Formation, ecology, and geography of Cryosols of an ice-free oasis in Coastal East Antarctica near Casey Station (Wilkes Land).
New soil studies in the cold suggest that in the terrestrial ecosystems of the coastal regions of the antarctic continent, soil formation and chemical weathering occur to a greater extent than previously expected. This paper summarises the pedogenic results of an Australian-funded expedition to Casey Station and presents a soil formation sequence on a small-scale database. The accumulation of soil organic matter and podzolisation are important soil-forming processes up to the antarctic polar desert. This study has revealed a high variability in soil geography and soil properties at both a profile and landscape level. However, previous results indicate a correlation between soil cover and vegetation pattern. Nutrient supply in soil is affected by high contents and availability of nitrogen, phosphate, potassium, and magnesium due to the presence of seabirds.
Additional keywords: soil temperature, podzolisation, available water, soil organic matter, ornithogenic soils, variability, future aspects.
The southern polar region has the Earth's coldest climate, primarily because of the high latitudes and altitude. The amount of solar radiation received in this region is relatively small. Nevertheless, current literature confirms that soil formation in Antarctica occurs at slow rates (e.g. Campbell and Claridge 1987; Bockheim and Ugolini 1990; Blume and Bolter 1993; Blume et al. 1997; Bockheim 1997). Recently, these soils have been distinguished from others in the world in recognition of their unique properties (e.g. Spaargaren 1994; Bockheim et al. 1997). According to the World Reference Base for Soil Resources, these soils belong to the Cryosol soil group, mainly because of the occurrence of permafrost within the first metre below the surface (Spaargaren 1994). Antarctic Cryosols occur primarily in scattered ice-free areas, mainly around the outer edge of the Antarctic continent, but the most extensive occurrences are along the Transantarctic Mountains in the McMurdo Dry Valleys (Fig. 1).
[Figure 1 ILLUSTRATION OMITTED]
Antarctic Cryosols have been widely studied since the 1950s and 1960s when reports showed the existence of soils and soil processes in the frigid and arid antarctic environment (e.g. Glazovskaya 1958; Ugolini 1963; Calkin 1964; Tedrow and Ugolini 1966; Campbell and Claridge 1967; Claridge and Campbell 1968; McCraw 1967; MacNamara 1969). This was confirmed with several extending studies (Beyer et al. 1998b and references therein). The main soil-forming processes in Antarctica are oxidation and salinisation, with almost complete absence of organic matter (Campbell and Claridge 1987; Bockheim 1990). Bockheim and Ugolini (1990) developed general theories of soil formation in Antarctica as a function of latitude. They used soil data from the antarctic continent primarily from the Dry Valleys region close to the Ross Sea; little pedogenic information was available from the ice-free areas in East Antarctica (e.g. Pickard 1986; Seppelt and Broady 1988; Kerry and Hempel 1990). However, our understanding of soil formation in East Antarctica changed with the publication of soil data from the Casey Station area, Wilkes Land (66 [degrees] 17'S, 111 [degrees] 32'E; Figs 1 and 2) (Blume and Bolter 1993). This study suggested that, in coastal regions of East Antarctica, soil formation and chemical weathering occur to a greater extent than previously thought (Blume et al. 1997, 1998). Obviously, soil formation in Antarctica is quite variable due to the effects of changing climate depending on the latitude and proximity to the ocean.
[Figure 2 ILLUSTRATION OMITTED]
In this paper, we extend the presentation and discussion on soil properties and ecology given by Blume et al. (1997, 1998). Our data are derived from the observations and investigations during an expedition to the Australian Casey Station in the antarctic summer of 1995-96. Firstly and primarily, we focus on the accumulation and composition of soil organic matter (SOM) as well as podzolisation. Secondly, we present a summarised description of the variability of soil units and their carbon (C) and nitrogen (N) stocks at a profile and landscape level in order to obtain a valid database for ecosystem modelling.
Materials and methods
The sites and soils are located south of the Australian Casey Station on Bailey Peninsula (66[degrees]17'S, 110[degrees]32'E) at Wilkes Land in coastal East Antarctica, about 700 m from the shore (Fig. 2). The parent materials are weathered gneiss and schists, moraine deposits, and outwash gravels (e.g. Paul et al. 1995), and deglaciation occurred between 5000 and 6000 years BP (Goodwin 1993). The annual precipitation (180 mm) is mostly snow. However, because of the strong drift due to the persistently high wind speeds (Pickard 1986), the real input of water in soil is highly heterogeneous (Beyer et al. 1998d). The mean annual temperature is -9.3[degrees]C. From November to February, the sun shines for 5-7 h/day. During the antarctic summer of nearly 6 weeks, the temperatures are above freezing point (e.g. mean in January, +0.2[degrees]C), and plant communities of mosses (e.g. Bryum pseudotriquetrum, Ceratodon pupureus, Grimmia antarctici), lichens (e.g. Usnea sphacelata, Pseudephebe minuscula, Umbilicaria decussata), and algae (e.g. Phormidium sp.) can establish and grow very slowly (Smith 1985, 1990).
Sampling and soil survey
Sampling and soil survey was carried out from January to April 1996. A small-scale soil and geomorphology mapping was done at 4 representative sites (A, B, C, D; squares 10 by 10 m) (Fig. 3). The soil survey was carried out according to the recent US Soil Taxonomy (Soil Survey Staff 1996). In addition, for purposes of comparison, we used the FAO classification (FAO 1994), and the recently discussed new Gelisol order of the US Soil Taxonomy (ICOMPAS 1996), as well as the new World Reference Base for Soil Resources (Spaargaren 1994).
[Figure 3 ILLUSTRATION OMITTED]
Temperatures were measured with maximum-minimum thermometers at the soil surface at 24-h intervals from 5 to 27 February, as well as from 19 March to 19 April 1996. In addition, soil temperature (depth 0-5 cm) was measured at 1-[m.sup.2] intervals at Sites A-D on selected days between 12 00 and 14 00 hours, using portable temperature sensors.
General soil investigations
Most determinations were carried out according to Schlichting et al. (1995) on air-dried soil samples. Composition of soil mineral particles was determined after sieving (2 mm) using the combination of a sieve and elutriate analysis. Soil texture was estimated by using the soil texture chart of the recent Keys to Soil Taxonomy (Soil Survey Staff 1996, p. 631). The pH value was measured in 10 mM [CaCl.sub.2] and aqua dest. with a commercial glass electrode. Electrical conductivity (EC) was measured in a 1:2.5 water extract and converted into the saturation extract. Loss-on-ignition (LOI) was determined gravimetrically after combustion at 650[degrees]C in a furnace. Total organic carbon (TOC) was calculated after dry combustion in a Coulomat 702 (Strohlein Instruments, Kaarst, Germany). The samples were heated (600[degrees]C) in an induction furnace under oxygen; carbon dioxide was trapped in [Ba(OH).sub.2], and the remaining [Ba(OH).sub.2] was neutralised by titration. Total nitrogen ([N.sub.t]) was assayed by the classical Kjeldahl digestion method and determined as nitrate in a flow injection analyser (Jones 1991). Pedogenic iron (Fe) and aluminum (Al) oxides were determined after extraction with dithionate-citrate ([Fe.sub.d], [Al.sub.d]) and oxalate ([Fe.sub.o], [Al.sub.o]). The organic-bonded Fe and Al was determined in the alkaline NaOH extract (Schnitzer 1982), because the sodium pyrophosphate extract usually applied overestimates organic Fe species by destruction of some minerals such as olivine (Grimme and Wiechmann 1969; Wiechmann and Grimme 1969). Extinction of the oxalate extract was measured at 472 nm (optical density of oxalate extract, ODOE) according to Daly (1982); a spodic horizon must be [is greater than] 250 (FAO 1994; Soil Survey Staff 1996). The cations sodium (Na), potassium (K), magnesium (Mg), and calcium (Ca) were extracted with unbuffered [BaCl.sub.2]. Potential hydrogen (H) and Al were extracted with Ca-acetate; the pH was measured and converted into a value for H+Al according to Schachtschabel (1951). The sum of the cations and potential H+Al is the potential cation exchange capacity ([CEC.sub.p]). The percentage of Ns, K, Mg, and Ca from [CEC.sub.p] is the base saturation. Plant-available potassium ([K.sub.lac]), magnesium ([Mg.sub.lac]), and phosphorus ([P.sub.lac]) were extracted with 0.04 N Ca lactate + 0-02 N HCl at pH 3.7 according to Egner et al. (1960). [K.sub.lac] and [Mg.sub.lac] were determined in an AAS (Perkin Elmer). [P.sub.lac] was determined colorimetrically as the blue coloured molybdate-phosphate complex according to Harwood et al. (1969). The immobile P fraction ([P.sub.c]) was extracted with 2% citric acid (modified, original 1%) according to Dyer (1894).
Cross polarisation magic angle spinning carbon-13 magnetic resonance spectroscopy (CPMAS [sub.13] C NMR)
The CPMAS [sub.13]C NMR were taken at 2.3 Tesla (25.2 MHz) with a Bruker MSL 100 equipped with a commercial 7-mm CPMAS probe at a rotation frequency of 4 kHz. A contact time of 1 ms was used. Owing to the short relaxation time ([T.sub.1H]) in SOM, a recycle delay of 0.3 s was chosen (Frund and Ludemann 1989). For the soil samples, the number of scans ranged from 4.7x[10.sup.6] to 9.9x[10.sup.6], and for the guano sample it was 8.2x[10.sup.5]. The line broadening was normally 50 Hz, in some cases higher. The chemical shift is given relative to tetramethylsilane (TMS, 0 ppm), which is used as reference point. The quantitative data were obtained with the integration routine of the spectrometer. The subdivision of the spectra was carried out according to Wilson (1987): alkylic units (0-45 ppm), O-alkylic units (45-110 ppm), aromatic units (110-160 ppm), and carboxylic units (160-220 ppm). For further details, see Frund and Ludemann (1989).
Pyrolysis field-ionisation mass spectrometry (py-FIMS)
The Py-FIMS spectra were also obtained from air-dried milled soil samples ([is less than]2 [micro]m) by using a double-focusing Finnigan MAT 731 mass spectrometer with a modified direct probe inlet system (Schulten et al. 1987). Samples (about 100 [micro]g) were heated without any pre-treatment from 50 to 750[degrees]C in high vacuum (10-a Pa) at a heating rate of about 12[degrees]C/s. During heating, approximately 30 spectra were recorded in the mass range from 50 to 600 Da. The thermal degradation products were ionised at +8 kV emitter potential and the counter electrode was set to -3 kV. All mass spectra were recorded electrically, integrated, and evaluated with the Finnigan MAT 200 data system. For further details of the equipment and methodology, see Schulten (1987, 1993).
An example of the temperature measurements in the late antarctic summer is shown in Fig. 4. At the different soil profile areas within the 10 by 10 m square at Site C (see Sampling and soil survey), the maximum temperatures at the soil surface were much higher than those in the air. In addition, the temperature varied up to 10[degrees]C between soil profiles (Fig. 4, upper graph) located within a distance of [is less than]10 m. The minimum temperatures exhibited a completely different pattern and correlated well with the minimum air temperatures (Fig. 4, lower graph). During the second period in the early antarctic winter, the temperature fluctuations were much less and the soil surface temperatures correlated well with the air temperatures (Fig. 5). In addition to the maximum-minimum variability in soil surface temperatures, Table 1 gives an impression of the short-time variability within the 4 sites investigated. The frequency distribution showed great geographical variability, despite the mean temperatures being very similar.
[Figures 4-5 ILLUSTRATION OMITTED]
Table 1. Mean (??), standard deviation ([Sigma]), and frequency distribution of soil temperatures ([degrees] C at a depth of 0-5 cm) within 10 by 10 m plots at Sites A-D (measurements each 1 [m.sup.2]), and mean air temperature (1 m above soil surface) on 23 February 1996 in an East Antarctic environment
Air Site ([degrees] C ?? [Sigma] < -1 A 0.3 1.3 1.4 1 B 1.0 1.5 1.5 n.o. C 4.1 1.2 1.1 1 D 4.8 1.9 0.9 n.o. Soil ([degrees] C) Site -1-0 0-1 1-2 2-3 A 11 36 27 20 B 8 25 39 18 C 15 33 25 19 D n.o. 18 38 30 Site 3-4 4-5 >5 A 1 1 2 B 8 2 n.o. C 4 2 n.o. D 11 2 n.o.
n.o., no occurrence.
