Acta Oecologica Carpatica I THE STRUCTURE AND DYNAMICS OF THE PHYTOPLANKTON FROM DRAGOMIRNA AND SOLCA LAKES (MOLDAVIA, ROMANIA) Cristina BLĂNARU 1, Mihaela ŢICULEAN 2 and Gabriela SASU 3 KEYWORDS: Romania, Moldavia, Dragomirna Lake, Solca Lake, phytoplankton, dynamics, numerical density, biomass. ABSTRACT In this paper was realised a has variations regarding its numerical comparative study regarding the density and biomass from one year to phytoplankton density and biomass of two another, without the presences of the algae artificial lakes: Dragomirna and Solca in the blooming phenomena appearance which can period 2001 - 2005. The water of both these show a hipertrophy level which modify the lakes was destinated for the local human organoleptical proprieties of the water. population needs, Dragomirna Lake water The predominance in the being used also for the Suceava locality phytopankton of the diatoms, both like industry. From the geographical point of density and biomass, confirm the relatively view both lakes are localised in the Suceava low level of trophicity of these lakes, a good Plateau, the Solca Lake being situated in a sign for the two ecosystems, indicating a forest area and Dragomirna Lake in a good quality of the water. hillocks lawn area. Based on the obtained results from The samplings were done with a the phytoplankton density and biomass frequency of 3 - 4 on year, starting in the analisis, the Solca Lake can be considered as month of April and finished in the first part oligotrophic and Dragomirna Lake as of November. It was highlighted that the mezotrophic. development degree of the phytoplankton REZUMAT: Structura şi dinamica fitoplanctonului lacurilor Dragomirna şi Solca (Moldova, România). În această lucrare s-a realizat un dezvoltare al fitoplanctonului a înregistrat studiu comparativ privind densitatea şi variaţii prinvind densitatea numerică şi biomasa fitoplanctonului a două lacuri de biomasa de la un an la altul, fără a se acumulare: Dragomirna şi Solca în perioada semnala fenomenul de înflorire a apei care 2001 - 2005. Ambele lacuri au fost destinate să indice un stadiu hipertrof şi să modifice alimentării cu apă a populaţiei umane, iar proprietăţile organoleptice ale apei. lacul Dragomirna este utilizat şi ca sursă de Predominanţa în fitoplancton a apă pentru zona industrială a oraşului diatomeelor, atât ca densitate cât şi ca Suceava. Din punct de vedere geografic, biomasă, confirmă nivelul relativ scăzut de ambele lacuri sunt localizate în Podişul troficitate al lacurilor, benefic pentru cele Sucevei, lacul Solca fiind situat într-o zonă două ecosisteme, indicând o apă de bună împădurită, iar lacul Dragomirna într-o calitate. pajişte colinară. Pe baza rezultatelor obţinute din Prelevările au fost făcute cu o calcularea densităţii şi a biomasei frecvenţă de 3 - 4 ori pe an, începând cu fitoplanctonice, lacul Solca se încadrează în luna aprilie şi terminând cu prima parte a categoria lacurilor oligotrofe, iar lacul lunii noiembrie. S-a constatat că, gradul de Dragomirna în categoria celor mezotrofe. The Dragomirna and Solca lakes phytoplankton structure and dynamics; 1/6 pp. - 1 - Acta Oecol. Carpat. I . ZUSSAMENFASSUNG: Struktur und Dynamik des Phytoplanktons in den Seen Dragomirna und Solca (Moldau, Rumänien). Die vorliegende Arbeit stellt die Biomasse jährlichen Schwankungen Ergebnisse einer zwischen 2001 - 2005 unterworfen ist, wobei jedoch keine durchgeführten vergleichenden Algenblüte festgestellt wurde, die ein Untersuchung betreffend Biomasse und hypertrophes Stadium angezeigt und die Dichte des Phytoplanktons der beiden organoleptischen Eigenschaften des Wassers Stauseen Dragomirna und Solca vor. Beide verändert hätte. Seen waren zur Trinkwasserversorgung der Die Dominanz der Diatomeen, Bevölkerung bestimmt, wobei der sowohl was ihre Dichte als auch die Dragomirna See auch zur Wasserversorgung Biomasse betrifft, bestätigt das relativ des Industriegebietes der Stadt Suceava niedrige, für die beiden Ökosysteme sehr dient. Geografisch gesehen, liegen beide gute trophische Niveau der Seen, das eine Seen im Hochland von Suceava, der Solca- gute Wasserqualität anzeigt. See in einem bewaldeten und der Auf Grund der Ergebnisse die sich Dragomirna-See in einem bergigen aus der Errechnung der Phytoplankton Grünland Gebiet. Dichte und Biomasse entnehmen lassen, ist Die Probenahmen fanden 3 - 4 der Solca-See in die Gruppe der mal/Jahr, von April bis zur ersten oligotrophen Seen einzustufen, während der Novemberhälfte statt. Es wurde festgestellt, Dragomirna-See in die Kategorie dass die Entwicklung des Phytoplanktons mesotropher Seen gehört. bezüglich der numerischen Dichte und der INTRODUCTION The Dragomirna lake has a length of Taking into account the importance 32 km, a total volume of 19.22 millions m3 of these lakes in providing water to Suceava and function as a reservoir of flows coming and Solca cities, we followed the biological from Suceava River and Dragomirna Stream. and chemical evolution of these two lakes The Solca Lake is located at the over a period of five years (2001 - 2005). border between the mountain area and the The most important criterion for this study piemont. The initial total volume of Solca was the trophicity of ecosystems based on lake was 3620 m3, but now it is found in an the quantitative analysis of phytoplankton advanced mudding status. and the level of nitrogen and phosphor. MATERIALS AND METHODS To be able to point out the qualitative The biological and chemical and quantitative structure of phytoplankton, characterization of these two lakes took into the samples were sampled quaterly from the consideration the recommendations enclosed following sections of Dragomirna Lake: in “Methodologic guide for following the feeding source; barrage 0 m, 3 m, 6 m; biological evolution of the lakes”, I.C.I.M, middle section 0 m, 3 m; rear end and from 1995, and in 1142/2002-Revised Order. the following sections of Solca Lake: feeding Density and biomass parameters source; barrage 0 m, 3 m; rear end. were calculated according to Pantle-Buck All the samples were preserved on method. It was also taken into consideration the field in Lugol solution, prepared the book “Volumetrical measurements of following the methodology and then they algae” by Cărăuş and Olteanu (2000, were concentrated in sedimentation cones revised). The results were represented as over the next 10 days. mean values and the units were exemplary/liter (ex./l) and milligrams per liter (mg/l). - 2 - C. Blănaru, M. Ţiculean and G. Sasu Acta Oecologica Carpatica I RESULTS AND DISCUSSIONS From physico - chemical and Solca Lake, over the five years biological point of view, the analysis of the period of interest, had the mean values of samples of water under investigation mineral nitrogen concentration comprised intended the determination of certain between 0.38 - 0.478 mg/l and 0.012 - parameters indicating the level of 0.033mg/l for mineral phosphor eutrophication and the quality of aquatic concentration. These values confined Solca environment. The most important parameter lake to oligo-mesotrophic lakes category to evaluate the trophic evolution of a lake are (Tab. 1). Dragomirna lake had the mean the nutrients and the phytoplanktonic values of mineral nitrogen concentration biomass. between 0.290 - 0.440 mg/l and the mineral phosphor concentration between 0.019 - 0.041 mg/l, reflecting the fact that Dragomirna Lake belongs to mesotrophic category (Tab. 1). Table 1: The yearly medium values of nutrients in the studyed lakes. 2001 2002 2003 2004 2005 Solca N mineral total mg N/l 0.467 0.487 0.38 0.449 0.464 Lake P mineral total mg P/l 0.019 0.0298 0.024 0.012 0.033 Dragomirna N mineral total mg N/l 0.321 0.29 0.235 0.401 0.454 Lake P mineral total mg P/l 0.041 0.037 0.019 0.023 0.029 In the same time, we performed the In the Solca Lake, the predominant biological analysis of these two lakes, taxonomic group of the phytoplankton is studying the quality parameter - the Bacillariophyta, which represents 50.24% in phytoplankton, in terms of density and 2001, 86.5% in 2002, 61.1% in 2003, 72.8% biomass and also in terms of taxonomic in 2004 and 83% in 2005. groups of algae. As shown in the figure 1, the other taxonomic groups are less well represented compared to main group with percentages between 1 - 25%. 100% 80% Euglenophyta 60% Chlorophyta Pyrrophyta 40% Bacillariophyta Chrysophyta 20% Cyanophyta 0% 2001 2002 2003 2004 2005 Year Figure 1: Distribution of algae groups (%) in Solca Lake during 2001 - 2005 period. The Dragomirna and Solca lakes phytoplankton structure and dynamics; 1/6 pp. - 3 - Acta Oecol. Carpat. I . The figure 2 shows the 2003, 67.8% in 2004 and 39.5% in 2005. predominance of Baccilariophyta group in Also well represented is the Chlorophyta Dragomirna Lake with a good representation group with the percentage of 9.6 - 30.6% of 35.7% in 2001, 33.3% in 2002, 35.3% in over the five year period. 100% 90% 80% 70% 60% Euglenophyta Chlorophyta 50% Pyrrophyta 40% Bacillariophyta Chrysophyta 30% Cyanophyta 20% 10% 0% 2001 2002 2003 2004 2005 Year Figure 2: Distribution of algae groups (%) in Dragomirna Lake during 2001 - 2005 period. Among the representative species of density and biomass in Solca Lake recorded Bacillariophyta group found in Solca Lake, it a reduced level between 2001 - 2004 with is worth mentioning the following: Synedra the most significant increase in 2005 ulna, Achnanthes minutissima, Gomphonema (560270 ex/l and 3.86 mg/l respectively). olivaceum, Cymbella ventricosa, Navicula sp. The lowest value was observed in 2003 Among the representative species (343332 ex/l and 0.94mg/l respectively). found in Dragomirna Lake are: Asterionella The phytoplanktonic biomass is usually formosa, Cyclotella sp., Navicula direct proportional with the cellular density, cryptocephala (Bacillariophyta), Oocystis which means that high cellular density sp., Coelastrum cambricum (Chlorophyta), corresponds to high phytoplanktonic Ceratium hirudinella (Pyrrophyta). biomass as a result of the presence of large As shown in the figure 3, the mean forms of algae.