A preliminary study on the soil diatom assemblages from Ile de la Possession (Crozet, Subantarctica)

Eur. J. Soil Biol., 1998, 34 (3), 133-141 0 Elsevier, Paris

A preliminary study on the soil diatom assemblages from Ile de la Possession (Crozet, Subantarctica) Bart Van de Vijver*,

Louis

Beyens

University of Antwerp (RUCA), Department of Biology, Polar Ecology, Limnology and Paleobiology Unit, Groenenborgevlaan 171, B-2020 Antwgb, Belgium. * Corresponding

author (fax: +32 3 218 04 17; e-mail: [email protected])

ReceivedNovember2, 1998;acceptedApril 18, 1999.

- Forty-eight soil sampleswere collectedfrom Ile de la Possession, Crozet Archipelago.One hundredsixty-five taxa belongingto 32 generawere recorded.The clusteranalysisrevealedfour assemblages, separated by a moistureanda possiblepHgradient.The Eunotia paludosa var. paludosa assemblage wasfound on relativewet acid soils,mostly boundto the valleys on the island.The lessdiverseDiadesmis contenta assemblage is typical for drier soils,occurringon the entireisland.Two assemblages, i.e. the Fragilaria maillardii andthe Achnanthes confusaassemblage, werefound on wetter,non-acidsoils.They areseparated from eachotherby the degreeof influenceof salinity causedby animaltransportand/orsea-spraywith the F maillardii assemblage occurring closerto the coastlineandthe penguinrookeriesof the island.0 Elsevier,Paris Abstract

Diatoms / soil / Crozet / Subantarctica R&urn6

- etude

premiminaire

sur la flore diatomique

des sols de l’ile de la Possession (Crozet,

Subantarctique).

La flore

diatomiquedessolsde l’ile de la Possession (archipeldeCrozet) a CtCexaminCedans48 Cchantillons. Au total, 165taxonsde diatomCesappartenant&32 genresont &tCobservCs.Uneanalysedeclassificationr&ble l’existancede quatrecommunautCs, distingukes par un gradientd’humiditCet probablementausside pH. La communautC de Eunotia paludosa var. paludosa a CtCtrouvCedansdes solsacideset relativementhumides,commeon en trouve danslesgrandesvallCesde l’ile. La communautide Diadesmis contenta, moins divers que les autres, est caractkristique des sols sets, prksents dans toutes Me. Les communautks de Fragilaria maillardii et Achnanthes con&a sont retrouvkes dans des sols humides et non-acides. Elles se sont sCparCes sous l’influence de la salinitC, due au transport animalier et/au les embruns et le vent. La communautk de Frugilaria maillardii estplut6t retrouvCepr&sdela zonec8tii%e.

0 Elsevier,Paris

DiatomCes I sols / Crozet / subantarctique

1. INTRODUCTION A large number of diatom taxa are able to survive in non-submerged or even dry habitats such as dry mossesand soils. In his work on soil algae, Lund [21] defined the term ‘soil diatoms’ as “those growing on soil moistened solely by direct atmospheric precipitation”. In fact, together with bacteria and mould, they form a major part of the microbial biomassin soils [8]. In the past, large studies describing the diatom flora of soils have been produced by e.g. Beger [l], Lund [21] Eur. 3. Soil Bid.,

1 1645563/98/03/O

Elsevier,

Paris

and Brendemiihl [5]. Unfortunately in the Antarctic and Subantarctic regions, soil diatoms have received little attention. Germain [7] investigated the diatom flora of a peat core on Kerguelen but no studies on the actual diatom flora, occurring in the first 10 cm of the subantarctic soils, have been made. The aim of the present study is to determine and characterize the typical soil diatom communities from different parts on Ile de la Possession,Crozet Archipelago. Although the necessary environmental data were not measured, it is still important to report the obtained observations.

134

B. Van de Vijver, L. Beyens

Future research will focus on the relationships between soil chemistry and diatom occurrences. The Crozet Archipelago (45”48’-46”26’ S, 50”14’52”15’ E) is a group of five small islands located in the southern Indian Ocean (figure I), 2 400 km south-east from the South African coast and 2 400 km north of the Antarctic continent. The group lies just north of the Antarctic convergence. The main island of the archipelago is Ile de la Possession @gure 1) with a surface area of 156 km2. More information regarding the topography, climate and vegetation are given in Van de Vijver and Beyens [35].

