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Sevinç Arcak 1 , Ahmet Altındağ 2 1 Department of Soil Science, Faculty of Agriculture, Ankara University, Ankara 2 Department of Biology, Faculty of Science Ankara University, Ankara ABSTRACT Due to its water quality class of C4S4 and the lack of hydraulic altitude, Lake Burdur is not suitable for the purpose of irrigation and the generating hydro- electrical energy. Burdur lake has an international reputation for its unique property of giving shelter to about 75 % of world white headed duck (Oxyura leucocephala) population. Within the context of the study, water quality parameters, phytoplankton, zooplankton and lake fauna observations were tried to perform for the period of two years. Zooplanktonic organisms identified in the lake are Hexarthra fennica and Brachionus plicatilis of Rotifera group. These organisms are dominant in the lake and the characteristic species of salty surrounding areas. It was also determined that Brachionus plicatilis is a pollution indicator of low alkaline brackish waters. In addition, Amphiprora alata which belongs to Bacillariophyta division of phytoplanktonic group was proved to be dominant species of salty and brackish waters. The overall water quality parameters used for the determination of the quality of the lake and its vicinity include; temperature (°C), secchi depth, pH, EC, dissolved oxygen, ammonia, permanganate consumption, carbonate, bicarbonate, chloride, sodium, potassium, calcium, magnesium, ortho-phosphate and boron. INTRODUCTION Burdur Lake is an internationally well known wetland of class A where about 150 000 waterbird inhabit regularly every year and 70 % of the world Oxyura Leucocephala population, total population of which is estimated to be 150 000 winter. It is an important Bird Area (Grimmett and Jones, 1989) and was one of five Turkish wetlands listed as Ramsar Sites when Turkey become the 83 rd party to the Ramsar Convention (Convention on wetlands of International Importance, especially as waterfowl Habitat) in 1994. The lake being a closed watershed, it has no outlet that results in salty and brackish water. Main streams contributing to the lake are Bozçay, Ulupınar, Bayındar, Büğdüz, Karna, Çerçin, Keçiborlu. The aforementioned streams carry pollutants to the lake deriving from sewer systems of the settlements and industrial facilities located in the vicinity. The Lake Burdur is one of the deepest lakes of Turkey. In observations made in this area it's stated that the lake has oligotrophic character and poor by foodstuff. Aquatic plants can not be seen in the lake water, because the amount of sodium sulphate and chlorine in the lake water, because the amount of sodium sulphate and chlorine in the lake water is high. Since the lake water do not freeze in winter, some species of ducks from crowded groups here wide and open water surface create a secure condition for the birds which pass the winter here. Shallow areas at the south-west and north-east parts of the lake and muddy plains near the shores provide possibility with their rich food stuff for birds to feed (Green, et al., 1996; Green and Anstey, 1992). For protection of the living areas of the species, International Waterbirds and Wetlands Searching Association and Waterbirds and Wetlands Association has been executing and International Searching and Protection program since 1989 Turkey and Russia come first among the countries which are given most importance. Protecting the Lake Burdur is very important for this species to be able to continue its generation (Anonymous, 1998). The aim of the study carried out in 1998-1999 is to determine water quality and ecological properties of Burdur Lake. MATERIALS & METHODS Site Description Burdur Lake is a closed-basin (endorreic), saline lake of c. 140 km2 at 845 m above sea level in south-west Anatolia, Turkey (37° 43ı N, 30° 15ı E, Figure 1) divided between the provinces of Burdur to the south and Isparta to the north. It is 30 km long by up to 7 km wide and lies on a geological fault in a earth-quake zone. The water has a high salt and soda content and never freezes. The lake has a catchment area of 6150 km2 and is fed by several rivers, many with erratic water flow. The maximum depth was 110 m, it is now either 42 m or 85 m (Salathe and Yarar, 1992). Burdur city has c. 60 000 inhabitants and lies on the eastern shore. There are numerous small towns in the catchment, which has a total of 150 000 inhabitants. Sugerbeet and cereals are grown in flat alluvial plains at both ends of the lake. Vines, roses (for perfume production) and fruit trees are