THE INFLUENCE OF DAM ON ALKALIZATION PROCESSES OF THE LOWER TISA RIVER Nemes, K. 1, Matavuly, M. 1, Bugarski, R. 2, Lozanov-Crvenković, Z. 1, Belić, S. 3 1University of Novi Sad, The Faculty of Sciences1 2Hydrometeorological Service of the Republic of the Serbia 3Faculty of Agriculture, University of Novi Sad 21000 Novi Sad, Serbia [email protected] Abstract The changeability of plankton dynamics was represented in our study of the lower river Tisa (157 – 9.5 r km) with characteristic changes of water trophic degrees depending on hydrometeorological station and influence of seasonal river water supply over the old reconstructed Danube-Tisa-Danube canal network. Therefore, the selected parameters of alkalization processes such as phosphatase enzyme activities- PAI, sodium adsorption ration- SAR, abundance of bacterioplankton, phosphate and iron content were compared and interpreted by matrices analyses and categorized graphs. PAI and oligotrophic bacteria were found to positively influence on SAR at the impounded water stretch St Novi Becej. At the downstream stations, the association of PAI and suspended solids was considerable. The obtained results of SAR index was found to be in negative relation with the iron content in boundary stretch St Martonos while at the St Novi Becej neutral phosphatase enzyme activities were positively correlated with the iron content. Therefore, we estimate relation of the SAR, PAI and iron content. Our study revealed that abundance of oligotrophs and centric diatoms influence on alkalization processes in Serbian part of the Tisa River, and are suitable for investigation of Ecological potential of regulated water bodies. The occurrence of brackish water diatom Entomoneis paludosa and small centric algae Cyclotella meneghiniana pointed to considerable problems of detailed canal network usage supplied by the river Tisa. Keywords: PAI, SAR, Dam, alkalization processes, river Tisa, Serbia. INTRODUCTION Concerning drought and flood conditions in the past in agricultural Vojvodina province of the Republic of Serbia, the construction of the canal network begun in the XVII century and was finished in 1977 when the Novi Becej Dam was put into the operation on the lower river Tisa (Tisza, Tissa). This Dam, situated at the 63rd killometre, make possible gravitational release of water into the Banat region from the Tisa river for purposes of irrigation of 300 000 ha of land as well as other requirements (Vajda, in Milovanov, 1972). The dam has 7 water gates of 24.5 m each, and a waterlock. The river Tisa formes a reservoir above the dam where the main channel is only a fraction of the total water surface in Hungary too (Honti et al. 2008). In the assessment of ecological potential (Directive 2000/60/EC) of ecohydrographical regions (Brilly et al. 2006), by the characteristic type of changes of water trophic degrees and influence on water supply after the gate, comparisons were made between long-term cation measurement and plankton research at four sampling stations. The lower part of the Tisa River, from the Moris mouth to its mouth into the Danube is 178 km long, and its makes a border of the Banat Region on the