Recent publications on the soils from Antarctica suggest that the SOM content is very low (e.g. Bockheim and Ugolini 1990; Bockheim 1997). In contrast, our data indicate a high TOC level in most of the soils (Table 2). Only in the very young soils at the L[Phi]ken moraine on the ice field close to the ice plateau (Fig. 2; Table 2, L2) was the TOC very low. TOC concentrations in the topsoil layer were similar in the Cryorthents and Haplocryods and much lower in the Cryaquepts (Table 3). However, occasionally, TOC content was elevated close to that of peat horizons (Tables 2 and 3).
Table 2. Representative soils and selected properties from the Casey area
EC, electrical conductivity; LOI, loss-on-ignition; TOC, total organic carbon; [N.sub.t], total nitrogen; sing., single grain; ves., vesicular; sa.blocky, subangular blocky; a.blocky, angular blocky
Hor. Depth >2 Colour Texture (cm) mm Munsell (g/kg) (moist) L2: Loamy-skeletal, mixed Lithic Cryorthent from moraine deposits with scattered mosses A 0-1 540 5Y4/2 Loamy sand AC -4 530 5Y5/1 Sandy loam C -15 430 5Y4.5/2 Sandy loam R >15 Bare rock fragments D2: Loamy-skeletal, mixed Lithic Cryorthent from moraine deposits with scattered vegetation A 0-2 630 7.5YR4/1 Sand ABw1 -6 480 7.5YR3/1 Sand ABw2 -9 460 7.5YR3.5/1 Loamy sand Cw -36 540 2.5Y6/2 Sandy loam R >36 Bare granite-gneiss rock C1: Coarse-loamy, mixed Lithic Cryorthent from gneiss under mosses and lichens A 0-9 430 10YR3/3 Loamy sand AC -15 140 10YR4/2 Sandy loam R >15 Bare rock B11: Loamy-skeletal, mixed Lithic Cryorthent from gneiss under mosses A 0-2 n.d. 10YR2/1 Sandy loam Bw -10 410 10YR2/2 Sandy loam R >10 Bare rock M2: Dysic, micro, Lithic Cryohemist under mosses Oi 0-2 n.e. n.d. Silt loam Oe -4 n.e. 7.5YR3/2 Loam Oa -15 n.e. 7.5YR3/3 Loam A1 -18 300 10YR3/2 Sandy loam A2 -22 230 10YR4/2 Sandy loam R >22 Bare rock Hor. Structure pH EC LOI (Ca (dS/m) [Cl.sub.2]) L2: Loamy-skeletal, mixed Lithic Cryorthent from moraine deposits with scattered mosses A Ves., sa.blocky 4.85 0.9 6.9 AC Ves., sa.-a, blocky 5.90 0.5 3.3 C Ves., a. 6.14 0.6 3.8 R blocky-prismatic D2: Loamy-skeletal, mixed Lithic Cryorthent from moraine deposits with scattered vegetation A Single grain 4.20 0.9 22.2 ABw1 Sing.-sa.blocky 3.95 0.7 21.0 ABw2 Sing.-sa.blocky 3.91 0.4 20.2 Cw Sa.-a. blocky 4.31 0.3 6.0 R C1: Coarse-loamy, mixed Lithic Cryorthent from gneiss under mosses and lichens A Sa.blocky 3.71 1.6 65.6 AC Coherent 3.76 1.1 36.4 R B11: Loamy-skeletal, mixed Lithic Cryorthent from gneiss under mosses A Sa. blocky 4.10 2.6 173.4 Bw Sa. blocky 3.80 1.5 140.6 R M2: Dysic, micro, Lithic Cryohemist under mosses Oi 1(A) 4.33 2.0 605.1 Oe 4 4.16 0.3 412.9 Oa 6 4.04 1.3 253.3 A1 Sa.blocky-sing. 3.86 1.6 92.3 A2 Sa.blocky 3.89 1.4 62.9 R Hor. TOC [N.sub.t] C:N (mg/g) L2: Loamy-skeletal, mixed Lithic Cryorthent from moraine deposits with scattered mosses A 3.6 0.27 13.2 AC 1.2 0.13 9.2 C 0.9 0.11 8.5 R D2: Loamy-skeletal, mixed Lithic Cryorthent from moraine deposits with scattered vegetation A 9.9 0.91 10.9 ABw1 10.5 0.73 14.3 ABw2 9.6 0.57 16.3 Cw 2.3 0.10 22.7 R C1: Coarse-loamy, mixed Lithic Cryorthent from gneiss under mosses and lichens A 32.1 2.69 11.9 AC 14.0 0.69 20.2 R B11: Loamy-skeletal, mixed Lithic Cryorthent from gneiss under mosses A 111.4 7.08 15.7 Bw 69.7 6.91 10.1 R M2: Dysic, micro, Lithic Cryohemist under mosses Oi 179.2 9.53 18.8 Oe 216.8 14.25 15.2 Oa 133.3 9.73 13.7 A1 43.6 3.63 12.0 A2 27.1 0.76 35.8 R
n.e., not evident; n.a., not determined.
(A) Humification degree according to Post (Schlichting et al. 1995).
Table 3. Mean (??) organic carbon content (TOC) in topsoil layers (depth 0-5 cm) and frequency distribution (percentage of total sample set) in different mineral Cryosols at the coast of East Antarctica
Percentage of Soil unit(A) n ?? total sample set <5 -10 -20 (mg TOC/g fine earth) Lithic Cryorthents 203 19 4 33 36 Lithic and Pergelic Haplocryods 99 22 7 17 29 Lithic and Pergelic Cryaquepts 42 9 28 42 19 Soil unit(A) Percentage of total sample set -30 -50 -100 -150 (mg TOC/g fine earth) Lithic Cryorthents 13 8 4 1 Lithic and Pergelic Haplocryods 26 15 5 0 Lithic and Pergelic Cryaquepts 7 2 2 0
(A) Soil unit according to Soil Survey Staff (1996).
The accumulation of organic matter in the topsoil induces the formation of A-C soils: Lithic or Pergelic Cryorthents (Blume et al. 1997; Beyer et al. 1998f). In addition, the occurrence of the high [Fe.sub.o] :[Fe.sub.d] ratio ([is greater than] 0.5) (Table 4) suggests the formation of Cambisols (Blume et al. 1997). However, in the Casey area, the SOM content was generally too high to classify as cambic horizon, or there was no change in colour with reference to the parent material (Beyer et al. 1998f). In contrast, in the maritime King George region, Gelic Cambisols were found (Blume et al. 1997; Beyer et al. (1998b). With the exception of a few very young soils, most are strongly acidified and have a low base saturation (Tables 2 and 4). Frequently, the Cryorthents show podzolic features (Table 2, D2) without fitting the definition of a spodic horizon (Beyer et al. 1998f). High phosphate contents reflect the present or relic influence of seabirds on soil (see Tables 5 and 7). In the Casey area at former penguin rookeries, penguins contributed P directly (Table 5; Blume et al. 1997). The high P level in most other soils is contributed to the topsoil by eolian dust (Beyer et al. 1998f).
[TABULAR DATA 4-5 NOT REPRODUCIBLE IN ASCII]
Some examples of soils which are supposed to be Podzols are given in Table 5. These soils have a typical horizon sequence of AE/Bh/Bhs, strong acidification, a low base saturation, and a [Fe.sub.o] :[Fe.sub.d] ratio that often exceeds 0-5, which indicates the existence of short-range-order pedogenic Fe compounds (McKeague et al. 1983; Schlichting et al. 1995). In antarctic Podzols, the C :N ratio was much lower than that known for temperate climate regions (McKeague et al. 1983; Beyer et al. 1997b). Iron and Al are mainly located in non-crystalline pedogenic oxides ([Fe.sub.o], [Al.sub.o]), or in organic complexes ([Fe.sub.NaOH], [Al.sub.NaOH]) (Table 5). However, the high [Al.sub.NaOH] values suggest an overestimation of the organic-bonded Al (Kaiser and Zech 1996) and confirmed the results of Jacobsen (1991), who showed that [Fe.sub.o] and [Al.sub.o] were higher in amount than [Fe.sub.d] and [Al.sub.d]. A high amount of P indicates the influence of guano input into the soil (Blume et al. 1997). This is why, in the Haplocryod on an abandoned penguin rookery, the immobile, citrate-soluble P data ([P.sub.c]) were the highest (Table 5). The Podzols from solid rock materials showed the most shallow AE horizons (Table 5; Quass et al. 1998).
The subsoil of the loamy soils frequently showed redoximorphic features with dark manganese (Mn)-mottles and/or reddish Fe-patches, Fe-mottles and/or Fe-layers, and a [Fe.sub.o] : [Fe.sub.d] ratio [is greater than] 0.5 in the hydromorphic horizons (Schlichting et al. 1995; Blume et al. 1997)--an example is presented in Table 6. According to the recent Keys to Soil Taxonomy (Soil Survey Staff 1996), these soils are classified as Cryaquepts. In the recently adopted Gelisol order (ICOMPAS 1996; Bockheim et al. 1997), the name Aquaturbel indicates the recent cryoturbation in these soils. Vivianite, which is only persistent under the absence or lack of oxygen, was found in the subsoil of a Haplocryod on an abandoned penguin rookery (Blume et al. 1997). The existence of redoximorphic features in the soils suggest that, for some time during the thawing period, water saturation, and therefore free water, can be expected to occur. However, in the Casey area, Cryaquepts comprise [is less than] 10% of the local area and, therefore, are probably of minor ecological importance (see Table 11).
[TABULAR DATA 6 NOT REPRODUCIBLE IN ASCII]
Table 11. Soil geography of investigation Sites A-D (10 by 10 m square plots) and the total landscape (overall) and percental standard deviation (a%) (adapted from Beyer et al. 1998f)
Soil unit(A) Site (% of covered area) A B Cryorthent Total 47.0 26.4 Loamy-skeletal, Lithic Cryorthent 27.0 9.0 (Lithic Orthohaplel or Haploturbel) Sandy-skeletal, Lithic Cryorthent 20.0 17.4 (Lithic Orthohaplel) Haplocryod Total 1.5 n.o. Sandy-skeletal, Lithic Haplocryod n.o. n.o. Loamy-skeletal, Pergelic Haplocryod n.o. n.o. Sandy, Lithic Haplocryod 1.5 n.o. Cryaquept Total 4.3 17.5 Loamy-skeletal, Pergelic Cryaquept n.o. 16.3 (Typic Aquaturbel) Loamy-skeletal, Lithic Cryaquept 4.3 1.2 (Lithic Aquaturbel) Fine-loamy, Lithic Cryaquept n.o. n.o. (Lithic Aquaturbel) Bare rock/ rock fragments Total 47.2 56.1 Site (% of covered area) Soil unit(A) C D Total 12.8 47.9 Loamy-skeletal, Lithic Cryorthent 12.8 47.9 (Lithic Orthohaplel or Haploturbel) Sandy-skeletal, Lithic Cryorthent n.o. n.o. (Lithic Orthohaplel) Total 51.2 26.8 Sandy-skeletal, Lithic Haplocryod 51.2 n.o. Loamy-skeletal, Pergelic Haplocryod n.o. 26.8 Sandy, Lithic Haplocryod n.o. 0.4 Total 7.8 n.o. Loamy-skeletal, Pergelic Cryaquept n.o. n.o. (Typic Aquaturbel) Loamy-skeletal, Lithic Cryaquept n.o. n.o. (Lithic Aquaturbel) Fine-loamy, Lithic Cryaquept 7.8 n.o. (Lithic Aquaturbel) Bare rock/ rock fragments Total 28.2 25.3 Soil unit(A) Overall % Total 33.5 44 Loamy-skeletal, Lithic Cryorthent 24.2 63 (Lithic Orthohaplel or Haploturbel) Sandy-skeletal, Lithic Cryorthent 9.4 100 (Lithic Orthohaplel) Total 19.9 106 Sandy-skeletal, Lithic Haplocryod 22.2 173 Loamy-skeletal, Pergelic Haplocryod 6.7 173 Sandy, Lithic Haplocryod 173 Total 7.4 87 Loamy-skeletal, Pergelic Cryaquept 4.1 173 (Typic Aquaturbel) Loamy-skeletal, Lithic Cryaquept 1.4 128 (Lithic Aquaturbel) Fine-loamy, Lithic Cryaquept 2.0 173 (Lithic Aquaturbel) Bare rock/ rock fragments Total 39.2 33
n.o., no occurrence.
