Soil-landform-vegetation interplays at Stinker Point, Elephant Island, Antarctica

Abstract

The geomorphic dynamics on ice-free areas are crucial for understanding soil formation, vegetation and landscape stability in maritime Antarctic. We aimed to describe the soil formation on different landforms, following the Holocene glacial retreat at Stinker Point. Twenty profiles were sampled and classified, grouped into three landforms units: middle platforms and scarps, till/glacial deposits and present/Holocene raised beaches. Soil chemical and physical attributes were determined, and the vegetation type identified and quantified. Soils from till and glacial deposits can be separated by the age of exposure: older soils are stony, skeletic; and recently exposed till has soils with moderate depth, alkaline reaction and very high base saturation. Soils at the middle platforms are shallow, coarse-grained, skeletic, with abundant vegetation. Soils from the present-day beaches are alkaline, very coarse with no horizon differentiation, whereas soils on Holocene beaches are acid and nutrient-rich due to past or present-day influence of fauna. Soils from Stinker Point are generally shallow, skeletic and strongly related to the landforms and biogenic influences. Compared with other islands of the South Shetlands, in Elephant Island soil development is less pronounced, being this mainly attributed to the metamorphic nature of parent material, with greater resistance to weathering.

Key words
Cryosol; Holocene landscape; lichens; mosses; ornithogenic soils; platforms

INTRODUCTION

Elephant Island is a remote island located around 61°10’S–55°10’W, in the south of the Drake Passage. Considered as part of the South Shetlands archipelago, its name is attributed to the presence of elephant seals colonies. The early sightings were reported by Captain George Powell in 1821, and are famous for having sheltered the men of the 1914 expedition led by Sir Ernest Shackleton, which was an extraordinary survival history in the glorious days of Antarctic exploration.

Set close to the southernmost border of the Scotia Arc, the island is basically composed by schists, derived from a Mesozoic–Cenozoic subduction complex, contrasting with other islands from the South Shetlands archipelago (Trouw et al. 1998, Dalziel et al. 2013). Outcrops show increasing metamorphism degree from NE to SW alignment and the foremost foliation presents E–W to NE–SW alignment mostly parallel to surface, among zones of orthogonal orientation (Trouw et al. 1991, 1998, 2000).

The first records of soils from Elephant Island came from fieldwork performed by O’Brien et al. (1979) in 1970-1971, which reported little mineral weathering and limited profile development, although modified by varying degrees of frost action. Wilson & Bain (1976) described leucophosphite related to the guano interaction with silicate minerals in samples from the same expedition, representing one of the pioneer reports on phosphatized soils in Antarctica.

Allison & Smith (1973) offered a first glance at extensive areas of ice-free ground with an unexpectedly wide range of habitats in which extensive plant communities developed, wherever melting water and some degree of shelter from the wind was afforded. The authors gave a detailed description and properly classified the vegetation communities occurring on headlands and raised marine terraces and platforms on the island southern coast (Allison & Smith 1973). Pereira & Putzke (1994) presented the floristic composition of Stinker Point as one of the first contributions of the Brazilian Antarctic Program in the island. These authors identified coarse soil enriched by faunal activity as an important substrate for flowering plants. The survey revealed the diversity of the vegetation cover reporting over 37 species of plants (the two native phanerogams Deschampsia antarctica and Colobanthus quitensis and 35 bryophytes) and 54 species of lichens (Pereira & Putzke 1994). The fauna is represented by a large number of marine mammals (weddell seals, antarctic fur seals, southern elephant seals); large colonies of penguins (Pygoscelis papua and P. antarcticus) and numerous nests of giant southern petrels (Macronectes giganteus), skuas (Stercorarius antarcticus) and other birds (Petry et al. 2018).

The paraglacial environments from of Maritime Antarctica with permafrost are sensitive to climate change, which can expose new areas to vegetation colonization and modify the soil formation (Bockheim et al. 2013, Navas et al. 2017). The investigations of accelerated geomorphic dynamics in such ice-free areas are crucial for understanding soil formation, vegetation establishment and landscape stability (Balks et al. 2013, Michel et al. 2014, Turner et al. 2016). López-Martínez et al. (2012) have identified the geomorphological features and mapped eight different periglacial landforms at Stinker Point area related to marine platforms (flat floored valleys, laminated cracking on rock, patterned ground, gelifluction sheets and lobes, and vertical stone fields), till deposits (patterned ground, gelifluction lobes, and vertical stone fields), and slopes (debris talus and cones) (Navas et al. 2018).

This study aims to describe the formation of soils and compare it with the vegetation cover on different landforms, following the Holocene glacial retreat at Stinker Point, Elephant Island. Thus, we hypothesize that vegetation cover and soils would be more developed in stable landforms with ice-free ground for longer exposure time, which had great faunal activity in the past.

MATERIALS AND METHODS

Study area

Elephant Island is the northernmost island in the South Shetlands archipelago (Fig. 1), with approximately 1400 km² (Allison & Smith 1973). It is covered by glaciers with only 5% of its area being ice-free (Navas et al. 2018), and Stinker Point, at the western shore is one of the largest ice-free areas. The morphology combines stable periglacial landforms with recently exposed surface, including platforms, beaches, strandflats, morainic complexes and glaciers (López-Martínez et al. 2012, 2016). Lithology comprises a metamorphic succession containing grey, green and blue phyllites and schists and layers of amphibolite and fine volcanic metaconglomerate (e.g. Marsh & Thompson 1985, Trouw et al. 1991). Trouw et al. (2000) identified a metamorphic succession with increasing intensity from northeast to southwest, Stinker Point belonging to the intermediate blueschist facies. In addition to the island location in the framework of the Scotia-Antarctic-South Shetland Block triple junction, glacioisostatic and neotectonic uplift have played a major role in shaping the landscape (Galindo-Zaldívar et al. 2006, López-Martínez et al. 2006, Abakumov et al. 2017).

Figure 1
Location of the study area: Antarctica (a), South Shetland Islands (b), Elephant Island (c), Stinker Point with 20 sampled profiles (d).

The region experiences a sub-Antarctic cold, moist, maritime climate, with mean air temperature ranging from -10 °C to 1 °C (Turner & Pendlebury 2004) and means summer air temperatures above 0 °C (Rakusa-Suszczewski 1993). Precipitation is abundant, compared to the rest of the archipelago and ranges between 500 and 800 mm per year (Øvstedal & Lewis-Smith 2001). Permafrost is regarded as sporadic or inexistent in altitudes below 20 m a.s.l. and occurs discontinuously in altitudes from 30 to 150 m a.s.l. (Serrano & López-Martínez 2000, Vieira et al. 2010, Bockheim et al. 2013). Freeze-thaw cycles are common and occur in daily periods (Turner et al. 2007).

Landforms and related processes were described during fieldwork based on the regional reference of López-Martínez et al. (2012) updated by Navas et al. (2018). Navas et al. (2018) reported eight glacial landforms (till, glacier among others) eight periglacial and nival landforms, three fluvial and lacustrine and two marine landforms and deposits (present-day and Holocene beaches, middle platforms and scarps) (Fig. 2) that were used to guide this work.

Figure 2
Map of the main geomorphological units, landforms, and periglacial features at Stinker Point area (b) in Elephant Island (a) (source Navas et al. 2018).

Soil characterization

Soil sampling was performed during the austral summer, in January and February of 2016. Twenty profiles distributed across Stinker Point were dug, sampled and analyzed down to the lithic contact or to the permafrost table (Table I). Soil profiles were grouped according to the landforms and landscape elements identified by López-Martínez et al. (2012) and Navas et al. (2018): till/glacial deposit (TGD); middle platforms and scarps (MPS); and present-day/Holocene beaches (PHB) (Fig. 3). We considered permafrost to be present (discontinuous) at middle platforms and till/glacial deposit (continuous) and sporadic at present-day/Holocene beaches. Seven profiles were located and collected at TGD: P1, P2, P10, P11, P12, P17 and P18 (Table II); ten profiles were located at MPS: P3, P4, P5, P7, P8, P9, P15, P16, P19 and P20; and three were at PHB: P6, P13 and P14.

Figure 3
Landforms and representative soil profiles, sampled at Stinker Point: P3 and P16 Middle platforms and scarps, P1 (older soils) and P10 (recently exposed) at Till and Glacial deposit, Present day (P6) and Holocene beaches (P14).

Table I
Location, soil classification and description of the areas (landscape and vegetation) of the 20 soil profiles (P) sampled at Stinker Point.