grown in terraces on gentle slopes above the lake. Methods of Water Quality Analysis The water Samples were collected during 1998-1999 inclusive at fourteen stations (Figure 1) The water quality parameters were analysed using the described methods by APHA. The parameters measured in the samples obtained from the lake are pH, electrical conduc tivity (EC), secchi depth, NH3-N, NO2-N, NO3-N, hardness, o-PO4, Cl, Na, K, calcium (Ca), magnesium (Mg), dissolved oxygen (DO), temperature (oC), alkalinity (CO3= and HCO3-) and potassium permanganate consumption (PV). The parameters measured by the field instruments were temperature, depth, secchi depth, DO, pH and EC water parameters were analysed as indicated by standard methods (APHA, 1992). The zooplankton and phytoplankton samples were collected from 10 different stations of Lake Burdur (Figure 1), by using Hydro-Bios Kiel brand plankton scoop net having pore size 55mm and mouth width 25 cm. Vertical and horizontal howls were made at 10 m depth for 5 minutes. The specimens were preserved in 4 % formaldehyde immediately after collection and subsamples examined microscopicalliy (Lund et al. 1958). DISCUSSION Bird Counting Total bird number counted in October is 343 619. This the highest value ever recorded so far in the lake. The lake has given shelter to about 150 000 birds between November 1997 and January 1998. 121 bird species were recorded in April 27, 1997. The lowest bird counting amount was recorded as 58 in March 1, 1998. Counting of April and June 1997 have shown that birds don't prefer the lake for feeding and stay. Number of waterfowl showed an abrupt increase in August 1997. Along the winter months 800 Oxyura leucocephala were defined. The highest number recorded in bird counting is 889 in January 1998. 1451 Oxyura leucocephala were counted in January 1999. (Can, 1999). Water Quality Studies Temperature of the lake water ranged from 18 °C to 22 °C in June 1998, from 14 °C to 17 °C in October 1998, from 17 °C to 22 °C in May 1999. There is difference between surface and depth measurements. Decrease depending on depth especially in spring months is due to spring cycle. pH was found between 9.1-9.5 in spring, 9.1- 9.3 in autumn periods. Electrical conductivity was found between 22 000 mScm-1 - 26 000 mScm-1 in spring, 30 200 mScm-1- 31 000 mScm-1 in autumn (Table1, 2 and 3). Secchi disc depth measurements were between 1.50 m - 3.22 m in spring, 3.10-4.20 m in autumn. Secchi depth measurements of the depth of 3-4 m . Corresponded to oligo-mesotrophic level. Dissolved oxygen values depending on depth ranged gradually from 6.2 to 9.5 mg l-1 in spring, from 7.6 to 9.0 mg l-1 in autumn. Nitrate and nitrite nitrogen were found zero. Increasing ammonia nitrogen was also determined in the lake. Orthophosphate phosphorous was defined as 0-0.291 mg l-1 , calcium values were between 18-39 mg l-1, magnesium 1159-1499 mg l-1 in spring, 60-180 mg l-1 and 2254-2432 mg l-1 in autumn respectively. Results obtained have shown that formation of ammonia in the lake is due to chemical reduction and N2 - synthesizing plankton. High content of ammonia is a phenomenon caused by industrial and urban waste waters. Potassium, sulfate and chloride values are at their heights levels. From the view point of sodium, chloride and pH values of its water, Burdur Lake is classified as IV. The fact that the lowest dissolved oxygen values were recorded in the samples taken around the mouth of the sewer system and MİS Dairy Facility is the indicator that the lake waters get mixed up with organic pollutants of anthropogenic origin. These organic waters are decomposed by aquatic microorganisms leading to decrease in oxygen level of the lake. The ecological character and conservation value of Burdur Lake is significantly threatened by a range of factors, as is typical of wetlands of importance for waterbirds in Turkey (Grimmett & Jones, 1989) and throughout the Mediterranean region (Hollis, 1992). Many current changes could have a negative impact on the white-headed ducks even if the problems of illegal hunting are solved. The distribution and abundance of their food solved. The distribution and abundance of their food supply is likely to be affected by man- induced changes. Enhanced sediment, organic and inorganic inputs to the closed lake system may have already changed its ecological character. The lake is undergoing eutrophication, which generally leads to a loss of biodiversity in wetlands, although it increases the numbers of certain species (Nilsson, 1978). In the long term, the input of acidic effluents from the industrial complex could cause major ecological change by exhausting the buffering capacity of the lake. Textile industry effluent is very acidic (Mason, 1981) and could markedly reduce lake pH. It has been suggested that a significant lowering of the pH of the lake would result in the release of hydrogen sulphide in toxic quantities, owing to the naturally high levels of sulphur compounds in the lake (Timur et al.. 1988). The bird-strike problem has not been considered during planning of the airport, and there is a possibility of hydrocarbon and other pollution entering the lake.    