Review of Hydrobiology www.reviewofhydrobiology.com 2: 165-205 (2008) RESEARCH ARTICLE The physico-chemical and biological characteristics of coastal crenogenic meromictic Köyce iz Lake in South-Western Turkey between 1991 and 1993 and future management proposals NILGÜN KAZANCI 1*, MUZAFFER DÜGEL 2 and SÖNMEZ GIRGIN 3 1 Hacettepe University Science Faculty Biology Department Hydrobiology Section Beytepe, Ankara, Turkey 2Abant zzet Baysal University Science Faculty Biology Department Hydrobiology Section Bolu-Turkey 3 Gazi University Gazi Faculty of Education Biology Section Be evler, Ankara, Turkey [ * Corresponding author: Prof. Dr. Nilgün Kazanc, nilgunkazanci@gmail.com] ABSTRACT 1. The limnological characteristics of Köyce iz Lake, a coastal and crenogenic meromictic lake in southwestern Turkey, were presented. 2. Physical and chemical variables indicated that the lake is composed of hydrochemically different water layers formed by cold-carstic and thermal groundwater sources located on the floor of the lake. 3. The lake is fed from groundwater recharge from alluvium, surface flow, coldcarstic and thermal discharges. 4. The lake is threatened by organic pollution. Recommendations for the conservation of the lake were presented. KEY WORDS: Chemical stratification, cold karstic groundwater, crenogenic meromictic lake, echo-sounding profile; Köyce iz Lake, limnology, nature reserve area, physicochemistry, protection, thermal groundwater, Turkey. 165
Review of Hydrobiology www.reviewofhydrobiology.com 2: 165-205 (2008) RESEARCH ARTICLE Türkiye nin güneybat s ndaki k y sal krenojenik meromiktik Köyce iz Gölü nün 1991 ve 1993 y llar aras ndaki fiziko-kimyasal ve biyolojik özellikleri ve gelece e yönelik koruma önerileri N LGÜN KAZANCI 1*, MUZAFFER DÜGEL 2 ve SÖNMEZ G RG N 3 2 Hacettepe Üniversitesi Fen Fakültesi Biyoloji Bölümü Hidrobiyoloji Anabilim Dal Beytepe, Ankara, Türkiye 2Abant zzet Baysal Üniversitesi Fen Fakültesi Biyoloji Bölümü Hidrobiyoloji Anabilim Dal Bolu-Türkiye 3 Gazi Üniversitesi Gazi E itim Fakültesi Biyoloji E itimi Anabilim Dal Be evler, Ankara, Türkiye [ * leti im: Prof. Dr. Nilgün Kazanc, nilgunkazanci@gmail.com] ÖZ 1. Bu çal mada Türkiye nin güneybat s ndaki k y sal ve krenojenik meromiktik Köyce iz Gölü nün limnolojik özellikleri verilmi tir. 2. Fiziksel ve kimyasal de i kenler göl su kütlesinin, göl taban nda yer alan karstik so uk ve s cak su kaynaklar taraf ndan biçimlenen ve hidrokimyasal aç dan farkl su tabakalar ndan olu tu unu göstermi tir. 3. Göl, alüvyondan gelen yeralt sular, yüzey ak nt lar, karstik so uk ve s cak su kaynaklar ile beslenmektedir. 4. Göl, organik kirlilik tehlikesi alt ndad r. Çal mada gölün korunmas için öneriler sunulmu tur. ANAHTAR KEL MELER: Do al koruma alan, eko-sounder grafi i, fiziko-kimyasal, kimyasal tabakala ma, koruma, Köyce iz Gölü, krenogenik meromiktik göl, limnoloji, so uk karstik yeralt suyu, termal kaynak, Türkiye. 166
The physico-chemical and biological characteristics of Köyce iz Lake in South-Western Turkey INTRODUCTION The Köyce iz Lake is a coastal ectogenic-crenogenic meromictic lake in southwestern Turkey. Meromictic lakes are defined by Hutchinson (1957) as lakes in which some water remains partially or wholly unmixed with the main mass of water at the normal circulation periods. They are permanently stratified by a chemical gradient that separates the dense underlying monimolimnion from the overlying less dense mixolimnion. These lakes occur throughout the world but they are rare. Walker and Likens (1975) listed 120 meromictic lakes. The Köyce iz Lake was the first scientifically described meromictic lake in Turkey with the unusual nature of the physical, chemical and biological properties of the lake (Kazanc et al. 1992a,b; Kazanc 1993). The Köyce iz Lake fed by a series of surface flow, water discharge from alluvium and from thermal discharge from groundwater sources on the floor of the lake. Some previous hydrogeologic studies Tansu and Öztunal (1976), Ye ertener (1986), Eraslan (1991) have stated that there were a number of karstic and thermal springs around the lake. But the first detailed research evaluated with echo-sounding profiles (Kazanc et al. 1992b) that the thermal springs were located in the southern part of the basin (Sultaniye Basin) and most of the karstic springs are located in