P	Elev m a.s.l.	Geographic position	Classification WRB-FAO	Description	Vegetation type/common species
1	120	S 61˚13’10.7” W 55˚21’28.0”	Turbic Leptic Skeletic Cryosol (Dystric, Ornithic)	Till/glacial deposit in top; well drained; plan to soft wavy; no current presence of bird nests	Moss carpet community associated with fruticose lichens: Sanionia uncinata, Polytrichastrum alpinum, Chorisodontium acyphillum, Usnea antarctica, Cladonia sp., Ochrolechia frigida, Himantormia lugubris, Psoroma sp., Prasiola crispa
2	110	S 61˚14’07.2” W 55˚21’17.2”	Turbic Cryosol (Dystric, Ornithic)	Till/glacial deposit in top; well drained; flat to wavy relief; Skua nests nearby	Mixed community moss cushions-musciculous lichens association: Andreaea sp., Bryum sp., Ochrolechia frigida, Cystocoleus niger and Caloplaca sp.
3	69	S 61˚13’17.9” W 55˚21’58.8”	Turbic Leptic Skeletic Cryosol (Dystric, Ornithic)	Middle platform, well drained; plan to soft wavy relief; Petrel and skua nests nearby	Moss carpet community associated with fruticose lichens: Sanionia uncinata, Sphaerophorus globosus, Polytrichastrum alpinum, Chorisodontium aciphyllum, Cladonia borealis, esporadic Deschampsia antarctica and Prasiola crispa.
4	65	S 61˚13’18.0” W 55˚21’58.1”	Turbic Leptic Skeletic Cryosol (Dystric, Arenic, Ornithic)	Middle platform, well drained; plan to soft wavy relief; Petrel and skua nests nearby	Moss carpet community: Sanionia uncinata with Deschampsia antarctica, esporadic Chorisodontium aciphyllum, and Polytrichastrum alpinum tufts.
5	60	S 61˚13’17.9” W 55˚21’57.0”	Turbic Leptic Cryosol (Dystric, Arenic)	Middle platform, well drained; plan to soft wavy; Skua nests and lake nearby;	Deschampsia antarctica phanerogamic community associated with Sanionia uncinata
6	4	S 61˚13’46.8” W 55˚21’46.3”	Dystric Arenosol (Gelic)	Present-day beaches, well drained, plan; presence of mammals and seabirds	Bare soil
7	60	S 61˚13’24.2” W 55˚21’34.8”	Turbic Leptic Skeletic Cryosol (“Patterned”, Dystric, Ornithic)	Middle platform, well drained; plan to soft wavy; occasional skuas and petrels	Moss turf community Chorisodontium aciphyllum associated with lichens: Sphaerophorus globosus, Cladonia borealis, Ochrolechia frigida, Usnea antarctica, Psoroma sp., Sanionia uncinata.
8	60	S 61˚13’23.8” W 55˚21’34.3”	Turbic Leptic Skeletic Cryosol (“Patterned”, Dystric, Ornithic)	Middle platform, well drained; plan to soft wavy; occasional skuas and petrels	Moss carpet community Sanionia georgicouncinata
9	60	S 61˚13’23.9” W 55˚21’35.9”	Turbic Leptic Skeletic Cryosol (“Patterned”, Eutric, Ornithic)	Middle platform, well drained; plan to soft wavy; occasional skuas and petrels	Fruticose lichens community: Sphaerophorus globosus associated with mosses: Chorisodonthium acyphillum, Himantormia lugrubis, Usnea antarctica, Psoroma sp., Cladonia borealis, Cladonia rangiferina, Polytrichastrum alpinum, Sanionia uncinata
10	52	S 61˚13’24.3” W 55˚21’04.0”	Turbic Cryosol (“Patterned”, Eutric)	Till/glacial front and deposit; moderately drained; flat to wavy relief	Bare soil
11	48	S 61˚13’36.5” W 55˚21’16.9”	Turbic Leptic Cryosol (“Patterned”, Eutric)	Till, glacial deposit; moderately drained; wavy relief; near lake; occasional skuas.	Moss cushion community Bryum orbiculatifolium, Hennediella heimii (fertile), Brachythecium sp.
12	50	S 61˚13’50.1” W 55˚21’27.5”	Turbic Leptic Cryosol (“Patterned”, Eutric)	Till/glacial deposit; moderately drained; wavy relief; near drain line and lake; occasional skuas.	Moss cushion community Bryum orbiculatifolium and Hennediella heimii
13	22	S 61˚13’33.1” W 55˚21’37.5”	Eutric Regosol (Gelic, Ornithic, Turbic)	Holocene beaches, raised marine terrace; well drained; wavy relief; occasional seabirds.	Phanerogamic community Colobanthus quitensis associated with mosses Sanionia uncinata and Polytrichastrum alpinum
14	20	S 61˚13’47.7” W 55˚21’39.4”	Dystric Regosol (Gelic, Ornithic, Turbic)	Holocene beaches, raised marine terrace; well drained; wavy relief; occasional seabirds.	Phanerogamic community Deschampsia antarctica; Caloplaca regalis on the rocks
15	92	S 61˚13’18.8” W 55˚22’04.7”	Turbic Leptic Skeletic Cryosol (Eutric, Ornithic)	Middle platform, moderately drained; wavy relief; in Pygocelis antarcticus active rookery.	Bare soil
16	90	S 61˚13’20.6” W 55˚22’04.0”	Turbic Leptic Skeletic Cryosol (Dystric, Ornithic)	Middle platform, well drained, wavy relief, Petrel nests nearby, adjacent to P15 (penguin rookery).	Macroscopic alga community Prasiola crispa
17	55	S 61˚13’57.6” W 55˚21’12.9”	Turbic Leptic Cryosol (“Patterned”, Eutric)	Till/glacial deposit; moderately drained; wavy relief; near lake; occasional skuas.	Moss cushion community Bryum orbiculatifolium, Hennediella heimii, Brachythecium sp.
18	58	S 61˚13’51.7” W 55˚20’59.1”	Turbic Cryosol (“Patterned”, Eutric)	Till/glacial front and deposit; moderately drained; flat to wavy relief	Bare soil
19	70	S 61˚13’21.0” W 55˚22’07.2”	Turbic Leptic Skeletic Cryosol (Dystric, Arenic, Ornithic)	Middle platform; well drained, plan relief, Petrel and skuas nests nearby	Moss carpet community associated with musciculous lichens: Sanionia uncinata, Andreaea sp., Usnea antarctica, Sphaerophorus globosus, Psoroma sp., Ochrolechia frigida, Cladonia sp.
20	90	S 61˚13’20.4” W 55˚21’26.9”	Turbic Leptic Cryosol (Eutric, Arenic, Ornithic)	Middle platform, well drained, wavy relief, occasional seabirds	Moss carpet community associated with musciculous lichens: Sanionia uncinata, Polytrichastrum alpinum, Usnea antarctica, Sphaerophorus globosus, Ochrolechia frigida, Cladonia sp.

Table II
Temperature (T), color, physical properties and texture of the 20 soil profiles sampled in Stinker Point.