(A) Soil unit according to Soil Survey Staff (1996) and according to ICOMPAS (1996).
Large quantities of N and P are contributed by the penguins and secondary Ca phosphates may form (Collins et al. 1975; Tatur and Barczuk 1985; Tatur and Keck 1990). Detailed studies by Ugolini (1972) confirmed the high N and P content of the soils and suggested that the salinity of these soils was due to salt-enriched excreta of penguins. Our data were in agreement with the well-known high nutrient level in C, N, and P, but contradicted previous data on salinity. With the exception of the recently colonised penguin rookeries (Table 7, WP2), we did not find salic horizons, which are characterised as having an EC [is greater than] 15 dS/m (Soil Survey Staff 1996). Consequently, we suggest a very rapid salt leaching in the abandoned rookeries, which requires unfrozen water in the subsurface soil as suggested for the formation of Podzols (Haplocyods) and Cryaquepts.
[TABULAR DATA 7 NOT REPRODUCIBLE IN ASCII]
Proposals for a soil classification in Wilkes Land are summarised in Table 8. In the Histosol and Podzol order there are only small differences among the 4 classification systems. The Histosols are distinguished according to their decomposition degree and/or their mineral content: lithic, a solum [is less than] 40 cm; pergelic, a solum [is greater than] 40 cm and a mean annual soil temperature [is less than] 0 [degrees] C (Soil Survey Staff 1996). The Haplocryods (FAO: Podzols) also show differences in the depth of the lithic contact. The Cryaquepts (FAO: Gleysols) are mostly characterised by active cryoturbation. This can be documented better by using the new Gelisol order (ICOMPAS 1996; Bockheim et al. 1997). Gelic soils with evidence of cryoturbation are termed Turbels, and gelic soils with minimal evidence of cryoturbation are classified as Haplels. This is why all Pergelic Cryaquepts are Aquaturbels (Tables 6 and 8). In the present study, we found no Aquahaplels. The nutrient level and the base saturation can be used to distinguish between eutric and dystric soil units (FAO 1994; Soil Survey Staff 1996). All Lithic Cryorthents were dystric, whereas the only Pergelic Cryorthent at the Loken moraine was a eutric soil (Table 2, L2). According to the recent Keys to Soil Taxonomy (Soil Survey Staff 1996), only Lithic and Pergelic Cryorthents can be distinguished. By using the new Gelisol order it is possible to indicate whether the soils are affected by cryoturbation (i.e. Haplels or Turbels). Bockheim (1997) also showed that Pergelic Cryorthents in the Ross Sea section, according to the recent Keys to Soil Taxonomy (Soil Survey Staff 1996), could be completely different soils. In the Gelisol order, a much more extensive differentiation was possible indicating the extremely dry and salty nature of these soils (Bockheim 1997). For the soil survey in the Casey area, none of the recent classification systems was appropriate to distinguish between the Cryorthents with a high TOC content and those with a very low TOC (Table 2: L2, D2, C1, B11).
Table 8. Classification of representative soils of the Casey area
References: 1, Blume et al. 1997; 2, Beyer et al. 1998a; 3, Blume and Bolter 1996; 4, Beyer et al. 1995; 5, Beyer et al. 1997a; 6, Blume et al. 1996; 7, Beyer et al. 1997b; 8, Beyer et al. 1998b; 9, Blume et al. 1998; 10, H-P. Blume, unpubl, data; 11, L. Beyer, unpubl, data
US Soil Taxonomy US Soil Taxonomy recent version(A) Gelisol order(B) Lithic Cryofolist Lithic Folistel Lithic Cryofibrist Lithic Fibristel Lithic Cryohemist Lithic Hemistel Pergelic Cryohemist Typic Hemistel Lithic Haplocryod Lithic Haplocryod Pergelic Haplocryod Pergelic Haplocryod Lithic Cryaquept Lithic Aquaturbel Pergelic Cryaquept Typic Aquaturbel Lithic Cryorthent Lithic Orthohaplel Lithic Cryorthent Lithic Haploturbel Pergelic Cryorthent Typic Orthohaplel US Soil Taxonomy FAO System recent version(A) (FAO 1994) Lithic Cryofolist Foli-gelic Histosol Lithic Cryofibrist Fibri-gelic Histosol Lithic Cryohemist Terri-gelic Histosol Pergelic Cryohemist Hapli-gelic Histosol Lithic Haplocryod Lepti-gelic Podzol Pergelic Haplocryod Hapli-gelic Podzol Lithic Cryaquept Lepti-gelic Gleysol Pergelic Cryaquept Hapli-gelic Gleysol Lithic Cryorthent Dystri-gelic Leptosol Lithic Cryorthent Dystri-gelic Leptosol Pergelic Cryorthent Dystri-gelic Regosol US Soil Taxonomy WRB System References recent version(A) (Spaargaren 1994) Lithic Cryofolist Folic Histic Cryosol 10 Lithic Cryofibrist Fibric Histic Cryosol 1, 2, 3 Lithic Cryohemist Mesic Histic Cryosol 1, 3, 4 Pergelic Cryohemist Mesic Histic Cryosol 1, 5 Lithic Haplocryod Spodic Haplic Cryosol 1, 3, 6, 7 Pergelic Haplocryod Spodic Haplic Cryosol 6, 7 Lithic Cryaquept Gleyic Turbic Cryosol 11 Pergelic Cryaquept Gleyic Turbic Cryosol 11 Lithic Cryorthent Regic Haplic Cryosol 1, 8 Lithic Cryorthent Regic Turbic Cryosol 1, 3, 8 Pergelic Cryorthent Regic Haplic Cryosol 1, 3, 9
(A) Soil Survey Staff (1996).
(B) ICOMPAS (1996).
The temperature measurements suggest a strong variation in the microclimate of the 4 sites investigated (Beyer et al. 1998d), which was probably responsible for the soil properties, colonisation of soil with microbes (Bolter 1992, 1995), and the adaptation of plants (Smith 1990) in this region. The dominant parent materials in the Casey area are weathered bare rock (gneiss and schists), moraine deposits, and outwash gravels (e.g. Paul et al. 1995). Based on new findings in Wilkes Land near Casey Station (Blume and Bolter 1996; Blume et al. 1996, 1997, 1998), soil formation in the coastal area of Continental Antarctica may be more advanced than previously thought (Fig. 6). The Cryorthents are the first step in soil formation due to the accumulation of organics. However, the present vegetation alone is not responsible for the organic matter input (Beyer et al. 1998e). During the thawing period, this organic matter is partly decomposed under oxic conditions (Beyer et al. 1998f). If the organic matter input by mosses in some Cryorthents is sufficient to enable an organic-rich A-horizon, the accumulation of organic materials leads to the development of thick O-horizons and therefore Dysic Lithic Cryohemists.
[Figure 6 ILLUSTRATION OMITTED]
Elsewhere in the landscape, the periodic lack of oxygen leads to the development of Cryaquepts with its typical reddish Fe pattern. The formation of these soils suggests that, in the short summer period, free water must be available (Beyer et al. 1998f). Most of the soils at Casey station are strongly acidified. This acidification is often combined with podzolic features in the Cryorthents and one of the striking discoveries recently made in Antarctica has been reports of these podzolised soils at Casey, East Antarctica, and King George Island, Antarctic Peninsula (Blume et al. 1996, 1997, 1998; Beyer et al. 1998f; Quass et al. 1998). According to these authors, the difference between the AE and the underlying Bh in TOC, [N.sub.t], and the metal fractions showed a wide variation ranging into the values of the sediments and rookeries. However, our data from Casey do not confirm the assumptions of Blume and Bolter (1993) that podzolisation in Antarctica is restricted on abandoned penguin rookeries (Table 5). Lithic Haplocryods are obviously a final stage of the recent soil formation.
Ornithogenic soils that developed around large rookeries of pygoscelid penguins were formed by the action of guano solutions on loams and gravels (Myrcha et al. 1985). Syroechkovsky (1959) was one of the first to describe and name these soils. Tedrow and Ugolini (1966) outlined the general nature of ornithogenic soils and pointed out that their organic matter does not accumulate by biosynthesis in situ but is brought to the rookeries from areas outside, during the summer periods that the penguins are ashore. Organic matter is contributed in the form of droppings, feathers, and bird remains (Campbell and Claridge 1987). At least 11% of the P brought by the penguins from the sea to the land accumulates in the form of phosphate deposits. About 50% of the C and N brought in by the penguins from the sea is volatilised during the first weeks after they have abandoned the rookeries (Myrcha et al. 1985). Ugolini (1972) suggested that there is negligible movement of decomposition products downwards into the soil; however, Myrcha and Tatur (1991) observed that chemically aggressive water solutions of guano react with the underlying rocks. Concentrations of more resistant components, such as chitin and urates of phosphates (e.g. apatite and struvite), increase with the length of abandonment (Tatur and Keck 1990). For the King George region, Myrcha and Tatur (1991) postulated that Fe was entirely leached from the soil by strong action of guano solutions. This is consistent with our earlier findings near Casey Station where the best developed Podzols (Haplocryods) with extremely bleached horizons were found on abandoned penguin rookeries (Blume and Bolter 1993; Blume et al. 1996, 1997; Beyer et al. 1997b). Gradual decomposition of organic matter continues with time, and is reflected chemically by the increase in the C:N ratio which is 1 in fresh guano, and [is greater than or equal to] 7 in the oldest soils examined (Campbell and Claridge 1966; Ugolini 1972; Collins et al. 1975). The guano layer is strongly reduced by erosion and weathering in penguin rookeries abandoned during the Holocene (Tatur 1989). However, the SOM is still rich in N-containing moities such as proteins, aminosugars, and uric acid (Beyer et al. 1997b). In maritime Antarctica, the assimilation and decomposition of this organic material seems to occur more rapidly than in continental Antarctica, probably due to a more intense leaching process and biological activity (Ugolini 1972; Tatur 1989; Blume et al. 1997). These observations suggest that, in East Antarctica, the ornithogenic soils would undergo a large release of nutrients in the event of global warming. Under present conditions, the high content of nutrients available in relic ornithogenic soils may be important in controlling the occurrence, productivity, chemical composition, and diversity of microorganisms and plant colonisation (Smith 1990; Tatur and Keck 1990). On these relic penguin rookeries, the Lithic Cryorthents are only short-term transition stages to Lithic Haplocryods. The formation of these soils implies the translocation of organic matter, Fe, and A1 from the upper soil into the subsoil during the unfrozen period when free water is available (Beyer et al. 1998f).
In wind-protected depressions and valleys, Histosols develop directly on rock. Euic (eutric according to Soil Survey Staff 1996) Lithic Cryofibrists occur in the landscape when a high groundwater table exists, or in bedrock depressions where meltwater and the leached nutrients accumulate (Blume et al. 1997). Decomposition of organic matter is reduced due to low temperatures (Beyer et al. 1998d) and lack of oxygen (Beyer et al. 1998f). In higher and drier elevations, greater decomposition leads to the formation of Dysic Lithic Cryohemists. All Histosols are characterised by high mineral contents (Beyer et al. 1995, 1997a, 1998a, 1998c; Blume et al. 1996, 1997) because of eolian dust deposition in coastal areas of Casey and Mawson stations (e.g. Smith 1990). With the exception of a few very young Lithic Cryorthents at the Loken moraine close to the permanent ice plateau, most of the soils are rich in N, P, K, and Mg (Blume et al. 1997, 1998; Beyer et al. 1998f). This might account for the rich and diverse plant communities in the coastal area of Clark and Bailey Peninsula (Smith 1990).
Cambisols have been found in the King George Island region (Blume et al. 1997, 1998), but not in the Casey area. The nutrient level and the base saturation distinguish between eutric and dystric soil units. Major parts of the antarctic ice-free landscapes are covered by weakly developed Cryorthents derived from rocks and loamy moraine deposits (Beyer et al. 1998f), or Cryopsamments from outwash or dune sands (Bockheim 1997). The latter are not found in the Casey and King George area because of the very high contents of gravel and stone (Blume et al. 1997; Beyer et al. 1998f).