‘Ilots des Aph-es

Crozet Archipelago

-_’

Indian Ocean

B.964 166,166A

Ile de la Possession

J

Figure 1. Sketch map of the study site with the locations ent sampling points.

of the differ-

So far, only one study on the diatom flora of the island has been made. Pierre [25] investigated the diatom composition of some rivers in the vicinity of the base. He listed 77 taxa belonging to 23 genera. On the nearby Kerguelen Archipelago, the diatom composition is better known. Germain [7], Bourrelly and Manguin [3], Le Cohu and Maillard [19, 201 and Van de Vijver et al. [37] produced detailed species lists of different parts of the main island. Van de Vijver et al. [37]

determined that a close relationship between the known diatom flora of Crozet and Kerguelen existed. Since many of the diatom taxa are typical for the subantarctic region, much work still has to be done in describing and refining their ecological characteristics. This study is part of a series of papers describing the diatom assemblages on Ile de la Possession, Crozet. Two other papers deal with the diatom flora of mosses and fresh waterbodies on the island [35, 361.

2. MATERIALS

AND METHODS

Forty-eight soil samples were collected on Be de la Possession during the austral summer of 1997-1998. Sampling sites were randomly chosen, but we tried to sample as much as possible the different soil types on the entire island to obtain a representative view of the soil flora. The location of the different study sites is given in$gure 1. Each sample was obtained by collecting the soil under the vegetation cover with a 50-mL PVC bottle. Formalin was added, in order to fix the samples for further analysis, at 3 % of the total volume. The samples were treated with H,O, and KMnO, to remove the organic material [38]. Cleaned diatom valves were mounted in NaphraxB. In each sample, 500 diatom valves were counted on random transects. Only sample BA003 yielded only 100 valves, even after counting a whole slide. Considering the extreme environments involved, these numbers seemed acceptable [33]. Information on the identification of so-called ‘Antarctic’ species is given in Van de Vijver and Beyens [35]. A complete floristic list of all diatoms counted can be found in appendix I. As an index of diversity, the Shannon-Wiener index was used. A hierarchic-agglomerative clustering, based on minimum variance strategy with the Squared Euclidian Distance as dissimilarity measure, was used to classify the samples [ Ill. Only taxa that occurred at least in one sample with a relative abundance higher than 2 % were used in the analysis. The assemblages were named after the dominant taxa, present in each assemblage. Ordination analysis was performed using the computer program CANOCO [30]. To discover the principal patterns in the distribution of diatoms and their communities within the soil samples of Ile de la Possession, principal component analysis (PCA) was carried out on the square-root-transformed abundance data. For a further analysis of the ordination output, TWINSPAN was used in order to determine the main indicator species in the different assemblages.

3. RESULTS

AND DISCUSSION

3.1. Species composition A total of 165 taxa (including species, varieties and forms), belonging to 32 genera were recorded from the 48 samples. Although Navicula and Pinnularia togeEur.

J.

Soil

Biol.

Soil diatoms from Crozet Islands

135 AZ89 A310 A295 A294 A296

A 1.1

A 1.2

I,00

,

1z

A 2

B 1

Figure 2. Cluster dendrogram based on species composition. ferent clusters are marked on the right side.

The dif-

ther composed almost 38 % of all observed taxa, they only constituted 21 % of all counted valves. The most recorded genera were Diadesmis (24 %), Achnanthes (18.5 % of all counted valves), Fragilaria (18 %) and Eunotia (12 %). In accordance with Round et al. [26] Navicula contenta f. undulata Manguin is transferred to Diadesmis. The new combination is now : Diadesmis contenta f. undulata (Manguin) Van de Vijver & Beyens nov. comb. Basionym: Navicula contenta f. undulata Manguin 1952 [4]. Five taxa showed a mean relative abundance higher than 4.5 %: Diadesmis contentu (Grun.) Mann (23.9 %), Eunotia paludosa Grunow var. paludosa (9.6 %), Fragilaria maillardii Le Cohu (9.5 %), Achnanthes confusa Manguin (4.9 %) and A. aueri (Hust.) Krasske (4.6 %). Short notes on the ecological preferences and their occurrence in the Antarctic region are given below [ 14, 16, 24,]. 3.1.1. Achnanthes aueri (formerly Achnanthes pseudolanceolata Hustedt) In his work on the types of Krasske, Lange-Bertalot [ 151 described this taxon from two peat areas in southVol. 34, no 3 - 1998

2 3 Assemblages

4

Figure 3. Histographs reflecting mean diversity, evenness and species richness. Standard deviations are shown as error bars. The numbers of the assemblages are: I, A 1.1; 2, Al .2; 3, A2; and 4, B.

em Chile strongly influenced by brackish water. It seems that A. aueri is a typical subantarctic species. It was reported from Crozet [25], Kerguelen [3, 18, 19, 371, where it occurred in both rivers and lakes and from Macquarie Island [22]. 3.1.2. Achnanthes

confusa

A. confusa is generally not considered to be a common soil diatom. On South Georgia, it was found on very wet and/or submerged mosses [33]. Bourrelly and Manguin [3] described the species from a subfossil peat sample taken on Kerguelen and stated that it was most probably an aerophilic species. Le Cohu and Maillard [19] found it together with A. abundans on some submerged mosses and filamentous algae.

