The Benthic Algae of Sarıyar Dam Lake, Ankara/Turkey

1. The Benthic Algae of Sarıyar Dam Lake, Ankara/Turkey Şirin DOKCAN Cengiz AKKÖZ and Tahir ATICI

2. The aim of this study was to investigate the abundance and species composition of benthic algae and to examine the physical and chemical properties of the lake water between 2008-2009. • Sariyar Dam Lake (SDL) is situated in the middle region of Turkey It is sourced from Sakarya River. It was constructed in 1956 for the purpose of to product of electrical energy.

3. Studyarea

4. Samples of the epipelic and epilithic algae were collected monthly from seven stations from 60-120 cm water depth. The epipelic algal samples were collected from sediment by using 1cm diameter PVC pipes. • Identification and determination of the quantitative analysis of all the epilithic algae were performed on many temporary slides prepared from the epilithic algae samples.

5. Water temperature, dissolved oxygen concentrations, pH, salinity, turbidity and conductivity were measured using a Multilap P4 (WTW) in the field at the sampling time. • Ca++, Mg++, SO42 and Cl-concentrations were determined by titration in the laboratory. NH4-N, NO2--N and NO3- -N (mg/L) measured using CADAS 200 UV spectrometer. Turbidity (NTU) was measured by turbidity meter.

6. Results • The surface water temperatures changed from 6.2 to 31 oC in the lake. Dissolved oxygen in the surface water fluctuated between 4.7 and 12.9 mg/l, and the average values were recorded throughout the study period. The pH fluctuated between 7.1 and 10 in the surface water. • Conductivity changed from 475mmhos/cm to 890 mmhos/cm. • Ca++ concentrations were measured between 0.56 and 70mg/l. • Mg++ concentrations ranged between 1.21mg/l and 36.2 mg/l. • Cl- concentrations ranged between 1 mg/l and 42mg/l. Cl-, • N02 concentrations ranged between 0.02mg/l and 0.96 mg/l, • N03 concentrations ranged between 0.02mg/l and 0.94 mg/l, and • NH4 concentrations ranged between 0.1mg/l and 1.42 mg/l were relatively low during the study period.

7. The physical features of sarıyar Dam Lake(surface water)

8. The Chemical features of Sarıyar Dam Lake (surface water)

9. Benthic Algae • The benthic algae of the SDL consisted of epipelic and epilithic algal communities. Totally, 64 taxa were recorded in the benthic algal communities. Most species identified in the study period belonged to the Bacillariophyta. A list of the identified taxa is presented in listed. Abundance of bentic algae is represented.

10. CYANOBACTERIA • Merismopedia elegans,Arthrospira major, Oscillatoriaprinceps, Pseudanabaena limnetica, CHLOROPHYTA • Chlamydomonas globosa,Sphaerocystis schroeteterii,Acutodesmus acuminatus,Spirogyra gratiana,Closterium dianaea, EUGLENOPHYTA • Euglena sp. BACILLARIOPHYTA • Melosira varians,Cyclotella meneghiniana,Cyclotella ocellata,Cyclotella comta,Asterionella formosa,Fragilaria sp.,Fragilaria capucina var. vaucheriae,Ctenophora pulchella,Diatoma vulgare,Diatoma tenuis,Ulnaria acus, Ulnaria ulna, Cocconeis pediculus, Cocconeis placentula, Achnanthes sp.,Rhoicosphaenia curvata,Mastoglia smithii var. amphicephala,Gyrosigma attenuatum,Naviculacryptocephala,Navicula tripunctata,Navicula veneta,Navicula radiosa,Craticula halophila,Caloneis ventricosa,Amphora ovalis,Amphora pediculus,Amphora veneta,Cymbella affinis,Cymbella cymbiformis,Cymbella cistula,Cymbella linearis,Cymbella parva,Cymbella tumidula,Cymbella lanceolata,Gomphonema angustatum,Gomphonema truncatum,Gomphonema intricatum,Gomphonema gracile,Gomphonema augur,Gomphonema angustatum var. producta,Epithemia sorex, Rhopalodia gibba ,Hantzschia amphioxys,Nitzschia acicularis,Nitzschia dissipata,Nitzschia pusilla,Nitzschia sigmoidea,Nitzschia tryblionella,Tryblionella hungarica,Cymatopleura elliptica,Cymatopleura solea,Surirella minuta,Surirella ovalis

11. Epipelic Algae • The epipelic algae percentages of the total number of organisms belonging to the Bacillariophyta, Chlorophyta, Cyanobacteria, Euglenophyta and Chrysophyta in the epipelic communities were 62%, 14%, 12%, 10% and 2%, respectively. The Bacillariophyta were dominant in terms of species number and abundance during the study period. However, members of the Cyanobacteria, especially Chroococcus limneticus, became dominant only at station II with a rapid increase in late summer and early autumn.