the north-eastern basin (Köyce iz Basin). Also in this research the effects of these bottom springs to the whole aquatic ecosystem of the lake and the determination of the origin of water layers is of utmost importance in the protection of the lake from pollution, this fact is stressed for the first time. The results of this research and some previous hydrogeologic studies were collected by Bayar et al. (1995). In this paper, physical and chemical characteristics are given and discussed in relation to the meromixis and water quality of the Köyce iz Lake between the years 1991and 1993. The recommendations were made for future conservation activities. SITE DESCRIPTION Köyce iz Lake is a crenogenic meromictic lake of 55km 2 surface area and its volume is around 860 x 10 6 m 3. The water depth generally ranges between 1 and 30m but there are several local depressions with depths of 70m. The lake is in the 167
N LGÜN KAZANCI, MUZAFFER DÜGEL AND SÖNMEZ G RG N downstream part of the Köyce iz Lake Basin covering an area of 1160km 2. The lake is comprising of two different basins Köyce iz and Sultaniye (Figure 1). Figure 1. Sampling sites and the locations in Köyce iz Lake. The Köyce iz Lake Basin is at the western end of the Taurus tectonic belt Graciansky (1968 and 1972), in his studies of an area covering the Köyce iz Lake Basin, determined that the geologic structure is composed of three structurally different sequences of rock units, namely autochthonous carbonates and detritics, allochthonous Lycien Nappes, and ophiolite nappe. During the Pliocene, the lowlands (grabens), which form the Köyce iz and Dalaman Plains, were filled with terrigenous material comprised of marl, conglomerate and limestone. The Köyce iz Lake started to form during the Plio-Quaternary time as a result of the clogging of the channel between the lake and the sea. 168
The physico-chemical and biological characteristics of Köyce iz Lake in South-Western Turkey The region, which was characterized by extensive tectonic activity in geologic times was also struck by many earthquakes during historic times (Bayar et al. 1995). The major water-bearing formations within the Köyce iz Basin are allochthonous limestone formations (Lycien Nappes) and the Plio-Quaternary alluvium. The thermal and karstic springs discharge from allochthonous limestone where it is intersected by faults. The thermal springs are located in the southern part of the basin, whereas most of the karstic springs are located in the north-eastern part (Bayar et al. 1995). Typical Mediterranean climate with hot and dry summers, mild and wet winters prevails in the area. Based on the long-term average data, the mean annual precipitation over the basin is 1202mm. The mean annual temperature is about 18 o C. Major streams draining various geologic units discharge into the Köyce iz Lake which in turn discharge its water into the Mediterranean Sea via a 14km long, meandering channel, namely Dalyan Channel. The Namnam and Yuvarlak Streams are the major surface waters in the basin. No serious long-term water level changes have been observed in the Köyce iz Lake (Eraslan 1991). The annual fluctuations of the lake level are between 1.5 and 2.5m (Bayar et al. 1995). The Köyce iz-dalyan region was established as a protected area to be administrated by the Turkish Ministry of Environment in 1988. It covers an area approximately 250km 2. The protected area is divided into two main basins as Köyce iz and Dalaman. METHODS Sampling was carried out monthly at a site near the middle of Köyce iz and Sultaniye Basins from April 1991 to December 1991, from January 1992 to September 1992 and from February 1993 to August 1993. Water samples were collected between 0-28 m depending on existence of different water layers. Water samples were collected using a Ruttner water sampler (Hydrobios, Kiel). Temperature, dissolved oxygen (Oxygen meter, OXI 96/B Set, WTW), conductivity (LF 95/Set WTW) and ph (ph meter 91/Set WTW) were determined immediately after sample collection. The depth of the euphotic zone was determined by secchi disk. Phosphate, nitrate, ammonia, Ca 2+, Mg 2+ were determined according to Merck (1986), nitrite according to Snel and Snel (1957), sulfate according to Rump and Krist (1988) and chloride according to Mohr (1856). A Hach DR 2000 photometer was used for spectrophotometric measurements. 169
