Vol. 73, No. 1: 39-46, 2004 ACTA SOCIETATIS BOTANICORUM POLONIAE 39 PEDIASTRUM SPECIES (HYDRODICTYACEAE, SPHAEROPLEALES) IN PHYTOPLANKTON OF SUMIN LAKE (£ÊCZNA-W£ODAWA LAKELAND) AGNIESZKA PASZTALENIEC, MA£GORZATA PONIEWOZIK Department of Botany and Hydrobiology, Catholic University of Lublin C.K. Norwida 4, 20-061 Lublin, Poland e-mail: [email protected] (Received: April 7, 2003. Accepted: July 18, 2003) ABSTRACT During studies of phytoplankton in Sumin Lake (£êczna-W³odawa Lakeland), conducted from May till Sep- tember 2001 and 2002, 15 taxa of the genus Pediastrum (Hydrodictyaceae, Sphaeropleales) were found. Among them there were common species as Pediastrum boryanum, P. duplex, P. tetras and P. simplex, but also rare spe- cies as P. integrum or P. kawraiskyi. An especially interesting species was P. orientale, the taxon that until now has not been noted in phytoplankton of Polish water bodies. The paper gives descriptions of the genus Pediastrum coenobia and physico-chemical conditions of the habitat. The original documentation of Pediastrum taxa is added. KEY WORDS: Pediastrum taxa, Chlorophyta, phytoplankton, £êczna-W³odawa Lakeland. INRTODUCTION rved in palynological preparations (Jankovská and Komá- rek 2000, Komárek and Jankovská 2001; Nielsen and Lakes of £êczna-W³odawa Lakeland are the only group Sørensen 1992). in Poland located beyond the limits of a continental glacier The taxonomical research of the genus Pediastrum was of the last glaciation. The genesis of lakes is still disputa- not conducted in phytoplankton of £êczna-W³odawa Lake- ble, but the most of them have a termo-karst origin (Hara- land lakes. Only some information on occurrence of this simiuk and Wojtanowicz 1998). The lakes are in different genus are included in works of Wojciechowski (1971) and succession stages and are of different trophic character. Malicki (1972). Some data on fossil Pediastrum gives Ba- The £êczna-W³odawa Lakeland has the specific qualitative ³aga (1998). In our work we present information of several differentiation of algae in comparison with others lake- Pediastrum species and varieties. The keys of Komárek lands in Poland. Some rare species as Fragilaria reicheltii and Fott (1983) and Komárek and Jankovská (2001) were (=Centronella rostafiñskii) or Gonatozygon aculeatum var. used for determining of the taxa. groenbladii were found here (Wojciechowski 1983). Ne- vertheless, there have been very few taxonomic researche of phytoplankton species in £êczna-W³odawa lakes. In the STUDY AREA, MATERIAL AND METHODS paper we present the phytoplankton of the shallow, eutro- phic lake Sumin and our special object of interest was Lake Sumin is situated in the central part of the £êczna- genus Pediastrum (Hydrodictyaceae, Sphaeropleales), W³odawa Lakeland (Eastern Poland), in the buffer zone of which appeared there in a great species diversity. These the Polesie National Park (Fig. 1). It is a shallow (max. planktic species are frequent in algal communities of ponds depth 6.5 m, mean depth 2 m), dimictic and eutrophic wa- and lakes. The Pediastrum genus is well known both from ter body (Radwan and Kornijów 1998). This area is taxonomical and ecological points of view; among others 84.5ha. The north waterside of the Sumin Lake is surroun- Sulek (1969), Komárek and Fott (1983), Komárek and Jan- ded by bogs. kovská (2001) presented reviews of the Pediastrum. The The physico-chemical water parameters of Sumin Lake outer layer of Pediastrum cell wall is composed of sporo- were as follows: pH from 8.4 to 8.8; temperature from pollenin combined with silicon oxide which causes its high 12.1 to 23.4°C; oxygenation from 7.7 to 9.2 mg/dm3; resistance to decay. Therefore, several species occur com- conductivity from 376 to 660 µS/cm2, and the SD values monly in the fossil record, and they are frequently obse- during studies were about 0.7-1.0 m. The contents of the 40 PEDIASTRUM SPECIES IN LAKE PHYTOPLANKTON Pasztaleniec A. et al. pleales). In spite of the great biodiversity (11 species and N 15 with all varieties) this genus never dominated in total number of planktic algae. The genus Pediastrum consists of colonial green algae, which occur naturally in freshwater environments, in parti- cular in standing water bodies (Nicholls 1997; Reynolds 1980; Sitkowska 1992). Many species of these algae have been described. Nowadays 24 species are known from this genus, but only four have a really world-wide distribution (P. boryanum, P. duplex, P. tetras and P. simplex), other ta- xa belong to a wide range of various ecologically and geo- graphically different types (Komárek and Jankovská 2001). Among world-wide distributed taxa, several varieties of P. boryanum, P. duplex and P. tetras could be dominant in eu- trophic reservoirs of the temperate zone. P. simplex occurs in the temperate zone in lower frequency in warm seasons. We determined many of cosmopolitan, commonly distributed taxa (f.e. Pediastrum boryanum (Turpin) Me- negh. var. boryanum, P. duplex (Meyen) var. duplex, P. te- Fig. 1. Location of £êczna-W³odawa Lakeland. Scale bars: 10 µm. tras (Ehrenberg)), and also rare species and varieties (f.e. P. kawraiskyi (Schmidle), P. integrum (Nägeli) or P. orien- tale (Skuja) Jankovská et Komárek. 