Fluctuations in Rotifera Fauna of Keban Dam Lake-Ova Region (Elazıg-Turkey) During Spring

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1 Turkish Journal of Science & Technology Volume 5, No 2, 53-58, 2010 Fluctuations in Rotifera Fauna of Keban Dam Lake-Ova Region (Elazıg-Turkey) During Spring Serap SALER Fırat University Faculty of Fisheries, Elazığ /Turkey (Received: ; Accepted: ) Abstract Fluctuations in rotifer fauna of Keban Dam Lake-Ova Region (Turkey) in spring were investigated at weekly intervals from March to May Totally 19 rotifer species were identified during whole spring period, but only a few of them appeared at significant densities. Keratella cochlearis was the dominant species with respect to individual number and frequency of occurrence. A maximum density of 4829 ind. m -3 rotifer was observed at the middle of May. Statistically a significant positive correlation between rotifer abundance and water temperature was recorded. Keywords: Abundance, Fluctuations, Keban Dam Lake, Rotifera. Keban Baraj Gölü-Ova Bölgesi (Elazığ-Türkiye) Rotifera Faunasının İlkbahardaki Değişimi Özet Keban Baraj Gölü-Ova bölgesi Rotifer faunasının ilkbahardaki değişimi Mart ile Mayıs 2006 arasında haftalık aralıklarla incelenmiştir. Tüm ilkbahar boyunca toplam olarak 19 rotifer türü teşhis edilmiş, fakat sadece bazı türler önemli yoğunluklarda ortaya çıkmışlardır. Keratella cochlearis birey sayısı ve ortaya çıkış sıklığı bakımından baskın tür olmuştur. Maksimum rotifer yoğunluğu 4829 birey m -3 ile Mayıs ortasında gözlenmiştir. İstatistiksel olarak rotifer bolluğu ve su sıcaklığı arasında önemli pozitif bir ilişki kaydedilmiştir. Anahtar Kelimeler: Bolluk, Değişim, Keban Baraj Gölü, Rotifera. 1. Introduction Rotifers are important components of planktonic communities. In spring, because of their rapid heterogonetic reproduction, they are the first metazooplankters to cause an impact by grazing on the phytoplankton. Furthermore, rotifers influence various interactions within the microbial food-web which occur at several trophic levels [1]. While many studies in Turkey have dealt with rotifers in lentic systems [2-11] considerably fewer have provided data about them in lotic environments [12-16]. The aim of this paper was to determine fluctuations in Rotifera fauna of Keban Dam Lake Ova Region during spring and hence contribute to the knowledge of Rotifera fauna of East Anatolia. 2. Materials and Methods Keban Dam Lake was built on Euphrates River in the eastern part of Turkey and is the second largest artificial lake in Turkey. It is 845 m above sea level and has a surface area of 675 km 2 at maximum level. Its maximum depth is 160 m and its catchment basin is km 2. Ova Region is located in east part of Keban Dam Lake and dense fishing activities were recorded in this Region of the dam lake (Figure 1) [17].

2 Serap Saler Figure 1. Keban Dam Lake-Ova Region and sampling stations Rotifera was sampled weekly at four stations between March and May Samples were collected with a plankton net (55u pore sized Hydro-Bios Kiel). Specimens were preserved in 4% formaldehyde solution in 100 ml plastic bottles. After providing to make plankton samples in the laboratory homogenous, 1 ml quantity was taken and put in the counting container and all of the samples were counted under microscope. This process was repeated for 10 times totally and the average number of individual 1 ml was determined. In addition, live rotifers were examined to obtain qualitative information about the soft-bodied species which are difficult to identify and easily overlooked in preserved samples. In some cases, reliable species identification requires examination of trophy, after the animals were macerated in 5% NaOH. Quantitative analysis and evaluation were carried out based Koste [18] Edmondson [19] and Telesh [20].The taxonomical investigations of samples were performed according to the key given by Koste [18], Edmondson [19] and Kolisko [21]. In addition, from the research platform, ph (Lamotte ph 5-WC), dissolved oxygen (mg L -1) 54 and water temperature ( o C) (Oxi 315i/SET) were determined using a transportable meter. Correlation analysis was computed using SPSS 12.0 for the following parameters; rotifer abundance with temperature, ph and dissolved oxygen at a level [22]. 3. Results and Discussion A total of 19 rotifer species is recorded from Keban Dam Lake Ova Region between March and May The most numerous rotifer species were representatives (six species) of the family Brachionidae. Two species of Keratella were encountered during this survey and form an important component of rotifer population of this Region. Keratella cochleraris was one of the dominant rotifer found in great numbers. Other very common species were included P. vulgaris and A. priodonta. While examining the weekly distributions of samples collected from Keban Dam Lake Ova Region, the most rotifers species were found in the end of March (13 taxa) and the least were found in the middle of May (3 taxa) (Table 1).