3.1.3. Diadesmis contenta (formerly Navicula contenta Gncnow) D. contenta is a typical cosmopolitan soil diatom, widely reported from the entire Antarctic region. Kawecka and Olech [lo] found D. contenta to be aerophilic and to occur in the boundary zone between air and water. According to them, the taxon was able to

B. Van de Vijver, L. Beyens

136

50

76.3%

Ass. B

45 43

Ass. Al .I

35

Ass. Al .2 30 25 20 15

10 5 a

Figure 4. Mean relative abundances of fourteen species in the different assemblages. Species are grouped assemblages (black bars, ass. A I. I ; white bars, Al .2; dashed bars, A2; and heavily dashed bars, B).

live in very low light conditions. Schmidt et al. [27] (King George Island) and Spaulding et al. [29] (Antarctic continent) reported D. contentu to be aerophilic.

3.1.4. Eunotia

paludosa &zr. paludosa

Oppenheim [23] found this cosmopolitan taxon in lake sediments on the South Orkney Islands. On South Georgia, the species seemed to prefer acid, wet mosses where it dominated the diatom community [33]. The taxon was also found in small acid ponds with a predominantly moss vegetation [32]. On Ile de la Possession, E. paludosa was one of the principal taxa in the moss diatom flora, forming one of the major assemblages [35], present in acid, relatively dry environments. In Europe, this species can be identified in moist and temporary dry places [31].

according

to their occurrence

3.1.5. Fragilaria maillardii (=Frankophila dii (Le Cohu) Lange-Bertalot)

in the different

maillar-

E maillardii was originally described from four lakes on Kerguelen [17]. No other records could be found in literature. It seems that this taxon is endemic to the French subantarctic islands in the southern Indian Ocean.

3.1.6. Others Highly remarkable is the almost complete absence. of so-called ‘typical’ soil diatoms. In fact the relative abundances of Hantzschia amphioxys (Ehr.) W. Smith, various Luticola taxa and Navicula atomus (Kiitz.) Grunow var. atomus are quite low. None of these taxa show a relative abundance higher than 4 % in at least one sample. Their absence might be explained by the Eur. J. Soil Biol.

Soil diatoms from Crozet Islands Table I. Results of the TWINSPAN dendrogram

277,278, 290,291, 306,308,

analysis.

137 The numbers

refer to the samples. The groups 00 and 1 (marked

0 279, 280, 281, 282, 283,284,285,286,287,2X8, 294, 295, 296, 297, 298, 299,300, 301, 302, 303, 304, 305, 309, 310, BAOOl, BA007, BAOI I, BA012, BA013

00 * 277, 278, 279, 280, 281,282, 283, 284, 290,291,306

1 276,292,293,307, BA003, BA004, BA008, BA009,

0100 285,286,287,288, 294,295, 296, 297, 298, 299, 300, 301, 302,303,304,305, BA007

011 BAOOI, BA013

* BA002, BA005, BA006, BAOlO

BA012.

0101 308, 309, 310, BAOll

lack of sufficient mineral material in the soil [21]. The same observation was made when studying the species composition of dry moss communities [35]. However, since no measurements of the mineral content of the soil were made, this is only an hypothesis, which will be tested in the future.

Eunotia Navicula

Pinnularia Pinnularia

analysis

The results of the cluster analysis cfigure 2) revealed four assemblages, forming two major sample groups. Figure 3 shows the mean species diversity, evenness and number of taxa found in each assemblage. Figure 4 presents the mean percentage abundances of fourteen important taxa in each assemblage. The first group consists of three assemblages: ass. Al. 1 Frugiluria maillardii assemblage (twelve samples), ass. Al .2 Achnanthes confisa assemblage (thirteen samples) and ass. A2 Diadesmis contentu assemblage (eleven samples). The second group includes only one assemblage, grouping twelve samples: ass. B Eunotia paludosa var. paludosa assemblage. Assemblage Al.1 shows a dominance of Fragiluria maillardii. Subdominant taxa are E pinnata Ehrenberg var. pinnata, Achnanthes aueri, F exigua and F: vaucheriae. Assemblage Al .2 is characterized by Achnanthes taxa: Achnanthes confusa, A. aueri and A. lanceolata Grunow var. lanceolata. Diadesmis contentu is subdominant, but is nevertheless present in every sample of this assemblage. Both assemblages have a high diversity and evenness caused by a relative high species richness, as can be seen in figure 3. The last assemblage of the first group (i.e. A2) is distinguished by the overall dominance of Diadesmis contenta. Some samples contained more than 80 % of this taxon Vol. 34, no 3 1998