N LGÜN KAZANCI, MUZAFFER DÜGEL AND SÖNMEZ G RG N RESULTS Physical variables The monthly temperature profile in Sultaniye Basin showed a minimum of 8.4 C in February 1993 (Figures 2-4) and 9.1 C in Köyce iz Basin in January 1992 (Figures 5-7). The maximum temperature value was 35 C in Sultaniye in July 1991 and 36 C in Köyce iz Basin in July 199 (Figures 2 and 5 respectively). Poikilothermic temperature profiles were observed in Sultaniye Basin in June and July and in Köyce iz Basin in April and July 1991 (Kazanc et al. 1992 a, b). The turbidity at Sultaniye and Köyce iz Basins increased below 10-12m. The layers which had different chemical composition have also different turbidities. The transparency of secchi disk was about 5-6m indicated oligothrophic lakes. Chemical variables Oxygen values were between 3.8-15 mg/l from surface to 9 m in Sultaniye Basin and 3.3-13.5 mg/l in Köyce iz Basin. Oxygen deficiency was observed from 12m with 1.1-4.3 mg/l in monimolimnion in Sultaniye Basin and 1.4-3.8 mg/l in monimolimnion in Köyce iz Basin (Figures 8-13). The distinctive water layers with different oxygen concentrations originated from the ground water sources with different hydrochemical properties existed in monimolimnion. The high oxygen value was caused by bloom of Microcystis sp. in mixolimnion of two basins during April 1992 and 1993 (Figures 9, 10, 12, 13). The water was generally alkaline with ph ranging from 7 to 8.9 between surface and 10-13m, except in Köyce iz Basin in 1991 (ph 6.6-7.4) but gradually decreased to 7.4-6.6 was caused by the existence of H 2 S in the monimolimnion (Figures 14-19). The conductivity value increased with depth. Conductivity ranged from 2.78 to 10.73 ms/cm in mixolimnion, from 4.42 to 18.8 ms/cm in chemocline, from 3.92 to 28.76 ms/cm in monimolimnion in Sultaniye Basin and from 2.67 to 10.01 ms/cm in mixolimnion, from 3.11 to 11.1 ms/cm in chemocline, from 3.18 to 15.01 ms/cm in monimolimnion in Köyce iz Basin (Figures 20-25). The chemocline was located approximately between 8-15m in two basins except in Köyce iz Basin (Figure 25) in February 1993 (between 14-18m). The sudden changes in conductivity and temperature profiles (poikilothermic) observed in Köyce iz Basin in April and in June 1991 (Figure 23) and in Sultaniye Basin in June and July 1991 (Kazanc et al. 1992 a, b) (Figure 20). But these unusual profiles disappeared in 1992 and 1993. 170
The physico-chemical and biological characteristics of Köyce iz Lake in South-Western Turkey Calcium (in Köyce iz Basin 92.18-769.5 mg/l and in Sultaniye Basin 108.00-673.3 mg/l) (Figures 26-29) and magnesium (in Köyce iz Basin 50.00-710 mg/l and in Sultaniye Basin 108.00-1293.3 mg/l) (Figures 30-33) concentrations were generally high. Chloride concentrations increased with depth and these ranged from 2.13 g/l to 10.15 g/l in Sultaniye Basin and from 1.17 g/l to 6.88 g/l in Köyce iz Basin (Figures 34-38). Sulfate concentrations were very high, the max of 33 g/l in Sultaniye Basin and the max of 42 g/l in Köyce iz Basin (Figures 39-42). Sulfide detected in monimolimnion after 12m depth. Inorganic nitrogen in two basins were mainly in the form of ammonia nitrogen and their concentrations increased in chemocline and monimolimnion and reached 5.38 mg/l (Figure 44) in Sultaniye Basin and 5.44 mg/l in Köyce iz Basin (Figure 47). The highest nitrite nitrogen concentration was 0.072 mg/l in Sultaniye Basin and was 1.88 mg/l in Köyce iz Basin, (Figures 49-52). The highest nitrate nitrogen concentration was 0.54 mg/l in Sultaniye Basin (Figure 53). (Figure 54). Phosphate concentration was maximum 1.48 mg/l in Köyce iz Basin in 1991 DISCUSSION Many of the groundwater sources were not active in 1992 and 1993 (Figures 3, 4, 6, 7) comparing to 1991 (in April and June) (Figures 2, 5) due to shorter rainy period in 1992 and 1993. Mediterranean climate conditions have important effect on activities of groundwater sources on the lake floor. Stratification and distinctive water layers The physical and chemical measurements made at various depths and times in Sultaniye and Köyce iz Basins indicate that the water body has crenogenic meromictic structure. The lake water was composed of oligohaline brackish water (0-8m) and of mesohaline brackish water (9-24m) in Köyce iz Basin and of mesohaline brackish water (0-11m) and of polyhaline brackish water (12-27m) in Sultaniye Basin. The upper boundary of the chemocline was at around 7-12m depth in Sultaniye Basin and 6-8m depth in Köyce iz Basin. The lower boundary was located at around 11-17m in Sultaniye Basin and 8-14m depth in Köyce iz Basin except in February 1993 (between 14-18m, Figure 25). The upper boundary of monimolimnion was at 14-18m depth depending on depth of chemocline. 171
