Testate amoebae inhabiting middle taiga bogs in Western Siberia

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  • ISSN 10623590, Biology Bulletin, 2010, Vol. 37, No. 4, pp. 357362. Pleiades Publishing, Inc., 2010.Original Russian Text I.V. Kurina, Yu.I. Preis, A.A. Bobrov, 2010, published in Izvestiya Akademii Nauk, Seriya Biologicheskaya, 2010, No. 4, pp. 423429.

    357

    INTRODUCTION

    The first publications concerning the quantitativeecology of sphagnobiont testate amoebae, commonfor bog ecosystems, appeared in the 1990s (Charman,Warner, 1992, 1997; Warner, Charman, 1994). Theshells of testate amoebae, able to remain in peat sediments for a long time, are used as indicators of climatic conditions in palaeoecological studies, including palaeoclimatic reconstructions (Warner, Charman, 1994; Booth, 2001).

    By now the wetness optimums and tolerance limitsfor testate amoebae have been determined in accordance with the subsoil water level and the substratewetness in oligotrophic peat moss bogs of the southernand middle taiga of the European part of Russia(Bobrov and Minaeva, 2000; Bobrov et al., 2002;Mazey et al., 2007), Europe (Tolonen et al., 1992;Woodland et al., 1998; Mitchell et al., 1999; Lamentowicz and Mitchell, 2005; Blundell and Barber,2005), North America (Booth, 2002; Booth and Zygmunt, 2005), and New Zealand (Charman, 1997).The relation of testate amoebae to the trophic status oftheir habitats still continues to be practicallyunknown.

    In the case of oligotrophic soils of Western Siberia,only a few studies of testate amoebae have been carriedout (Ratkova, 1971; Bobrov et al., 1995; Rakhleeva,2002). The vast territory of marshlands, occupyingmore than 40% of the total area of Western Siberia,determines the diversity of bog formation conditionsand, therefore, the diversity of habitats for testateamoebae inhabiting different bog types.

    The purpose of this study was to reveal quantitativeecological characteristics of testate amoebae in relation to different environmental factors (index of wet

    ness, pH, and the trophic status) in the mires of themiddle taiga of Western Siberia by the example of bogsof the KhantyMansi Autonomous Area.

    MATERIAL AND METHODS

    The material was collected in Kondinskie OzeraNational Park, located at the latitude of 6058 northand the longitude of 7011 east, and in the Kukushkino bog, located at the latitude of 6051 north andthe longitude of 6331 east. Both objects were locatedin the middle taiga subzone of Western Siberia(KhantyMansi Autonomous Area).

    To analyze the communities of testate amoebae, wecollected 33 surface samples from 6 bogs with differingwater regimes and ash levels; all bogs were located inKondinskie Ozera National Park.

    A series of microhabitats was selected on the studied bogs, which included tussocks, intertussock hollows, flat and wet mossy mats, and mire areas. Eachsample represented a surface specimen of sphagnumfrom 5 to 10 cm in depth, which was divided into threeparts to analyze testate amoebae, determine the ashlevel and botanical composition, and measure the pHvalue.

    The index of wetness (IW), calculated according tothe botanical composition of the mossy sample, wasconsidered as the characteristic of the watering level ofhabitats (Elina and Yurkovskaya, 1992). The trophicstatus was determined through the ash level value; todo this, samples were dried and burned at 800according to the standard procedure (State Standard, 1985). The pH of the water extract of a mossysample was measured by a HI8314 pH meter (HannaInstruments, Germany).