Horizons	Depth	T	Color (dry)		Gravel		Sand		Silt		Clay	Texture
	(cm)	(°C)			-----------------------%--------------------
Till/glacial deposit (TGD)
P1 – Turbic Leptic Skeletic Cryosol (Dystric, Ornithic)
A	5-15	8.0	10YR 3/2	Very dark grayish brown	85		74		19		7	Loamy sand
B	15-35+	5.9	2.5Y 4/2	Dark grayish brown	52		66		31		3	Sandy loam
P2 – Turbic Cryosol (Dystric, Ornithic)
A	5-10	6.9	5Y 5/1	Gray	38		58		37		5	Sandy loam
B1	10-22	5.9	5Y 5/1	Gray	33		57		38		6	Sandy loam
B2	22-35	5.5	5Y 5/1	Gray	51		54		41		6	Sandy loam
C	35-48	5.0	5Y 5/1	Gray	38		51		35		5	Sandy loam
P10 - Turbic Cryosol (“Patterned”, Eutric)
C1	0-25	6.2	10Y 6/1	Greenish Gray	29		46.4		19.5		34.1	Clay loam
C2	25-50	5.3	7.5Y 5/1	Gray	37		52.8		39.8		7.4	Loam
C3	50-65+	5.0	7.5Y 5/1	Gray	44		51.5		41.8		6.7	Loam
P11 - Turbic Leptic Cryosol (“Patterned”, Eutric)
C1	0-10	8.3	7.5Y 5/1	Gray	54		57		39.3		3.6	Sandy loam
C2	10-20	5.5	7.5Y 5/1	Gray	48		51.6		38.6		9.8	Sandy loam
C3	20-35+	4.0	5Y 5/1	Gray	44		52.3		41.0		6.7	Sandy loam
P12 - Turbic Leptic Cryosol (“Patterned”, Eutric)
C1	0-12	8.6	7.5Y 5/1	Gray	51		52.5		38.4		9.8	Sandy loam
C2	12-40	5.0	5Y 5/1	Gray	63		49.9		40.2		9.9	Sandy loam
P17 – Turbic Leptic Cryosol (“Patterned”, Eutric)
C1	0-12	6.3	7.5Y 5/1	Gray	33		45.3		47.1		7.6	Loam
C2	12-35+	4.0	7.5Y 5/1	Gray	25		43		48.9		8.1	Loam
P18- Turbic Cryosol (“Patterned”, Eutric)
C1	0-10	12.0	7.5Y 5/1	Gray	35		51.5		44.6		4.0	Sandy loam
C2	10-22	5.4	7.5Y 5/1	Gray	38		42.8		51.4		5.9	Silt loam
C3	22-30	3.9	7.5Y 5/1	Gray	27		41.5		54.7		3.8	Silt loam
Middle platforms and scarps (MPS)
P3 - Turbic Leptic Skeletic Cryosol (Dystric, Ornithic)
A	0-12	5.6	7.5YR 3/1	Very Dark Gray	29		96.1		2.4		1.5	Sand
BC	12-40	4.9	7.5YR 4/2	Brown	65		78.7		8.1		13.3	Sandy loam
P4 – Turbic Leptic Skeletic Cryosol ( Dystric, Arenic, Ornithic )
A/O	3-6	6.8	5YR 3/1	Very Dark Gray	11		96.6		0.3		3.0	Sand
A	6-10	6.5	7.5YR 3/2	Dark Brown	33		96.9		1.6		1.5	Sand
BR	10-35+	4.6	7.5YR 4/2	Brown	57		86.7		6.1		7.2	Sand
P5 - Turbic Leptic Cryosol (Dystric, Arenic)
A/01	0-8	5.7	7.5YR 3/1	Very Dark Gray	22		98.4		1.3		0.3	Sand
A/02	8-22	5.1	5YR 3/1	Very Dark Gray	10		99.1		0.7		0.2	Sand
B	22-40	4.8	7.5YR 4/2	Brown	54		88.7		5.3		6.0	Sand
P7 - Turbic Leptic Skeletic Cryosol (“Patterned”, Dystric, Ornithic)
A	0-10	4.3	2.5Y 4/1	Dark Gray	94		71.8		19.4		8.9	Sandy loam
AB	10-17	3.9	2.5Y 5/1	Gray	72		75.3		16.8		7.9	Sandy loam
B	17-40+	3.5	2.5Y 6/1	Gray	37		54.4		39.5		6.1	Loam
P8 - Turbic Leptic Skeletic Cryosol (“Patterned”, Dystric, Ornithic)
O	0-5	6.8	10YR 4/2	Dark Grayish Brown	32		77		12.9		10.1	Sandy loam
A	5-10	6.4	10YR 5/2	Grayish Brown	72		79		12.8		8.2	Sandy loam
BR	10-30	4.4	7.5 YR 5/2	Grayish Brown	79		76.3		18.1		5.6	Sandy loam
P9 - Turbic Leptic Skeletic Cryosol (“Patterned”, Eutric, Ornithic)
A	0-15	-	2.5Y 4/1	Dark Gray	97		75.8		11.2		13.1	Sandy loam
B	15-30	-	10YR 5/2	Grayish Brown	84		62.5		18.6		18.9	Sandy loam
P15 – Turbic Leptic Skeletic Cryosol (Eutric, Ornithic)
A	0-12	7.6	10YR 5/2	Grayish Brown	90		55.6		30.1		14.3	Sandy loam
B	12-35+	6.4	10YR 5/2	Grayish Brown	91		54.8		28.2		17.1	Sandy loam
P16 – Turbic Leptic Skeletic Cryosol (Dystric, Ornithic)
A	0-5	6.3	7.5YR 3/2	Dark Brown	80		68.6		14.7		16.7	Sandy loam
C1	5-15	5.0	10YR 5/2	Grayish Brown	72		68.1		21.0		10.9	Sandy loam
C2	15-40+	4.0	2.5Y 5/2	Grayish Brown	52		62.7		31.4		5.9	Sandy loam
C2 incl	25-35	-	7.5YR 4/3	Brown	25		64.6		27.9		7.4	Sandy loam
P19 - Turbic Leptic Skeletic Cryosol (Dystric, Arenic, Ornithic)
O/A	0-12	6.8	2.5Y 3/1	Very Dark Gray (brownish)	73		75.9		15.8		8.4	Sandy loam
B	12-20	6.5	10YR 4/2	Grayish Yellow Brown	51		61.6		28.3		10.0	Sandy loam
C	20-40	-	2.5Y 5/2	Dark grayish yellow	51		55.3		31.8		13.0	Sandy loam
P20 - Turbic Leptic Cryosol (Eutric, Arenic, Ornithic)
A	0-5	5.4	2.5Y 5/2	dark grayish yellow	54		75.2		22.8		2.0	Loamy Sand
B	5-15	4.4	5Y 5/1	Gray	45		72.4		27.1		0.6	Loamy Sand
C	15-40+	3.5	5Y 5/1	Gray	52		69.0		29.6		1.4	Sandy loam
Present-day/Holocene beaches (PHB)
P6- Dystric Arenosol (Gelic)
1A	0-25	-	5YR 3/1	Very Dark Gray	14	98.9		1.0		0.1			Sand
2B1	25-55	-	2.5YR 3/1	Gark Reddish Gray	3	99.3		0.4		0.3			Sand
2B2	55-70+	-	5YR 3/1	Very Dark Gray	5	99.2		0.7		0.0			Sand
P13 - Eutric Regosol (Gelic, Ornithic, Turbic)
A	0-10	16.0	5Y 5/1	Gray	40		62.8		34.4		2.9	Sandy loam
B	10-28	10.0	5Y 5/1	Gray	38		68.3		28.4		3.3	Sandy loam
C1	28-45	6.8	5Y 5/1	Gray	38		65.7		32.2		2.1	Sandy loam
C2	45-60+	5.0	5Y 5/1	Gray	36		67.8		29.8		2.5	Sandy loam
P14 - Dystric Regosol (Gelic, Ornithic, Turbic)
A	0-10	13.8	5Y 5/1	Gray	49		65.7		30.9		3.3	Sandy loam
B	10-25	12.1	5Y 6/1	Gray	45		61.8		33.8		4.4	Sandy loam
C1	25-45+	6.9	5Y 5/1	Gray	37		54.7		39.4		5.9	Sandy loam
Ex. samp	0-10	-	2.5Y 5/1	Gray	59		80.1		19.1		0.8	Loamy sand

The morphology of the profile was described, and samples of soil horizons were collected following Bockheim et al. (2006). Soil classification followed the World Reference Base for Soil Resources (IUSS Working Group WRB 2015). Soil properties were measured at the soil laboratory, following international standard protocols (EMBRAPA 2017). Soil texture was analyzed by mechanical dispersion of <2 mm samples in distilled water, sieving and weighting of the coarse and fine sand, sedimentation of the silt fraction followed by siphoning of the <2 μm fraction (Gee & Bauder 1986). Soil textural classes were determined using a soil textural chart (Sand 0.05-<2mm, silt 0.002-<0.05 mm and clay < 0.002 mm). The pH in water and KCl were determined using the ratio soil:liquid 1: 2.5; acidic components (H + Al) were extracted with Ca(OAc)₂ 0.5 mol L^-1 buffered to pH 7.0 and quantified via titration with NaOH 0.06 mol L^-1. Exchangeable Ca, Mg, and Al were extracted with 1 mol L^-1 KCl, and determined via atomic absorption spectroscopy. Available P, K, Na, Fe, Zn, Cu and Mn, were extracted with Mehlich-1 (0.05 mol L^-1 HCl in 0.0125 mol L^-1 H₂SO₄), and quantified using flame photometry. Element’s concentrations in the extracts were determined by atomic absorption (Ca²⁺, Mg²⁺ and Al³⁺), flame emission (K⁺ and Na²⁺) and photocolorimetry (P), microelements were determined using inductively coupled spectroscopy. Organic matter (OM) was determined by wet combustion with external heating (Yeomans & Bremner 1988). We also evaluated the capacity of soils to adsorb P (P-rem) by shaking 2.5 g of soil for 1 h with 25 ml of 0.01 mol L^-1 CaCl₂ containing 60 mg L^-1 of P. The suspension was filtered and the P remaining in solution (P-rem) was measured by photocolorimetry (Alvarez et al. 2000).

Effective cation exchange capacity (CECeff) was calculated via determining the sum of cations (Ca²⁺, Mg²⁺, Na⁺, K⁺, and A³⁺) whereas the total cation exchange capacity (CEC_T) was estimated using the bases sum (BS) and potential acidity (H+Al). We determined the percentage of base saturation (PSB) and aluminum saturation (Al_sat).

Vegetation classification and fauna activity

The vegetation surrounding the profile was collected and identified according to Ochyra et al. (2008) and Putzke & Pereira (2001); and evaluated the type of community according to Longton’s classification (1988). The associations are characterized by codominant species or by restricted occurrence in more specific habitats (Schmitz et al. 2020a, b). The fauna activity was evaluated by observing the animals that inhabited the site at the time of collection of traces found (nests, bones, guano).

Data analyses

Physical and chemical soil properties were summarized through a principal component analysis (PCA) on the correlation matrix using the ‘FactoMineR’ package (Husson et al. 2017). This analysis was applied to reduce the number of redundant soil properties and identify patterns of similarity between landforms samples (i.e. Schmitz et al. 2020a, b). We also calculated Pearson correlations among soil properties and the PCA ordination axes. The attributes with greater correlation in the PCA axes were used for descriptive analysis of the three landforms through boxplots. All analyses were carried out using the R environment (R Core Team 2021).

RESULTS

General soil characteristics and main descriptors

Soils at Elephant Island were predominantly shallow and rich in coarse materials (Table II). Soils from recently exposed areas were alkaline and eutric (P10, P11, P12, P13, P17, and P18), whereas those soils from older areas were more developed, presented low pH and dystric character (P3, P4, P5, P8, P16, and P19), even when affected by faunal nutrient inputs (Table III). All soil structures were weak or moderate, fine or medium, and blocky or subangular blocky. Horizon transition was mainly gradual or diffuse with little horizon differentiation, probably by cryoturbation when the active layer in the soil can erode moving from the soil surface downwards as from permafrost upwards. However, during this process, patterned ground and gelifluction sheets are rare, whereas stone fields are more common due to the high parent material strength. Vegetation cover was abundant on most profiles being influenced by landscape stability, faunal colonization, and wind exposure. Stinker Point can be divided into two major landscapes, ones occupied by glaciers during the last glacial advance of the Little Ice Age, and areas that remained ice-free during this period; vegetation has just begun colonizing the first.

Table III
Chemical properties of the 20 soil profiles sampled in Stinker Point.