Tisa left-hand bank. The segment of the River is characterized by an almost horizontal riverbed (total slope is only 6m), and it is about the peak of elevation 64 m. In this segment the Tisa receives the waters of its main Banat tributaries- the Zlatica, Old Begej, Navigable Begej and Great Backa canal (Munteanu, 1997). MATERIAL AND METHODS The heterotrophic plate count in the colony forming units of bacteria (CFU cm-3) was determined by means of cultivation on nutrient agar in the period of 5-7 days at a temperature of 22°C. The oligotrophs were counted on ten times diluted nutrient agar (Gajin et al. 1992). The phosphatase enzyme reaction took place at 30°C by the use of substrate p- nitrophenylphosphate (5% final concentration of reaction mixture; the concentration of p- nitrophenol) was determined by measurement of absorption at 420 nm (Flint & Hopton, (1976); pH of un-filtered water samples was adjusted for acid (pH 5), neutral (pH 7) and alkaline (pH 9) conditions of water and average values of phosphatase activities were described as PAI index by Matavulj (1986); PAI- (In Serbian: indeks fosfatazno-enzimske aktivnosti) was chosen as an indicative parameter in evaluation and description of ecological potential: good (0.10-2.30 µmol pNP s-1 dm-3), moderate (2.30 - 5.00 µmol pNP s-1 dm-3), poor (5.00-10.00 µmol pNP s-1 dm-3), and bad potential (>10.00 µmol pNP s-1 dm-3). Chlorophyll a and physico-chemical analyses and was determined by the use of standard methods (APHA, 1995; HYDROLOGICAL YEARBOOKS, 1981-1987; 1998-2006) and toxicity test in accordance with Teodorović, (2004). The SAR index (Sodium adsorption ratio) was calculated according to guidelines for interpretations of irrigation water quality SAR=+ Na/( Ca Mg )/2 (Ayers & Westcot, 1976). Miliequivalents were calculated from miligrams per liter (Belic et al. 1997; Dalmacija, 2002). All data were analyzed using categorized graphs and correlation matrices by the software Statistica 8 (2008). RESULTS AND DISCUSSION Following the results of research showed in categorized graphs and tables, the succession of parameters is interpreted (Figure 1-6; Table 1-5). Scatterplot (Seasonal dynamics of phosphatase enzyme activities in Serbian part of the Tisa River) 21.6.82. 15.9.82. 22.6.83. 6.9.83. 26.6.84. 2.10.84. 26.6.85. 9.8.85. 15.12.02. activity: pH 5 3.7.03. 2.12.03. 31.7.04. 17.3.05. 21.6.82. 15.9.82. 22.6.83. 6.9.83. 26.6.84. 2.10.84. 26.6.85. 9.8.85. 15.12.02. day activity: PH 7 3.7.03. 2.12.03. 31.7.04. 17.3.05. 21.6.82. 15.9.82. 22.6.83. 6.9.83. 26.6.84. 2.10.84. 26.6.85. 9.8.85. 15.12.02. activity: pH 9 3.7.03. 2.12.03. 31.7.04. 17.3.05. -101234567-101234567-101234567-101234567 Martonos Novi Becej Zabalj Titel activity (μmol pNp s-1 dm -3) Figure 1. Shows features of PAI index: acid, neutral and alkaline phosphatase enzyme activities (µmol pNP s-1 dm-3) of four sampling stations (1982-2005). Table 1-4. Correlation matrix of parameters in Serbian part of the Tisa River at four sampling stations: temperature\total suspended solids\ oxygen\ pH condition\ conductivity\sodium adsorption ratio- SAR index\ phosphate concentration\phosphatase enzyme activities on pH 5, pH 7 