N LGÜN KAZANCI, MUZAFFER DÜGEL AND SÖNMEZ G RG N The upper boundary of the metalimnion was at around 5-12m depth in Sultaniye Basin and 6-9m depth in Köyce iz Basin. The lower boundary was located at around 9-18m depth in Sultaniye Basin and 8-17m depth in Köyce iz Basin (Fig. 3, 4, 6, 7). The thermal groundwater sources on the floor of the lake (Figures 2-7) were the main reason of high temperatures. But the higher temperature in monimolimnion was due to effect of thermal groundwater sources and anaerobic bacterial activities. Turbidity increased with depth. The turbidity at Sultaniye Basin increased below 10-12m. It was high in monimolimnion of two basins: 1-184 FTU in Sultaniye Basin and 2-222 FTU in Köyce iz Basin. The transparency of secchi disc is about 2.5-4m in two basins. The light penetration ranged from 100% to 4.9% between surface and 9m. The distinctive water layers of different quality in the monimolimnion originating from randomly distributed thermal and cold karstic groundwater sources with different hydrochemical properties were observed in the main water body of the lake in 1992 and 1993. These groundwater discharges from allochthonous limestone where it was intersected by faults at the floor of the lake. The thermal groundwater sources were located in Sultaniye Basin, whereas most of the karstic groundwater sources were located in Köyce iz Basin. For example, if a layer originated from thermal groundwater input, it had a higher conductivity and lower dissolved oxygen values. This was clearly seen in 11, 14, 19, 20 and 20.5m depths in June 1991 in Köyce iz Basin (Figures 11, 23). Many of the groundwater sources were not active in 1992 and 1993 (Figures 3, 4, 6, 7) comparing to 1991 (in April and June) (Figures 2, 5). Therefore many of the distinctive water layers disappeared. The increasing of conductivity generally indicated chemocline layers (Figures 20-25). Some of the most distinctive water layers, according to their water quality are: Sultaniye Basin: 1. January 1992 (Figures 49, 30, 34). At 12m there were increases in nitrite (from 0.016 to 0.034 mg/l), in magnesium (from 357.3 to 430.3 mg/l), in chloride (from 6.25 to 7.1 g/l) indicated an organically polluted water. 2. May 1992 (Figures 49, 44, 30). At 9 m there were increases in nitrite (from 0.038 172
The physico-chemical and biological characteristics of Köyce iz Lake in South-Western Turkey to 0.052 mg/l), in ammonia (from 0 to 0.06 mg/l), in magnesium (from 313.27 to 486.20 mg/l) indicated organically polluted water layer. 3. August 1992 (Figures 3, 49, 21, 34, 26). At 20.5m there were increases in temperature (from 16.3 to 17.6 o C), in nitrite (from 0.015 mg/l to 0.06 mg/l) with decreases in electrical conductivity (from 5.8 to 5.6 ms/cm), in chloride (from 9.8 to 9.4 g/l), in calcium (from 224.45 to 192.38 mg/l) indicated organically polluted water layer originated from thermal groundwater sources. Köyce iz Basin: 1. May 1992 (Figures 51, 12, 32). At 12m there were increases in nitrite (from 0.51 to 0.65 mg/l) whilst there were decreases in dissolved oxygen (from 2.2 to 2 mg/l) and in magnesium (from 486.2 to 340.34 mg/l) indicated organically polluted water layer. 2. August 1992 (Figures 51, 12, 28). At 19m there were increases in nitrite (from 1.43 to 1.88 mg/l) whilst there were decreases in dissolved oxygen (from 1.5 to 1.3 mg/l), in calcium (from 336.7 to 230 mg/l) indicating organically polluted water layer. 