Horizon	Depth (cm)	pH		P	K	Na	Ca	Mg	Al	H+Al	BS	CECeff	CECT	PSB	Al sat	OM	P-Rem		Cu		Mn	Fe	Zn	N
		H 2 O	KCl	---------- mg/dm3---------			--------------------------cmol o /dm 3 --------------------------							%		dag/kg	mg/L		------------mg/dm3--------------					dag/kg
Till/glacial deposit (TGD)
P1 – Turbic Leptic Skeletic Cryosol (Dystric, Ornithic)
A	5-15	4.84	4.5	279.2	166	146.2	1.41	1.54	0.2	7.8	4.01	4.21	11.81	34	4.8	3		44.6	1.12		2.1	112.6	1.82	0.21
B	15-35+	4.64	4.19	374.3	152	315.3	3.13	2.23	1.9	17.2	7.12	9.02	24.32	29.3	21.1	1.3		12.4	5.22		5.8	318.3	1.87	0.14
P2 – Turbic Cryosol (Dystric, Ornithic)
A	5-10	5	4.09	325	115	285.4	3.69	2.05	1.3	14.7	7.28	8.58	21.98	33.1	15.2	1.43	11.3		6.08		5	437.6	0.7	0.32
B1	10-22	4.77	2.96	287	91	155.2	2.11	2.49	7.4	21.3	5.51	12.91	26.81	20.6	57.3	0.52	19.3		4.83		6.4	460.3	0.79	0.15
B2	22-35	4.54	2.09	445.1	82	173.1	1.84	1.81	7.7	21.9	4.61	12.31	26.51	17.4	62.6	1.04	19.2		4.64		3.4	467.4	1.06	0.12
C	35-48	3.75	2.91	562.5	76	144.2	0.96	0.39	4.4	27.1	2.17	6.57	29.27	7.4	67	0.78	17.9		4.29		0.8	425.9	1.08	0.14
P10 - Turbic Cryosol (“Patterned”, Eutric)
C1	0-25	7.83	7.78	168.1	231	27.4	3.69	0.36	0	0.3	4.76	4.76	5.06	94.1	0	0.9	37.4		11.91		57.6	1140.2	5.96	0.25
C2	25-50	7.96	7.6	200	155	18.5	3.64	0.3	0	1.5	4.42	4.42	5.92	74.7	0	1.29	40.2		17.03		39.7	899.5	4.8	0.14
C3	50-65+	7.91	7.82	225.3	181	20.5	4.53	0.38	0	0.3	5.46	5.46	5.76	94.8	0	1.03	43.1		19.45		51.6	1251.8	5.81	0.23
P11 - Turbic Leptic Cryosol (“Patterned”, Eutric)
C1	0-10	7.69	7.6	123	116	31.4	2.62	0.23	0	0.2	3.28	3.28	3.48	94.3	0	1.42	37.6		13.39		53.6	1036.3	5.81	0.08
C2	10-20	7.98	7.82	135.5	181	37.4	4.35	0.37	0	0.2	5.35	5.35	5.55	96.4	0	1.55	28.4		9.84		41	710.3	4.32	0.12
C3	20-35+	7.85	7.01	195.6	127	32.4	3.64	0.55	0	0.2	4.66	4.66	4.86	95.9	0	1.16	42.9		8.87		36.1	480.7	3.28	0.14
P12 - Turbic Leptic Cryosol (“Patterned”, Eutric)
C1	0-12	7.9	7.58	280.6	154	32.4	4.03	0.48	0	0.3	5.05	5.05	5.35	94.4	0	1.68	32.9		13.92		46.8	725.1	5.85	0.04
C2	12-40	6.22	7.58	255.7	196	36.4	3.62	0.38	0	0.7	4.66	4.66	5.36	86.9	0	2.45	31.7		12.21		37.8	440.4	4.34	0.18
P17 – Turbic Leptic Cryosol (“Patterned”, Eutric)
C1	0-12	7.73	6.98	183.9	173	56.3	4.82	0.45	0	0.5	5.96	5.96	6.46	92.3	0	0.13	37.4		13.25		46	985.7	6.2	0.21
C2	12-35+	7.93	7.47	186.8	191	52.3	5.17	0.39	0	0.8	6.28	6.28	7.08	88.7	0	0.39	33.6		14.69		58.6	1242.6	7.55	0.30
P18 - Turbic Cryosol (“Patterned”, Eutric)
C1	0-10	7.84	7.72	163.8	171	59.3	4.49	0.54	0	0.3	5.73	5.73	6.03	95	0	1.81	36.3		13.86		51.1	1358.5	7.4	0.12
C2	10-22	7.91	7.85	172.6	176	42.4	5.07	0.58	0	0.8	6.29	6.29	7.09	88.7	0	0.9	33.7		9.66		34	721.6	4.42	0.10
C3	22-30	7.89	7.76	148.2	166	37.4	4.89	0.57	0	0.3	6.05	6.05	6.35	95.3	0	1.68	32.7		9.47		32.8	725.2	4.25	0.16
Table III. (continued)
Horizon	Depth (cm)	pH		P	K	Na	Ca	Mg	Al	H + Al	BS	CECeff	CECT	PSB	Al sat	OM dag/kg	P-Rem		Cu		Mn	Fe	Zn	N dag/kg
		H 2 O	KCl	---------- mg/dm3--------			--------------------------cmol o /dm 3 --------------------------							%			mg/L		------------mg/dm3--------------
Middle platforms and scarps (MPS)
P3 - Turbic Leptic Skeletic Cryosol (Dystric, Ornithic)
A	0-12	4.24	3.56	710	63	85.4	1.14	0.23	5.7	30.2	1.9	7.6	32.1	5.9	75	1.17	28.6		3.47	0.4		292.1	0.75	0.17
BC	12-40	4.17	3.22	1142.5	82	112.3	1.48	0.36	5.5	25.2	2.54	8.04	27.74	9.2	68.4	1.04	28.2		4.88	0.5		301.9	0.97	0.22
P4 – Turbic Leptic Skeletic Cryosol (Dystric, Arenic, Ornithic)
A/O	3-6	4.25	3.84	560.6	76	89.4	0.68	0.26	4.4	21.6	1.52	5.92	23.12	6.6	74.3	2.48	24.6		8.06		1.8	902.2	1.81	0.14
A	6-10	4.14	4.13	787.4	79	167.1	1.24	0.38	3.1	17.7	2.55	5.65	20.25	12.6	54.9	1.43	13		6.69		1.4	563.6	2.18	0.15
BR	10-35+	4.14	3.6	622.7	91	90.4	0.75	0.24	4.3	17.3	1.62	5.92	18.92	8.6	72.6	1.17	30.5		5.13		1.1	558.5	1.22	0.03
P5 - Turbic Leptic Cryosol (Dystric, Arenic)
A/O1	0-5	4.65	4.35	15.8	15	2.6	1.45	0.38	0.6	4.8	1.88	2.48	6.68	28.1	24.2	1.43	24.7		1.87		23.9	67.7	1.59	0.17
A/O2	5-10	4.82	3.95	21.7	41	0.6	0.68	0.27	1.1	4.5	1.06	2.16	5.56	19.1	50.9	1.43	34.3		0.88		7.2	135.2	0.87	0.22
B	10-30	4.66	5.28	3.9	58	0	1.09	0.23	0.9	9.6	1.47	2.37	11.07	13.3	38	1.57	11		1.94		3.9	43.8	3.15	0.03
P7 - Turbic Leptic Skeletic Cryosol (“Patterned”, Dystric, Ornithic)
A	0-10	5.35	4.82	5894	76	215.6	6.63	1.47	0	6.6	9.23	9.23	15.83	58.3	0	1.43	44.1		30.24		16.4	296.5	84.78	0.19
AB	10-17	5.54	5.56	5644.5	56	235.5	4.55	0.73	0	4	6.45	6.45	10.45	61.7	0	1.3	42.5		43.62		13.1	327.6	90.3	0.32
B	17-40	5.3	4.06	1217.1	55	55.5	2.83	0.36	0.5	4.5	3.57	4.07	8.07	44.2	12.3	1.43	47.5		9.53		1.6	169.5	6.37	0.21
P8 - Turbic Leptic Skeletic Cryosol (“Patterned”, Dystric, Ornithic)
O	0-5	4.81	4.27	4547.2	48	181.1	5.15	1.37	0.3	10.4	7.43	7.73	17.83	41.7	3.9	10.1	38.9		12.73		8.4	175.2	63.4	0.19
A	5-10	5.24	4.5	6761.8	38	192.1	4.49	0.83	0	7.1	6.25	6.25	13.35	46.8	0	2.61	46.3		22.91		11.6	364.9	81.1	0.38
BR	10-30	5.16	3.7	880.2	65	71.4	3.03	0.28	0.5	5.6	3.79	4.29	9.39	40.4	11.7	1.3	48.2		5.47		0.9	144.2	3.2	0.29
P9 - Turbic Leptic Skeletic Cryosol (“Patterned”, Eutric, Ornithic)
A	0-15	4.64	4.08	1019.9	76	108.3	3.82	1.38	0.5	8.1	5.87	6.37	13.97	42	7.8	2.61	38.6		7.06		6.2	165.2	8.16	0.21
B	15-30	5.21	5.02	6880.9	35	175.7	8.19	1.29	0	8.6	10.33	10.33	18.93	54.6	0	4.17	32.9		42.3		15	176	112.38	0.14
P15 – Turbic Leptic Skeletic Cryosol (Eutric, Ornithic)
A	0-12	5.69	5.34	5407.8	176	314.1	8.15	2.99	0	10.7	12.96	12.96	23.66	54.8	0	3.1	42.3		25.95		7	209.2	92.2	0.15
B	12-35+	5.33	4.35	7742.3	183	314.1	6.09	1.16	0	11.1	9.08	9.08	20.18	45	0	3.23	56.7		19.01		6.4	246.5	88.8	0.23
Table III. (continued)
Horizon	Depth (cm)	pH		P	K	Na	Ca	Mg	Al	H + Al	BS	CECeff	CEC T	PSB	Al sat	OM dag/kg	P-Rem		Cu		Mn	Fe	Zn	N dag/kg
		H2O	KCl	----------- mg/dm3--------			--------------------------cmol o /dm 3 --------------------------							%			mg/L		------------mg/dm3--------------
P16 – Turbic Leptic Skeletic Cryosol (Dystric, Ornithic)
A	0-5	4.97	4.32	154.6	87	87.2	1.32	0.65	0	5.4	2.57	2.57	7.97	32.2	0	6.46	56.1		0.99		1.1	108.3	2.12	0.25
C1	5-15	4.69	4.09	4805.8	131	294.2	5.01	0.82	0	9.2	7.45	7.45	16.65	44.7	0	4.13	47.5		30.05		8.4	305.6	99.7	0.22
C2	15-40+	4.6	3.62	3010.7	251	185.9	5.59	0.53	0.7	14.7	7.57	8.27	22.27	34	8.5	3.23	52.1		16.14		4	410.2	28.4	0.06
C2incl	25-35	4.37	3.37	5452.6	441	184.6	4.17	0.54	1.3	21.8	6.64	7.94	28.44	23.3	16.4	4	45.2		21.68		1.2	606.3	10.8	0.15
P19 - Turbic Leptic Skeletic Cryosol (Dystric, Arenic, Ornithic)
O/A	0-12	4.8	4.1	3362.88	157	324.1	4.72	1.54	0.1	10.7	8.07	8.17	18.77	43	1.2	10.9	58.6		14.71		5.4	287.8	40.8	0.03
B	12-20	5	4.42	7764.2	89	344	7.89	1.37	0.1	12.2	10.9	11.08	23.18	47.4	0.9	3.88	44.9		31.35		11	227.4	93.6	0.04
C	20-40	4.8	3.89	4117.5	166	324.1	6.4	0.89	0.1	12.4	9.12	9.22	21.52	42.4	1.1	3.1	52		17.73		8.2	287.1	61.1	0.37
P20 - Turbic Leptic Cryosol (Eutric, Arenic, Ornithic)
A	0-5	5.5	4.52	3667.8	36	152	3.12	1.06	0	5.3	4.93	4.93	10.23	48.2	0	0.52	42.8		15.87		24	799.5	38.6	0.07
B	5-15	5.81	4.37	1326.2	56	77.2	2.09	0.54	0	2.5	3.11	3.11	5.61	55.4	0	0.78	50.4		14.17		8.9	628.5	14.63	0.10
C	15-40+	6.34	5.02	655.5	59	42.4	2.24	0.49	0	1.8	3.07	3.07	4.87	63	0	1.03	54		19.89		11	628.4	6.68	0.06
Present-day/Holocene beaches
P6- Dystric Arenosol (Gelic)
1A	0-25	5.29	5.2	13.3	109	5.6	1.76	0.44	0	7.1	2.5	2.5	9.6	26	0	0.78	15.9		1.7		6.5	35.4	5.45	0.15
2B1	25-55	5.15	4.55	11.9	40	0	1.35	0.43	0	3.8	1.88	1.88	5.68	33.1	0	0.65	32.4		2.06		6.1	42.4	6.73	0.18
2B2	55-70+	4.9	3.74	1228.9	38	14.6	0.18	0.04	0.3	1.5	0.38	0.68	1.88	20.2	44.1	1.17	49.5		0.97		0.5	227.4	0.31	0.22
P13 - Eutric Regosol (Gelic, Ornithic, Turbic)
A	0-10	7.9	5.31	338.5	116	80.2	2.34	0.74	0	1.5	3.73	3.73	5.23	71.3	0	1.03	48.3		10.34		23.1	383.7	4.2	0.03
B	10-28	7.1	6.38	694.3	124	69.3	2.44	0.53	0	0.8	3.59	3.59	4.39	81.8	0	3.1	46.8		14.32		31.4	625.7	5.34	0.03
C1	28-45	7.15	6.56	361.8	112	54.3	2.68	0.39	0	0.8	3.59	3.59	4.39	81.8	0	1.42	51.8		13.21		30.4	667.7	4.8	0.08
C2	45-60+	7.26	4.48	383.8	115	44.4	3.15	0.33	0	0.7	3.97	3.97	4.67	85	0	1.68	49.5		10.22		24	427.3	3.51	0.05
P14 - Dystric Regosol (Gelic, Ornithic, Turbic)
A	0-10	5.43	4.5	1726.2	173	139	2.34	0.67	0	5.4	4.06	4.06	9.46	42.9	0	0.26	55.5		5.57		3.9	641.3	9.36	0.06
B	10-25	4.44	3.37	638.6	166	60.3	1.21	0.33	0.4	7.3	2.23	2.63	9.53	23.4	15.2	0.52	47.3		8.47		3.7	549.2	3.87	0.05
C1	25-45+	5.32	3.85	657.6	167	48.4	1.78	0.49	0.1	3.8	2.91	3.01	6.71	43.4	3.3	0.26	46.4		17.52		11.6	802	6.66	0.05
C	15-40+	6.34	5.02	655.5	59	42.4	2.24	0.49	0	1.8	3.07	3.07	4.87	63	0	1.03	54		19.89		11	628.4	6.68	0.06

