Biologia 63/6: 901—906, 2008 Section Botany DOI: 10.2478/s11756-008-0140-x Diversity of desmids in three Thai peat swamps* Neti Ngearnpat1, Peter F.M. Coesel2 &YuwadeePeerapornpisal1 1Department of Biology, Faculty of Science, Chiang Mai University,Chiang Mai 50200, Thailand; e-mail: [email protected], [email protected] 2Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, Kruislaan 318,NL-1098 SM Amsterdam, The Netherlands; e-mail: [email protected] Abstract: Three peat swamps situated in the southern part of Thailand were investigated for their desmid flora in relation to a number of physical and chemical habitat parameters. Altogether, 99 species were encountered belonging to 22 genera. 30 species are new records for the Thai desmid flora. Laempagarung peat swamp showed the highest diversity (45 species), followed by Maikhao peat swamp (32 species) and Jud peat swamp (25 species). Despite its relatively low species richness, Jud swamp appeared to house a number of rare taxa, e.g., Micrasterias subdenticulata var. ornata, M. suboblonga var. tecta and M. tetraptera var. siamensis which can be considered Indo-Malaysian endemics. Differences in composition of the desmid flora between the three peat swamps are discussed in relation to environmental conditions. Key words: desmids; ecology; peat swamps; Indo-Malaysian region; Thailand Introduction The desmid flora of Thailand has been investigated by foreign scientists for over a hundred years. The first records of desmids were published by West & West (1901). After that there were reports by Hirano (1967, 1975, 1992), Yamagishi & Kanetsuna (1987), Coesel (2000) and Kanetsuna (2002). The checklist of algae in Thailand (Wongrat 1995) mentions 296 desmid species plus varieties, belonging to 22 different genera. How- ever, when compared with many other tropical coun- tries, the Thai desmid flora is less well documented in terms of diversity, distribution patterns and related eco- logical data. From 2005 on, the first author aims to fill this scientific gap by investigating as many potential desmid sites as possible, distributed all over the Thai country. The present paper reports the results from some three peat swamps, a habitat that is very rare in Thailand. Material and methods Study sites The peat swamps in question are situated in the south- ◦ ◦ Fig. 1. Map showing location of the three peat swamps investi- ern part of Thailand, between 18 47 and 19 52 North and gated. 98◦59 to 99◦50 East (Fig. 1). The climate in this region is tropical, with well demarcated rainy and dry seasons. Nor- mally, the dry season is from November to April and the Laempagarung peat swamp (LP) rainy season from May to October. Samples were collected Located in the province of Phung-Nga, 9 m above sea level. in the year 2006. The samples were taken from a pool which was 1–2 m in * Presented at the International Symposium Biology and Taxonomy of Green Algae V, Smolenice, June 26–29, 2007, Slovakia. c 2008 Institute of Botany, Slovak Academy of Sciences 902 N. Ngearnpat et al. Table 1. Physical and chemical features and trophic status of the 5.6–6.1). Conductivity values in Laempagarung and three swamps investigated. LP – Laempagarung peat swamp; MP Maikhao swamps were slightly above 300 µScm−1, but – Maikhao peat swamp; JP – Jud peat swamp. distinctly lower in Jud swamp (81 µScm−1). Laempa- Sampling site LP MP JP garung swamp appeared to be lowest in nitrate concen- tration but highest in ammonium concentration. Temperature ( ◦C) 29.1 32.2 28.8 Concentration of soluble reactive phosphorus in pH 5.9 5.6 6.1 Jud swamp was about ten times higher than in Laempa- Conductivity (µScm−1) 315 327 81 DO (mg L−1)84.24garung and Maikhao swamps. The trophic status of all −1 Total Alkalinity (mg CaCO3 L ) 11 11.5 19 three swamps was determined to be oligo-mesotrophic, − −1 NO3 (mg L ) 0.06 2.4 1.8 in combination with a moderate water quality. + −1 NH4 (mg L ) 0.13 0.04 0.04 A total of 99 species and nine additional vari- + −1 PO4 (mg L ) 0.09 0.07 0.85 eties were found (Table 2). They belong to 22 genera, i.e., Actinotaenium (2 species), Bambusina (1 species), Trophic status meso meso meso Closterium (14 species, 3 varieties), Cosmarium (24 species, 1 variety), Cylindrocystis (1 species, 1 vari- ety), Desmidium (5 species), Euastrum (11 species), depth. Most of the bottom was beset with Hydrilla verticil- Gonatozygon (1 species),Hyalotheca(2 species),Mi- lata and Utricularia sp.. crasterias (8 species), Netrium (1 species, 2 vari- eties),Penium(2 species), Pleurotaenium (6 species, Maikhao peat swamp (MP) Located in the province of Phaket, near the village of 1variety), Phymatodocis (1 species), Spondylosium (1 Maikhao, 5 m above sea level. The samples were taken species), Staurastrum (12 species, 1 variety),Stau- from a small pool covered with Salvinia spec., Pistia sp. rodesmus (1 species),Teilingia(1 