    Testate Amoebae Inhabiting Middle Taiga Bogs in Western SiberiaI. V. Kurinaa, Yu. I. Preisa, and A. A. Bobrovb

    a Institute of Monitoring of Climatic and Ecologic Systems, Siberian Branch,Russian Academy of Sciences, Tomsk, 63402 Russia

    b Department of Soil Sciences, Moscow State University, Moscow, 119899 Russia;email: klimirin@submail.com

    Received January 26, 2010

    AbstractThe population of testate amoebae from the most typical middle taiga bogs of Western Siberia havebeen studied. More than one hundred (103) species and intraspecific taxons of testate amoebae have beenrevealed in recent surface samples. The relation between ecological characteristics of habitats and the composition of a Protozoa population has been demonstrated. The ecological preferences of species concerningthe index of wetness, ash level, and acidity have been revealed. Using the correspondence analysis, the ecological optimums and the tolerance of species and intraspecific taxons of testate amoebae have been established.

    DOI: 10.1134/S1062359010040059

    ZOOLOGY

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    Kukushkino bog (samples 111). The bog is locatedin the northern part of the ObIrtysh interfluve. Thesamples were collected in pineshrubsphagnummires (3 samples) and a hummockridge complex(8 samples). These habitats are oligotrophic and havelow acidity (pH 3.54.9) and ash (2.244.38%) levels,and the IW value varies from 4 to 9.

    The northeastern shore of Rangetur Lake (samples 1217). The samples were collected from oligotrophicscheuchzeriasphagnum mire (one sample), mesotrophicgrass sedgebogbeansphagnum mire (one sample),sedgescheuchzeriasphagnumhypnum mire (onesample), and sedgebogbeanbludderwort mire(three samples). All samples had a low pH value (3.44.8); three samples had a low ash value (less than10%), whereas two other samples had a high ash value(up to 37%).

    Yuzhnoe bog (samples 1819). This bog is locatedto the south of Rangetur Lake and represents amesotrophic grassysphagnum mire with a runningwater regime. The samples had a low pH value and alow ash value (4%).

    Polosatoe bog (samples 2029). The central hollowmesotrophiceutrophic part of the aapa complex(8 samples) and the peripheral oligotrophicmesotrophic part (2 samples) represented the mostvarious habitats, in which pH and ash levels variedfrom 3.8 to 6.5 and from 2.48% to 38.22%, respectively. The IW value varied from 2.9 to 9.

    Drying aapa complex with dwarf shrubs and a Sphagnum magellanicum cover (sample 30). The pH valueof the water extract was 5.1.

    Zhuravlinoe bog (samples 3133) represented arunning mesotrophic mire with a sedgegrassysphagnum quagmire. The pH value varied from 4 to 5.1,and the ash level varied from 7.5 to 18.47%.

    In general, the examined samples represented aseries of habitats with a wide range of the wetness gradient (2.99), substrate ash level (2.2438.33%), andpH values (3.56.5).

    To reveal the species diversity and to calculate thenumber of testate amoebae, we prepared a water suspension of fresh tow samples using the standard procedure (Rakhleeva and Korganova, 2005). For eachsample at least 300 shells were determined. We alsodetermined the total density for all shells and for eachspecies separately per 1 g of the ovendry substance.

    The rhizopodium analysis data were treated statistically using the Statistica 6.0 and PAST 1.87 software.Samples with an abnormally high ash level and too lowdensity of testate amoebae (nos. 12, 16, 17, 25, 27, 32,33) were excluded from the analysis.

    RESULTS

    Biodiversity. The analysis of surface sphagnumsamples revealed 103 species, varieties, and forms oftestate amoebae. Each sample contained from 11 to 47

    species and forms of Testacea. The dominant complexincluded 13 species and intraspecific forms: Heleoperapetricola, Hyalosphenia papilio, H. elegans, Nebelatincta, Phryganella hemisphaerica, Assulina muscorum,Euglypha cristata, E. rotunda, Sphenoderia lenta,Trinema complanatum, T. enchelys, T. lineate, andAmphitrema flavum. The following species wererevealed in more than 30% of samples, but their abundance in communities did not exceed 5%: Bullinulariaindica v. minor, Centropyxis aculeate, Euglypha compressa, E. cristata v. decora, E. cuspidate, E. filifera,E. strigosa, Corythion delamarei, C. dubium, andTrinema penardi.

    The maximum species diversity was observed forthe oligo and mesoeutrophic hollows and mires (upto 4647 species and intraspecific forms). The minimum diversity was observed for mesotrophic sphagnum mires with a running water regime and for a monodominant sphagnum microstand of a drying aapacomplex (11 species, varieties, and forms; see Fig. 1).

    The examined samples did not contain any stenotopic species, except for the rare subspecies C. aculeatev. lata Decloitre.

    The density of amoeba populations in the examined samples varied from 7500 to 3 330 400 shells per1 g of the ovendry substrate (Fig. 2). The maximumdensity was registered in samples with both the lowest(sample nos. 19, 30) and the highest (sample no. 27)species diversity.

    A canonical correspondence analysis showed thatthe watering factor, trophic status, and acidity ofbiotopes could explain only 31% of all variations in thestructure of the Testacea community. Only the firstcanonical root was determined as significant (0.976, = 0.012), and it was closely associated with the IWvalue (the correlation coefficient was 0.98). This resultagrees with the conclusions of other authors that thewatering level of the environment is the main factorinfluencing the community of testate amoebae(Bobrov et al., 2002; Booth, 2001, 2002; Lamentowiczand Mitchell, 2005; Blundell and Barber, 2005; Boothand Zygmunt, 2005).

    The dependence of the diversity of Testacea on theacidity and trophic status of their habitats is ratheruncertain. The shell density in the samples did notdepend on the watering level, pH, and trophic status ofthe environment; the correlation coefficients were 0.05, 0.33, and 0.49, respectively ( > 0.05). RegardingpH and ash levels, we observed two groups of Testaceacommunities, one group from highash habitats, andanother group from lowash habitats (Fig. 3). The firstgroup was represented by the samples with unusuallyhigh ash content. In both cases we did not reveal anycorrelation between the composition of Testacea communities and changes in the ash content and pH value.

    Species optimum and tolerance. In the case of optimal environmental conditions, species reach theirmaximum abundance; this fact allowed us to deter

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    TESTATE AMOEBAE INHABITING MIDDLE TAIGA BOGS 359

    mine species optimums for testate amoebae. For species found in fewer than 3 samples, optimal conditionswere not determined. Taking into consideration ecological optimums, Testacea species were classified bytheir relation to the IW value (Table 1) and the ashlevel (Table 2). The following ecological groups wererevealed:

    species preferring a strongly watered oligotrophicacid environment (IW = 9, ash level 2.33.8, pH 3.53.7): Difflugia leidyi, Phryganella hemisphaerica, Euglypha strigosa, Placocista spinosa, Amphitrema flavum,and A. wrightianum;

    species preferring a watered mesotrophic moderateacid environment (IW = 79, ash level 5.56.7,pH 4.55.3): Centropyrix aculeate, Euglypha cristata,E. filifera, Sphenoderia lenta, and Trinema lineare;

    species preferring a xeromorphic oligotrophicacid environment (IW = 34(6), ash level 2.43.9,pH 3.54.2): Arcella catinus, Centropyxis laevigata,Cyclopyxis euristoma, C. euristoma v. parvula, Trigonopyxis arcula, T. minuta, Heleopera petricola,Hyalosphenia elegans, H. papilio, Nebela griseola, N.militaris, Euglypha compressa f. glabra, E. cuspidate, E.rotunda, and E. strigosa f. glabra;

    species preferring a wet mesotrophic acid environment (IW = 4.34.8, ash level 5.36.4, pH 3.84.2): Centropyrix platystoma, Nebela tincta, Euglyphacompressa, Trinema complanatum, T. penardi, andCryptodifflugia compressa;

    species preferring a watered eutrophic subacidenvironment (IW = 6.37.2, ash level 11.736.8, pH4.6): Centropyrix aerophila, C. constricta v. minima,