12. The epipelic algae displayed similar seasonal variations in 2009; however, the ranges of distribution of the epipelic algal composition and dominant species differed from each other at all stations. A higher abundance of epipelic algae was recorded at stations IV and III than at station I throughout the study. During the spring, numbers of the epipelic algae were very low at station I, and members of the Bacillariophyta constituted almost 80% of the epipelic algal community in both years.

13. During the summer (July and August) of 2009, while notable decreases in the total counts of epipelic algae were observed. The Bacillariophyta were dominant at station I, with 80% of the total individual counts of the epipelic algae. No changes in the numbers of members of the Chlorophyta and Cyanobacteria were observed at station I in this period on comparing with the spring period. Almost all of the Bacillariophya species dominating in spring were also superior in summer at all stations.

14. The maximum number of epipelic algae was recorded in September of both years, followed by a steady decline to the end of the year. Members of the Bacillariophyta were found at higher numbers than the Chlorophyta and Cyanobacteria at station I. Achnanthesminutissima was continuously to exist at station I and II. In particularly at station III Oscillatoria tenuisC. A. Ag (Cyanobacteria) grew rapidly in late summer and autumn at stations II , III and IV. Cocconeis placentula was continuously to exist at station II and III, in rarely at station I.

15. Neidium and Surirella species were constituted the majority of the epipelic community at all stations. The sediment of station I was mostly dominated by members of the Bacillariophyta and Cyanobacteria. Euglena acus, E. gracilis and Phacus lemmermannii (Euglenophyta) were widespread at stations II and III in the summer and autumn, but they were observed rarely at station I.

16. Epilithic Algae • The epilithic algal flora was mainly dominated by diatoms at all stations, and the dominating species in the epilithic algal flora differed from each other at all stations. Cocconeis placentula, Navicula lanceolata and N. helvetica were the most abundant species at all stations. Achnanthes ovalis, Hantzia amphioxys, Cymbella ventricosa, Epithemia sorex Kütz., Gomphonema acuminatum Ehr., Nitzschia tenuis Grun.were dominant at all station.

17. Discussion • Members of Bacillariophyta are usually dominated in the benthic algal flora of lakes and reservoirs in Turkey. Seasonal variations and the composition of the epipelic algal flora of the SDL were different from each other at all stations. Many studies concerning with diatoms in Turkey reported similarly that these results could be associated with different environmental conditions such as the chemical and physical nature of the sediment at the stations.

18. Whilst the Bacillariophyta were dominant at station I throughout the study period, they were dominant together with the Cyanobacteria at stations II and III during the summer and autumn.Navicula lanceolata, N. tuscula, Cocconesis placentula and Pinnularia viridis were dominant at all stations.

19. Similarly, the diatoms that grow well in calcareous and slightly alkaline water were also dominant in the benthic algal flora of the SDL.The results of chemical analyses of the reservoir water showed that it was slightly alkaline and was very suitable for diatoms. • In some members of the Cyanobacteria were subdominant at stations II and III, whereas they were not dominant at station I.

20. Euglena gracilis, Oscillatoria tenuis and O. minima were recorded in high numbers in the SDL during the summer and early autumn. The dominance of Nitzschia amphibia, Euglenaacus and Oscillatoria acutissima species suggested that the sediments of these stations are very rich in organic matter. Round indicated that members of the Euglenophyta were abundant in eutrophic water and on sediments polluted with organic matter.

21. When Sarıyar Dam Lake is also considered ecologically, of course, it is very important source for both Ankara city and central Anatolia. Remarkably, this study presents very important results and contributions relevant to productivity of the SDL. • However, there is no any guarantee for the its future, if it is polluted continually. Due to this cause, we have to make a comprehensively plan to protect in its natural environment. In a short time we must prevent the pollution sourced from anthropogenic effects. If not, SDL will be not in the next.

22. Asterionellaformasa Ulnariaulna Melosira varians Cyclotella ocellata Spirogyra gratiana Chlamydomonas globosa Epithemiasorex Oscillatoria princeps Merismopedia elegans

23. Scenedesmus acuminatus Fragilaria intermedia Diatoma vulgare Closterium dianaea

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