According to the recent Keys to Soil Taxonomy (Soil Survey Staff 1996), only Lithic and Pergelic soil units can be distinguished. In the new Gelisol order, it is possible to indicate whether the soils are affected by cryoturbation (i.e. Haplels or Turbels) (ICOMPAS 1996). The completely different soils of the Ross Sea section are mostly Pergelic Cryorthents (Bockheim 1997). However, the new Gelisol order recognises the extremely dry and salty nature of these soils (Beyer et al. 1998b).
The theories of soil formation in Antarctica proposed by Bockheim and Ugolini (1990) should be broadened (Blume et al. 1998). Podzolisation occurs to a limited extent in antarctic polar desert, particularly in the coastal region of East Antarctica. In addition, there is a strong enrichment of organic matter in many soils of the same region. The rubification of soils in the subantarctic tundra and in parts of the polar desert results in reddish-brown organic Fe compounds. In the coastal region of the antarctic continent, Blume et al. (1997, 1998) and Beyer et al. (1998f) did not find the Red Ahumisols of the cold desert described in detail by MacNamara (1969). In this area, cold restricts soil-forming processes such as chemical weathering and organic matter accumulation, whereas in the cold desert of the Ross Sea section aridity is of major importance.
Variability of soil and plant geography
Site A was covered with nearly 50% bare rock and moraine deposits (Table 9), which were partly colonised with lichens (e.g. Usnea sphacelata, Pseudephebe minuscula, Umbilicaria decussata). The inner part of the stone circles was free of vegetation and characterised by Lithic Cryaquepts. On average, the loamy parts of the Lithic Cryorthents had a 30% coverage of mosses (e.g. Bryum pseudotriquetrum, Ceratodon pupureus, Grimmia antarctici) and lichens. These soils had no podzolic features. In contrast, the sandy Lithic Cryorthents had a 100% coverage of mosses together with a permanent occurence of initial podzolisation (Tables 2 and 4, D2). Haplocryods were only found on scattered patches in small hollows. Site B was characterised by a huge solifluction tongue from loamy fine material with loamy, Pergelic Cryaquepts showing scattered vegetation (Table 10) due to an active cryoturbation (Washburn 1980). The soil texture of the Cryorthents varied across short distances not visible in the field by utilising the vegetation cover (Beyer et al. 1998f). The podzolic loamy Cryorthents and the sandy Cryorthents both had the same vegetation cover (Table 10). In small depressions and valleys in between the upright gneiss layers and huge bare rock fragments, the SOM-enriched Cryorthents occurred. Site C was located in the middle of a slope in the lee of the dominant katabatic winds (Fig. 3). The sandy, Lithic Haplocryod was the dominant soil unit (Table 11), which was completely covered with mosses (Table 10). At this site, loamy, Lithic Cryorthents with a thick coverage of moss and a high SOM content were found, with properties very close to those of the Histosol order (Beyer et al. 1998f). These soils in shallow depressions are probably transition segments from mineral soils to Lithic Cryohemists (e.g. Tables 2 and 4, M2). In the landscape, Lithic Cryohemist were found very close to Site C (Blume and Bolter 1993). At Site C, Cryaquepts occurred under a thick coverage of moss, whereas all other Cryaquepts had no vegetation or only scattered vegetation (Table 10). By comparison with the Cryaquepts from Sites A and B, the stone content was much lower and the soils were not classified as loamy-skeletal. Site D was divided into 2 parts. Under the gravel pavement (Table 9) on an abandoned penguin rookery (Blume and Bolter 1993) with no vegetation, we found the best developed Haplocryods of the whole Casey area (Table 5). The second part of Site D was covered by loamy, Lithic Cryorthents in between rock fragments with an initial moss and lichen colonisation.
Table 9. Summary of geomorphological surface features (as a percentage of total surface) of the investigated 10 by 10 m square plots at Sites A-D (for location of sites, see Fig. 3)
Site Bare rock/ Gravel Loose soil material rock fragments pavement without vegetation A 47 n.o. 27 B 56 n.o. 26 C 28 n.o. 12 D 25 27 n.o. Site Loose soil material with vegetation A 26 B 18 C 48 D 48
n.o., no occurrence.
Table 10. Correlation between soil units and vegetation pattern in the landscape of the antarctic Casey area
Soil unit(A) Vegetation(B) Sandy-skeletal, Lithic Haplocryod(c) Mosses and lichens--100% Loamy-skeletal, Pergelic Haplocryod Nil Loamy-skeletal, Lithic and Pergelic Cryaquept Scattered mosses, lichens, algae Fine-loamy, Lithic Cryaquept Mosses--100% Sandy-skeletal, Lithic Cryorthent Mosses and lichens--100% Loamy-skeletal, Lithic Cryorthent: With initial Podzol features Mosses and lichens--100% With no initial Podzol features Mosses and lichens--030%
(A) Soil unit according to Soil Survey Staff (1996).
(B) For botanical species, see site description.
(C) Including sandy, mixed.
The data in Table 10 suggest a weak correlation between soil and plant geography. On loamy parent rock or moraine materials, podzolisation is connected to the occurrence of a 100% coverage of vegetation, whereas podzolic features disappear with decreasing coverage of vegetation. However, the loamy Pergelic Haplocryods on relic penguin rookeries showed no vegetation at all, because of the thick gravel pavement, which requires a very long time to be colonised by plants (Smith 1990). Most of the Cryaquepts were free of vegetation, because of active cryoturbation (Washburn 1980). In the sandy materials, it was not possible to distinguish between the soil unit Cryorthent and Haplocryod by using the vegetation cover. We suggest that on the sandy parent materials cryoturbation is much less active. However, the early colonisation by mosses did not necessarily induce podzolisation processes as known from temperate climate regions (McKeague et al. 1983). A very thick coverage of moss may also affect the A horizons by raising the SOM content close to the content of an organic layer as Oe and Oa (Soil Survey Staff 1996). In shallow hollows and depressions, the recent moss vegetation may not stimulate podzolisation, but may stimulate organic matter accumulation and peat development (Beyer et al. 1998a). In a higher position with more water leaching, podzolisation is the main soil-forming process. Our observations suggest that plant cover affects soil formation and that special soil units are favourite habitats for plants. However, a systematic correlation of soil and vegetation surveys, including soil properties such as temperature, moisture, SOM, and nutrients, needs to be carried out in the future using a geographic information system to obtain valid vegetation-soil correlations.
Results of the detailed soil survey at Sites A-D are summarised in Table 11. In correlation to the texture sandy- and loamy-skeletal, mixed Lithic Cryorthents were the predominant soil units. Frequently, the loamy fine earth material was separated from sand and gravel due to an intensive cryoturbation (Blume et al. 1997). According to the new Gelisol order of the Soil Taxonomy (ICOMPAS 1996; Bockheim et al. 1997), the sandy Lithic Cryorthents were mostly Haplels with no cryogenic features and the loamy Lithic Cryorthents were Turbels with recent cryogenic features. From the loamy parent material, Cryaquepts were formed.
The occurrence of Haplocryods was observed at Sites A and C, and particularly at the abandoned penguin rookery at Site D. The small-distance soil survey indicates great variability of soil formation and an extraordinary small-distance variation in soil geography (see Table 11, [Sigma]%). This suggests the possibility of a wide range in soil properties with respect to microbial turnover, nutrient supply, and plant colonisation. Surprisingly, we found only weak correlations between the soil units and the temperature regime (Beyer et al. 1998d).
Soil organic matter
The C storage in the mineral Cryosols (Cryorthent, Cryaquept, Haplocryod of the Casey area ranged between 0.3 and 8.3 kg/[m.sup.2] and the N storage range between 21 and 736 g/[m.sup.2] (cf. Table 12), whereas in organic Cryosols (Cryohemisi Cryofibrist) the mean storage of both was much higher (Beyer et al. 1997a, 1998e). We suggest that TOC is derived from several sources which can change rapidly in the field. Firstly, the vegetation cover and composition is important for the recent organic matter input (Beyer et al. 1998e). Secondly, microbial left-overs influence SOM content because of the reduced decomposition in the cold (Melick and Seppelt 1992; Melick et al. 1994; Bolter et al. 1994, 1997). Thirdly, organic matter input by seabirds is possible at every place close to the coast (Blume et al. 1997). Fourthly, there might be long-term conservation due to the burying of organic matter by relic cryoturbation (Washburn 1980). In the Haplocryods, the content of TOC (Table 5) and the amount of TOC (cf. Table 12) was also very high, because soluble organic matter is translocated into the subsoil (Blume et al. 1997; Beyer et al. 1998f). In addition, a significant amount of N is stored in the relic ornithogenic soils derived from N-rich penguin guano (Beyer et al. 1997b). This induces the narrow C:N ratios in the recent ornithogenic soils (cf. Table 7), and in several layers of their relic counterparts (cf. Table 5).
Table 12. Total organic carbon (TOC, kg/[m.sup.2]) and total nitrogen storage ([N.sub.t], g/[m.sup.2]) in the soil solum (range, 0-7 cm to 0-50 cm) of the investigated profiles, means overall soils and sites, and the percental standard deviation ([Sigma] %) (adapted from Beyer et al. 1998e)
Site A B C Cryorthent(A) Loamy-skeletal, Lithic 1.4 3.4, 3.6, 8.2 6.1, 0.3 Sandy-skeletal, Lithic 1.6 3.3 n.o. Haplocryod(A) Sandy-skeletal, Lithic n.o. n.o. 3.5 Loamy-skeletal, Pergelic n.o. n.o. n.o. Sandy, Lithic 8.2 n.o. n.o. Cryaquept(A) Loamy-skeletal, Pergelic n.o. 0.8 n.o. Loamy-skeletal, Lithic n.o. 4.4 n.o. Fine-loamy, Lithic 4.4 n.o. 1.8 Mean overall soils TOC 3.9 4.0 2.9 [Sigma] % 71 57 74 [N.sub.t] 218 362 177 [Sigma] % 45 49 64 Mean [Sigma] % D overall sites Cryorthent(A) 2.1(B) 55 Loamy-skeletal, Lithic 1.4 1.9(C) 63 Sandy-skeletal, Lithic n.o. 2.4 36 Haplocryod(A) 4.6 55 Sandy-skeletal, Lithic n.o. 3.5 n.d. Loamy-skeletal, Pergelic 2.2 2.2 n.d. Sandy, Lithic n.o. 8.2 n.d. Cryaquept(A) 2.8 57 Loamy-skeletal, Pergelic n.o. 0.8 n.o. Loamy-skeletal, Lithic n.o. 4.4 n.o. Fine-loamy, Lithic n.o. 3.1 43 TOC 1.8 3.4 69 [Sigma] % 23 56 n.d. [N.sub.t] 227 267 62 [Sigma] % 64 62 n.d.
n.o., no occurrence; n.d., not determined.
(A) Soil unit according to Soil Survey Staff (1996).
(B) Excluding 8.2 and 6.1 kg TOC/[m.sup.2], including 3.2 kg ([Sigma] % = 74).
(C) Excluding 8-2 and 6.1 kg TOC/[m.sup.2], including 3.4 kg ([Sigma] % = 76); only soil organic marl enriched Cryorthents (8.2 and 6.1 kg), [Phi] 7.2 kg TOC ([Sigma] % = 15).
In a Pergelic Cryohemist (Terri-Gelic Histosol) from mosses, the depth distribution of C forms suggested a decomposition of carbohydrates and the enrichment of alkyl C in the deeper horizons (Fig. 7). Py-FIMS showed signals for lipids (n-[C.sub.10] to n-[C.sub.20] alkyl-diester, n-[C.sub.20] to n-[C.sub.30] alkenes/alkanes, n-[C.sub.16] to n-[C.sub.34] fatty acids, n-[C.sub.44] to n-[C.sub.46] alkyl-monoesters, sterols) and carbohydrates (Fig. 8). Although mosses do not contain lignins (Hurst and Burges 1967), both CPMAS [sup.13]C-NMR and Py-FIMS showed signals for aromatics. This indicates the formation of aromatic humic substances without lignin precursors from plants and confirmed previous results obtained from extracted humic materials (Wilson et al. 1986; Wilson 1990). In a wet Lithic Cryofibrist (Fibri-Gelic Histosol) from algae, Beyer et al. (1995) found only a slight decomposition of carbohydrates and no selective preservation of alkylic biomacromolecules (Fig. 9). Owing to the extreme climatic conditions and the high water capacity, SOM transformation processes in these soils are retarded (Beyer et al. 1998d).