are found back in the

01 285, 286,287,288, 294, 295, 296, 297, 298, 299, 300, 301, 302, 303, 304, 305, 308, 309, 310, BAOOI, BAO07, BAOII, BA012, BA013 010 285, 286, 287, 288, 294, 295, 296, 297, 298, 299, 301, 302, 303, 304, 305,308,309,310, BA007,BAOII

3.2. Community

with an asterisk)

Diadesmis

paludosa var. paludosa soehrensis var. mUSCiCO/a microstauron subcapitata contenta

borealis var. scatark Pinnularia divargentissima var.minor Fragilaria maillard Achnanthes aueri Achnanthes combsa Fragilaria vauchenbe Achnanthes lancedata var. lenCaO/ete Fragilaria pinnata var. pinnata Navicula geniculata Eunotia muscicola var. mUSCiCO/a Fragilada exigua Pinnularia obscura Pinnularia

Figure 5. TWINSPAN results ples (see ruble I for a list of mean percentage abundances ",2-5 %;0,5-lO%;X,> IO

1

00

01

X 0 0 0

+ + + + X (I + + + + + + + + + + +

+ + +

0 + + + + + + +

+ + +

i + X 0 0 0 0 D D 0 D +

showing the different groups of samsamples in each group) and associated of the most important taxa (+, < 2 %; %).

(A277: 85 %, A282: 84 %, A291: 86 % and A306 9 1.5 %). Other important taxa are Pinnularia borealis (Ehr.) Rabenhorst var. scalaris and P obscura Krasske. The diversity (i.e. 1.1 f 0.4) and the evenness (0.3 f 0.13) of this assemblage are relatively low, compared with the other assemblages. Assemblage B is dominated by Eunotia paludosa var. paludosa and Navicula soehrensis var. muscicolu (Pet.) Krasske. Other important taxa in this assemblage are various Pinnularia taxa such as P microstauron (Ehr.) W. Smith, l? subcapitata Gregory and P divergentissima (Grun.) Cleve var. minor.

B. Van de Vijver, L. Beyens

138

Figure 6. PCA-analysis of samples plotting the first axis against the second. Axis 1 probably represents a pH-gradient whilst the second axis might represent the moisture content of the different samples. The different assemblages defined by the agglomerative cluster analysis are marked. The principal taxa are shown (Ach aue, Achnanthes nueri; Ach con, A. confusa; Dia con, Din&smis contenta; Eun pal, Eunotia paludosa var. paludosa; Fra mai, Fragilaria maillardii; Fra pin, F: pinnata var. pinnata; Fra vau, F: vaucheriae; Nav gen, Navicula geniculata; Pin bsc, Pinnularia borealis var. scalaris; Pin div, I? divergentissima var. minor; Pin obs, P. obscure; Pin sub, P. subcapitata).

N_

/

_--

Eunotia

The TWINSPAN-analysis supports the results of the agglomerative cluster analysis. Two main groups can clearly be identified from the diagram (tuble I>. The first division separates the Eunotia paludosa var. paludosu assemblage. The main indicator species for this first division are E. paludosa var. paludosa and Fragilaria pinnata var. pinnata. The remaining samples are further divided in the Diadesmis contenta assemblage and a large group containing a mixture of the other two assemblages. Figure 5 shows the distribution of the main species in the different TWINSPAN groups. The main species of group 01 are Frugilaria maillardii, Diadesmis contenta, Achnanthes aueri, A. confusa, A. lanceolata var. lanceolata and E vaucheriae. This group clearly consist of the characteristic species of the l! maillardii and the A. confusa assemblage. Since the distinction between these two assemblages is rather subtle, the final division does not correspond exactly to the results from the agglomerative clustering. The ordination diagram (tisure 6) shows almost the same two groups corresponding to the different assemblages obtained in the cluster analysis. Axes 1 and 2 together account for 43.7 % of the cumulative variance in the diatom data. The group of samples on the right side is the Eunotia paludosa var. paludosa assemblage. Most of these samples were taken from relative wet soils that contained a lot of undigested plant material (e.g. grass leaves, moss rhizoids). As already mentioned, E. paludosa dominated also one of the major assemblages observed in mosses [35] growing in acid,