3. May 1993 (Figures 25, 48, 42, 29). At 16m there were increases in electrical conductivity (from 9.67 to 10.64 ms/cm), in ammonia (from 0.23 to 1.18 mg/l), in sulfate (from 0.29 to 0.72 g/l) and in calcium (from 96.2 to 395 mg/l) indicated slightly polluted water layer. The groundwater discharges from allochthonous limestone where it was intersected by faults at the floor of the lake. The thermal groundwater sources were located in Sultaniye Basin, whereas most of the karstic groundwater sources were located in Köyce iz Basin. In all sampling periods dissolved oxygen concentrations were decreased below 10m depth (Figures 8-13). The monimolimnion had dissolved oxygen values between 1-4.5 mg/l formed dangerous conditions for living organisms. After 9-11m ph value decreased (Figures 14-19) related with increase of H 2 S and organic matter concentrations. H 2 S observed with higher concentration of SO 4 which was due to the effect of thermal water input but SO 4 concentration did not decrease with increasing of H 2 S concentration because of continuous addition of SO 4 by thermal ground water sources. Addition of H + to monimolimnion due to reduction of SO 4 by bacterial activities caused to decrease in ph value. At 12-13m depths, the purple color of water appeared due to growth of 173
N LGÜN KAZANCI, MUZAFFER DÜGEL AND SÖNMEZ G RG N phototrophic sulfur bacteria in two basins in June and July 1991 and 1992. The interface between oxic and anoxic waters is generally found in the chemocline, and the oxidation of reduced metabolic end-products produced in the monimolimnion, such as H 2 S and CH 4, occurs at this interface. Often, a green or reddish purple water discoloration in the chemocline is associated with near continuous blooms of pigmented phototrophic sulfur bacteria, e.g. Chlorobium and Chromatium sp. (Guerrero et al. 1985, Tuomi et al. 1997). The phosphate value begin to increase in 14m with the existence of H 2 S (Figure 54). The high value of phosphate was due to the domestic wastewater, organically polluted ground water and surface water from agricultural area. The high PO 4 value in June and July 1991 decreased after the bloom of Microcystis sp. in July 1991. When Ca 2+ concentration is high, the accumulation of phosphate as hydroxyl apatite can be seen in lake sediment (Wetzel 1983). It could be expected in Köyce iz Lake. The value of NO 2 -N, NH 4 -N, NO 3 -N increased after 7-12m (in monimolimnion) (Figures 43-53). High concentrations of NH 4 in monimolimnion were due to organic pollution and fertilizers. According to Wetzel (1983), low dissolved oxygen concentration inhibited nitrification process. Therefore, it was possible to observe high NH 4 -N concentration when NO 2 -N concentration was low in monimolimnion. NO 2 -N existence showed a continuous effect of septic leakage originated from groundwater sources in various depths of monimolimnion. During the algal bloom in July 1991, NH 4 in monimolimnion was disappeared because NH 4 was used as nitrogen source. The origin of SO 4 was thermal springs, fertilizers and organic materials transported to the lake by groundwater sources. Also, contributions of fossil sea water to thermal springs are possible (Bayar et al. 1995) and some SO 4 transported to the lake by fossil sea water. H 2 S existed after 10-12m depths (in monimolimnion). The H 2 S amount is generally high in the monimolimnion of crenogenic meromictic lakes which is fed by sulfuric ground water sources (Wetzel 1983). Therefore, the presence of hydrogen sulfide-rich water in the monimolimnion can be accepted as evidence for thermal water input. A little metal sulfide is transported from the sediment to the water by the reduction of SO 4 to sulfide. PO 4 and other salts are transported from the sediment to the water by the oxidation of H 2 S to SO 4. Therefore SO 4 is a catalyst in nutrient cycle in a lake (Wetzel 1983). The chloride was high due to water of thermal springs mixing with sea water and 174
The physico-chemical and biological characteristics of Köyce iz Lake in South-Western Turkey some fossil sea water (Bayar et al. 1995). After 8-10m the chloride concentration increased (5000-7500 mg/l) with chemocline layer and reached the value of two times of mixolimnion (2000-3500 mg/l) in monimolimnion. Calcium and magnesium concentrations were also high due to water input of thermal springs and cold karstic springs in the lake bottom discharges from the contact with limestone, ophiolite and alluvium and soil structure of the region (Bayar et al. 1995). After 10 m Mg 2+ and Ca 2+ concentration increased with conductivity value. The water layers that have different chemical compositions can be identified with change of Cl -, Mg 2+ and Ca 2+ concentrations. CONCLUSIONS