    Num

    ber

    of s

    peci

    es

    50

    45

    40

    35

    30

    25

    20

    15

    10

    5

    01 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33

    Samples

    3431

    21

    30

    15

    23 22

    15

    24

    1619

    29

    4341

    11

    22

    47

    40

    20

    44

    17

    27

    46

    25

    11

    36

    16

    24 24

    15

    19

    46

    16

    Fig. 1. Number of testate amoeba taxons in the examined samples. Here and in Fig. 2: 111, Kukushkino bog; 1217, northeastern shore of Rangetur Lake; 1819, Yuzhnoe bog; 2029, Polosatoe bog; 30, drying aapa complex; 3133, Zhuravlinoe bog.

    Den

    sity

    , th

    ousa

    nd

    shel

    ls p

    er 1

    g

    350

    300

    250

    200

    150

    100

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    01 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31

    Samples

    of t

    he

    oven

    dry

    sam

    ple

    Fig. 2. Density of testate amoebae in the examined samples.

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    Difflugia 0bacillifera, D. globulosa, D. pulex,Lesquereusia spiralis, Tracheleuglypha dentate, andTrinema enchelys.

    The analysis of the distribution of testate amoebaedepending on different habitat types allowed us toselect five groups of habitats: oligotrophic mossy hummocks and hillocks, oligotrophic mossy covers andinterhummock areas, oligotrophic mossy mires,mesoeutrophic mossy mires, and mesoeutrophicgrassy mires.

    In the group of oligotrophic mossy hummocks, thedominant complex (the abundance exceeded 10%)included Assulina muscorum, Centropyxis laevigata,Cyclopyxis eurystoma, C. eurystoma v. parvula,

    Hyalosphenia papilio, Euglypha rotunda, Nebela militaris, Trigonopyxis arcula, T. minuta, and Trinemacomplanatum. All these species, except for the last two,reached their maximum relative abundance in thisgroup.

    The dominant complex in the group of oligotrophic mossy covers included Hyalosphenia elegans,H. papilio, Amphitrema flavum, Assulina muscorum,Nebela tincta, and Phryganella hemisphaerica. Thefirst two species had the maximum abundance in thisgroup of biotopes (the total relative abundance was3556%). These species were also continually presentin oligotrophic mossy mires, but their total abundancein this case did not exceed 16%.

    The dominant complex of oligotrophic mossymires included Amphytrema flavum, Difflugia leidyi,Nebela griseola, Phryganella hemisphaerica, Heleoperapetricola, and Hyalosphenia elegans.

    It seems that the watering level preferences ofPhryganella hemisphaerica and Placocista spinosainclude both oligotrophic mossy covers and mires,since these species are abundant in both biotopegroups, whereas in other groups their density was verylow.

    The samples from mesoeutrophic mossy miresalways included Euglypha cristata and Hyalospheniapapilio and also many various species from the generaArcella and Centropyxis. The dominants of this groupwere Difflugia globulosa, Euglypha cristata, Sphenoderia lenta, Trinema complanatum, T. enchelys, T. lineare, Euglypha rotunda, Lesquereusia spiralis, Nebelatincta, and Tracheleuglypha dentate.

    pH

    6

    5

    4

    3

    2

    1

    0 10 20 30 40

    Ash level

    AB

    Fig. 3. Ordination of testate amoeba communities regarding the acidity and ash level of their habitats. A, lowashhabitat group; B, highash habitat group.

    Table 1. Ordination of testate amoebae regarding the index of wetness (IW)

    Species IW optimum

    Amphitrema wrightianum, Arcella arenaria, A. discoides v. scutelliformis, A. hemisphaerica, A. intermedia, A. intermedia v. laevis, A. jurassica, Centropyxis aculeata v. minima, C. cassis f. spinifera, C. constricta, Difflugia angulostoma, D. bacillariarum, D. bacillifera, D. leidyi, D. pulex, Difflugiella oviformis f. fusca, Euglypha anodonta, E. ciliata, Phryganella hemisphaerica, Le...

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