Phytoplankton A total of 41 genera of phytoplankton identified in samples collected from Burdur lake. From these, 18 belong to Bacillariophyta, 16 to Chlorophyta, 6 to Cyanophyta and Chrysophyta and one to Euglenophyta and Dinophyta divisions. The dominant genera of the lake were observed Bacillariophyta, Chlorophyta and Cyanophyta. Amphipora sp., Synedra sp. and Cyclotella sp. belong to Bacillariophyta, Spirogyra sp. and Cladophora sp. belong to Chlorophyta and Oscillatoria sp. belong to Cyanophyta divisions (Table 4). Pytoplanktons were studied at various stations of Lake Burdur (Figure 1.). Most of the species (16) were observed at station 4 and very few (2 sp.) at station 9. Amphiprora sp. were found dominant species of the lake and are the characteristic species of brackish and salty waters (Germain, 1981). In addition, Scenedesmus sp. and Pediastrum sp. of belonging to Chlorophyta division are reported dominant species of eutrophic lakes (Hutchinson, 1967, Harper 1992), Synedra sp. has been reported characteristic species of eutrophic lakes (Hutchinson, 1967). Among Cyanophyta, Microcystis, Chooccocus, Spirulina, Oscillatoria etc. species are found abundant in still waters. Microcystis inhabits in mesotrophic lakes, however some species of Oscillatoria and Anabeana are in a recorded very polluted waters. Zooplanktonic Organisms From the groups of zooplanktonic organisms in Burdur Lake, a total of 18 taksons (Copepoda 3, Cladocera 5, Rotifera 10) were determined. In addition, from the Özdere (stream) which is connected with Burdur Lake, a total of 23 species of zooplanktons (Copepoda 3, Cladocera 6, Rotifera 14) were examined. The dominant group of the lake is Rotifera and species belonging to his group (Brachionus plicatilis and Hexarthra fennica) were noted at all the sampling stations. In present study, species belonging to Rotifera (Cephalodella catellina, C.gibba, Colurella adriatica, Lecane lamellata, Keratella guadrata, Synchaeata oblonga, Polyarthra vulgaris), Cladocera (Diaphanosoma brachyurum, Daphnia magna, D. Longispina and Alona sp.), Copepoda (Cylops sp. and Harpacticoid Copepod Canthocmpus sp.) have been reported first time and are new for this lake (Table 4). Of the dominant species, Arctodiaptomus burduricus has been observed endemic species of Lake Burdur (Kosswig, 1956). Among other dominant groups Brachionus plicatilis and Hexarthra fennica are reported characteristic species of salty waters (Hecky and Kilham, 1973; Sharma 1983, Bayly, 1976 and Koste 1978), however, according to Sharma (1983) B.plicatilis found in low alkaline and salty waters and is a characteristic pollution indicator species. Saksena (1987) has reported B.plicatilis indicator species of eutrophic lakes. Besides, Hexarthra fennica, B. plicatilis, Keratella quadrata, Lecane sp. are eurythermal and euryhaline species of the lake (Berzins and Pejler 1989). According to Koste (1978) a rotifer, Colurella adriatica is a euryhaline species and generally found in waters with pH 5.5-10.5. The pH of the Lake Burdur ranges between 8.5-9.6 and is suitable habitat for this species. Keratella quadrata and Polyarthra vulgaris are the eurythermal species and inhabits in both salty and freshwaters and are known as cosmopolitian species. Polyarthra vulgaris mostly found in waters with high oxygen concentrations (Koste, 1978). Fish Fauna During the study at Burdur Lake, a total of 20 Aphanius sp. wese captured live and examined. The species Aphanius burduricus already present in the lake was re-identified as Aphanius anatoliae, However, taxonomic position of this species was not determined properly.  