3 Fluctuations in Rotifera Fauna of Keban Dam Lake-Ova Region (Elazıg-Turkey) During Spring Table 1. Changes in rotifer abundance (ind.m -3 ) in Keban Dam Lake Ova Region between March and May 2006 March April May Rotifer taxon Brachionus urceolaris (Müller, 1773) Brachionus calyciflorus (Pallas, 1776) Keratella cochlearis (Gosse, 1851) Keratella quadrata (O. F. M., 1786) Notholca squamula (O. F. M., 1786) Kellicottia longispina (Kellicott,1879) Trichotria tetractis (Ehrenberg, 1830) Colurella uncinata (O. F. M., 1773) Lepadella ovalis (Müller, 1786) Lecane luna (Müller, 1776) Lecane lunaris (Ehrenberg, 1832) Lecane pyriformis Daday, 1905 Cephalodella gibba (Ehrenberg, 1838) Cephalodella forficula (Ehrenberg, 1838) Synchaeta pectinata Ehrenberg, 1832 Polyathra vulgaris Carlin, 1943 Asplanchna priodonta Gosse, 1850 Filinia longiseta Ehrenberg, 1834 Filinia terminalis (Plate, 1886) % From beginning of March to the second week of April water temperature showed increases from 7 to 17 o C, rising 20 o C in the end of May. ph values were changed between The highest ph value was recorded in end of May. In the beginning of March, dissolved oxygen was recorded in its highest value as 10.3 mg L -1 (Table 2). 55 During March the rotifer density was reached below 2375 ind.m -3. In the beginning of April rotifer individual numbers had reached 2388 ind.m -3. In the middle of the same month an increase was occurred. A maximum density of 4829 ind.m -3 was reached in the middle of May, followed by a decrease to 4744 ind.m -3 at the end of the month (Table 1).

4 Serap Saler Table 2. Changes in water temperature ( o C), ph and dissolved oxygen (mg L -1 ) in Keban Dam Lake Ova Region between March and May 2006 Sampling Temperature Dissolved oxygen periods ph C (mg L -1 ) Mar ,1 10,3 Mar ,2 10 Mar ,3 7,6 Mar ,4 8,9 Apr ,5 9,6 Apr ,6 8,9 Apr ,5 8,6 Apr ,4 9,2 May ,5 8,9 May ,9 7,6 May ,6 7,3 May ,9 7,1 In early March Brachionus urceolaris, Keratella cochlearis and Lecane lunaris were the dominant species but the abundance of each taxon remained below 2229 ind.m -3. B. urceolaris, K. cochlearis, K. quadarata and A. priodonta were the most common rotifers in early April. At the beginning of May K. longispina reached its peak abundance with ind m -3. In mid-may K. cochlearis attained a peak of 6050 ind. m -3 and T. tetractis showed its maximum abundance of 5732 ind.m -3. The slight decrease in total rotifer abundance observed towards the end of May (Table 1). According to the frequency of occurrence Keratella cochlearis which occurred during in all sampling period reached its maximum in the end of May 7165 ind. m -3. Its lowest individual number was recorded in the beginning of March 2070 ind.m -3. P. vulgaris, the second dominant species, as frequency of occurrence, was observed 10 sampling during the study period and showed its peak in the beginning of May with 4617 ind.m -3, and the lowest was recorded in the beginning of March with 1273 ind.m -3. A. priodonta was the third dominant species among of all. It was observed 8 sampling and reached its maximum in the end of April with 5095 ind.m -3. K. longispina has been found in 4 samples, but this species has got the highest individual numbers with ind. m -3. The population structure of K. longispina is usually unimodal, in most lakes the peaks occurred in spring. The timing of the population peak appears to depend upon the size of overwintering population. 