pal. var. paludosa

assemblage

shallow pools, mainly found in the larger valleys. Moreover, the same assemblage was found on South Georgia in both freshwater lakes and mosses [32, 331, where it was characterized by a very low pH-value and a low conductivity. The other composing taxa of this assemblage reinforce this statement. Navicula soehrensis var. muscicola is known to prefer acid conditions [ 13, 3 11. This might indicate that pH separates this assemblage from the other three and that the horizontal axis (i.e. axis I) is likely to indicate a pH-gradient. Unfortunately, at this moment this assumption cannot be verified for the Crozet soils due to the lack of appropriate soil pH-values. However, indirect evidence confirms our hypothesis since sampled lakes and mosses in the vicinity of the soil sampling sites show pH-values between 4.8 (A276) and 6.3 (BA006). Furthermore, Frenot [6] already measured a pH-value of 4.45 t 0.15 in the soils of the different valleys on Ile de la Possession. He compared his results with Smith [28] who found similar pH-values in valley soils of nearby Marion Island (4.2 < pH < 5.0). The second (i.e. vertical) axis is clearly connected with the moisture content of the soil samples, separating the Diadesmis contenta assemblage from the Achnanthes confusa and the Fragilaria maillardii assemblages. Beyens [2] in the Arctic and Van de Vijver and Beyens [33] on South Georgia reported already that humidity acts as a very important ecological parameter, strongly influencing the composition of the diatom communities. The D. contentu assemblage represents Eur. J. Soil Biol.

Soil diatoms from

Crozet Islands

drier conditions. This is clearly reflected in the species composition of the different samples. D. contenta, Pinnularia borealis var. scalaris and P obscura are all taxa that are associated with dry soils [l, 9, 121. In fact, all samples of this assemblage contained only dry soil material. These dry soils, covered by a AcaenaPoa vegetation can be found everywhere on the island [6]. A similar assemblage, completely dominated by D. contenta, was reported from very dry mosses on Ile de la Possession [33], so that we can safely state that the assemblage is typical for dry environments on the island (both soils and mosses). The separation of the Achnanthes con&a assemblage from the E maillardii assemblage is more difftcult to explain. The TWINSPAN analysis groups them as a single unit. Both assemblages are found on relatively wet soils. However, when analysing more thoroughly the PCA diagram, a clear distinction can be noticed. Most of the samples forming the E maillardiii assemblage were taken very near to the coastline or in Macaroni penguin rookeries where a possible influence of salt (sea-spray) and nutrient enrichment (bird dejection, carrion) is very likely. This is reflected in the presence of taxa such as E pinnata var. pinnata and A. delicatula var. australis Manguin. This last taxon was found in penguin rookeries on the Antarctic Peninsula [34] and in freshwater lakes influenced by sea-spray on King George Island [27]. E pinnata var. pinnata is a very widespread taxon in the Antarctic zone. It was reported from almost every studied Antarctic location where it is normally found in rivers and lakes with a high salinity (e.g. Schmidt et al. [27]). Another factor that may influence this community, is the continuous input of nutrients, due to the immediate presence of large animal colonies. The other assemblage contains a lot of species that are typical for wet and/or semi-dry mosses (e.g, A. con&a, A. aueri, A. lanceolata var. lanceolata, Navicula bryophila Petersen and Eunotia muscicola Krasske var. muscicola). Samples of this assemblage were usually taken in places where water was still influencing the soil, e.g. on dripping mud walls and rocks (A285, BAOll) and in drying pools (BA013). The location of the different samples reduced the influence of sea-spray on the soils.

4. CONCLUSION The investigated soils on Ile de la Possession presented a very diverse diatom flora, dominated by taxa typical for subaerial conditions such as Diadesmis contenta, Achnanthes confusa, Pinnularia borealis var. scalaris and Eunotia paludosa var. paludosa. The soil samples could be divided in four clearly defined assemblages. Although environmental data are lacking, it is clear from the species composition that, besides the moisture content of the soil, pH and salinity determine the major divisions. Vol. 34, n” 3 - 1998

139 Acknowledgements This survey has been made possible with the logistic and financial support of the ‘Institut francais pour la recherche et la technologie polaires’ (France) in the frame of Terrestrial Ecology Programme 136 (Dr Y. Frenot). Figure I is basedon mapspreparedby Dr Y. Frenot. Additional funding wasprovided by the ScienceFoundation,Flanders(IWO). Bart Van de Vijver is a research-assistant of the FWO, Flanders.