[Figures 7-9 ILLUSTRATION OMITTED]
In a Pergelic Haplocryod on an abandoned penguin rookery, the SOM had a high percentage of amino derivates from proteins, polysaccharides, urates, and chitin, resulting in a mean C:N ratio of 10 and a high content of carboxyl-C units, which were probably derived from amino and other organic acids (Beyer et al. 1997b). The CPMAS [sup.13]C-NMR of penguin guano (Fig. 10) shows the presence of uric acid (2,6,8-trioxypurine), which was suggested to be typical for ornithogenic soils (Tatur 1989). During the podzolisation process, organic acids and non-humified carbohydrates, as well as N-containing moieties, move from the topsoil into the spodic horizons of the ornithogenic soils (Beyer et al. 1997b).
[Figure 10 ILLUSTRATION OMITTED]
The SOM composition of some antarctic Podzols according to the [sup.13]C NMR experiments is shown in Table 13. The increase of the alkyl-C and simultaneous decrease of O-alkyles with increasing soil depth is comparable to the pattern observed in Podzols in temperate climate regimes (Post et al. 1988; Sorge et al. 1994; Beyer 1996). However, the high level of carboxyl-C in the whole profile is highly unusual. This might explain the high [CEC.sub.pot] in the Haplocryods at the abandoned penguin rookeries (Table 5) and their recently colonised counterparts (Table 7, WP2). The abrupt change of SOM composition between the third and fourth soil horizon in the Haplocryod on the penguin rookery (Table 13) is probably due to the aggregation in layers of droppings with different materials by the penguins. In contrast to the spodic horizons in Germany, SOM is characterised by a high percentage of amino derivates from proteins, polysaccharides, urates and chitin, resulting in a mean C:N ratio of 10 and a high content of carboxyl-C units, which are probably derived from amino and other organic acids (Beyer et al. 1997b). With respect to aromatic-C, the Lithic Haplocryod from solid rock under mosses and lichens showed a pattern comparable to Podzols in temperate climate regions (Beyer 1996). However, the aromatic-C content in the AE was very high and cannot be explained with residual preservation from the mosses. We do not know whether there is another source of SOM in the area as relic organic matter or an input by eolian transport. The input by seabirds can be ignored because the P contents were low (Table 5). The greatest similarity between SOM composition of Podzols under Antarctica and from temperate climates was found in the soil from outwash sediments under mosses. However, comparison of AE horizons under mosses confirms the assumption that, in the Lithic Haplocryod from gneiss and schist, another C source present in recent vegetation is probable.
Table 13. Composition of soil organic matter (as a percentage of TOC) according to the carbon-13 NMR spectroscopy of antarctic Haplocryods near Casey Station (Wilkes Land) (adapted from Quass et al. 1998)
TOC, total organic carbon Hor. Depth TOC Soil organic matter (cm) (mg/g) Alkyl O-alkyl Aromatic (0-46 ppm) Loamy-skeletal, mixed Pergelic Haplocryod on an abandoned rookery AE 3-9 27.6 19 36 24 Bh -11 36.5 25 32 23 Bhs -16 30.6 23 27 25 Bs -35 25.7 34 28 18 [Phi] Bh/Bs(A) 29 33 21 Guano 29 37 20 Sandy-skeletal, mixed Lithic Haplocryod from gneiss and schist Mosses 23 52 13 AE 0-2.5 23.7 16 33 30 Bh -10 38.5 24 29 22 Sandy-skeletal, mixed Pergelic Haplocryod from outwash sediments Mosses 23 52 13 AE 0-4 39.5 25 45 16 Bh -7 64.7 28 44 14 C -20 19.0 25 37 23 [Phi] Bh/Bs /Germany 34 37 20 9 Hor. Carboxyl-C (160-210 ppm) Loamy-skeletal, mixed Pergelic Haplocryod on an abandoned rookery AE 21 Bh 20 Bhs 25 Bs 20 [Phi] Bh/Bs(A) 18 Guano 14 Sandy-skeletal, mixed Lithic Haplocryod from gneiss and schist Mosses 12 AE 21 Bh 25 Sandy-skeletal, mixed Pergelic Haplocryod from outwash sediments Mosses 12 AE 14 Bh 14 C 15 [Phi] Bh/Bs /Germany 9
(A) Other locations near Casey.
The great difference in SOM composition and SOM depth function in the profiles suggests that parent materials and different C sources influence the mechanisms of humification and translocation in the soil. We believe that it is not only a special vegetation, as it is known from temperate climate regimes with heather (Beyer 1996), that is responsible for the occurrence and intensity of podzolisation; the microclimate, soil microbial colonisation, and parent organic materials all exert an effect (Bolter 1992; Beyer et al. 1998d, 1998f). With respect to the podzolisation process, our data suggest the migration of organic acids, non-humified carbohydrates, and N-containing moieties from the topsoil into the spodic horizons of the ornithogenic soils (Beyer et al. 1997b); whereas in the SOM of the German Podzols, N-compounds and non-humified carbohydrates are of minor importance within the SOM translocation processes (Beyer 1996). The formation of Podzols suggests the occurrence of free water in soil and the possibility of leaching through the profile despite a mean precipitation rate of [is less than] 200 mm. The high aridity in the Ross Sea section in the McMurdo Dry Valleys might explain why Ugolini (1972), Campbell and Claridge (1987), and Bockheim and Ugolini (1990) suggested that there is negligible movement of SOM decomposition products downwards into the soil. This is not the case for the more northerly coastal Casey area.
The wide range of TOC storage in the soil solum at a profile level, calculated at the very small scale level of 1 [m.sup.2], is reflected in Table 12. The C storage ranged between 0-3 and 8.2 kg/[m.sup.2] and the N storage ranged between 21 and 736 g/[m.sup.2]. By comparison with the mineral Cryosols in the peat soils, the C storage was much higher with a maximum 28.6 kg/[m.sup.2] and that of N was 1.3 kg/[m.sup.2] (Beyer et al. 1995). The C and N amounts are comparable to stocks known from arctic regions (Batjes 1996). The storage data of the soils confirmed the great variability in concentration within the single soil units (Table 3). Comparing the 4 sites, the mean TOC storage ranged from 1.8 to 4 kg/[m.sup.2], and the mean [N.sub.t] storage ranged from 180 to 360 g/[m.sup.2], including a deviation of [is greater than] 60% (Table 12).
The summarised stocks of TOC and [N.sub.t] in the soils of the 100-[m.sup.2] plots at Sites A-D are compared with respect to soils as a C and N sink at a landscape level in Table 14. Site C showed the highest stock of TOC and [N.sub.t] compared with the other 3 sites. The TOC storage variability of 42% is related to the extraordinary occurrence of Haplocryods and SOM-enriched Cryorthents (Beyer et al. 1998e). However, focusing on the comparison of landscape level and profile level, the variability of C storage decreased from 69% to 42%, and that of N decreased from 62% to 31% (compare Tables 12 and 14, [Sigma]%). Excluding Site C, the variability of C storage dropped below 10% and that of N dropped to 25%. A detailed soil survey enables an acceptable estimation of the stock of C and N and our results suggest that, at 75% of the landscape sites, the stock of C and N is very similar. A widespread podzolisation and/or extraordinary organic matter accumulation may increase these stocks to a great extent (Table 14).
Table 14. Total organic carbon (TOC, kg/100 m2) and total nitrogen stock ([N.sub.t], g/100 [m.sup.2]), in the soil solum at a landscape level, means over all sites, and the percental standard deviation ([Sigma] %) (adapted from Beyer et al. 1998e)
Site Mean A B C D overall sites Cryorthent(A) TOC 68.4 93.7 59.2 65.8 [N.sub.t] 5594 8478 2777 39286 Haplocryod(A) TOC 12.2 n.o. 181.5 59.0 [N.sub.t] 471 n.o. 14592 9970 Cryaquuept(A) TOC 18.9 17.8 13.8 n.o. [N.sub.t] 1320 2911 897 n.o. Sum/100 [m.sup.2] TOC 99.5 111.5 254.5 124.8 147.8 TOC(B) 111.9 [N.sub.t] 7385 11389 18266 13898 12735 [N.sub.t](B) 10890 [Sigma] % TOC [N.sub.t] TOC [N.sub.t] TOC [N.sub.t] TOC 42 TOC(B) 9 [N.sub.t] 31 [N.sub.t](B) 25
n.o., no occurrence.
(A) Soil unit according to Soil Survey Staff (1996).
(B) Excluding Site C.
Data on the storage of C and N at the 4 sites are summarised in Table 15 in order to show the significance of single soil units as C and N sinks. Haplocryods were an important soil unit for C and N storage in the Casey area. Only 20% of the area was covered by this soil unit, but the C and N storage was between 40% and 50%. This is because the Haplocryods had a high content of C and N at a depth of 30 and 40 cm (Blume et al. 1997; Beyer et al. 1998e). In the loamy Pergelic Haplocryods, a large amount of N was stored because these soils are mostly relic ornithogenic soils with a high concentration of penguin guano (Beyer et al. 1997b), rich in N (Croxall 1987). These soils showed the lowest C:N ratio of all soils in the landscape. The next important soil units are the Lithic Cryorthents, which cover about 33% of the area and contributed 49% of the C, but only 42% of the N. The source of this organic matter is not clear (Blume et al. 1997). We think such high amounts cannot only be derived from the recent, and often sparse, vegetation cover and might be left-overs from microbial activity and translocation into the subsoil (Melick and Seppelt 1992; Bolter 1993a, 1993b; Melick et al. 1994; Beyer et al. 1998e). The parent material of the local Cryaquepts had a mainly loamy texture. These soils are still active in cryoturbation. Plant colonisation is inhibited due to the permanent movement of the soil material (Washburn 1980). In addition, the aquic conditions suggest a temporary lack of oxygen during the unfrozen season (Beyer et al. 1998d, 1998f). This might affect plant sucession negatively. In summary, the Cryaquepts cover only small areas in the Casey region and were of minor importance with respect to C and N storage.
Table 15. Significance of mineral Cryosols in total organic carbon (TOC) and total nitrogen ([N.sub.t]) storage (evaluated from Sites A-D; square plots, 10 by 10 m) in the coastal area of East Antarctica near Casey Station (Wilkes Land) (adapted from Beyer et al. 1998f)
Area (%)(A) (kg) Cryorthent(C) Total 33 287 Loamy-skeletal, mixed Lithic Cryorthent 24 198 Sandy-skeletal, mixed Lithic Cryorthent 9 89 Haplocryod(D) Haplocryod 21 252 Sandy-skeletal, mixed Lithic Haplocryod 13 181 Loamy-skeletal, mixed Lithic Haplocryod 7 59 Sandy, mixed Lithic Haplocryod <1 12 Cryaquept(C) Total 7 51 Loamy-skeletal, mixed Lithic Cryaquept 4 13 Loamy-skeletal, mixed Pergelic Cryaquept 1.4 24 Fine-loamy, mixed Lithic Cryaquept 2 14 TOC (%)(B) (kg) (%)(B) Total 49 21.5 42 Loamy-skeletal, mixed Lithic Cryorthent 34 12.2 24 Sandy-skeletal, mixed Lithic Cryorthent 15 9.3 18 Haplocryod 43 25.1 48 Sandy-skeletal, mixed Lithic Haplocryod 31 14.6 28 Loamy-skeletal, mixed Lithic Haplocryod 10 10.0 19 Sandy, mixed Lithic Haplocryod 2 0.5 1 Total 8 5.1 10 Loamy-skeletal, mixed Lithic Cryaquept 2 2.5 5 Loamy-skeletal, mixed Pergelic Cryaquept 4 1.7 3 Fine-loamy, mixed Lithic Cryaquept 2 0.9 2 C: N Total 13.3 Loamy-skeletal, mixed Lithic Cryorthent 16.2 Sandy-skeletal, mixed Lithic Cryorthent 9.6 Haplocryod 10.0 Sandy-skeletal, mixed Lithic Haplocryod 12.4 Loamy-skeletal, mixed Lithic Haplocryod 5.9 Sandy, mixed Lithic Haplocryod 24.0 Total 10.0 Loamy-skeletal, mixed Lithic Cryaquept 5.2 Loamy-skeletal, mixed Pergelic Cryaquept 14.1 Fine-loamy, mixed Lithic Cryaquept 15.6
(A) Percentage of covered area, excluding bare rock.
(B) Percentage of total amount of TOC and [N.sub.t].
(C) Soil unit according to Soil Survey Staff (1996).
In Antarctica, only a few lower plants such as lichens, mosses, fungi, and algae are typical members of plant communities. On some maritime antarctic Cryosols, the grass Deschampsia antarctica occurs (e.g. Seppelt 1984; Longton 1988; Seppelt and Broady 1988; Kappen 1990, 1993; Kappen et al. 1990; Smith 1990; Kappen and Breuer 1991). Despite the hostile conditions for most of the plants, soil microbial data indicate fairly active populations, although actual numbers and biomass show low levels by comparison with temperate environments (Bolter 1990a). Bacteria are the dominant microorganism group (Roser et al. 1993a, 1993b; Bolter 1995); the occurrence of fungi and yeast has been debated in recent literature (e.g. Latter and Heal 1971; Wynn-Williams 1982, 1984; Line 1988; Vincent 1988; Heatwole et al. 1989; Kerry 1990; Roser et al. 1993a, 1993b; Bolter 1995). The bacteria show high metabolic rates (Bolter 1989, 1994a).
Mosses, algae, and lichens produce carbohydrates (sugars and polyols), which are leached into the underlying soil horizon (Dudley and Lechowicz 1987; Tearle 1987; Nakatsubo and Ino 1989; Melick and Seppelt 1992; Roser et al. 1992, 1993a, 1993b; Kappen 1993; Melick et al. 1994). These organics may stimulate microbial activity (Bolter 1993a), because of the high availability of the organic compounds (Bolter 1991; Beyer et al. 1997b). However, great variability in the concentrations of SOM (Bolter 1990b, 1993b; Beyer et al. 1998e) and nutrients (Heatwole et al. 1989; Bolter 1992; Beyer et al. 1998f) probably induce a large variation in microbial activity of antarctic soils. There are wide ranges of environmental and microbiological properties within a few [dm.sup.2] (Speir and Ross 1984; Tearle 1987; Vincent 1988; Bolter 1992; Beyer et al. 1998d). This led Bolter (1990b) to conclude that: `The antarctic microbial system is regarded to be simple with only a few components of producers and consumers. But the small patches lead to increased surface areas of the contact zones of quite different small-scale ecosystems, which consequently results in enhanced fluxes of energy, matter and information'. Bolter (1990b) concluded further that: `This hypothesis of organisation of the ecosystems needs further investigations' and it is obvious that microbiologists should cooperate closely with other disciplines (Bolter 1994a, 1994b). Much more information is needed about the various constituents and the availability of organic matter, and base parameters for calculation of microbial activity. In this context, the soil ecosystems of special interest are, of course, the ornithogenic soils with narrow C:N ratios and high nutrient levels (e.g. Ugolini 1972; Roser et al. 1993a, 1993b; Beyer et al. 1997b, 1998f; Blume et al. 1997). These soils provide a diversity of favourite habitats for microorganisms (e.g. Ramsay 1983; Speir and Ross 1984; Ramsay and Stannard 1986; Roser et al. 1993a, 1993b).
Conclusions and future perspectives
In the coastal region of Continental Antarctica (about 65-70 [degrees] S), the soil water contents are higher than those in the more arid environment of the Ross Sea section and the Dry Valleys ([is greater than or equal to] 77 [degrees] S) (Campbell and Claridge 1987; Bockheim 1997). Colonisation by lower plants such as mosses, lichens, and algae is greater in the more northerly latitudes (Smith 1990). Soil formation is mainly restricted by low temperatures and a relatively short period of vegetation colonisation. To some extent, SOM accumulation is correlated with the vegetation cover. However, the high SOM content without any vegetation observed at the soil surface suggests additional inputs from seabirds and microorganisms, or the occurrence of relic C. The origin of C and N in antarctic Cryosols should be a major topic of future investigations in order to understand nutrient cycling in these coastal ecosystems (e.g. Smith 1985; Ferris et al. 1986; Pickard 1986).
Antarctic Cryosols in the coastal region may be sinks for C, N, P, and other nutrients. To improve the global database on soil storage of C and N, it is desirable to collect more precise information on soils of the southern circumpolar region (Lal et al. 1995). These data are still available for the northern polar regions (Eswaran et al. 1995; Lal et al. 1995; Batjes 1996; Tarnocai 1997). Our data confirm the high C and N concentration in antarctic soils found by Blume et al. (1997). The accumulation of organic matter in soils of the coastal antarctic region is similar to that from comparable arctic regions (Batjes 1996; Jacobsen 1997). Soil formation in the ice-free areas of Coastal East Antarctica is characterised by a tremendous humus accumulation in the landscapes. The very narrow C:N ratio indicates a higher accumulation of N as known from the northern polar regions. This suggests a potentially high availability of the organic matter observed with the occurrence of N compounds such as [Alpha]-[NH.sub.2]-N moieties and uric acid. The humus is probably only preserved due to the prevailing cold conditions (Rosswall and Heal 1975; Smith 1990), but this might change with global climate warming trends (Selkirk 1992; Adamson and Adamson 1995).
Small-distance variations of the topographical, geomorphological, geological, and pedogenic patterns induce great variation in the concentration and storage of C and N. This fact complicates the calculation of soil C and N storage of the total landscape. However, the survey at a landscape level suggests that, at 75% of the landscape sites, the storage of C and N is very similar, but a widespread podzolisation and/or extraordinary accumulation of organic matter may increase these stocks to a great extent. Storage estimation could be improved by using a more detailed soil survey. This knowledge would be useful with respect to modelling C and N release in the case of global warming (Scharpenseel et al. 1990; Lal et al. 1995) and/or anthropogenic disturbances (e.g. Adamson and Seppelt 1990; Vanhala et al. 1996; Tarnocai 1997; Zamolodchikov et al. 1997).
The theories of soil formation in Antarctica suggested by Bockheim and Ugolini (1990) should be extended. Podzolisation is an important soil-forming process in the coastal region of the antarctic continent. In addition, there is strong enrichment of organic matter in many soils of the same region. In the coastal region of the antarctic continent, we did not find the ahumic red soils of the cold antarctic polar desert described in detail by Campbell and Claridge (1987). Recent data suggest a correlation between the soil cover and the vegetation pattern. Nutrient supply in soil is affected by the high availability of K, Mg, and P due to the input from seabirds and the eolian distribution throughout the whole landscape.
Soil-forming processes in the coastal region of continental Antarctica (e.g. podzolisation, redoximorphism) indicate the occurrence of free and available water during the short thawing period. To a certain extent, the moisture regime allows the transfer of weathering products and nutrients into the subsoil, or to the lowest positions on the landscape. A detailed investigation of the water, air, thermal, and nutrient regime would enable a better understanding of the soil input/output balance, as well as transfers in the landscape for developing ecosystem models. These models would enable the prediction of increased temperatures and/or human disturbances on terrestrial ecosystems in coastal Antarctica (Abbott and Benninghoff 1990; Hempel 1990; Adamson and Adamson 1995).
Antarctic Cryosols provide clear evidence of the direct importance of solar energy in soil processes. In soils with a predominantly light-coloured surface pavement, the thermal regime, salinity, and ice-cemented permafrost depth differ from those in soils with dark-coloured surface pavement (e.g. Campbell et al. 1997). This suggests a strong link between available energy and soil properties in Antarctica.
Antarctic Cryosols are particularly sensitive to human disturbances and effects may be long lasting (Chen and Blume 1997; Campbell et al. 1998). Continued human activities in this region must be kept at low levels and within the capacity for natural ecosystems to recover. This will require a greater level of understanding of soil ecosystem relationships (Bolter 1994b).
The widespread occurrence of young, last glaciation aged, soils in the coastal region of East Antarctica and West Antarctica, such as the Antarctic Peninsula, illustrates that these areas are most likely to be influenced by global climate change (Adamson and Adamson 1995). In addition, the SOM properties indicate narrow C:N ratios and high potential availability, which is at present limited due to the cold climate conditions. Increased global warming is likely to be accompanied by an increase in thawing depth, release of water from ice-cemented permafrost, release of C, N, and P, increased salinisation, and extended colonisation of moistened sites by a range of soil organisms (Smith 1985).
This investigation was supported financially by the Australian Antarctic Divison, Kingston, Tasmania, and to a certain extent by the German Research Council (DFG), Bonn-Bad Godesberg (Be1259/4-1). The Australian Antarctic Research Expeditions, and especially the Casey crew in the summer of 1995-1996, supported the field and laboratory work at Casey. Sudelia Kneesch, Solveig Mevold-Lanzius, Kristina Pingpank, Birgit Vogt, and G. Wriedt carried out the soil investigations and preparation of the graphs. Prof. Dr J. G. Bockheim, Madison, improved the first draft of the present paper and 2 anonymous reviewers improved the final revision with respect to interpretation and language editing. The authors gratefully acknowledge all of these people. Special thanks to Prof. Dr Dr h.c. H-P. Blume; because of his involvement as the senior pedologist in the Casey area, L.B. had the opportunity to participate in the field expedition during the antarctic summer of 1995-1996.
Abbott, S. B., and Benninghoff, W. S. (1990). Orientation of environmental change studies to the conservation of antarctic ecosystems. In `Antarctic Ecosystems. Ecological Change and Conservation'. (Eds K. R. Kerry and G. Hempel.) pp. 394-403. (Springer: Berlin.)
Adamson, E., and Seppelt, R. D. (1990). A comparison of airborne alkaline pollution damage in selected lichens and mosses at Casey Station, Wilkes Land. In `Antarctic Ecosystems. Ecological Change and Conservation'. (Eds K. R. Kerry and G. Hempel.) pp. 347-53. (Springer: Berlin.)
Adamson, H., and Adamson, E. (1995). Possible effects of global change on antarctic terrestrial vegetation. In `Impact of Climate Change on Antarctica'. (Ed. Department of Arts, Sport, the Environment and Territories.) pp. 52-62. (Australian Government Publishing Service: Canberra.)
Batjes, N. H. (1996). Total carbon and nitrogen in the soils of the world. European Journal of Soil Science 47, 151-63.
Beyer, L. (1996). Soil organic matter composition of spodic horizons in Podzols of the Northwest German Lower Plain. The Science of the Total Environment 181, 167-80.
Beyer, L., Blume, H-P., Sorge, C., Schulten, H-R., Erlenkeuser, H., and Schneider, D. (1997a). Humus composition and transformation in a Pergelic Cryohemist of coastal Antarctica. Arctic and Alpine Research 29, 358-65.
Beyer, L., Bockheim, J. G., Campbell, I. B., and Claridge, G. G. C. (1998b). Properties, genesis and global significance of Antarctic Cryosols. Permafrost and Periglacial Processes (In press.)
Beyer, L., Bockheim, J. G., Campbell, I. B., and Claridge, G. G. C. (1998c). Properties, genesis and global significance of Antarctic Cryosols. In `Proceedings from the 16th ISSS Congress, Montpellier'. (ISSS: Montpellier.)
Beyer, L., Bolter, M., and Seppelt, R. (1998d). Nutrient and thermal regime, microbial biomass and vegetation pattern of Antarctic Cryosols in the coastal region of East Antarctica (Wilkes Land). Arctic and Alpine Research 30 (in press).
Beyer, L., Knicker, H., Blume, H-P., Bolter, B., Vogt, B., and Schneider, D. (1997b). Soil organic matter of suggested spodic horizons in relic ornithogenic soils of coastal continental Antarctica (Casey Station, Wilkes Land) in comparison with that of spodic soil horizons in Germany. Soil Science 162, 518-27.
Beyer, L., Pingpank, K., Bolter, M., and Seppelt, R. (1998e). Small-distance variation of carbon and nitrogen storage in different Antarctic mineral Cryosols near Casey Station. Zeitschrifi fur Pflanzenernahrung und Bodenkunde 161, 211-20.
Beyer, L., Pingpank, K., Wriedt, G., and Bolter, M. (1998f). Soil formation in coastal continental Antarctica. Geoderma 87 (in press).
Beyer, L., Sorge, C., Blume, H-P., and Schulten, H-R. (1995). Soil organic matter composition and transformation in gelic Histosols of coastal continental Antarctica. Soil Biology and Biochemistry 27, 1279-88.
Beyer, L., Vogt, B., Blume, H-P., and Erlenkeuser, H. (1998a). Soil organic matter composition and transformation in a swamp soil from algae of Coastal Continental Antarctica. Polarforschung 65, 7-22.
Blume, H-P., Beyer, L., Bolter, M., Erlenkeuser, H., Kalk, E., Kneesch, S., Pfisterer, U., and Schneider, D. (1997). Pedogenic zonation in soils of southern circumpolar region. Advances in GeoEcology 30, 69-90.
Blume, H-P., Beyer, L., and Schneider, D. (1998). Soils of Southern circumpolar region and their classification. Pochvovedenie 31, 531-39/Eurasian Soil Science 31, 477-85.
Blume, H-P., and Bolter, M. (1993). Soils of Casey Station (Wilkes Land, Antarctica). In `Proceedings of the 1st International Conference of Cryopedology, November 1992'. (Ed. D. Gilichinski.) pp. 96-103. (Russian Academy of Sciences: Pushchino.)
Blume, H-P. and Bolter, M. (1996). Correlations between soil and vegetation development in continental Antarctica. Verhandlungen der Gesellschaft fur Okologie 25, 25-34.
Blume, H-P., Schneider, D., and Bolter, M. (1996). Organic matter accumulation in and podzolization of antarctic soils. Zeitschrift fur Pflanzenernahrung und Bodenkunde 159, 411-12.
Bockheim, J. G. (1990). Soil development rates in Transantarctic Mountains. Geoderma 47, 59-77.
Bockheim, J. G. (1997). Properties and classification of cold desert soil from Antarctica. Soil Science Society America Journal 61, 224-31.
Bockheim, J. G., Tarnocai, C., Kimble, J. M., and Smith, C. A. S. (1997). The concept of gelic materials in the new Gelisol order for permafrost-affected soils. Soil Science 162, 927-39.
Bockheim, J. G., and Ugolini, F. C. (1990). A review of pedogenic zonation in well-drained soils of the southern circumpolar region. Quaternary Research 34, 47-66.
Bolter, M. (1989). Microbial activity in soils from Antarctica (Casey Station, Wilkes Land). Proceedings NIPR Symposium Polar Biology 2, 146-53.
Bolter, M. (1990a). Microbial ecology of soils from Wilkes Land, Antarctica. 1. The bacterial population and its activity in relation to dissolved organic matter. Proceedings NIPR Symposium Polar Biology 3, 104-19.
Bolter, M. (1990b). Microbial ecology of soils from Wilkes Land, Antarctica. 1. Patterns of microbial activity and related organic and inorganic matter. Proceedings NIPR Symposium Polar Biology 3, 120-32.
Bolter, M. (1991). Microbial mineralization in soils and plant material from Antarctica. In `Proceedings of the International Conference on the Role of the Polar Regions in Global Change, June 1990'. (Eds G. Welles and S. Wilson.) pp. 418-22. (University of Fairbanks.)
Bolter, M. (1992). Environmental conditions and microbiological properties from soils and lichens from Antarctica (Casey Station, Wilkes Land). Polar Biology 11, 591-9.
Bolter, M. (1993a). Effects of carbohydrates and leucine on growth of bacteria from Antarctic soils (Casey Station, Wilkes Land). Polar Biology 13, 297-306.
Bolter, M. (1993b). Organic matter and its availability to microorganisms in Antarctic soils. In `Proceedings of the 1st International Conference of Cryopedology, November 1992'. (Ed. D. Gilichinski.) pp. 189-99. (Russian Academy of Sciences: Pushchino.)
Bolter, M. (1994a). Estimations of microbial biomass by direct and indirect methods with special respect to monitoring programs. Proceedings NIPR Symposium Polar Biology 7, 198-208.
Bolter, M. (1994b). Microcalorimetry and [CO.sub.2]-evolution of soils and lichens from Antarctica. Proceedings NIPR Symposium Polar Biology 7, 209-20.
Bolter, M. (1995). Distribution of bacterial numbers and biomass in soils and on plants from King-George Island (Arctowski Station, Maritime Antarctica). Polar Biology 15, 115-24.
Bolter, M., Blume, H-P., Beyer, L., and Schneider, D. (1997). Soil biological investigations in the maritime and continental Antarctic (King George Island and Windmill Islands). 2. Dissolved and particulate organic nutrients. Polar Biology 18, 295-304.
Bolter, M., Blume, H-P., and Erlenkeuser, H. (1994). Pedogenic, isotopic and microbiological properties of Antarctic soils. Polarforschung 64, 1-7.
Calkin, P. E. (1964). Geomorphology and glacial geology of the Victoria Valley system, Southern Victoria Land, Antarctica. Ohio State University, Institute of Polar Studies 10, 1-66.
Campbell, I. B., and Claridge, G. G. C. (1966). A sequence of soils from a penguin rookery, Inexpressible Island, Antarctica. New Zealand Journal of Science 9, 361-72.
Campbell, I. B., and Claridge, G. G. C. (1967). Site and soil references in the Brown Hills region of the Darwin Glacier, Antarctica. New Zealand Journal of Science 10, 563-77.
Campbell, I. B., and Claridge G. G. C. (1987). `Antarctica: Soils, Weathering Processes and Environment.' (Elsevier: Amsterdam.)
Campbell, I. B., Claridge G. G. C., Campbell, D. I., and Balks, M. R. (1998). `Short and Long term Impacts of Human Disturbances on Snow Free Surfaces in Antarctica.' (Polar Records: Christchurch, NZ.) (In press.)
Campbell, I. B., MacCulloch, R. J. L., and Campbell, D. I. (1997). `Thermal Regimes of some Soils in the McMurdo Sound Region, Antarctica.' (Balkema Press: Rotterdam.)
Chen, J., and Blume, H-P. (1997). Impact of human activities on the terrestrial ecosystems of Antarctica--a review. Polarforschung 65, 83-92.
Claridge, G. G. C., and Campbell, I. B. (1968). Soils of the Shackleton Glacier region, Queen Maude Range, Antarctica. New Zealand Journal of Science 11, 171-218.
Collins, N. J., Baker, J. H., and Tilbrook, P. J. (1975). Signy Island, Maritime Antarctic. Ecological Bulletin 20, 345-74.
Croxall, J. P. (1987). (Ed). `Seabirds, Feeding Ecology and Role in Marine Ecosystems.' (Cambridge University Press: Cambridge.)
Daly, B. K. (1982). Identification of Podzols and podzolised soils in New Zealand by relative absorbance of oxalate extracts of A and B horizons. Geoderma 28, 29-38.
Dyer, B. (1894). On the analytical determination of probable mineral plant food in soils. Transacta Chemical Society 65, 115-67.
Dudley, S. A., and Lechowicz, M. J. (1987). Losses of polyol through leaching in subarctic lichens. Plant Physiology 83, 813-15.
Egner, H., Riehm, H., and W. R. Domingo. (1960). Untersuchungen fiber die chemische bodenanalyse als grundlage fur die beurteilung des nahrstoffzustandes des bodens. II. Chemische extraktionsmethoden zur phosphor- und kaliumbestimmung. Koenigl. Lant. Annaler 26, 204-9.
Eswaran, H., Van den Berg, E., Reich, P., and Kimble, J. (1995). Global soil carbon resources. In `Soils and Global Change'. (Eds R. Lal, J. Kimble, E. Levine and B. A. Stewart.) pp. 27-44. (Lewis Publishers: Boca Raton, FL.)
FAO (1994). `Soil map of the World.' Technical Paper No. 20 (International Soil Reference and Information Centre: Wageningen.)
Ferris, J. M., Burton, H. R., and Bayly, I. A. E. (Eds) (1986). `Biology of the Vestfold Hills, Antarctica.' (Kluwer Academic Publisher: Dordrecht.)
Frund, R., and Ludemann, H-D. (1989). The quantitative analysis of the solution- and CPMAS [sup.13]C-NMR spectra of humic material. The Science of the Total Environment 81/82, 157-68.
Goodwin, I. D. (1993). Holocene deglaciation, sea-level change, and the emergence of the Windmill Islands, Budd Coast, Antarctica. Quaternary Research 40, 70-80.
Grimme, H., and Wiechmann, H. (1969). Eine methode zur extraktion organisch gebundenen eisens aus boden. Zeitschrift fur Pflanzenernahrung und Bodenkunde 122, 268-79.
Glazovskaya, M. A. (1958). Vyvetrivanie i perbichnoe pochboobrazovanie v Antarktide (Weathering and primary soil formation in Antarctica). Nauch. Dok. Vish., Geol. Geog. Nauki 1, 63-76.
Harwood, J. E., van Steenderen, R. E., and Kuhn, A. L. (1969). A rapid method for orthophosphate analysis at high concentrations in water. Water Research 3, 417-23.
Heatwole, H., Saenger, P., Spain, A., Kerry E., and Donelan, J. (1989). Biotic and chemical characteristics of some soils from Wilkes Land, Antarctica. Antarctic Science 1, 225-34.
Hempel, G. (1990). Antarctic ecosystems. Change and conservation. Review of the fifth symposium on antarctic biology. In `Antarctic Ecosystems. Ecological Change and Conservation'. (Eds K. R. Kerry and G. Hempel.) pp. 407-14. (Springer: Berlin.)
Hurst, H. M., and Burges, N. A. (1967). Lignin and humic acids. In `Soil Biochemistry. Vol. 1'. (Eds A. D. McLaren and G. H. Peterson.) pp. 260-86. (Dekker: New York.)
ICOMPAS. (1996). Gelisols. International Committee on Permafrost-affected Soils Circumpolar Letter 5.
Jacobsen, B. H. (1991). Multiple processes in the formation of subarctic podzols in Greenland. Soil Science 152, 414-26.
Jacobsen, B. H. (1997). A soil map of Greenland. In `Abstracts Cryopedology 1997, August 1997.' Syktyvkar, Russia. p. 43. (Ed. I. V. Zaboeva.) (Institute of Biology, Komi Republic: Syktyvkar.)
Jones, J. B. (1991). `Kjeldahl Method for Nitrogen Determination.' (Micro-Macro Publishing: Athens.)
Kaiser, K., and Zech, W. (1996). Defects in estimation of aluminum in humus complexes of the podzolic soils by pyrophosphate extraction. Soil Science 161, 252-8.
Kappen, L. (1990). Usnea sphacelata, its role in the vegetation and its possible growth capacity on Bailey Peninsula, Wilkes Land. Bibliography of Lichenology 38, 277-89.
Kappen, L. (1993). Lichens in the Antarctic region. In `Antarctic Microbiology'. (Ed. E. I. Friedmann.) pp. 433-90. (Wiley: Chichester.)
Kappen, L., and Breuer, M. (1991). Ecological and physiological investigations in continental Antarctic cryptogams. II. Moisture relations and photosynthesis of lichens near Casey Station, Wilkes Land. Antarctic Science 3, 273-8.
Kappen, L., Meyer, M., and Bolter, M. (1990). Ecological and physiological investigations in continental Antarctic cryptogams. I. Vegetation pattern and its relation to snow cover on a hill near Casey Station, Wilkes Land. Flora 184, 209-30.
Kerry, E. (1990). Microorganisms colonizing plants and soil subjected to different degrees of human activity, including petroleum contamination, in the Vestfold Hills and MacRobertson Land, Antarctica. Polar Biology 10, 423-30.
Kerry, K. R., and Hempel, G. (Eds) (1990). `Antarctic Ecosystems. Ecological Change and Conservation.' (Springer: Berlin.)
Lal, R., Kimble, J., Levine, E., and Whitman, C. (1995). Towards improving the global data base on soil carbon. In `Soils and Global Change'. (Eds R. Lal, J. Kimble, E. Levine and B. A. Stewart.) pp. 433-6. (Lewis Publishers: Boca Raton, FL.)
Latter, P. M., and Heal, O. W. (1971). A preliminary study of growth of fungi and bacteria from temperate and Antarctic soils in relation to temperature. Soil Biology and Biochemistry 3, 365-79.