3 The results of our observations are presented below. main nutrients were (in mg/dm ): N-NH4: 0.66-0.8; N-NO3: 0.11-0.24; P-PO4: 0.002-0.03; Ptot: 0.08-0.14; Ntot: 0.52- -2.24. Chlorophyll-a concentration was between 14-37 µg/dm3. Conductivity and acidity of water were measured World-spread, usually common taxa: under field conditions. The other analyses of water were made in a laboratory. Pediastrum boryanum (Turpin) Menegh. var. boryanum Qualitative studies of phytoplankton were carried out in (Fig. 2) the pelagic zone in the years 2001 and 2002. The samples Coenobia (40.0-103.7 µm) circular or irregular in outline. were collected from May till September in one-month inte- Coenobia always without holes, 16-32 cells. Marginal cells rvals, using a plankton net (mesh size 35 µm). The studies (10.0-13.6 × 13.0-27.2 µm) with two lobes ending in two were carried out on living and preserved material (formal- narrow processi. Inner cells: 10.0-14.8 × 9.8-17.8 µm. Inci- dehyde-glycerin solution were used). Observations were sion between processi V-shaped. Cell wall regularly granu- made with a Nikon Eclipse E 200 light microscope equip- lar. Occurred very often in studied samples. ped with an oil-immersion objective, and photos with Ni- According to Komárek and Jankovská (2001) this spe- kon FDX-35. For each found species microphotographs or cies is typical of slightly alkaline, eutrophic, but not pollu- drawings were made. ted waters. Taxonomical descriptions of taxa were determined on the basis of morphological features such as: outline of cells, Pediastrum boryanum (Turpin) Menegh. var. brevicorne A. number of lobes and processi, depth of incisions in margi- Braun (Fig. 3) nal cells, sculpture of cell wall. Cells dimensions given in Coenobia circular with 14-16 cells, without holes. Dia- description concern the relations: width × length. In the ca- meter of coenobium from 59.3 to 61.8 µm. Marginal cells se of marginal cells the length of a cell includes length of with two very short processes. Dimensions of marginal and lobes and processi. All observations were made using light inner cells: 10.0-14.8 × 12.3-16.0 µm. Cell wall granular. microscopy under immersion (with focus level ×2000). Incision shallow, in shape of U. Recently known as termophilic, occurring in tropical co- untries up to warmer regions of temperate zone (Komárek RESULTS AND DISCUSSION and Jankovská 2001). During the studied period the phytoplankton of Sumin Pediastrum boryanum (Turpin) Menegh. var. longicorne Lake was dominated by Chlorophyta (about 70% share in Reinsch (Fig. 4) the total numbers of phytoplankton) and Cyanoprokaryota Coenobia without holes, 32 celled 39.5-170 µm in dia- algae (30% of phytoplankton abundance). None of the spe- meter. Dimensions: marginal cells with two long processes cies reached a strong quantitative predominance, but the slightly curved, 6.2-12.3 µm wide, 10.0-15.0 µm long. In- most frequent among Chlorophyta were: Tetraëdron mini- ner cells: 7.4-34 × 4.9-22.5 µm. Cell walls scarcely granu- mum, Scenedesmus spp., Coelastrum sphaericum, Oocystis lar. Incision shallow. lacustris; among species belonging to Cyanoprokaryota: Species ecologically restricted (peaty waters) known Aphanothece clathrata, Chroococcus limneticus, Microcy- from all climatic zones (Komárek and Jankovská 2001). stis aeruginosa and Lyngbya sp. Green-algae had not only Based on cell wall sculpture variety longicorne stands out a high percentage share, but were also characterized by by having the most constant set of characters and is the a high biodiversity. A special species richness was obse- most easily recognized variety of P. boryanum (Nielsen rved in the genus Pediastrum (Hydrodictyaceae, Sphaero- 2000). Vol. 73, No. 1: 39-46, 2004 ACTA SOCIETATIS BOTANICORUM POLONIAE 41 2 3 4 5 6 7 Fig. 2. Pediastrum boryanum (Turpin) Menegh. var. boryanum. Scale bars: 10 µm. Focus level 800×. Fig. 3. Pediastrum boryanum (Turpin) Menegh. var. brevicorne A. Braun. Scale bars: 10 µm. Fig. 4. Pediastrum boryanum (Turpin) Menegh. var. longicorne Reinsch. Scale bars: 10 µm. Focus level 800×. Fig. 5. Pediastrum duplex (Meyen) var. duplex. Scale bars: 10 µm. Focus level 1200×. Fig. 6. Pediastrum duplex (Meyen) var. gracillimum. Scale bars: 10 µm. Fig. 7. Pediastrum tetras (Ehrenberg). Scale bars: 10 µm. Pediastrum duplex (Meyen) var. duplex (Fig. 5) Typical of water bodies in temperate zone, probably with Coenobia circular, 44.5-222.2 µm in diameter (the most naturally increasing trophic level (Komárek and Jankovská of individuals found had more then 100 µm) with regularly 2001).