CZECH POLAR REPORTS 3 (1): 7-18, 2013 Biodiversity and ecological classification of cryptogamic soil crusts in the vicinity of Petunia Bay, Svalbard Ekaterina Pushkareva1, Josef Elster1,2 1University of South Bohemia, České Budějovice, Czech Republic 2Institute of Botany, Academy of Sciences of the Czech Republic, Třeboň, Czech Republic Abstract The objective of this study was to describe various types of Arctic soil crust that were collected in the vicinity of Petunia Bay, Svalbard in the 2012 summer season. The photosynthetically active area of different soil crust samples was estimated by a chlorophyll fluorescence imaging camera. Biodiversity of cyanobacteria and microalgae from the collected soil crusts was analyzed using a stereomicroscopy and light microscopy. In most cases, cryptogamic crusts were dominated by cyanobacteria such as Gloeocapsa sp., Nostoc sp., Microcoleus sp., Scytonema sp., and Chroococcus sp. The dominant green microalgae were Coccomyxa sp., Hormotila sp., and Trebouxia sp. which commonly occurred in a lichenised soil crust. Soil crusts that were located in conditions with high water content were dominated by Nostoc sp. Cryptogamic soil crusts from the studied area can be divided into three different types and classified: (1) black-brown soil crusts (with low diversity of cyanobacteria and microalgae), (2) brown soil crusts (with high diversity of cyanobacteria and microalgae) and (3) grey- brown soil crusts (with low diversity of cyanobacteria and algae). The occurrence of similar soil crust types were compared at different altitudes. Altitude does not affect the biodiversity of cyanobacteria and microalgae. However, cyanobacteria and microalgae abundance increases with altitude. Key words: soil crust, microalgae, cyanobacteria, photosynthetic area, variable chlorophyll fluorescence, diversity. DOI: 10.5817/CPR2013-1-3 Introduction In polar deserts, soil cyanobacteria and water-stable, surface soil aggregates held microalgae can form distinct visible biotic together by cyanobacteria, microalgae, crust layers on the ground surface which fungi, lichens and mosses. These layers are called cryptogamic crusts (Broady protect the soil from wind and water 1996, Elster et al. 1999). They consist of erosion (Leys et Eldrige 1998), and ——— Received November 20, 2012, accepted March 31, 2013 *Corresponding author: Katya Pushkareva <[email protected]> Acknowledgements: The work was supported by the Grant Agency of the Ministry of Education of the Czech Republic (LM – 2010009 CzechPolar, CZ.1.07/2.3.00/20.0064). We are very grateful to Mrs. Jana Šnokhousová for her technical assistance and Dr. Jana Kvíderová who introduced us to fluorescence imaging camera measurements. Prof. Jiří Komárek helped us with cyanobacteria and algae identification. We also appreciate the help given by Keith Edwards for language revision. 7 E. PUSHKAREVA et J. ELSTER contribute to plant growth (Belnap et higher photosynthetic activity, because of Lange 2001). In cold regions, the higher high pigment content (Housman et al. species diversity of biological crusts 2006). positively effects structural diversity of Crusts are formed by living organisms vascular vegetation. Soil crusts accumulate and their by-products, creating a surface organic carbon and nutrients which are crust of soil particles bound together by used by plants for their growth. organic material. Surface crust thickness These communities influence key can reach up to 10 cm (Belnap et Lange ecosystem processes and their character- 2003). The general appearance of the istics such as water infiltration, moisture crusts in terms of color, surface topo- holding capacity, organic matter content, graphy, and surficial cover varies. CO2 fluxes, and nitrogen fixation and Biological soil crusts have considerable transformations (Bond et Harris 1964). photosynthetic potential (Evans et Therefore, biological soil crusts are impor- Johansen 1999). Water content and tem- tant in maintaining ecosystem structure perature can influence their photosynthetic and functioning in dry lands. However, activity (Yoshitake et al. 2010). Cyano- biological soil crusts have only recently bacteria, together with some green algae, been recognized as having a major in- are the most conspicuous elements of fluence on terrestrial ecosystems (Belnap cryptogamic crusts (Elster et al. 1999). et Lange 2001). Nostoc sp. is widely found in all types of Composition of biological soil crusts is soil crusts and usually located on the very diverse. In many arid and semi-arid surface (Belnap et Lange 2001). In most communities, there are often many more cases, cryptogamic crusts are also species associated with the biological soil dominated by filamentous cyanobacteria. crust at a given site than there