lake CALM-S site over the period 2006 to 2014 are analyzed. Thaw depth (TD) was measured by mechanical probing once per year in the end of January or early February in a 100 × 100 m with a 10 m spacing grid. The results show a trend for decreasing thaw depth from ci. 36 cm in 2006 to 23 cm in 2014, while MAAT, as well as ground temperatures at the base of the active layer, remained stable. However, the duration of the snow cover at the CALM-S site, measured through the Snow Pack Factor (SF) showed an increase from 2006 to 2014, especially with longer lasting snow cover in the spring and early summer. The negative correlation between SF and the thaw depth supports the significance of the influence of the increasing snow cover in thaw depth, even with no trend in the MAAT. The lack of observed ground cooling in the base of the active layer is probably linked to the high ice/water content at the transient layer. The pyroclastic soils of Deception Island, with high porosity, are key to the shallow active layer depths, when compared to other sites in the Western Antarctic Peninsula (WAP). These findings support the lack of linearity between atmospheric warming and permafrost warming and induce an extra complexity to the understanding of the effects of climate change in the ice-free areas of the WAP, especially in scenarios with increased precipitation as snow fall.

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Section: Thaw Depthmentioning

confidence: 98%

Recent shallowing of the thaw depth at Crater Lake, Deception Island, Antarctica (2006–2014)

Ramos

Vieira

Pablo

et al. 2017

CATENA

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“…The annual air temperature ranges between +10 and −30 • C on the Ulu Peninsula (Hrbáček et al, 2016a;Láska et al, 2011). The year 2015 marked the warmest summer ever measured on the Ulu Peninsula, having a mean seasonal summer temperature (MSST) of 0.0 • C and a maximum air temperature of 13.3 • C (Hrbáček et al, 2017a), even though the mean annual air temperature (MAAT) decreased slightly from −6.8 • C in 2011 to −7 • C in 2015 (Hrbáček et al, 2016b;Láska et al, 2012).…”

Section: Regional Setting Of James Ross Island Maritime Antarcticamentioning

confidence: 99%

“…BB is located windward towards the mainly southwesterly winds (Hrbáček et al, 2016c;Nývlt et al, 2016), whereas SMC is located leeward, shielded by the Lachman Crags from the stronger winds. This results in less precipitation in the eastern part of JRI (Davies et al, 2013).…”

Section: Regional Setting Of James Ross Island Maritime Antarcticamentioning

confidence: 99%

Pedogenic and microbial interrelation in initial soils under semiarid climate on James Ross Island, Antarctic Peninsula region

Meier

Krauze

Prater³

et al. 2019

Biogeosciences

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Abstract. James Ross Island (JRI) offers the exceptional opportunity to study microbial-driven pedogenesis without the influence of vascular plants or faunal activities (e.g., penguin rookeries). In this study, two soil profiles from JRI (one at Santa Martha Cove – SMC, and another at Brandy Bay – BB) were investigated, in order to gain information about the initial state of soil formation and its interplay with prokaryotic activity, by combining pedological, geochemical and microbiological methods. The soil profiles are similar with respect to topographic position and parent material but are spatially separated by an orographic barrier and therefore represent windward and leeward locations towards the mainly southwesterly winds. These different positions result in differences in electric conductivity of the soils caused by additional input of bases by sea spray at the windward site and opposing trends in the depth functions of soil pH and electric conductivity. Both soils are classified as Cryosols, dominated by bacterial taxa such as Actinobacteria, Proteobacteria, Acidobacteria, Gemmatimonadetes and Chloroflexi. A shift in the dominant taxa was observed below 20 cm in both soils as well as an increased abundance of multiple operational taxonomic units (OTUs) related to potential chemolithoautotrophic Acidiferrobacteraceae. This shift is coupled by a change in microstructure. While single/pellicular grain microstructure (SMC) and platy microstructure (BB) are dominant above 20 cm, lenticular microstructure is dominant below 20 cm in both soils. The change in microstructure is caused by frequent freeze–thaw cycles and a relative high water content, and it goes along with a development of the pore spacing and is accompanied by a change in nutrient content. Multivariate statistics revealed the influence of soil parameters such as chloride, sulfate, calcium and organic carbon contents, grain size distribution and pedogenic oxide ratios on the overall microbial community structure and explained 49.9 % of its variation. The correlation of the pedogenic oxide ratios with the compositional distribution of microorganisms as well as the relative abundance certain microorganisms such as potentially chemolithotrophic Acidiferrobacteraceae-related OTUs could hint at an interplay between soil-forming processes and microorganisms.

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“…This is the case of the CALM and GTN-P sites at the Ulu Peninsula on the James Ross Island, Eastern AP, under the responsibility of a research team from Czech Republic (e.g., Engel et al, 2010;Laska et al, 2012;Hrbáček et al, 2014Hrbáček et al, , 2015. In this region of the Antarctica, although air temperatures are somewhat colder, there is a known correlation factor and the snow precipitation is lower than in South Shetland Archipelago (e.g., Hrbáček et al, 2016, and references therein). Annual and interannual comparative analyses between data from both monitoring sites will allow a better understanding, not only of the permafrost and active layer state and evolution related the global warming but also of the role of snow on the control of the thermal state of the ground.…”

Section: Snow Cover Monitoringmentioning

confidence: 99%

Frozen ground and snow cover monitoring in the South Shetland Islands, Antarctica: Instrumentation, effects on ground thermal behaviour and future research

Pablo

Ramos

Molina

et al. 2016

CIG

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Active layer thermal regime in two climatically contrasted sites of the Antarctic Peninsula region

Abstract: ABSTRACT. Permafrost controls geomorphic processes in ice-free areas of the

Cited by 15 publications

References 22 publications

Recent shallowing of the thaw depth at Crater Lake, Deception Island, Antarctica (2006–2014)

Recent shallowing of the thaw depth at Crater Lake, Deception Island, Antarctica (2006–2014)

Pedogenic and microbial interrelation in initial soils under semiarid climate on James Ross Island, Antarctic Peninsula region

Frozen ground and snow cover monitoring in the South Shetland Islands, Antarctica: Instrumentation, effects on ground thermal behaviour and future research

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