High variability in soil properties was observed in the three different landforms (Fig. 4). The chemical soil properties are explained by the first and two PCA axes with 61.3 % of the data variation (Fig. 4a). Thus, the first axis being positively correlated with the BS (r = 0.92), P (r = 0.89), Zn (r = 0.89) and Na (r = 0.86). The second axis being positively correlated with BS (r = 0.94) and Mn (r = 0.86). The PCA of physical soil properties (Fig. 4b) showed that the first PCA axis explained 68.5 % of the data and was positively correlated with silt fraction (r = 0.91) and negatively with a sand fraction (r = -0.99). The most accentuated gradient was verified in the soil acidity (pH and H + Al) (Fig. 4c), where the PCA Axis 1 explained 87.7 % of the variation in the soil data, and was positively correlated with exchangeable acidity (r = 0.93) and negatively with pH (r = -0.93).

Figure 4
Principal component analysis (PCA) for the soil parameters of three different landscapes elements: PHB: Present-day and Holocene beaches; MPS: Middle platforms and scarps; TGD: Till glacial deposit. For analysis, available: a) chemical properties (P, K, Na, Ca, Mg, Al, BS, CECeff, CTC_T, Zn, Cu, OM, N, Zn, Mn, PBS, Al_sat, N); b) physical properties (Sand, Silt and Clay); and c) Acidity properties (pH and H + Al).

Middle platforms and scarps (MPS)

The soils were shallow and coarse, mostly with high P, Ca, and Mg contents, and low pH (Table III, Fig. 5). Cobles and boulders of various shapes, pebbles, and gravels are commonly observed; altitude varies from 60 to 70 m a.s.l. All profiles were well-drained and stone fields and snow patches are widespread. The degree of ornithogenic influence varies (all profiles being ornithic), but the middle platforms are the landscape more colonized by birds. All profiles were classified as Cryosols being always turbic and leptic, frequently patterned, dystric, and skelectic (IUSS Working Group WRB 2015). Few profiles were found to be eutric, only those affected by recent guano deposition, close to petrel nests (P7 and P20) or penguin rookery (P15). For representing the most stable landform at Stinker Point, all buildings are located on it, despite the logistical challenges, of reaching these high grounds.

Figure 5
Boxplots soil properties. For analysis, available: exchangeable acidity (H + Al), pH (H₂O), phosphorus (P), potassium (K), sodium (Na), calcium (Ca), magnesium (Mg), bases sum (BS), percentage of bases saturation (PSB), effective cation exchange capacity (CTCeff), organic matter (OM), copper (Cu), manganese (Mn), iron (Fe) and zinc (Zn).

Soil structure is weak medium/small blocky, and texture is dominated by sand and silt fractions (Table II). Profiles presented acid pH and high P content, mainly in depth (Table III), meanwhile, K is more abundant in surface with low totals when compared to other nutrients, such as Ca and Mg that present high values (mean 3.87 cmol/dm³ ±2.46 and 0.82 cmol/dm³ ±0.60, respectively). Na⁺ concentration varies depending on the wind exposure to marine sprays and can expressively reach more than 300 mg/dm³ (P15 and P19). Cation exchange capacity (CECeff) was low to medium (mean 6.73 cmol/dm³ ±2.79) and Al has a considerable percentage of charges (mean 1.06 cmol/ dm³ ±1.76). Organic matter is always above 1 % in all horizons reaching more than 10 % in some cases (P8 and P19); although organic carbon resilience in the island can be limited due to soil texture and effective drainage. The remaining P (P-rem) was high for most of the profiles (mean 40.8 mg/L ±12.92) with high exchangeable P content (mean 3244.18 mg/dm³ ±2724.68). The amounts of extractable microelements are variable; Zn rates were high (40.45 mg/dm³ ±41.24) for most Cryosols, with remarkably higher values for ornithogenic soils. The Fe distribution is regular with depth for all profiles but the middle platforms support high iron contents, especially in the more weathered and deeper profiles (mean 319.36 mg/dm³ ±217.10). On the other hand, ornithogenic soils reached values up to 902.2 mg/dm³ (P4), suggesting ferrolysis. Copper contents were also more expressive in sites affected by intense bird colonization, and Mn amounts were relatively low (7.7 mg/dm³ ±6.73) (Fig. 5).

All profiles located on the platforms were vegetated, except for P15, which had bare soil since it was located in an active penguin rockery area. Soils P3, P4, P7, P9, P19, and P20 had an abundant and diverse vegetation cover, formed by different species associations of mosses and lichens, and eventually with the sporadic presence of grass and terrestrial algae. The P5 had a dominant coverage of the grass Deschampsia antarctica associated with the moss Sanionia uncinata, with less occurrence. The P8 had an exclusive cover of Sanionia georgicouncinata, located in a small depression on the platform. Also, the P16, located in an area adjacent to an active penguin rookery of Pygoscelis antarcticus (P15) and nests of giant petrels (Macronectes giganteus), had a dominant coverage of macroscopic algae Prasiola crispa.