are vascular Microcoleus sp., Phormidium sp., Plec- plants (Ponzetti et al. 1998). As harsh tonema sp., Schizothrix sp., Tolypothrix sp. environmental conditions limit vascular and Scytonema sp. are the most common plant cover, a greater cover of crusts genera found in both hot and cold deserts probably occurs at lower elevations in worldwide (Johansen 1993). They par- spite of, but not because of, these con- ticularly have been shown to be important ditions (Belnap et al. 2001). in binding surface soil particles (Anantani Soil cyanobacteria and microalgae play et Marathe 1974). Cyanobacteria and a major role in the initiation of crust microalgae appear to play important roles development and the early stages of its in the northern and southern polar growth. Algal components of cryptogamic ecosystems, including the nitrogen econo- crusts are found in the upper few my of certain environments (Dickson centimeters of soil. The low biomass of 2000). cyanobacteria and microalgae is associated The objective of this study was to de- with a colourless soil surface. On the con- scribe different types of Arctic soil crusts trary, with higher cyanobacteria and that were collected in the Petunia Bay, microalgal biomass, the soil surface is central Svalbard using various methods. usually covered by variously coloured We hypothesized that there would be crust patches, including lichenised communities type- and altitude-dependent differences in and mosses (Lange et al. 1992, Zaady et their biodiversity and photosynthetic ca- al. 2000). Such types of crusts have a pacity. 8 BIODIVERSITY OF SOIL CRUST Material and Methods Crust samples were collected during The diversity of cyanobacteria and August 2012 in various sites across the microalgae from collected soil crusts was vicinity of the Petunia Bay (78°40'60" N, studied using an Olympus SZX-ZB7 16°33'0" E), the northwestern branch of stereomicroscope and Olympus BX-51 Billefjorden, Dickson Land, Svalbard. light microscope (Olympus C&S, Japan). Each site contained different types of soil By using the stereomicroscope, various crust that were selected by ocular parts of each soil crust were chosen for observation using visible features of the measuring of several parameters, including crusts. Three soil subsamples were taken morphological characteristics of the soil, in each site by a corer (diameter of 5 cm) photosynthetic area, the presence of with a depth of 2-3 cm. lichens, and Nostoc colonies on the crust The same types of soil crust were taken surface. from various altitudes and compared. Soil Using light microscopy, the diversity of crusts from four different areas were cyanobacteria and microalgae was ob- studied: 350, 500, 700, and 800 m a.s.l. served in the chosen parts of the soil The photosynthetic area of different crusts. Dominant species were identified samples was estimated using 2D epifluo- by morphological characteristics such as rescence images of the visible crust using colony or cell habitats, size, colour, shape a FluorCam 700MF fluorescence imaging of colonies and cells, presence of akinetes, camera (Photon Systems Instruments, heterocysts and sheath (Komárek et Czech Republic). Circles of soil crusts Anagnostidis 1999, Komárek et Anagnos- were put into the dark adaptation compart- tidis 2005, Ettl et Gartner 1995). Micro- ment of the device to allow photosynthetic photographs of samples were taken using organisms, their reaction centers of photo- an Olympus DP71 digital camera (Olym- system II (RCs PS II), to open. Then, pus C&S, Japan) and processed using the using the measurements of single Kautsky Quick Photo Camera 2.3 software (Pro- kinetics, images of the photosynthetic area micra, Czech Republic). were obtained. Results and Discussion a b Fig. 1. Dark (a) and light (b) types of soil crust. 9 E. PUSHKAREVA et J. ELSTER Based on data from the literature amount of these organisms usually have a (Dunne 1989), our study has confirmed light colour (Fig. 1b). Crusts generally that the dark colour of soil crusts is due to cover all soil spaces which are not oc- the density of the organisms and their dark cupied by vascular plants. They may colour: cyanobacteria, lichens, and mosses account for 70% or more of the ground (Fig. 1a). Soil crusts that contain a low cover (Belnap et Lange 2003). Chlorophyll fluorescence analysis The study of the fluorescent area such as the light blue (marked on a Fig. 2 showed the parts of soil crust that by green circles). It can be considered that contained photosynthetic organisms (Fig higher absolute values of chlorophyll fluo- 2). The higher intensity of colour (i.e. Chl. rescence come from lichens and mosses fluorescence signal) shows higher concen- rather than from free-living microalgae tration of photosynthetic pigments.