Line, M. A. (1988). Microbial flora of some soils of Mawson Base and the Vestfold Hills, Antarctica. Polar Biology 8, 421-7.
Longton, R. E. (1988). `The Biology of Polar Bryophytes and Lichens.' (Cambridge University Press: Cambridge.)
MacNamara, F. F. (1969). Soils and geomorphic surfaces in Antarctica. Biul. Peryglajalny 20, 299-320.
McCraw, J. D. (1967). Soils of Taylor Dry Valley, Victoria Land, Antarctica, with notes on soils from other localities in Victoria Land. New Zealand Journal of Geology and Geophysics 10, 498-539.
McKeague, J. A., DeConnick, F., and Franzmeier, D. P. (1983). Spodosols. In `Pedogenesis and Soil Taxonomy. II. The Soil Orders'. (Eds L. P. Wildung, N. E. Smeck and G. F. Hall.) pp. 217-52. (Elsevier: Amsterdam.)
Melick, D. R., Bolter, M., and Muller, R. (1994). Rates of soluble carbohydrate utilization in soils from Windmill Islands Oasis, Wilkes Land, Continental Antarctica. Polar Biology 14, 59-64.
Melick, D. R., and Seppelt, R. D. (1992). Loss of soluble carbohydrates and changes in freezing points of Antarctic bryophytes after leaching and repeated freeze-thaw cycles. Antarctic Science 4, 399-404.
Myrcha, A., Pietr, S. J., and Tatur, A. (1985). The role of pygoscelid penguin rookeries in nutrient cycles at Admiralty Bay, King George Island. In `Antarctic Nutrient Cycles and Food Web'. (Eds W. R. Siegfried, P. R. Condy and R. M. Laws.) pp. 156-62. (Springer: Berlin.)
Myrcha, A., and Tatur, A. (1991). Ecological role of the current and abandoned rookeries in the land environment of the maritime Antarctic. Polish Polar Research 12, 3-24.
Nakatsubo, T., and Ino, Y. (1989). Distribution of nitrogen in moss communities in east Antarctica. Memoirs National Institute Polar Research 44, 257-8.
Paul, E., Stuwe, K., Teasdale, J., and Worley, B. (1995). Structural and metamorphic geology of the Windmill Islands, east Antarctica: field evidence for repeated tectonothermal activity. Australian Journal of Earth Sciences 42, 453-69.
Pickard, J. (1986). `Antarctic Oasis. Terrestrial Environment and History of the Vestfold Hills.' (Academic Press: London.)
Post, B., Hempfling, H., Klamberg, H., and Schulten, H-R. (1988). Zur Charakterisierung von Boden-Huminstoffen. Fresenius Zeitschrift fur Analytische Chemie 331, 273-81.
Quass w., Beyer, L., Schneider D., and Blume, H-P. (1998). Podzolization and soil organic matter transfer in soils of Antarctica. In `Proceedings of the 16th ISSS Congress, Montpellier'. (ISSS: Montpellier.) (In press.)
Ramsay, A. J. (1983). Bacterial biomass in ornithogenic soils of Antarctica. Polar Biology 1, 221-5.
Ramsay, A. J., and Stannard, R. (1986). Numbers and variability of bacteria in ornithogenic soils of Antarctica. Polar Biology 5, 195-8.
Roser, D. J., Melick, D. R., Ling, H. U., and Seppelt, R. D. (1992). Polyol and sugar content of terrestrial plants from continental Antarctica. Antarctic Science 4, 413-20.
Roser, D. J., Seppelt, R. D., and Ashbolt, N. (1993a). The microbiology of ornithogenic soils from the Windmill Islands, Budd Coast, Continental Antarctica: microbial biomass distribution. Soil Biology and Biochemistry 25, 165-75.
Roser, D. J., Seppelt, R. D., and Ashbolt, N. (1993b). The microbiology of ornithogenic soils from the Windmill Islands, Budd Coast, Continental Antarctica: some observations on methods for measuring soil biomass in ornithigenic soils. Soil Biology and Biochemistry 25, 177-83.
Rosswall, T., and Heal, O. W. (1975). Structure and functions of tundra ecosystems. Ecological Bulletin No. 20. (Swedish Natural Research Council: Stockholm.)
Schachtschabel, P. (1951). Die Methoden zur Bestimmung des Kalkbedarfes. Zeitschrift fur Pflanzenernahrung und Bodenkunde 54, 134-45.
Scharpenseel, H. W., Schomaker, M., and Ayoub, A. (1990). (Eds) `Soil on a Warmer Earth.' (Elsevier: Amsterdam.)
Schlichting, E., Blume, H.-P., and Stahr, K. (1995). `Bodenkundliches Praktikum.' 2nd Edn. (Blackwell: Berlin.).
Schnitzer, M. (1982). Organic matter characterization. In `Methods of Soil Analysis. Part 2. Chemical and Microbiological Properties'. (Ed. A. L. Page.) pp. 581-94. (ASA & SSSA: Madison, WI.)
Schulten, H-R. (1987). Pyrolysis and soft ionization mass spectrometry of aquatic/terrestrial humic substances and soils. Journal of Analytical and Applied Pyrolysis 12, 149-86.
Schulten, H-R. (1993). Analytical pyrolysis of humic substances and soils: geochemical, agricultural and ecological consequences. Journal of Analytical and Applied Pyrolysis 25, 97-112.
Schulten, H-R., Simmleit, N., and Muller R. (1987). High-temperature, high-sensitivity pyrolysis field ionization mass spectrometry. Analytical Chemistry 59, 2903-8.
Selkirk, P. M. (1992). Climate Change and the Subantarctic. In `Impact of Climate Change on Antarctica--Australia'. (Ed. Department of Arts, Sport, the Environment and Territories.) pp. 43-51. (Australian Government Publishing Service: Canberra.)
Seppelt, R. D. (1984). The bryoflora of Vestfold Hills and Ingrid Christensen Coast, Antarctica. Australian National Antarctic Research Expeditions Research Notes 20, 1-31.
Seppelt, R. D., and Broady, P. A. (1988). Antarctic terrestrial ecosystems: the Vestfold Hills in context. In `Biology of the Vestfold Hills, Antarctica'. (Eds J. M. Ferris, H. R. Burton and I. A. E. Bayly.) pp. 177-84. (Kluwer: Dordrecht.)
Smith, R. I. L. (1985). Nutrient cycling in relation to biological productivity in antarctic and sub-antarctic terrestrial and freshwater ecosystems. In `Antarctic Nutrient Cycles and Food Webs'. (Eds W. R. Siegfried, P. R. Condy and R. M. Laws.) pp. 138-55. (Springer: Berlin.)
Smith, R. I. L. (1990). Plant community dynamics in Wilkes Land, Antarctica. Proceedings NIPR Symposium Polar Biology 3, 229-44.
Soil Survey Staff (1996). `Keys to Soil Taxonomy. 7th Edn.' (USDA-NRC: Washington.)
Sorge, C., Schnitzer, M., Leinweber, P., and Schulten, H-R. (1994). Molecular-chemical characterization of organic matter in whole soils and particle-size fractions of a Spodosol by pyrolysis-field ionization mass spectrometry. Soil Science 158, 189-203.
Spaargaren, O. C. (1994). `World Reference Base for Soil Resources. A Draft.' (International Soil Reference and Information Centre: Wageningen.)
Speir, T. W., and Ross, D. J. (1984). Ornithogenic soils of the cape Bird Adelie penguin rookeries, Antarctica. 2. Ammonia evolution and enzyme activites. Polar Biology 2, 207-12.
Syroechkovsky, E. E. (1959). The role of animals in the formation of primary soils under the condition of circumpolar regions of the earth (Antarctica). Zoolog. Zhur. 38, 247-8.
Tarnocai, C. (1997). The Canadian GIS organic carbon data base and its application to Cryosols. In `Abstracts Cryopedology 1997, August 1997'. Syktyvkar, Russia. p. 59. (Institute of Biology, Komi Republic: Syktyvkar.)
Tatur, A. (1989). Ornithigenic soils of the maritime Antarctica. Polish Polar Research 10, 481-532.
Tatur, A., and Barczuk, A. (1985). Ornithogenic phosphates on King George Island in the Maritime Antarctic. In `Antarctic Nutrient Cycles and Food Web'. (Eds W. R. Siegfried P. R. Condy and R. M. Laws.) pp. 163-8. (Springer: Berlin.)
Tatur, A., and Keck, A. (1990). Phosphates in ornithogenic soils of the maritime Antarctic. Proceedings NIPR Symposium Polar Biology 3, 133-50.
Tearle, P. V. (1987). Cryptogamic carbohydrate release and microbial response during freeze-thaw cycles in Antarctic fellfield fines. Soil Biology and Biochemistry 19, 381-90.
Tedrow, J. C. F., and Ugolini, F. C. (1966). Antarctic soils. American Geophysical Union Antarctic Research Series 8, 161-77.
Ugolini, F. C. (1963). Soil investigations in the lower Wright Valley. Proceedings of the International Permafrost Conference. Natural Academic Science Research Council, Publications No. 1287. pp. 55-61.
Ugolini, F. C. (1972). Ornithogenic soils of Antarctica. In `Antarctic Terrestrial Biology'. (Ed. G. A. Liano.) American Geophysical Union Antarctic Research Series 20, 181-93.
Vanhala, P., Fritze H., and Neuvonen, S. (1996). Prolonged simulated acid rain in the subarctic: effect on the respiration rate and microbial biomass. Biology and Fertility of Soils 23, 7-14.
Vincent, W. F. (1988). `Microbial Ecosystems of Antarctica.' (Cambridge University Press: Cambridge.)
Washburn, A. L. (1980). `Geocryology: a Survey of Periglacial Processes and Environments.' (Wiley: New York.)
Wiechmann, H., and Grimme, H. (1969). Extraktion von organisch gebundenem Eisen aus Sandboden. Zeitschrift fur Pflanzenernahrung und Bodenkunde 122, 260-7.
Wilson, M. A. (1987). `NMR Techniques and Applications in Geochemistry and Soil Chemistry.' (Pergamon Press: Oxford.)
Wilson, M. A. (1990). Application of nuclear magnetic resonance spectroscopy to whole soil. In `Humic Substances in Soil and Crop Sciences'. (Eds P. MacCarthy, C. E. Clapp, R. L. Malcolm and P. R. Bloom.) pp. 221-60. (SSSA: Madison, WI.)
Wilson, M. A., Goh, K. M., Collin, P. J., and Greenfield, L. G. (1986). Origins of humus variations. Organic Geochemistry 9, 225-31.
Wynn-Williams, D. D. (1982). Simulation of seasonal changes in microbial activity of maritime Antarctic peat. Soil Biology and Biochemistry 14, 1-12.
Wynn-Williams, D. D. (1984). Comparative respirometry of peat decomposition on a latitudinal transsect in the maritime Antarctic. Polar Biology 3, 173-81.
Zamolodchikov, D. G., Karelin D. V., and Ivaschenko, A. I. (1997). Geoinformation system-based approach to studying carbon fluxes in tundra landscapes. In `Abstract from the International Conference on The Problems of Earth Cryoshere'. Pushchino, April 1997. (Ed. D. Gilichinski.) p. 304. (Russian Academy of Sciences: Pushchino.)
Manuscript received 4 February 1998, accepted 20 August 1998
Lothar Beyer(A) and Manfred Bolter(B)
(A) Institute of Soil Science, University Kiel, OlshausenstratBe 40, D-24098 Kiel, Germany; email: email@example.com
(B) Institute of Polar Ecology, University Kiel, WischhofstraBe 1-3, Bldg. 12, D-24148 Kiel, Germany; email: firstname.lastname@example.org
Dedicated to Prof. Dr Dr h.c. H-P. Blume on the occasion of his 65th birthday.
|Printer friendly Cite/link Email Feedback|
|Author:||Beyer Lothar; Bolter, Manfred|
|Publication:||Australian Journal of Soil Research|
|Date:||Jan 1, 1999|
|Previous Article:||Prediction of cadmium concentrations in potato tubers (Solanum tuberosum L.) by pre-plant soil and irrigation water analyses.|
|Next Article:||Changes in dispersible clay content, organic carbon content, and electrolyte composition following incubation of sodic soil.|