REFERENCES [l] Beger H., Beitrage zur Gkologie und Soziologie der luftlebigen (atmophytischen)Kiesel-algen,Ber. Dtsch. Bot. Ges.XLV (1927) 385-407. [2] Beyens L., Moss dwelling diatom assemblages from Edgeoya(Svalbard),PolarBiol. 9 (1989)423-430. [3] Bourrelly I!, Manguin E., Contribution a la flore algale d’eau deucedesiles Kerguelen,MCm. Inst. Sci. Madagasc.Ser.B 5 (1952)7-58. [4] Bourrelly P, Manguin E., Algues d’eau deuce de la Guadelouueet deuendances recueilliesear la Mission Allorge ei 1936,Sedes,Paris,1954,p.6i, pl. 3 fig. 63. [5 BrendemtihlI., Uber die Verbreitungder Erddiatomeen, Arch. Mikrobiol. 14 (1949)407-449. 16 Frenot Y., Interactionsentrela faunelombricienneet les systbmesCdaphiques d’une ile subantarctique:ile de la Possession,archipel Crozet, these, Universite de Rennes,France,1986. [7 Germain H., Diatomeesd’une tourbe des Fles Kerguelen,Bull. Sot. Fr. Microscop. VII (1937) 11-17. [8 Hahn A., NeubausW., Boden-Diatomeeneiner landwirtschaftlichenNutzflache bei Potsdam,Deutschland, Nov. Hedw.65 (1997) 285-298. [9 Hustedt F., Die KieselalgenDeutschlands,Gsterreichs und der Schweiz. Rabenhorst’sKryptogamen-Flora VIII, Koeltz SciencePublishers,Leipzig, 1927-1966. [lo] Kawecka B., Olech M., Diatom communitiesin the Vanishingand Ornitologist Creek, King GeorgeIsland, South Shetlands, Antarctica, Hydrobiol. 269/270 (1993)327-333. [ 1l] Kovach Computing Services, Multivariate Statistical Package,version2.1, users’manual,1993. [ 121KrammerK., Pin&aria, eine Monographie der EuroptischenTaxa,Bibl. Diatom. 26 (1992) l-353. [13] Krammer K., Lange-BertalotH., Stisswasserflora von Mitteleuropa Bacillariophyceae, Teil 14, Gustav FisherVerlag, Stuttgart 1986-l 991. [ 141Lange-BertalotH., 85 neue und tiber 100 weitere neu definierteTaxaergtizend zur Siisswasserflora von Mitteleuropa,vol. 2/l-4, Bibl. Diatom. 27 (1993) l-453. [ 151Lange-Bertalot H., Diatom taxa introducedby Georg Krasske,Documentationand Revision. Iconogr. Diatom., vol. 3, Koeltz Scientific Books, 1996. [ 161Lange-BertalotH., KrammerK., Achnunthes, eineMonograpbieder Gattung,Bibl. Diatom. 18 (1989) l-393. [ 171Lange-BertalotH., Le Cohu R., Raphelike vestigesin the pennatediatom suborderAraphidinae,Ann. Limnol. 21 (1985)213-220.

140

[ 181 Larson D.D., Paleoecological investigations of diatoms in a core from Kerguelen Islands, southeast Indian Ocean, Inst. Pol. Studies, report No. 50, 1974. [ 191 Le Cohu R., Maillard R., Les diatomees monoraphidees des iles Kerguelen, Ann. Limnol. 19 (1983) 143-167. [20] Le Cohu R., Maillard R., Diatomees d’eau deuce des iles Kerguelen a l’exclusion des Monoraphidees, Ann. Limnol. 22 (1986) 99-118. [21] Lund J.W.G., Observations on soil algae. I. The ecology, size and taxonomy of British soil diatoms, New Phytol. 45 (1946) 196-219. [22 ] McBride T.P., Selkirk P.M., Adamson D.A., Present and past diatom communities on subantarctic Macquarie Island, Proc. 14th Int. Diat. Symp., Tokyo (1999) (in press). ~23 ] Oppenheim D.R., A preliminary study of benthic diatoms in contrasting lake environments, in: Kerry K.R., Hempel G. (Eds.), Antarctic Ecosystems: Ecological Change and Conservation, Springer Verlag, Berlin, 1990, pp. 9 l-99. [24] Oppenheim D.R., Taxonomic studies of Achnanthes (Bacillariophyta) in freshwater maritime Antarctic lakes, Can. J. Bot. 72 (1994) 1735-1748. [25] Pierre J.-F., Les Algues des eaux courantes de I’ile de la Possession (archipel Crozet), Bull. Sot. Phycol. Fr. 22 (1977) 79-86. [26] Round F.E., Crawford R.M., Mann D.G., The Diatoms, Biology and Morphology of the Genera, Cambridge University Press, Cambridge, 1990. ]27 ] Schmidt R., Mausbacher R., Miiller J., Holocene diatom flora and stratigraphy from sediment cores of two Antarctic lakes (King George Island), J. Paleolim. 3 (1990) 55-74. P8 ] Smith V.R., The nutrient statuses of Marion Island plants and soils, Ph.D. thesis, University of Bloemfontein, South Africa, 1976. [29] Spaulding S.A., McKnight D.M., Stoermer E.F., Doran, P.T., Diatoms in sediments of perennially ice-covered