Till and glacial deposits (TGD)

Soils from the till and glacial deposits can be divided by the age of exposure: older skeletic profiles with limited depth (P1 and P2), acid reaction (pH ~ 4.5) and moderate contents of P (mean 378 mg/dm³), OM (1.3 dag/Kg) and PSB (23.6 %); and recently exposed deep profiles (P10, P11, P12, P17, and P18) which showed fine texture, alkaline reaction (pH ~ 7.7) and high PSB (91.65 %). This contrast illustrates how the landscape at Stinker Point has been differentially exposed and weathered, aided by faunal activity and vegetation. P1 presented a well-developed vegetation cover formed by a moss carpet community associated with fruticose lichens species (Table I, Fig. 3); and P2, a mixed community formed by moss cushions associated with musciculous lichens, with many crusted lichens on exposed rocks.

On the other hand, the recently exposed ice-free zone forms extensive areas of Till, following the last deglaciation phase. These soils have an alkaline reaction increasing with depth, moderate amounts of P (187.62 mg/dm³ ±45.23) and Na (mean 89.65 mg/dm³), high Ca (4.19 mg/dm³ ±0.73) (Fig. 5), and low Mg content. Furthermore, these areas represent a typical paraglacial environment of Stinker Point that underwent alteration processes after becoming ice-free; it is a landscape of great instability, where cryoturbation processes are widespread (generating patterned ground), and active fluvioglacial erosion (especially in the channels emerging from the glacier). Soils showed high silt content (always above 30%), with textural classes from sandy loam or finer, turbic, patterned, and eutric (IUSS Working Group WRB 2015). The recently exposed soils at the glacier front (P10 and P18) are barelycovered. Soils near lakes and drainage lines, and constantly visited by birds (P11, P12, and P17) have a vigorous vegetation cover but discontinuous, with low diversity. The vegetation was represented by moss cushion communities with a dominance of species as Bryum orbiculatifolium and Hennediella heimii (Table I).

Present-day/Holocene beaches (PHB)

The soil from the present-day beaches (P6) was acid, very coarse with no horizon differentiation; it was formed over marine sand sediments, covered by debris from up slopes, connecting with the upper platforms. Nival landforms and processes dominate, including slow sediment transfer, weathering (wet-drying and freeze-thaw cycles), and frost cracking. Periglacial features or permafrost were not detected, and the landscape is constantly reworked by marine erosion. Weathered moraines and till deposits were overlaid of the present-day beaches, and are the preferred sites for fauna. Due to the intense trampling of soil by animals, the vegetation is unable to establish.

Profiles on the Holocene beaches (located on low platforms) (P13 and P14) are eutrophic and nutrient-rich (Table III, Fig. 5) and showed cryoturbation, despite the absence of permafrost during fieldwork. Marine terraces are uplifted about 20 m a.s.l from present beaches and experienced severe reworking where vegetation is scarce. Soils are deep, with horizon development and differentiation, gradual transition, and coarse texture with a great amount of gravel at the surface (Table II). The pH varied from alkaline to slightly acid reflect diverse parent material and age of exposure. The P content was high, notably at P14, affected by fauna influence. Also, amounts of K⁺, Na⁺, and Ca²⁺ were high, mainly at the surface, while Mg²⁺ content was moderate (Table III). Base saturation was high, but P14 was classified as dystric; despite its proximity to the sea, both profiles had Na⁺ with only 6 % of the cation exchange complex. The OM was greater in soil P13, reaching 3 % at the B horizon, and soil P14 presented only 0.5 % at the same depth. Micronutrients levels were high, particularly Fe.

The vegetation cover was discontinuous in both profiles. P13 showed a dominance of the phanerogam C. quitensis associated with mosses S. uncinata and Polytrichastrum alpinum less frequent, with the presence of roots in horizon A. The main cover of P14 was the grass D. antarctica, with roots present in the A horizon. The orange-colored crustose lichen Caloplaca regalis was frequent on exposed rocks.

DISCUSSION

Previous studies show that Elephant Island has an evident landform gradient (López-Martínez et al. 2012), soil types (Navas et al. 2018), vegetation establishment (Pereira & Putzke 1994, Schmitz et al. 2020a), and glacier retreat (Navas et al. 2018). Furthermore, Stinker Point is strongly influenced by the intense activity of seabirds (Petry et al. 2018) and a milder climate compared to continental Antarctica and other islands in the Antarctic Peninsula region. Our results present elements for understanding weathering, soil formation, and vegetation establishment in an isolated Maritime Antarctic spot. In addition, the local rocks are more resistant, and marine animals occupy extensive ice-free areas recently exposed.

Despite the milder climate, permafrost is found above 50 m a.s.l., mostly continuous under till and glacial deposits, and discontinuous on platforms, as confirmed observations by Navas et al. (2018). Clasts mantles of gravel and platy boulders are widespread and connect the upper platforms with the till accumulations, or the Holocene beaches. Despite the coarse texture of soils, water is abundant, and freezing-thawing cycles allow cryoclasty and movement of pebbles and blocks, frequently resting in planar positions (Simas et al. 2008, Chaves et al. 2017). Frost weathering is responsible for most of the physical break-up of the resistant metamorphic rocks accounting for the large quantity of coarse material at the surface (O’Brien et al. 1979). According to Navas et al. (2018), the bedding plans of these metamorphic rocks play an important role in physical weathering. On the other hand, the availability of liquid water and large breeding colonies favors chemical weathering (Michel et al. 2006, Simas et al. 2007, Siqueira et al. 2021). For example, these processes promote bases leaching, Fe availability, clay formation, and low pH in many soils, especially on platforms (MPS) and present-Holocene beaches (PHB) (Simas et al. 2008, Almeida et al. 2021). Hence, the rock constitution and sub-horizontal schistosity and bedding of regional outcrops are key for differences in weathering intensity found in Elephant Island, although both physical and chemical weathering is quite limited, resulting in shallow soils (Navas et al. 2018). Compared with other South Shetlands soils with rocks of volcanic origin, such as andesites and basalt mostly (e.g. Rei George, Nelson, Livingston, and Barrientos) (Navas et al. 2008, Francelino et al. 2011, Moura et al. 2012, Michel et al. 2014, Lopes et al. 2019, Daher et al. 2019, Rodrigues et al. 2019, Almeida et al. 2021) the soil development is less pronounced, due to the metamorphic nature of parent material, with much greater weathering resistance.

Most soils studied are located on the middle platforms, representing more stable surfaces exposed for a long time. On platforms, stable soils are suitable places for the occurrence of periglacial processes linked with active layers and snow patches (Navas et al. 2018). The most common periglacial features are stone fields, due to the abundance of coarse material (López-Martínez et al. 2012, 2016). There are significant differences in gravel contents when comparing TGD and PHB soils, suggesting differences in periglacial processes between landforms. In this sector, soils with the greatest ornithogenic influence are also found, with the typical higher P concentration. Because these areas were colonized by penguins, in the past, and at present, extending to adjacent sites, that are only indirectly influenced (Michel et al. 2006, Simas et al. 2007, Rodrigues et al. 2021). Similarly, higher soil organic matter on platforms is related to both biogenic activity and longer exposure time, with the presence of seabirds, responsible for soil nutrient input (Beyer et al. 2000, Bockheim & Haus 2014), and vegetation development (Schmitz et al. 2020b, Ferrari et al. 2021). The local vegetation is diverse and vigorous on the platforms of Stinker Point (Abakumov et al. 2017), with extensive moss carpets associated with fruticose and musciculous lichens, despite the common vertical stone fields at the surface. On the wind protected faces, where little snow accumulation takes place, crustose lichens develop. The highest species richness described for Stinker Point occurs on the platforms, where the native phanerogam specie D. antarctica is also found (Pereira & Putzke 1994, Schmitz et al. 2020a).

Till and glacial deposits dominate the ice-free areas of Stinker Point (López-Martínez et al. 2012, Navas et al. 2018). Extensive areas of till dominate sections of modern deglaciation, at the study site, the ice has moved back further 200 m since it was drawing 1971 (Burley 1972, Navas et al. 2018). A large glacier surrounds Stinker Point, its front is a domain by dead ice and no paraglacial processes were identified. On the till deposits, periglacial features associated with active layer processes, frost heave, and ice segregation are common (gelifluction lobes, frost mounds, and patterned ground). In these recently exposed areas with continuous permafrost, the soils remain saturated, forming meltwater lakes, during the snowmelt period, and following the glacier retreat. These lakes are often used by skuas (Quintana & Travaini 2000), representing initial spots for plant colonization, and nutrient input in the soil (Otero et al. 2018, Schmitz et al. 2020a).

In soils at the present-day and Holocene beaches, permafrost was not detected. The P contents showed the present or past influence of the fauna (Michel et al. 2006, Simas et al. 2007). The vegetation is discontinuous, formed by communities dominated by phanerogamous plants, such as D. antarctica (as also found on Livingston Island beaches by Navas et al. (2008) and C. quitensis that have a positive relationship with ornithogenic soils and tend to grow primarily in nutrient-rich environments influenced by birds (Ferrari et al. 2021). Despite being an area of strong marine influence, Na⁺ levels are low than other sheltered areas, which were also reported by Schmitz et al. (2020a) elsewhere on Stinker Point Holocene beaches.