species), Tetmemorus and Utricularia sp. (1 species), Triploceras (1 species) and Xanthidium (2 species). The distribution of the taxa over the three Jud peat swamp (JP) peat swamps is listed in Table 2. Located in the province of Trung, 15 m above sea level. The Of the three swamps investigated, Laempagarung, swamp, surrounded by agricultural areas, is subjected to various human activities. The samples were collected from with 13 genera, 45 species and 2 additional varieties, ap- a small drainage-canal with mats of filamentous algae and peared to house the most diverse desmid flora. The sec- Utricularia sp. along the banks. ond richest was Maikhao swamp (11 genera, 32 species and 2 additional varieties) whereas the lowest diversity Sampling and analytical methods was found in Jud swamp (11 genera, 28 species and two Water samples were collected in polyethylene bottles and additional varieties). kept in a cool box (5–7 ◦C). Planktonic desmids were col- µ lected by filtering 20 liters of water through 10 mmeshsize Discussion plankton net. Periphytic desmids were collected by suck- ing 12 mL of water by a cylindrical syringe set from the surface of any bottom sediment or submerged plant. This The total number of 99 species collected from the peat procedure was repeated at 5 different locations on each sam- swamps investigated is not particularly high when com- pling site. Subsequently, the 5 samples were put together as pared with species numbers found in European peat a 60 mL mixed sample (Watanabe & al. 2000). The algal lands (e.g. Coesel 1981). Likely, this may be related to samples were preserved with Lugol’s iodine solution. The the relatively poor development (in size and internal desmid species were identified at a magnification of 400× × differentiation) of the three Thai peat swamps under and 1000 . Drawings were made with the help of a drawing discussion. tube (camera lucida). Water temperature, conductivity, pH and dissolved When comparing the species composition of Laem- oxygen (DO) were measured in the field using portable pagarung, Maikhao and Jud swamps, it is striking meters. Alkalinity, ammonium nitrogen, nitrate nitrogen that they have not a single species in common. Only and soluble reactive phosphorus (SRP) were determined in four species, i.e. Bambusina borreri, Cosmarium con- the laboratory by phenolphthalein methyl orange indicator natum, Micrasterias foliacea and Pleurotaenium tra- method, nesslerization method, cadmium reduction method becula) were encountered in two of the three swamps, and ascorbic method (APHA, AWWA, WPCF, 1998), re- all the other ones were found in but one of the three spectively. swamps (Table 2). Assuming that the swamps have The trophic status of the water was classified according been sampled in an adequate way, it might indi- to the methods of Wetzel (2001) and Lorraine & Vollenwei- der (1981). The parameters DO, conductivity and the con- cate that the ecological conditions in the swamps are − + 3− centrations of NO3 ,NH4 and PO4 were used to calculate different. the water quality index according to the modified method Laempagarung swamp is characterized by a (rel- of Peerapornpisal et al. (2004). atively) large number of Cosmarium and Staurastrum species (Fig. 2). This might be attributed to the nature Results of the water body sampled, i.e., a relatively deep, large pool in which planktic species are to be expected. Many Results of the chemical analyses are given in Table 1. of the Cosmarium and Staurastrum species encountered Water at all sampling sites was slightly acidic (pH in this pool are adapted to a planktic way of life, either Desmids of Thai peat swamps 903 Table 2. Desmid taxa encountered in the three swamps investigated. LP – Laempagarung peat swamp; MP – Maikhao peat swamp; JP – Jud peat swamp. The symbol (*) indicates a new record for Thailand. Mesotaeniaceae Cylindrocystis brebissonii (Ralfs) De Bary var. brebissonii JP C. brebissonii var. minor W. et G.S.West * JP Netrium digitus (Bréb.) Itzigs. & Rothe var. digitus MP N. digitus var. lamellosum (Bréb.) Gr¨onblad * MP N. digitus var. parvum (Borge) Willi Krieg.* MP Desmidiaceae Actinotaenium adelochondrum (Elfving) Teiling forma * MP A. curtum (Bréb.) Teiling MP A. turgidum (Bréb.) Teiling var. ovatum (Nordst.) Teiling MP Bambusina borreri (Ralfs) Cleve MP, JP Closterium cf. angustatum Ralfs MP C. baillyanum Bréb. * MP C. cf. calosporum Wittr. MP C. cynthia De Not. MP C. dianae Ralfs var. dianae JP C. dianae var. arcutum (Bréb.) Rabenh. MP C. dianae var. compressum G.A.Klebs * JP C. didymotocum Ralfs * JP C. directum W.Archer * MP C. gracile Ralfs var. gracile JP C. gracile var. striolatum Willi Krieg. * JP C. jenneri Ralfs MP C. leibleinii Ralfs var. minimum Schmidle * JP C. lineatum Ralfs JP C. navicula (Bréb.) L¨utkem. * M C. nematodes Joshua MP C. striolatum Rafts * JP Cosmarium angulosum Bréb.