and pH 9\PAI\abundances of bacterioplankton oligotrophs-O and heterotrophs- H\ ratio of O/H \iron content. Correlations (Tisa- parameters) Marked correlations are significant at p < .05000 N=12 St Martonos 165 river km T TSS O2 pH EC SAR PO4 pH 5 pH 7 pH 9 PAI O H O/H Fe T 1.00 -0.03 -0.76* 0.28 0.73 0.32 0.32 -0.13 -0.41 -0.31 -0.23 0.14 0.36 -0.38 0.20 TSS -0.03 1.00 -0.19 -0.22 -0.49 -0.54 0.03 0.40 0.42 0.37 0.47 0.64* 0.74* -0.06 0.85* O2 -0.76* -0.19 1.00 0.32 -0.43 0.15 -0.45 -0.03 0.24 0.20 0.07 -0.16 -0.49 0.37 -0.52 pH 0.28 -0.22 0.32 1.00 0.34 0.65* -0.48 -0.29 -0.26 -0.20 -0.33 -0.08 -0.14 -0.00 -0.41 EC 0.73* -0.49 -0.43 0.34 1.00 0.64* 0.22 -0.33 -0.47 -0.44 -0.40 -0.04 -0.06 -0.14 -0.24 SAR 0.32 -0.54 0.15 0.65* 0.64* 1.00 -0.10 -0.41 -0.40 -0.36 -0.36 -0.45 -0.44 -0.15 -0.60* PO4 0.32 0.03 -0.45 -0.48 0.22 -0.10 1.00 -0.26 -0.37 -0.39 -0.17 0.22 0.01 0.19 0.24 pH 5 -0.13 0.40 -0.03 -0.29 -0.33 -0.41 -0.26 1.00 0.89* 0.95* 0.91* 0.03 0.28 -0.34 0.40 pH 7 -0.41 0.42 0.24 -0.26 -0.47 -0.40 -0.37 0.89* 1.00 0.97* 0.87* 0.13 0.15 -0.03 0.34 pH 9 -0.31 0.37 0.20 -0.20 -0.44 -0.36 -0.39 0.95* 0.97* 1.00 0.91* 0.04 0.17 -0.18 0.28 PAI -0.23 0.47 0.07 -0.33 -0.40 -0.36 -0.17 0.91* 0.87* 0.91* 1.00 0.07 0.23 -0.26 0.35 O 0.14 0.64* -0.16 -0.08 -0.04 -0.45 0.22 0.03 0.13 0.04 0.07 1.00 0.68* 0.39 0.59* H 0.36 0.74* -0.49 -0.14 -0.06 -0.44 0.01 0.28 0.15 0.17 0.23 0.68* 1.00 -0.34 0.71* Fo/H -0.38 -0.06 0.37 -0.00 -0.14 -0.15 0.19 -0.34 -0.03 -0.18 -0.26 0.39 -0.34 1.00 -0.12 Fe 0.20 0.85* -0.52 -0.41 -0.24 -0.60* 0.24 0.40 0.34 0.28 0.35 0.59* 0.71* -0.12 1.00 Correlations (Tisa- parameters) Marked correlations are significant at p < .05000 N=12 St Novi Becej 65 river km T TSS O2 pH EC SAR PO4 pH 5 pH 7 pH 9 PAI O H O/H Fe T 1.00 -0.01 -0.82* -0.12 0.81* 0.30 0.39 0.19 0.25 0.16 0.13 -0.32 -0.24 0.10 0.11 TSS -0.01 1.00 -0.05 0.08 -0.25 -0.49 0.09 0.60* 0.75* -0.24 0.70* 0.22 0.01 0.01 0.85* O2 0.82* -0.05 1.00 0.31 -0.58* 0.01 -0.45 -0.48 -0.44 -0.45 -0.34 0.28 0.25 -0.31 -0.17 pH -0.12 0.08 0.31 1.00 -0.17 -0.05 0.21 -0.19 -0.14 -0.43 -0.26 -0.03 0.10 -0.49 0.24 EC 0.81* -0.25 -0.58* -0.17 1.00 0.29 0.35 0.07 0.15 0.43 0.10 -0.24 -0.17 0.11 -0.19 SAR 0.30 -0.49 0.01 -0.05 0.29 1.00 -0.32 -0.62* -0.63* -0.23 0.59* -0.41 -0.20 -0.23 -0.52 PO4 0.39 0.09 -0.45 0.21 0.35 -0.32 1.00 0.21 0.24 0.01 0.10 -0.43 -0.26 -0.27 0.52 pH 5 0.19 0.60* -0.48 -0.19 0.07 -0.62* 0.21 1.00 0.93* 0.46 0.90* 0.18 -0.06 0.40 0.46 pH 7 0.25 0.75* -0.44 -0.14 0.15 -0.63* 0.24 0.93* 1.00 0.39 0.96* 0.17 -0.04 0.28 0.60* pH 9 0.16 -0.24 -0.45 -0.43 0.43 -0.23 0.01 0.46 0.39 1.00 0.45 0.12 -0.05 0.60* -0.34 PAI 0.13 0.70* -0.34 -0.26 0.10 -0.59* 0.10 0.90* 0.96* 0.45 1.00 0.34 0.12 0.27 0.52 O -0.32 0.22 0.28 -0.03 -0.24 -0.41 -0.43 0.18 0.17 0.12 0.34 1.00 0.82* 0.15 0.05 H -0.24 0.01 0.25 0.10 -0.17 -0.20 -0.26 -0.06 -0.04 -0.05 0.12 0.82* 1.00 -0.33 -0.02 Fo/H 0.10 0.01 -0.31 -0.49 0.11 -0.23 -0.27 0.40 0.28 0.60* 0.27 0.15 -0.33 1.00 -0.22 Fe 0.11 0.85* -0.17 0.24 -0.19 -0.52 0.52 0.46 0.60* -0.34 0.52 0.05 -0.02 -0.22 1.00 Statistically significant correlation between parameters as standard indicators of water quality may be observed from table 1-4.