B. Van de Vijver, L. Beyens

Lake Hoare, and implications for interpreting lake history in the McMurdo Dry Valleys of Antarctica, J. Paleolim. 17 (1997) 403420. [30] ter Braak C.F.T., Canoco - a Fortran program for canonical community ordination by (partial) (detrended) (canonical) correspondance analysis, principal components analysis and redundancy analysis, Wageningen ITI-TNO, 1987. $1 Van Dam H., Mertens A., Sinkeldam J., A coded checklist and ecological indicator values of freshwater diatoms from the Netherlands, Neth. J. Aq. Ecol. 28 (1994) 117-133. ]32 1 Van de Vijver B., Beyens L., Freshwater diatom communities of the Stromness Bay area, South Georgia, Antarc. Sci. 8 (1996) 359-368. ]33 1 Van de Vijver B., Beyens L., The epiphytic diatom flora of mosses from Stromness Bay area, South Georgia, Polar Biol. 17 (1997) 492-501. 134 1 Van de Vijver B., Beyens L., Freshwater diatoms from some islands in the maritime Antarctic region, Antarc. Sci. 9 (1997) 418-425. [35] Van de Vijver B., Beyens L., Moss diatom communities from Ile de la Possession (Crozet, Subantarctica) and their relationship with moisture, Polar Biol. 19 (1999) (in press). [36] Van de Vijver B., Beyens L., Freshwater diatoms from Be de la Possession (Crozet Archipelago, Subantarctica): an ecological assessment. Polar Biol. 19 (1999) (in press). 137 ] Van de Vijver B., Beyens L., Gloaguen J.C., Frenot Y., La flore diatomique de quelques sediments tourbeux holodnes des iles Kerguelen, Ann. Limnol. 34 (1998) 3-11. ] [38 Van der Werff A., A new method of concentrations and cleaning diatoms and other organisms, Verh. Int. Ver. Theor. Angew. Limnol. 12 (1955) 276-277.

Eur. J. Soil Bid.

Soil diatoms from Crozet Islands

Appendix

I. Taxonomical

141

list of all diatom taxa observed in this study. Unidentified

species are given provisional letter codes.

Achnanthes abundans Manguin A. aueri Krasske A. biasollertinna Grunow A. bioretii Germain A. brevipes var. intermedia (Kiitzing)

N. bryophila Petersen N. aff. bryophila N. bryophiloides Manguin Navicula capiroradiara Germain

A. confusa

N. geniculara Germain N. gregaria Donkin N. halophila (Grunow) Clew N. hererostauron Germain N. ignota var. palustris (Hustedt) Lund N. joubaudii Germain N. maillardii Gennain N. minima Gnrnow N. perminuta Grunow N. porromonrana Clew N. seminulum Grunow N. soehrensis var. muscicola (Petersen) N. submolesta Hustedt N. subtilissima Clew N. virabunda Hustedt Navicula A Navicula B Navicula C Navicula D Navicula E Neidium aubertii Manguin Nirzschia acidoclinata Lange-Bert&t N. archibaldii Lange-Bertalot N. fonricola Grunow

Clew Manguin A. delicatula (Kiltzing) Grunow var. australis Manguin A. germainii Manguin A. helvetica (Hustedt) Lange-Bertalot A. invesrians Carter A. laevis Oestrup var. laevis A. lanceoluta (BrCbisson) Gnmow var. lanceoluta A. lanceolatu var. lanceolatoides (Sovereign) Reimer A. munguinii Hustedt A. manguinii var. elliptica Manguin A. minurissima var. gradlima (Meister) Lange-Bertalot A. minutissima Kiitzing var. minutissima A. modestiformis Lange-Bertalot A. ninckei Guermeur & Manzuin A. oblongella Oestrup A. petersenii Hustedt A. qwdripunctata Oppenheim A. stauronrioides Mangui” A. subatomoides (Hustedt) Lange-Bert&t Achnanthes A