56 Maximum egg production occurres in spring [21]. A significant positive correlation between rotifer abundance and water temperature was observed (r s = α = 0.01). Rotifer abundance and ph showed a direct relationship (r s = α = 0.01), an inverse relationship between rotifer abundance and dissolved oxygen (r s = α = 0.05) were recorded. Rotifer communities in freshwater are often dominated numerically by members of the genera Keratella and Brachionus. Keratella founds throughout the world in freshwaters and successful in brackish and marine habitats as well [20-23]. In eutrophic lakes, permanent dominant rotifer species have been reported as Brachionus and Keratella [24]. K. cochlearis was dominant in Keban Dam Lake Ova Region almost in all sampling periods. Kellicottia longispina one of the member of family Brachionidae was found to be the most important species as relative abundance (10.4 %). Various researches have used the rotifer species as indicator organisms in determining the water quality of fresh-water ecosystems. Saksena [25], regards the Brachionus type as an indicator of eutrophication, whereas Baker [26], stated that Keratella quadrata and Keratella cochlearis existed abundantly in eutrophic lakes. These rotifer species were dominant in Ova Region in all sampling period. According to Kolisko [21], the predominant representatives of mesotrophic lake in temperate climatic Regions are Keratella cochlearis,

5 Fluctuations in Rotifera Fauna of Keban Dam Lake-Ova Region (Elazıg-Turkey) During Spring Polyarthra vulgaris and Asplancna priodonta.these three species were the most important species of the survey area (Table 1). When the species numbers according to the families are taken into consideration, it appears that Brachionidae (6 species) is the richest. Members of this family are commonly found in the plankton of lakes and ponds are able to adapt to various physical and chemical environments [21]. The nature of Ova Region and abundance of these species support the above conclusion. The fluctuations in rotifer relative abundance were directly related with temperature variations. It has been demonstrated that abundance of rotifers closely follows temperature variations. Temperature has a major influence on their reproductive rate, feeding, movement and longevity [21-27]. At the beginning of March low water temperature was presumably the main factor limiting the growth of rotifer populations. Throughout April and May, the individual numbers of rotifers were increased due to water temperature in Ova Region. Temperature does not exert a single simple influence on rotifers. Growth functions such as embryonic development or somatic growth and other physiological functions are temperature 4. References 1. Arndt, H. (1993). Rotifers as Predators on Components of the Microbial Web (bacteria, heterotrophic flagellates, ciliates) a review. Hydrobiologia, 255/256, Ustaoğlu, M. R. (1986). Zooplankton of the Karagöl (Yamanlar-İzmir). Biologia Gallo- Hellenica, 20 (1), Tellioğlu, A., Şen, D. (2002). Hazar Gölü (Elazığ) Rotifer Faunasının Taksonomik Yönden İncelenmesi. Ege Üniversitesi Su Ürünleri Dergisi, 19, 1-2, Saler (Emiroğlu), S., Şen, D. (2000). Cip Baraj Gölü (Elazığ) Rotifera Faunasının Taksonomik Yönden İncelenmesi. Fırat Üniversitesi Fen ve Mühendislik Bilimleri Dergisi, 12 (1), Saler (Emiroğlu) S. (2001). Keban Baraj Gölü Gülüşkür Koyu Kesimi nin Rotifera Faunası ve Mevsimsel Değişimleri, Fırat Üniv. Fen Bilimleri Enstitüsü, Doktora Tezi, 113s. dependent. Rotifer species have a preferred temperature range is well established [28]. The data presented here reveal that rotifer densities show a direct correlation with temperature (r s = α = 0.01). Less rotifer abundance was recorded during March between 7-14 o C in Ova Region. It is clear that species abundance of Rotifera increased gradually from the beginning of March to the end of May. Rotifer individual numbers were reached their maximum in the middle (4829 ind.m -3 ) and at the end of May (4744 ind.m -3 ) when temperatures were changed between o C. This diversity patterns greatly depend on the water temperature. In summary, results of this study indicated that rotifers were significant component of zooplanktonic community of Ova Region. The ecological features of the species show that most of the rotifer species are cosmopolitan and it is possible for them to exist in all freshwater systems. Continuous studies of the plankton communities should become an inalienable feature in the management of Keban Dam Lake, due to ability both phytoplankton and zooplankton assemblages to rearrange their relative composition and growth in reply changing conditions. 6. Saler,(Emiroğlu), S., Şen, D. (2002). A Taxonomical Study on the Rotifers Fauna of Tadım Pond (Elazığ). Ege Üniversitesi Su Ürünleri Dergisi, 19, Saler, S. (2004). Observations on the Seasonal Variation of Rotifera Fauna of Keban Dam Lake (Çemişgezek Region., Fırat Üniv. Fen ve Mühendislik Bilimleri Dergisi, 16 (4), Bekleyen, A. (2001). Taxonomical Study on the Rotifera Fauna of Devegeçidi Dam Lake (Diyarbakır-Turkey). Turk J. Zool., 25, Bekleyen, A. (2003). Taxonomical Study on the Zooplankton of Göksu Dam Lake (Diyarbakır). Turk J. Zool., 27, Yalım, F. B. (2006). Rotifera Fauna of Yamansız Lake (Antalya) in South West of Turkey. E. U. J. of Fisheries and Aquatic Sciences, 23 (3-4), Kaya, M., Altındağ, A. (2007). Zooplankton Fauna and Seasonal Changes of Gelingülü Dam Lake, (Yozgat, Turkey). Turk J. Zool., 31,

6 Serap Saler 12. İpek, N., Saler, S., (2008). Seli Çayı (Elazığ- Türkiye) Rotifer Faunası ve Bazı Biyoçeşitlilik İndeksleri İşle Analizi. Ege Üniversitesi Su Ürünleri Dergisi, 25 (3), Göksu, M.Z., Çevik, F., Bozkurt, A., Sarıhan, E. (1997). Rotifera and Cladocera Fauna of Seyhan River (within the border of Adana city center). Tr. J. Zool., 21: Saler (Emiroğlu), S., Şen, B., Şen, D. (2000). Fırat Nehri Kömürhan Bölgesi Rotiferleri ve Mevsimsel Değişimleri. Su Ürünleri Sempozyumu, Sinop, Saler, S., Şen, B. (2001). Elazığ Hazar Gölü ne Dökülen Zıkkım Deresi Rotiferleri ve Mevsimsel Değişimleri. XI. Ulusal Su Ürünleri Sempozyumu, Hatay, 1: Bozkurt, A., Göksu, M. Z. L., Sarıhan, E., Taşdemir, M. (2002). Asi Nehri (Hatay, Türkiye) Rotifer Faunası. E. U. Journal of Fisheries and Aquatic Sciences, 19 (1-2), DSİ (Devlet Su İşleri), (1994). Keban Baraj Gölü Limnolojik Raporu, DSİ IX. Bölge Müdürlüğü. 18. Koste, W. (1978). Die Radertiere Mitteleuropas I. Textband, Berlin. 19. Edmondson, W. T. (1959). Fresh Water Biology, Second Edition, University of Washington, Seattle. 20. Telesh I. V. (1986). Comparative Effectiveness of Methods of Counting Planktonic Rotifers, Scripta Technica, Kolisko, R. M. (1974). Planktonic Rotifers Biology and Taxonomy Biological Station. Lunz of The Austrian Academy of Science, Stuttgart. 22. Fowler, J., Cohen, L. (1992). Practical Statistics for Field Biology, John Wiley and Sons Inc, New York. 23. Dolan, J. R., Gallegos, C. L. (1992). Trophic Role of Planktonic rotifers in the Rhode River estuary, spring- summer Marine Ecology Progress Series, 85: Tanyolaç, J. (1993). Limnoloji, Hatipoğlu Basımevi, Ankara. 25. Saksena, H. D. (1987). Rotifers as Indicators of Water Quality. Acta Hydrochim. Hydrobiologia, 15: Baker, R. L. (1979). Birth Rate of Planktonic Rotifers in Relation to Food Concentration in a Shallow Eutrophic Lake in Western Canada, Can. J. Zool., 57: Berzins, B.,Pejler, B. (1989). Rotifer Occurence in Relation to Temperature. Hydrobiologia, 175: Holst, H., Zimmermann, H., Kausch, H., Koste W. (1998). Temporal and Spatial Dynamic of Planktonic Rotifers in the Elbe Estuary During Spring. Estuarine Coastal and Shelf Science, 47: