Ecological Potential of Phytoplankton Communities in the Danube- Tisza-Danube Hydrosystem in Southern Region ()

Karolina Nemes, Milan Matavuly, Zagorka Lozanov-Crvenković, Slavka Gajin, Božo Dalmacija [email protected]

The Faculty of Sciences, University of Novi Sad, Trg Dositeja Obradovica 2, 21000 Novi Sad, Serbia

Abstract

Ecological potential of the phytoplankton communities was evidented by extracellular phosphatase enzyme activity, ratio of oligotrophs and heterotrophs, Pantle-Buck indices and SEM research. The diatom species belonged to the following genera: Cyclotella, Diatoma, Stephanodiscus, Cymbella, Amphora, Cocconeis, Gomphonema, Rhoicosphenia, Nitzschia, Navicula, Aulacoseira, Surirella, Achnanthes spp. The use of spatially distributed qualitative and quantitative data of water is showing that phytoplankton communities of DTD canals differed moderately to poorly from Romanian rivers entering Serbia.

Key words: phytoplankton, indices, DTD canals, moderate ecological potential

Introduction

The Danube-Tisza-Danube canals in Province are sinks for nutrients and pollutans. In European water quality system (DIRECTIVE 2000/60/EC), recent algal studies are based calculations of different indices, mainly characterized by benthic diatoms species richness (Van Dam et al. 1994; 2006; Ács et al. 2006) and phytoplankton functional assemblages (Reynolds et al. 2002). Having in mind that the main difference between communities and assemblages is in the definition of assemblages- no interaction is postulated (Gallé, 1998). In our study, the indices of plankton activities are proposed.

Results and discussion

The investigation of the Southern Banatian Rivers and Danube-Tisza-Danube Canal - Novi Becej in Serbia has been carried out six times in the course of 2003 and 2004 by collecting the surface water samples and sporadically periphyton probes at selected sampling stations (Fig. 1). The research was made along the northern-southern channel development: The Tamis River- boundary sampling site Jasa Tomic, then the confluence of the River to the DTD canal and canal in Botos after the dam; The Brzava River (boundary site) and downstream DTD canal in Banatska Dubica and small villages; Romanian river tributaries The Moravica, The Karas and The River; confluence of the DTD Canal network to the Danube River at sampling site and lastly, The Danube River (Banatska Palanka)- left bank. Identification of algae was based on light microscopy and Scanning electron microscope (SEM JEOL JSM-6460LV). Using bioindicative values of species determined by Gulyás (1998), saprobity indices were evaluated from phytoplankton according to Pantle-Buck (1955); Klee, & Steineberg, (1987); Krammer & Lange-Bertalot, (1988), and saprobic conditions were characterized as high <1.8 (oligosaprobity); good 1.8-2.3 (β-mesosaprobity); moderate 2.3-2.8 (β-α- mesosaprobity); poor 2.8-3.3 (α-mesosaprobity) and above 3.3 as bad status (polysaprobity). Phosphatase enzyme activity (PME- phosphomonoesterase) of untreated water sample was measured spectrophotometrically using p-nitrophenylphosphate as a substrate for acid, neutral, and alkaline enzyme activity of water (OD420nm). The phosphatase enzyme activity revealed the potential of transformations of phosphorus-containing organics of water by the heterotrophic and autotrophic microbial communities. Therefore, ecological potential was proposed using the PAI index described by Matavulj, (1986) (In Serbian: Indeks fosfatazno-enzimske aktivnosti- IFA): high 0.01-0.10 µmol PNP s-1dm-3, good 0.10-2.50 µmol PNP s-1dm-3, moderate 2.50-5.00 µmol PNP s-1dm-3, poor 5.00-10.00 µmol PNP s-1dm-3, and bad

BALWOIS 2008 – Ohrid, Republic of Macedonia – 27- 31 May 2008 1/7 status above 10.00 µmol PNP s-1dm-3. The heterotrophic plate count in the colony forming units of bacteria (CFU cm-3) was determined by means of cultivation of series of diluted water samples on nutrient agar in the period of 5-7 days at a temperature of 22°C (cultivation of oligotrophs was made on ten times diluted nutrient MPA media). Fo/H index pointed out oligotrophication processes: excellent (>10), moderate (1-10) and poor (<1) (Gajin et al. 1990). Basic water analyses from Hydrological yearbooks (2004-2005) and Nemes (2006), were coordinated by factor analyses by the use of Statistica 8 (2008) provided from the University of Novi Sad.

Figure 1. Distribution of sampling sites of the HS DTD (canal Banatska Palanka – Novi Becej with the river tributaries entering from ). In Banat region, the canal network Banatska Palanka – Novi Becej is disturbed with floodings, droughts and the level of the wastewater purification, not only in Vojvodina but also in the countries located upstream.

Results and discussion

The European Water Framework Directive proposed algae to be included in the assessment of ecological status/potential that would be one of hydrobiological elements in an estimate of changes in the quality of water and rational use of resources. The bacterioplankton influnce was recorded on plankton community when the changes occured in March and Avgust. The lowering of Pantle-Buck index was estimate in July of 2003 and November of 2004, when the water level reaches its lowest peaks during the years (Hydrological yearbooks, 2004-2005) (Fig. 5). However, these period of research has been characterized with highest max. values of precipitation (Meteorological yearboks, 2002-2005).

Histogram ( 14v*136c) Histogram ( 14v*136c) Histogram ( 14v*136c) Fo/H = 60*2*normal(x; 4,1538; 3,5361) S = 63*0,1*normal(x; 2,2085; 0,1191) PAI = 58*2*normal(x; 3,4726; 2,7998) 20 22 30 20 28 18 26 18 16 24 16 22 14 20 14 12 18 12 16 10 10 14 No of obs No of No ofobs

No of obs No of 8 12 8 10 6 6 8 4 4 6 4 2 2 2 0 0 0 1,8 1,9 2,0 2,1 2,2 2,3 2,4 2,5 2,6 -20 2 4 6 8 10121416 -2024681012141618 S PAI Fo/H Figure 2-4. Histograms of frequencies of the parameters Fo/H index, PAI and Pantle-Buck index. In accordance with the graphs, the qualitative and quantitative biological quality element was categorized in Figures 5 and 6.

BALWOIS 2008 – Ohrid, Republic of Macedonia – 27- 31 May 2008 2/7 Scatterplot (Seasonal dynamics of Pantle- Buck (1955) in the HS DTD in Southern Banat region)

Tamis JT Tamis B DTD Botos Brzava DTD BD DTD J Moravica DTD V Karas Nera DTD K Danube BP

1,80 2,00 2,20 2,40 1,80 2,00 2,20 2,40 1,80 2,00 2,20 2,40 1,90 2,10 2,30 2,50 1,90 2,10 2,30 2,50 1,90 2,10 2,30 2,50

July `03 December `03 March `04 St

Tamis JT Tamis B DTD Botos Brzava DTD BD DTD J Moravica DTD V Karas Nera DTD K Danube BP

1,80 2,00 2,20 2,40 1,80 2,00 2,20 2,40 1,80 2,00 2,20 2,40 1,90 2,10 2,30 2,50 1,90 2,10 2,30 2,50 1,90 2,10 2,30 2,50

June `04 August `04 November `04

Figure 5. Seasonal dynamics of Pantle–Buck index (1955) of northern-southern direction of sampling stations in the HS DTD canal network) during the 2003-2004 was shown. Saprobity- S, pointed by markers became possible to categorize Ecological potential of the Danube-Tisza-Danube canals (blue- excellent, green- good, yellow- moderate, orange- poor, red– bad).

The algal composition was basically sustained of a planktonic-benthic species in spring and summer (Diatomaeae-Chlorophyceae) and epiphytic-benthic composition in autumn and winter (mainly Diatomeae- Cyanobacteria-Flagellata). Phytoplankton communities have been characterized with the presence of 140 of algal taxa of which 19 Cyanobacteria, 18 Euglenophyta, 64 Bacillariophyceae, 2 Chrysophyceae, 39 Chlorophyta, 2 Dinophyta during the „dry year“ of 2003 folowed by 2004. Downstream of the Tamis River, common species included Cyclotella meneghiniana, Rhoicosphenia abbreviata, Cymbella tumida, C. affinis, C. minuta, Cymatopleura solea, Stephanodiscus hantzschii, S. neoastrea, Fragilaria ulna, F. capucina, Gyrosigma attenuatum, Nitzschia levidensis (sin. Tryblionella levidensis), etc. (Fig. 5) which were detected in the DTD canals together with desmids characteristic for eutrophic waters (Closterium moniliferum, Closterium ehrenbergii, Closterium aciculare, Cosmarium botrytis, Cosmarium laeve). In June the dominance of centric diatom Stephanodiscus was recorded comparing to the group Euglenophyta and green algae abundant in The Brzava River, respectively. The Moravica River almost lost its feature when the blooming of cyanobacteria Anabaena flos-aquae with max. chlorophyll- a content exceeded 1001.2 mg m-3, which caused the decrease in the number of phytoplankton species and highest phosphatase activity of water- 66.65 µmol pNP s-1dm-3 in August of 2004. Phytoplankton communities were characterized with increase of green algal inedible species as Scenedesmus opoliensis,

BALWOIS 2008 – Ohrid, Republic of Macedonia – 27- 31 May 2008 3/7 Scenedesmus quadricauda and Pediastrum spp., in canal and Pandorina morum in the rivers together with increase of coliform bacteria (Nemes & Matavuly, 2006).

Scatterplot (Seasonal dynamics of PAI (Matavuly, 1986) and Fo/ H index in the HS DTD in Southern Banat region)

Tamis JT Tamis B DTD Botos Brzava DTD BD DTD J Moravica DTD V

index: PAI Karas Nera DTD K Danube BP

St Tamis JT Tamis B DTD Botos Brzava DTD BD DTD J Moravica DTD V

index: Fo/H Karas Nera DTD K Danube BP

-2 2 6 10 14 18 -2 2 6 10 14 18 -2 2 6 10 14 18 -2 2 6 10 14 18 -2 2 6 10 14 18 -2 2 6 10 14 18 0 4 8 12 16 0 4 8 12 16 0 4 8 12 16 0 4 8 12 16 0 4 8 12 16 0 4 8 12 16

m: July `03 m: December `03 m: March ` 04 m: Ju n e `04 m: August `04 m: November `04

Figure 6. Ecological potential shown with Fo/H index (cfu/ml) and phosphatase enzyme activity of water (µmol pNP s-1 dm-3) of the DTD hydrosystem in Banat region (Northern-southern sampling stations development) during the 2003-2004 (blue- excellent, green- good, yellow- moderate, orange- poor, red– bad).

In DTD hydrosystem in the Southern Banat region, the phytoplankton growth was found simultaneosly with the decrease of Fo/H index when PAI indicated Ecological potential with yellow- moderate and orange- poor markers (Fig. 2-6). Comparing of water quality of the canal DTD in 1984 with the condition sixteen years later in 2000 significant improvement of water quality due to the measures of protection and conservation undertaken and also due to reduced water transportation and industrial production has been recorded at the Zrenyanin-Banatska Palanka stretch of Main canal of DTD canal net. Only samples taken at Botosh sampling site in the spring and at Vlaykovac during the summer season belonged to moderate class, or to the category of polluted water estimated by PAI. The heterotrophic bacteria pointed out third water class of Vlaykovac and Banatska Palanka in spring of 2000 (Matavuly et al. 2004). The diatoms consist predominantely of cosmopolite eurihaline fresh-water forms, e.g. detritus is deposited on the slip off the slope may here form area of rich in sediments extending into the further fresh water region. The species which occured in plankton and periphyton, such as Cyclotella meneghiniana, exhibit

BALWOIS 2008 – Ohrid, Republic of Macedonia – 27- 31 May 2008 4/7 similiar coordinates with phosphatase activities, phosphorus concentration and is following the processes of alkalization, represented by factor analyses graphs (Fig. 7). Represented by SEM micrographs Cymbella species attributed to the secretion and adhesion processes, and on the other on phosphorus concentration (Fig. 8). Accordingly, protein phosphatase detected in variable pH conditions, enables the cells to maintain the effectively the concentration of its physiologicaly important nutrients. It has long been known that in warmer region brackish water species, such as the Entomoneis paludosa in northern sector will penetrate further into freshwater than in the northern region (Remane, & Schlieper, (1971). Altogether, DTD hydrosystem in Banat Region is an area in which the sequence of species form the salt to fresh water changes compared with the other continental European Ecoregions for rivers and lakes (Directive 2000/60/EC). The diatom E. paludosa, prominent in The Old Begey River (Nemes & Matavuly, 2005) sporadically occurred at the sampling site- Tamis Botos. Actively migrating forms mobile algae such as Nitzshia and as well as attached algae- Rhoicosphenia and Cymbella with their salinity tolerance through the particular condition of the canal are found in all samples. The matching of areole, shown in the DTD hydrosystem in Banat region, is showing that a small, specialized area located on algae from which spines, or branches may arise is the similarity with plants such as cactus. On the other hand, the species which are not exposing the spines have a unique mobility, by the coiling of secreted silicon structures and attachment (Fig. 8). Therefore, the importance of species in southern sector of DTD hydrosystem should not be underestimate. The identical properties of phytoplankton communities are rare, and change point is pointed out the affected region by the drought in 2003 in southern sector (sampling site downstream the Brzava River) (Fig. 1-3). The occurences of Rhoicosphenia abbreviata was detected at the sites of confluence of investigated rivers which are entering Serbian teritory such as Old Begej, Navigable Begej and Tamis or small canal to the Canal Banatska Palanka-Novi Becej and the Danube (Fig. 1). Diatoma vulgare occured in stretches of consistent flow of freshwater into the another water, and followed the bacterioplankton abundance and oxygen balance (Fig. 7-8). The confluence of the DTD canal to The Danube River at Kajtasovo-Banatska Palanka stretch was characterized with Stephanodiscus species which showed thickened morphology similiar to Cyclotella meneghiniana of the same stretch in June 2004 (Fig. 8). The habitat requirements of these prominent centric algae is related to heterotrophy which is moving the species toward biondication of alkalization processes in southern sector of the Canal Banatska Palanka-Novi Becej and tributaries The Karas and The Nera (Fig. 7).

Figure 7. Factor analyses graph of environmental Factor Loadings, Factor 1 vs. Factor 2 condition of dominant Extraction: Principal components diatoms Cyclotella, 1,2 Diatoma, Cymbella and NO3 1,0 Stephanodiscus (T- PO4 temperature, PR- 0,8 precipitation, IN- insolation, Water level, 0,6 PRIN PA pH 5 pH concentration of 0,4 phosphorus(P),phosphate (PO4), dissolved oxygen, 0,2 PhosphorusPAI conductivity (EC), O2 nitrogen- ammonium 0,0 PA TpH 7 (NH4), nitrate (NO3),

Factor 2 Fo/H chlorides- Cl, sodium, -0,2 PACO2 pH 9 Diatomaolig. Hla SAR index, pH, alkaline, -0,4 Cyclotella Cl StephanodiscusCymbella neutral and acid SAREC phosphatase enzyme -0,6 NH4 activities (pH 5, pH 7, pH -0,8 Het. 9), phosphatase activity water level index- PAI, conc. of -1,0 chlorophyll- a, abundance -1,2 of oligotrophs-olig., -1,2 -1,0 -0,8 -0,6 -0,4 -0,2 0,0 0,2 0,4 0,6 0,8 1,0 1,2 heterotrophs- het. (2003- 2004). Factor 1

BALWOIS 2008 – Ohrid, Republic of Macedonia – 27- 31 May 2008 5/7

a b c

d e f

Figure 8. SEM micrographs of prominent diatoms of the sample of the southern DTD hydrosystem at the confluence of the Canal Banatska Palanka - Novi Becej to The Danube River in Banat region of the early summer (June ’04): a) Cymbella tumida and Stephanodiscus hantzschii, b) Stauroneis anceps with C. meneghiniana and Cymbella, c) Stephanodiscus neoastrea with Cymbella, d) Stephanodiscus hantzschii, e) Rhoicosphenia abbreviata with Diatoma, Cymbella and S. hantzschii, f) Diatoma vulgare, Cymbella minuta, Cyclotella, Nitzschia.

Conclusion

In the Danube-Tisza-Danube canal network in Banat region, the growing algae pointed out determination of the changes in Ecological potential of the canalized DTD sector. The use of spatially distributed qualitative and quantiative data put into indices Pantle-Buck, ratio of oligotrophs and heterotrophs, phosphatase activity index of water with the SEM micrographs of periphyton is showing that phytoplankton communities of DTD canals differed moderately to poorly from Romanian rivers entering Serbia.

Acknowledgement

These studies were supported by the Ministry of Science of the Republic of Serbia as a part of the Project No 1945, No 144025 and No 142058. We are grateful to University of Novi Sad- Center of Scanning Electron Microscopy research.

References

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