N. fossadis

Achnanthes B Aulacoseira alpigena (Grunuw) Krammer A. distans (Ehrenberg) Simonsen Brachysira minor (Krasske) Lange-Bertalot Caloneis bacillum (Grunow) Clew C. marnieri Mangui”

C. tenuis

(Gregory)

C. silesiaca Bleisch Denticula A D. gullica

contenta (Grunow) Mann f. undulara (Manguin) Van de Vijver (W. Smith) Mann hustedrii Manguin

& Beyens

Diatomella Diploneis subovalis Clew Eunotia arcubus Nijrpel & Lange-Bertalot E. bilunaris (Ehrenberg) W. Mills var. bilunaris E. fullax A. Cleve E. muscicola Krasske var. muscicola E. paludosa Grunow var. paludoaa E. praerupta var. cwta Gnmow Eunotia A Frugilaria construens f. subs&u (Hustedt) Hustedt

E exigua Grunow E germainii Reichardt & Lange-Bertalot E maillardii Le Cohu E pinnata Ehrenberg var. pinnata F pulchella (Ralfs ex K&zing) Lange-Bertalot E ulna (Nitzsch) Lange-Bertalot var. ulna I? vaucheriae (Kiitzing) Petersen F: vaucheriae var. longissima Manguin E virescens Ralfs Fragilariopsis angulata Hale F: kerguelensis (O’Meara) Hustedt Frusrulia pulchra var. lanceolata Manguin E rhomboida (Ehrenberg) De Toni var. rhomboides E vulgaris Thwaites Gomphonema qj’ine Kiitzing G. angusrarum var. aequalis f. kerguelensis Maillard G. parvulum var. exilissimum Grunow G. parvulum (Kiitzing) Kittzing var. par&urn G. sarcophagus Gregory Gomphonema A Gomphonemopsia littoralis (Hendey) Medlin Hantzschia amphio.xys (Ehrenberg) W. Smith Luticola goeppertiuna (Bleisch) Mann L. mutica (K&zing) Mann var. mutica L. SUYCO~UM var. dismutica (Hustedt) Mann Melosira dickiei (Thwaites) i
var. fossalis

Krasske

N. frustulum (Kiitzing) Grunow var. frustulum N. gracilis Hantzsch N. linearis (Agradh) W. Smith N. palea (Kiitzing) W. Smith N. perminura (Grunow) M. Peragallo N. rubicola Grunow Nupela chilensis (Krasske) Lange-Bertalot Opephora martyi HBribaud Orthoseira raxana (Rabenhorst) O’Meara

Krammer

Cocconeis costata Gregory var. cost&u C. therezienii Le Cohu & Maillard Cymbellu minuta Hilse ex Rabenhorst

Diadesmis D. contenta

Krasske

nav. Comb.

Pinnularia aff. pseudogibbo P. anglica Krammer P. backenbergii Manguin P. borealis var. cuneomsrmta Mangui” P. borealis var. scalaris (Ehrenberg) Rabenhorst P. borealis var. thuringiaca (Rabenhorst) Krammer l? brebissonii morphotype 5 (Kiitzing) Rabenhorst P circumducta Manguin P. divergentissima var. minor Krammer F ! kolbei Manguin p. lagerstedti (Clew) Cleve-Euler

P. lata var. kerguelensis (Manguin) Pierre lundii Hustedt microstuuron (Ehrenberg) Cleve microstauron var. australis Manguin microstaumn var. elongara Manguin p. obscura Krasske F ! rupestris Hantzsch P silvarica Petersen P similiformis Krammer P. sinistra Krammer P subcapitatu Gregory P viridis (Nitzsch) Ehrenberg P. viridis var. semicruciata (Grunow) Cleve Pinnularia A Pinnularia B l? I? P. I?

Pin&aria Pinnularia Pinnulariu Pinnularia Pinnularia Rhopalodia

C D

E F G rupestris

(W. Smith) Krammer Stauroneis acuta W. Smith S. kriegeri Patrick S. nana Hustedt S. obrusa Lagerstedt S. phoenicenteron (Nitzsch) Etwnberg Sraumneis A Srauroneis 8 Surirella angusrata var. constricra Hustedt Synedra rumpens var. familiaris (K&zing) Grunow Thalassionema nirzschioides Grunow Thalassiosira gracilis var. expecra (Van Landingham) Thalassiosira A

Fryxell

& Hale