The Köyce iz-dalyan region is an important protected area due to the high biological diversity in the eastern Mediterranean region. The complex aquatic ecosystem in this region has special value (Kazanc et al. 1992 a, b, Kazanc 1993, Kazanc 1995, Kazanc et al. 1999a,b, Kazanc et al. 2000, Kazanc and Dügel 2000, Kazanc and Girgin 2001). The center of the aquatic ecosystem is the meromictic Köyce iz Lake. The protection of the lake is necessary for the health of whole ecosystems in the nature reserve area. Preliminary recommendations for protection of water quality and management of the lake 1. The phosphate input to the lake must be prevented. After the algal bloom of Microcystis sp. the orthophosphate value was decreased. This shows that phosphate is a limiting factor in the lake. 2. The pollution factors for running waters are due to the direct discharge of domestic waste water and fisheries waste water from Yuvarlakçay Stream. Sewer system problem of Köyce iz and Dalyan Towns must be solved. The septic tanks must be well isolated. The various kinds of fertilizers, herbicides and pesticides are used excessively without any control. This is another source of serious pollution. During planning of land use all these factors must be taken in consideration. 3. According to the physico-chemical variables and distribution of benthic macroinvertebrates, continuous slight, moderate and heavy organic pollution exists in the running waters (Kazanc and Dügel 2000). Therefore, protection and monitoring of water quality of running waters is necessary for the 175
N LGÜN KAZANCI, MUZAFFER DÜGEL AND SÖNMEZ G RG N protection of Köyce iz Lake. 4. There is a high degree of hydraulic relationship between the lake and permeable aquifers and the lake position in the ground water-flow system. These relationships must be clearly defined. 5. Ground waters are widely used for domestic and agricultural purpose by local people. Therefore the use of ground water by pumping must be monitored and necessary precautions must be taken to prevent water quality. Because ground water and lake interactions are very important for the phosphorus, nitrogen budget of the lake and also ground water quality. 6. The water quantity of running waters is not sufficient for the regeneration of the mixolimnion. The excessive use of running waters for irrigation must be prevented. 7. The motorboat traffic is hazardous for the critical habitat and fauna, flora therefore must be controlled i.e. dimension, number and speed. Also discharging of petroleum residues from motorboats must be prevented. 8. The reed areas are burned by local people to gain agricultural land. This must be prevented. 9. To conserve the rich biodiversity of the aquatic ecosystem, it must be kept away touristic stress. 10. Physical, chemical and biological parameters in the critical localities of the aquatic ecosystem should be monitored. 11. Lake hydrology is influenced by climatological conditions. Water levels of karstic lakes like Köyce iz Lake are changed with respect to groundwater fluxes. The shorter rainy periods due to global warming prevent water discharge from groundwater sources and running waters. Use of groundwater sources and running waters must be planned. ACKNOWLEDGEMENTS This study is a part of Protection of Environment and Nature in Köyce iz- Dalyan which was supported by Gesselschaft für Technische zusammenarbeit mbh, Frankfurt, Germany (GTZ) and T.R. Ministry of Environment. We also thank Assoc Prof. Dr. Afife zb rak, Assist. Prof. Dr. Didem Gökçe and Prof. Dr. Selim Ça lar for their technical assistance, field work and chemical analysis. Prof. Dr. Nilgün Kazanc thanks Alexander von Humboldt foundation for literature support. 176
The physico-chemical and biological characteristics of Köyce iz Lake in South-Western Turkey Fig. 2 Sultaniye 1991, Temperature ( o C) Fig. 3 Sultaniye 1992, Temperature ( o C) Plate 1a. Vertical profiles of temperature in Köyce iz Lake (Sultaniye Basin) over the study periods 177
N LGÜN KAZANCI, MUZAFFER DÜGEL AND SÖNMEZ G RG N Fig. 4 Sultaniye 1993, Temperature ( o C) Fig. 5 Köyce iz 1991, Temperature ( o C) Plate 1b. Vertical profiles of temperature in Köyce iz Lake (Sultaniye and Köyce iz Basins) over the study periods 178