CONCLUSIONS However, Burdur Lake lacks of quality and hydraulic potential in terms of water resources, it is of great importance due to having two endemic fish species. From the view point of the protection of the species, life in the lake should be sustained. Due to environmental factors and water chemistry of the lake, less frost incident takes place in the region than other wetlands that makes possible more than 100 000 birds be able to winter in the region. Because region has a unique ecological conditions, Oxyura leucocephala which is believed to have a population of 30 000 -32 000 worldwide and confronted with extinction, maintains its life in the lake. In spite of unwanted physio-chemical properties of its waters relating to irrigation, lake offers an opportunity of benefiting from its recreational and aesthetical properties to the people living in the region. Gradual depletion that can be readily monitored on the water level of the lake must be investigated in connection with the climatic characteristics. It is very important that the threats facing the lake are addressed, particularly to conserve its endemic species and population of white-headed ducks. Measures required to solve these problems need not conflict with the needs and activities of the local human population around the lake. Since the lake is an important leisure area in the summer, and thousands of people live on the lake shores all year round, there is a common interest that further degradation of the lake should be prevented. Treatment plants should be fitted to the sugar factory, milk factory and Burdur sewage system to minimise the quantity of pollutants entering the lake. Remedial action is required at the sulphur mine to minimise the leaching of inorganic pollutants into the lake from old mine workings. There is a need to establish an adequate programme of site wardening to eliminate waterbird hunting at Burdur Lake. REFERENCES American Public Health Association (ed.) (1985). Standard methods for the examination of water and wastewater. APHA, AWWA - WPCF, Washington DC. Anonymous (1998). Lake Burdur. Republic to Turkey Ministry of Environment, General Directorate of Environmental Protection 1-28, Ankara. Arcak, S., Haktanır, K., Arcak, Ç., Altındağ A. (1999). Management project of wetlands final report of the subproject of the wetland management plan of Burdur Lake. Republic of Turkey Ministry of Environment, Ankara. Bayly, I.A.E. (1976). The plankton of lake Eyre. Aust. J.Mar. Freshwater Res., 27: 661-665. Berzins, B., Pejler, B. (1989).Rotifer occurrence in relation to oxygen content. Hydrobiol. 183: 165-172. Can, O. (1999). Ornithological Monitoring and Counting. Society for the protection of Nature. Germain, H. (1981). Flore Des diatomees, Diatomophycees, Societe Nouvelle Des Editions Boubee II. Place Saint-Michel, 235 p.75006 Paris. Green, A.J. Anstey, S. (1992). The status of the white-headed duck Oxyura leucocephala. Bird Conserv. Int., 2, 185-200. Green, A.J., Fox, A.D., Hilton, G., Hughes, B., Yarar, M., Salathe, T. (1996). Threats to Burdur Lake ecosystem, Turkey and its waterbirds, particularly the white-headed duck. Biological Conservation 76, 241-252. Grimmett, R.F.A , Jones, T.A. (1998). Important bird areas in Europe Int. Counc. Bird Preseru.Tech. Publis. No.9. Grimmett, R.F.A. , Jones, T.A. (1989). Important bird areas in Europe. Int. Counc. Bird Preserv. Tech, Publs, No.9. Hecky, R.E., Kılham, P. (1973). Diatoms in alkaline, saline lakes: Ecology and Geochemical. Limnol. Oceanegr. 18: 53-71 . Hollis, T. (1992). The causes of wetland loss and degradation in the Mediterranean. In Manag Hutchinson, G.E. (1967). A treatise on limnology. Introduction to lake biology and the limnoplankton, John wiley, USA. 2.McGraw Hill, N.Y., Vol.2. 1115 pp. ing Mediterranean wetlands and their birds. Proc. Symp., Grado, Italy, 1991. Ed. C.M. Finlayson, G.E. Hollis, T.J. Davis. IWRB Spec. Publs, No. 20, 83-90. Kosswig, C. (1956). Über Makro-und Mikropopulationen des Zahnkarpfens Anatolichtys, Zool. Anz., 156: 74-90. Koste, W. (1978). Die Radertiere Mitteleuropas I. Textband, 673 p.Berlin, Stutgart. Lund, J.W.G., Kiplng, C., Gren, E.D. (1958). The inversted microscope method of estimating algal numbers and the statitical basis of entimations by counting, Hydrobiologia, 11:113-170. Mason, C.F. (1981). Biology of freshwater pollution. Longman, Colchester. Nilsson, L. (1978). Breeding waterfowl in eutrophicated lakes in south Sweden. Wildfowl, 29, 101-110. Saksena, N.D. (1987). Rotifera as indicators of water quality Acta.Hydrochim. Hydrobiol. 15:481-485. Salathe, T., Yarar, M. (1992). Towards a management plan for Lake Burdur. DHKD and Station Biologigue de la Tour du Valat, Arles (Unpublished report). Sharma, B.K. (1983). The Indian species of the genus Brachionus (Eurotatoria: Monogononta: Brachionida) Hydrobiol. 104-31-39. Timur, M., Timur, G. , Özkan, G. (1988). A study on physical and chemical changes in Burdur Lake, and its effects on living organisms. Akdeniz Üniversitesi Su Ürün. Müh. Derg. 1, 75-144 (in Turkish). |