CONCLUSION

Our study provides an updated description of the main patterns that determine the soil-landform-vegetation interplays at Stinker Point, Elephant Island, Antarctica, which are shallow and skeletic, and show an intimate interplay with landform configuration and biogenic activity. The age of soil formation is similar to other islands of the South Shetland archipelago; however, presumably, the resistant metamorphic parent material and bedding do not favor chemical and physical weathering. Our results highlight that the middle platforms soils were the oldest but shallow, with discontinuous permafrost, and mostly ornithogenic, which is directly associated with the vegetation cover. Thus, this study allows us to infer that the soils affected by current penguin activity, hinder the growth of vegetation due to excess trampling. However, soils with intermediary ornithogenic influence have discontinuous vegetation and few species, whereas aged soils on old, abandoned penguin rookeries showed great vegetation diversity and growth.

ACKNOWLEDGMENTS

We acknowledge Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES), the Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) for financial support of this project #556794/2009-5 and PROANTAR- Permaclima project #442703/2018-0. We are grateful to Marinha do Brasil and Secretaria Interministerial para os Recursos do MAR (SECIRM) for financial support and field assistance. This work is a contribution of the INCT-Criosfera TERRANTAR group.

REFERENCES

• ABAKUMOV E, LUPACHEV A AANDREEV M. 2017. Trace element content in soils of the King George and Elephant islands, maritime Antarctica. Chem Ecolog 856-868. DOI: 10.1080/02757540.2017.1384821.
• ALLISON JS SMITH RIL. 1973. The vegetation of Elephant Island, South Shetlands Islands. Brit Antarct Sur Bull 33-34: 185-212.
• ALMEIDA ICC, SCHAEFER CEGR, BRAGANÇA RBA, OLIVEIRA FS PEREIRA TTC. 2021. Clay mineralogy and micropedology of phosphate-rich soils from Lions Rump, Maritime Antarctica. J South Am Earth Sci 105: 102967. https://doi.org/10.1016/j.jsames.2020.102967.
  » https://doi.org/10.1016/j.jsames.2020.102967
• ALVAREZ VHV, NOVAIS RF, DIAS LE OLIVEIRA JA. 2000. Determinação e uso do fósforo remanescente. B Inf SBCS 25: 27-32.
• BALKS MR, LÓPEZ-MARTÍNEZ J, GORYACHIKIN SV, MERGELOV NS, SCHAEFER CEGR, SIMAS FNB, ALMOND PC, CLARIDGE GGC, MCLEOD M SCARROW J. 2013. Windows on Antarctic soil-landscape relationships: comparison across select regions of Antarctica. In: HAMBREY MJ ET AL. (Eds), Antarctic Palaeoenvironments and Earth-Surface Processes. Geological Society, London 381, p. 397-410. doi: 10.1144/SP381.9.
• BEYER L, PINGPANK K, WRIEDT G BÖLTER M. 2000. Soil formation in coastal continental Antarctica (Wilkes Land). Geoderma 95: 283-304.
• BOCKHEIM J, VIEIRA G, RAMOS M, LÓPEZ-MARTÍNEZ J, SERRANO E, GUGLIELMIN M, WIHELM K NIEUWENDAM A. 2013. Climate warming and permafrost dynamics on the Antarctic Peninsula region. Glob Planet Chang 100: 215-223. doi: 10.1016/j.gloplacha.2012.10.018.
• BOCKHEIM JG, BALKS MR MCLEOD M. 2006. ANTPAS Guide for Describing, Sampling, Analyzing, and Classifying Soils of the Antarctic Region, ANTPAS 1-12.
• BOCKHEIM JG HAUS NW. 2014. Distribution of organic carbon in the soils of Antarctica. In: HARTEMINK A MCSWEENEY K (Eds), Soil carbon, Progress in Soil Science. Springer, Madinson, 373-380, 497 p.
• BURLEY M. 1972. Joint Services expedition to Elephant Island. Geogr J 138, 298-308. https://doi.org/10.2307/1795437
  » https://doi.org/10.2307/1795437
• CHAVES DA, LYRA GB, FRANCELINO MR, SILVA LDB, THOMAZINI A SCHAEFER CEGR. 2017. Active layer permafrost thermal regime in a patterned ground soil in Maritime Antarctica, and relationship with climate variability models. Sci Total Environ 584-585: 572-285. https://doi.org/10.1016/j.scitotenv.2017.01.077.
  » https://doi.org/10.1016/j.scitotenv.2017.01.077
• DAHER M, SCHAEFER CEGR, THOMAZINI A, NETO EL, SOUZA CD LOPES DV. 2019. Ornithogenic soils on basalts from maritime Antarctica. Catena 173: 367-374. https://doi.org/10.1016/j.catena.2018.10.028.
  » https://doi.org/10.1016/j.catena.2018.10.028
• DALZIEL IWD, LAWVER LA, PEARCE JA, BARKER PF, HASTIE AR, BARFOD DN, SCHENKE HW DAVIS MB. 2013. A potential barrier to deep Antarctic circumpolar flow until the late Miocene? Geology 41(9): 947-950. doi:10.1130/G34352.1.
  » https://doi.org/10.1130/G34352.1
• EMBRAPA - EMPRESA BRASILEIRA DE PESQUISA AGROPECUÁRIA. 2017. Manual de Métodos de Análise de Solo. Centro Nacional de Pesquisa de Solos, Rio de Janeiro.
• FERRARI FR, SCHAEFER CEGR, PEREIRA AB, THOMAZINI A, SCHMITZ D FRANCELINO MR. 2021. Coupled soil-vegetation changes along a topographic gradiente on King George Island, maritime Antarctica. Catena 198, 105038. https://doi.org/10.1016/j.catena.2020.105038
  » https://doi.org/10.1016/j.catena.2020.105038
• FRANCELINO MR, SCHAEFER CEGR, SIMAS FNB, FILHO EIF, SOUZA JJLL COSTA LM. 2011. Geomorphology and soils distribution under paraglacial conditions in an ice-free area of Admiralty Bay, King George Island, Antarctica. Catena 85: 194-204. https://doi.org/10.1016/j.caten a.2010.12.007.
  » https://doi.org/10.1016/j.caten a.2010.12.007
• GALINDO-ZALDÍVAR J, MAESTRO A, LÓPEZ-MARTÍNEZ J SANZ DE GALDEANO C. 2006. Elephant Island recent tectonics in the framework of the Scotia-Antarctic-South Shetland Block triple junction (NE Antarctic Peninsula). In: FÜTTERER DK ET AL. (Eds), Antarctic Contributions to Global Earth Science 5.8: 271-276. Berlin-Heildelberg-New York: Springer. doi: 10.1007/3-540-32934-x_33.
• GEE GW BAUDER JW. 1986. Particle-size analysis. In: KLUTE A (Ed) Methods of Soil Analysis. Part 1: Physical and Mineralogical Methods. Soil Science Society of America, Madison, p. 383-412.
• HUSSON F, JOSSE J, LE S MAZET J. 2017. “FactoMineR” package Multivariate: Exploratory Data Analysis and Data Mining. http://CRAN.R-project org/package= FactoMineR. RStudio package version 1.0.14.
  » http://CRAN.R-project
• IUSS WORKING GROUP WRB. 2015. World Reference Base for Soil Resources 2014, update 2015 International soil classification system for naming soils and creating legends for soil maps. World Soil Resources reports no. 106. FAO, Rome.
• LONGTON R. 1988. Biology of Polar Bryophytes and Lichens. Cambridge University Press, Cambridge, 391 p.
• LOPES DV, SCHAEFER CEGR, SOUZA JJLL, OLIVEIRA FS, SIMAS FNB, DAYER M GJORUP DF. 2019. Concretionary horizons, unusual pedogenetic processes and features of sulfate affected soils from Antarctica. Geoderma 347: 13-24. https://doi.org/10.1016/j.geoderma.2019.03.024.
  » https://doi.org/10.1016/j.geoderma.2019.03.024
• LÓPEZ-MARTÍNEZ J, SCHMID T, SERRANO E, MINK S, NIETO A GUILLASO S. 2016. Geomorphology and surface landforms distribution in selected ice-free areas within the South Shetland Islands, northern Antarctic Peninsula region. Cuad de Investig Geogr 42(2): 435-455. https://doi.org/10.18172/cig.2965.
  » https://doi.org/10.18172/cig.2965
• LÓPEZ-MARTÍNEZ J, SERRANO E, SCHMID T, MINK S LINÉS C. 2012. Periglacial processes and landforms in the South Shetland Islands (northern Antarctic Peninsula region). Geomorph 155-156: 62-79. doi:10.1016/j.geomorph.2011.12.018.
• LÓPEZ-MARTÍNEZ J, TROUW RAJ, GALINDO-ZALDÍVAR J, MAESTRO A, SIMOES LSA, MEDEIROS FF TROUW CC. 2006. Tectonics and geomorphology of Elephant Island, South Shetland Islands. In: FÜTTERER DK ET AL. (Eds), Antarctic Contributions to Global Earth Science 5.9, 277-282. Berlin-Heildelberg-New York, Springer. doi: 10.1007/3-540-32934-x_34.
• MARSH PD THOMPSON JW. 1985. The Scotia metamorphic complex on Elephant Island and Clarence Island, South Shetland Islands. Brit Antarct Sur Bull 69: 71-75.
• MICHEL RFM, SCHAEFER CEGR, DIAS L, SIMAS FNB, BENITES V MENDONÇA ES. 2006. Ornithogenic Gelisols (Cryosols) from Maritime Antarctica: pedogenesis, vegetation and carbon studies. Soil Sci Soc Am J 70: 1370-1376.
• MICHEL RFM, SCHAEFER CEGR, LÓPEZ-MARTINEZ J, SIMAS FNB, HAUS NW, SERRANO E BOCKHEIM JG. 2014. Soils and landforms from Fildes Peninsula and Ardley Island, Maritime Antarctica. Geomorph 225: 76-86. http://dx.doi.org/10.1016/j.geomorph.2014.03.041.
  » https://doi.org/10.1016/j.geomorph.2014.03.041
• MOURA PA, FRANCELINO MR, SCHAEFER CEGR, SIMAS FNB MENDONÇA BAF. 2012. Distribution and characterization of soils and landform relationships in Byers Peninsula, Livingston Island, Maritime Antarctica. Geomorph 155-156: 45-54. https://doi.org/10.1016/j.geomorph.2011.12.011.
  » https://doi.org/10.1016/j.geomorph.2011.12.011
• NAVAS A, LÓPEZ-MARTINEZ J, CASAS J, MACHÍN J, DURÁN JJ, SERRANO E, CUCHÍ JÁ MINK S. 2008. Soil characteristics on varying lithological substrates in the South Shetland Islands, maritime Antarctica. Geoderma 144: 123-139.
• NAVAS A, OLIVA M, FERNÁNDEZ J, GASPAR L, QUIJANO L LIZAGA I. 2017. Radionuclides and soil properties as indicators of glacier retreat in a recently deglaciated permafrost environment of the Maritime Antarctica. Sci Total Environ 609: 192-204. https://doi.org/10.1016/j.scitotenv.2017.07.115.
  » https://doi.org/10.1016/j.scitotenv.2017.07.115
• NAVAS A, SERRANO E, LÓPEZ-MARTÍNEZ J, GASPAR L LIZAGA I. 2018. Interpreting environmental changes from radionuclides and soil characteristics in different landform contexts of Elephant Island (maritime Antarctica). Land Degrad Developm 29: 3141-3158. doi: 10.1002/ldr.2987.
• O’BRIEN RMG, ROMANS JCC ROBERTSON L. 1979. Three soil profiles from Elephant Island, South Shetland Island. Brit Antarct Sur Bull 47: 1-12.
• OCHYRA R, LEWIS-SMITH RI BEDNAREK-OCHYRA H. 2008. The Illustrated Moss Flora of Antarctic. Cambridge: Cambridge University Press, 709 p.
• OTERO XL, PEÑA-LASTRA SDL, PÉREZ-ALBERTI A, FERREIRA TO HUERTA-DIAZ MA. 2018. Seabird colonies as important global drivers in the nitrogen and phosphorus cycles. Nat Commun 9: 246. DOI: 10.1038/s41467-017-02446-8.
• ØVSTEDAL DO LEWIS-SMITH RI. 2001. Lichens of Antactica and South Georgia: a guide to their identification and ecology. Cambridge: Cambridge University Press, 453 p.
• PEREIRA AB PUTZKE J. 1994. Floristic Composition of Stinker Point, Elephant Island, Antarctica. Korean J Polar Res 5: 37-47.
• PETRY MV, VALLS FCL, PETERSEN ES, FINGER JVG KRÜGER L. 2018. Population trends of seabirds at Stinker Point, Elephant Island, Maritime Antarctica. Antarct Sci 30(4): 220-226. https://doi.org/10.1017/S0954102018000135.
  » https://doi.org/10.1017/S0954102018000135
• PUTZKE J PEREIRA AB. 2001. The Antarctic Mosses with special reference to the South Shetlands Islands. 1st ed., Canoas: Editora da Ulbra, 196 p.
• QUINTANA RD TRAVAINI A. 2000. Characteristics of nest sites of skuas and kelp gull in the Antarctic Peninsula. J Field Ornithol 71: 236-249.
• R CORE TEAM. 2021. R: A language and environment for statistical computing. R Foundation for Statistical Computing. Vienna: Austria. https://www.R-project.org/
  » https://www.R-project.org/
• RAKUSA-SUSZCZEWSKI S. 1993. The Maritime Antarctic Coastal Ecosystem of Admiralty Bay. Polish Academy of Sciences, Warsaw, 216 p.
• RODRIGUES WF, OLIVEIRA FS, SCHAEFER CEGR, LEITE MGP, GAUZZI TG, BOCKHEIM JG PUTZKE J. 2019. Soil-landscape interplays at Harmony Point, Nelson Island, Maritime Antarctica: Chemistry, mineralogy and classification. Geomorph 336: 77-94. https://doi.org/10.1016/j.geomorph.2019.03.030.
  » https://doi.org/10.1016/j.geomorph.2019.03.030
• RODRIGUES WF, SOARES FS, SCHAEFER CEGR, LEITE MGP PAVINATO PS. 2021. Phosphatization under birds’ activity: Ornithogenesis at diferente scales on Antarctic Soilscapes. Geoderma 391: 114950. https://doi.org/10.1016/j.geoderma.2021.114950.
  » https://doi.org/10.1016/j.geoderma.2021.114950
• SCHMITZ D, SCHAEFER CERG, PUTZKE J, FRANCELINO MR, FERRARI FR, CORREA GR VILLA PM. 2020b. How does the pedoenvironmental gradient shape non-vascular species assemblages and community structures in Maritime Antarctica? Ecol Indic 108: 105726. https://doi.org/10.1016/j.ecolind.2019.105726.
  » https://doi.org/10.1016/j.ecolind.2019.105726
• SCHMITZ D, VILLA PM, PUTZKE J, MICHEL RFM, CAMPOS PV, MEIRA NETO JAA SCHAEFER CEGR. 2020a. Diversity and species associations in cryptogam communities along a pedoenvironmental gradient on Elephant Island, Maritime Antarctica. Folia Geobot 55: 211-224. https://doi.org/10.1007/s12224-020-09376-2.
  » https://doi.org/10.1007/s12224-020-09376-2
• SERRANO E LÓPEZ-MARTÍNEZ J. 2000. Rock glaciers in the South Shetland Islands, Western Antarctica. Geomorph 35: 145-162. doi: 10.1016/s0169-555x(00)00034-9.
• SIMAS FNB, SCHAEFER CEGR, ALBUQUERQUE FILHO MR, FRANCELINO MR, FERNANDES FILHO EI COSTA LM. 2008. Genesis, properties and classification of Cryosols from Admiralty Bay, maritime Antarctica. Geoderma 144: 116-122. doi:10.1016/j.geoderma.2007.10.019.
• SIMAS FNB, SCHAEFER CEGR, MELO VF, ALBUQUERQUE-FILHO MR, MICHEL RFM, PEREIRA VV, GOMES MRM DA COSTA LM. 2007. Ornithogenic Cryosols from Maritime Antarctica: phosphatization as a soil forming process. Geoderma 138: 191-203.
• SIQUEIRA RG, SCHAEFER CEGR, FERNANDES FILHO EI, CORRÊA GR, FRANCELINO MR, SOUZA JJLL ROCHA PA. 2021. Weathering and pedogenesis of sediments and basaltic rocks on Vega Island, Antarctic Peninsula. Geoderma 382: 114707. https://doi.org/10.1016/j.geoderma.2020.114707.
  » https://doi.org/10.1016/j.geoderma.2020.114707
• TROUW RAJ, PASSCHIER CW, VALERIANO CM, SIMÕES LSA, PACIULLO FVP RIBEIRO A. 2000. Deformational evolution of a Cretaceous subduction complex: Elephant Island, South Shetland Islands, Antarctica. Tectonophysics 319: 93-110. https://doi.org/10.1016/S0040-1951(00)00021-4.
  » https://doi.org/10.1016/S0040-1951(00)00021-4
• TROUW RAJ, RIBEIRO A PACIULLO FVP. 1991. Structural and metamorphic evolution of the Elephant Island group and Smith Island, South Shetland Islands. In: THOMSON MRA ET AL. (Eds), Geological evolution of Antarctica, Cambridge University Press, UK, p. 423-428.
• TROUW RAJ, SIMÕES LSA VALLADARES C. 1998. Metamorphic evolution of a subduction complex, South Shetland Islands, Antarctica J Metam Geol 16: 475-490.
• TURNER J, LU H, WHITE I, KING JC, PHILLIPS T, HOSKING JS, BRACEGIRDLE TJ, MARSHALL GJ, MULVANEY R DEB P. 2016. Absence of 21st century warming on Antarctic Peninsula consistent with natural variability. Nature 535: 411-415. https://doi.org/10.1038/nature18645.
  » https://doi.org/10.1038/nature18645
• TURNER J, OVERLAND JE WALSH JE. 2007. An Arctic and Antarctic perspective on recent climate change. Int J Climatol 27: 277-293. https://doi.org/10.1002/joc.1406.
  » https://doi.org/10.1002/joc.1406
• TURNER J PENDLEBURY S. 2004. The international Antarctic weather forecasting handbook. Cambridge: British Antarctic Survey, 663 p. http://nora.nerc.ac.uk/id/eprint/17324
  » http://nora.nerc.ac.uk/id/eprint/17324
• VIEIRA G ET AL. 2010. Thermal State of permafrost and active-layer monitoring in the Antarctic: advances during the International Polar Year 2007-09. Permafr Periglac Process 21: 182-197. doi: 10.1002/ppp.685.
• WILSON MJ BAIN DC. 1976. Occurrence of leucophosphite in a soil from Elephant Island, British Antarctic Territory. Am Mineral 61: 1027-1028.
• YEOMANS JC BREMNER JM. 1988. A rapid and precise method for routine determination of organic carbon in soil. Comm Soil Sci Plant Anal 19: 1467-1476.

Publication Dates

• Publication in this collection
  30 May 2022
• Date of issue
  2022

History

• Received
  29 Apr 2021
• Accepted
  13 Feb 2022