The physico-chemical and biological characteristics of Köyce iz Lake in South-Western Turkey Fig. 6 Köyce iz 1992, Temperature ( o C) Fig. 7 Köyce iz 1993, Temperature ( o C) Plate 1c. Vertical profiles of temperature in Köyce iz Lake (Köyce iz Basin) over the study periods 179
N LGÜN KAZANCI, MUZAFFER DÜGEL AND SÖNMEZ G RG N Fig. 8 Sultaniye 1991, DO (mg/l) Fig. 9 Sultaniye 1992, DO (mg/l) Plate 1d. Vertical profiles of dissolved oxygen (DO) in Köyce iz Lake (Sultaniye Basin) over the study periods 180
The physico-chemical and biological characteristics of Köyce iz Lake in South-Western Turkey Fig. 10 Sultaniye 1993, DO (mg/l) Fig. 11 Köyce iz 1991, DO (mg/l) Plate 1e. Vertical profiles of dissolved oxygen (DO) in Köyce iz Lake (Sultaniye and Köyce iz Basins) over the study periods 181
N LGÜN KAZANCI, MUZAFFER DÜGEL AND SÖNMEZ G RG N Fig. 12 Köyce iz 1992, DO (mg/l) Fig. 13 Köyce iz 1993, DO (mg/l) Plate 1f. Vertical profiles of dissolved oxygen (DO) in Köyce iz Lake (Köyce iz Basin) over the study periods 182
The physico-chemical and biological characteristics of Köyce iz Lake in South-Western Turkey Fig. 14 Sultaniye 1991, ph Fig. 15 Sultaniye 1992, ph Plate 2a. Vertical profiles of ph in Köyce iz Lake (Sultaniye Basin) over the study periods 183
N LGÜN KAZANCI, MUZAFFER DÜGEL AND SÖNMEZ G RG N Fig. 16 Sultaniye 1993, ph Fig. 17 Köyce iz 1991, ph Plate 2b. Vertical profiles of ph in Köyce iz Lake (Sultaniye and Köyce iz Basin) over the study periods 184
The physico-chemical and biological characteristics of Köyce iz Lake in South-Western Turkey Fig. 18 Köyce iz 1992, ph Fig. 19 Köyce iz 1993, ph Plate 2c. Vertical profiles of ph in Köyce iz Lake (Köyce iz Basin) over the study periods 185
N LGÜN KAZANCI, MUZAFFER DÜGEL AND SÖNMEZ G RG N Fig. 20 Sultaniye 1991, EC (ms/cm) Fig. 21 Sultaniye 1992, EC (ms/cm) Plate 2d. Vertical profiles of conductivity (EC) in Köyce iz Lake (Sultaniye Basin) over the study periods 186
The physico-chemical and biological characteristics of Köyce iz Lake in South-Western Turkey Fig. 22 Sultaniye 1993, EC (ms/cm) Fig. 23 Köyce iz 1991, EC (ms/cm) Plate 2e. Vertical profiles of conductivity (EC) in Köyce iz Lake (Sultaniye and Köyce iz Basin) over the study periods 187
N LGÜN KAZANCI, MUZAFFER DÜGEL AND SÖNMEZ G RG N Fig. 24 Köyce iz 1992, EC (ms/cm) Fig. 25 Köyce iz 1993, EC (ms/cm) Plate 2f. Vertical profiles of conductivity (EC) in Köyce iz Lake (Köyce iz Basin) over the study periods 188
The physico-chemical and biological characteristics of Köyce iz Lake in South-Western Turkey Fig. 26 Sultaniye 1992, Ca +2 (mg/l) Fig. 27 Sultaniye 1993, Ca +2 (mg/l) Plate 3a. Vertical profiles of calcium in Köyce iz Lake (Sultaniye Basin) over the study periods 189
N LGÜN KAZANCI, MUZAFFER DÜGEL AND SÖNMEZ G RG N Fig. 28 Köyce iz 1992, Ca +2 (mg/l) Fig. 29 Köyce iz 1993, Ca +2 (mg/l) Plate 3b. Vertical profiles of calcium in Köyce iz Lake (Köyce iz Basin) over the study periods 190
The physico-chemical and biological characteristics of Köyce iz Lake in South-Western Turkey Fig. 30 Sultaniye 1992, Mg +2 (mg/l) Fig. 31 Sultaniye 1993, Mg +2 (mg/l) Plate 3c. Vertical profiles of magnesium in Köyce iz Lake (Sultaniye Basin) over the study periods 191
N LGÜN KAZANCI, MUZAFFER DÜGEL AND SÖNMEZ G RG N Fig. 32 Köyce iz 1992, Mg +2 (mg/l) Fig. 33 Köyce iz 1993, Mg +2 (mg/l) Plate 3d. Vertical profiles of magnesium in Köyce iz Lake (Köyce iz Basin) over the study periods 192
The physico-chemical and biological characteristics of Köyce iz Lake in South-Western Turkey Fig. 34 Sultaniye 1992, Cl - (mg/l) Fig. 35 Sultaniye 1993, Cl - (mg/l) Plate 3e. Vertical profiles of chloride in Köyce iz Lake (Sultaniye Basin) over the study periods 193
N LGÜN KAZANCI, MUZAFFER DÜGEL AND SÖNMEZ G RG N Fig. 36 Köyce iz 1991, Cl - (mg/l) Fig. 37 Köyce iz 1992, Cl - (mg/l) Plate 3f. Vertical profiles of chloride in Köyce iz Lake (Köyce iz Basin) over the study periods 194
The physico-chemical and biological characteristics of Köyce iz Lake in South-Western Turkey Fig. 38 Köyce iz 1993, Cl - (mg/l) Plate 3g. Vertical profiles of chloride in Köyce iz Lake (Köyce iz Basin) over the study periods 195
N LGÜN KAZANCI, MUZAFFER DÜGEL AND SÖNMEZ G RG N Fig.39 Sultaniye 1992, SO 4 (mg/l) Fig.40 Sultaniye 1993, SO 4 (mg/l) Plate 4a. Vertical profiles of sulfate in Köyce iz Lake (Sultaniye Basin) over the study periods 196
The physico-chemical and biological characteristics of Köyce iz Lake in South-Western Turkey Fig.41 Köyce iz 1992, SO 4 (mg/l) Fig.42 Köyce iz 1993, SO 4 (mg/l) Plate 4b. Vertical profiles of sulfate in Köyce iz Lake (Köyce iz Basin) over the study periods 197
N LGÜN KAZANCI, MUZAFFER DÜGEL AND SÖNMEZ G RG N Fig.43 Sultaniye 1991, NH 4 -N (mg/l) Fig.44 Sultaniye 1992, NH 4 -N (mg/l) Plate 4c. Vertical profiles of ammonia nitrogen in Köyce iz Lake (Sultaniye Basin) over the study periods 198
The physico-chemical and biological characteristics of Köyce iz Lake in South-Western Turkey Fig.45 Sultaniye 1993, NH 4 -N (mg/l) Fig.46 Köyce iz 1991, NH 4 -N (mg/l) Plate 4d. Vertical profiles of ammonia nitrogen in Köyce iz Lake (Sultaniye and Köyce iz Basin) over the study periods 199
N LGÜN KAZANCI, MUZAFFER DÜGEL AND SÖNMEZ G RG N Fig.47 Köyce iz 1992, NH 4 -N (mg/l) Fig.48 Köyce iz 1993, NH 4 -N (mg/l) Plate 4e. Vertical profiles of ammonia nitrogen in Köyce iz Lake (Köyce iz Basin) over the study periods 200
The physico-chemical and biological characteristics of Köyce iz Lake in South-Western Turkey Fig.49 Sultaniye 1992, NO 2 -N (mg/l) Fig.50 Sultaniye 1993, NO 2 -N (mg/l) Plate 5a. Vertical profiles of nitrite nitrogen in Köyce iz Lake (Sultaniye Basin) over the study periods 201
N LGÜN KAZANCI, MUZAFFER DÜGEL AND SÖNMEZ G RG N Fig.51 Köyce iz 1992, NO 2 -N (mg/l) Fig.52 Köyce iz 1993, NO 2 -N (mg/l) Plate 5b. Vertical profiles of nitrite nitrogen in Köyce iz Lake (Köyce iz Basin) over the study periods 202
The physico-chemical and biological characteristics of Köyce iz Lake in South-Western Turkey Fig.53 Sultaniye 1993, NO 3 -N (mg/l) Fig.54 Köyce iz 1991, PO 4 -P (mg/l) Plate 5c. Vertical profiles of nitrate nitrogen and phosphate phosphor in Köyce iz Lake (Sultaniye and Köyce iz Basin) over the study periods 203
N LGÜN KAZANCI, MUZAFFER DÜGEL AND SÖNMEZ G RG N REFERENCES Bayar, C. S., Kazanc, N., Koyuncu, H., Ça lar, S.S. and Gökçe, D., 1995. Determination of the origin of the waters of Köyce iz Lake, Turkey, J. Hydrol. 166: 171-191. Eraslan, M., 1991. Preliminary hydrogeological investigation of the Köyce iz Basin and its vicinity, B. Sc. Thesis, Hacettepe University, Turkey. Graciansky, P. C., 1968. Stratigraphy of the overlapped units of the Lycien Nappes in the Teke Peninsula and their position within the Dinaro-Taurids, Bull. Miner. Res. Explor. Inst., Ankara, 71: 73-92. Graciansky, P. C., 1972. Recherces geologiques dans le Taurus Lycien Occidentales, Ph. D. Thesis, Universite de Paris-Sud. Guerrero, R., Montesinos, E., Pedros-Alio, C., Esteve, I., Mas, J., Vangemerden, H., Hofmanand, P. A. G. and Bakker, J.F., 1985. Phototrophic sulfur bacteria in two Spanish lakes: Vertical distribution and limiting factors, Limnol. Oceanogr. 30: 919 931. Hutchinson, G. E., 1957. A treatise on Limnology, I. Geography, Physics and Chemistry, (J.Wiley and Sons, New York). pp 1015. Kazanc, N., Plasa, R., Neubert, E. and Izb rak, A., 1992a. On the limnology of the Lake Köyce iz (SW Anatolia), Zool. Middle East 16:109-126. Kazanc, N., Izb rak, A., Ça lar, S. S. and Gökçe, D., 1992b. Köyce iz-dalyan Özel Çevre Koruma Bölgesi sucul ekosisteminin hidrobiyolojik yönden incelenmesi, Özyurt Press, Ankara. Kazanc, N., 1993. Protection of Environment and Nature in Köyce iz-dalyan, Final Report of Hydrobiological Subproject (GTZ) GmbH. Darmstadt, pp. 229. Kazanc, N., 1995. Odonata of the Köyce iz-dalyan Nature Reserve Area in South- Western Turkey, with Lindenia tetraphylla (Vander L.), new to Turkish Fauna (Anisoptera: Gomphidae), Notul. Odonatol 4: 105-106. Kazanc, N., Dügel, M., O uzkurt, D. and Girgin, S., 1999a. Limnology of Meromictic Lake Köyce iz in Köyce iz-dalyan Nature Reserve Area in South-Western Turkey and Preliminary Recommendations for Its Management, paper presented at the 8 th International Conference on the Conservation and Management of Lakes, Lake 99 Conf., Copenhagen. Kazanc, N., Girgin, S., Dügel, M., O uzkurt, D., Mutlu, B., Dere,., Barlas, M. and Özçelik, M., 1999b. Türkiye ç Sular Ara t rmalar Dizisi IV (Ed. N. Kazanc ): Köyce iz, Bey ehir, E irdir, Ak ehir, Eber, Çorak, Kovada, Yar l, Bafa, Salda, Karata, Çavu çu Gölleri, Büyük ve Küçük Menderes Deltas, Güllük ve Karamuk Batakl n n limnolojisi, çevre kalitesi ve biyolojik çe itlili i, Form Ofset, Ankara. 204
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