Volume 11 (2006)
Articles
THE CHARACTERISTICS OF THE BIOCENOSES IN THE THREE LAKES FROM THE NEPTUNE – JUPITER RESORTS (CONSTANTZA COUNTY)
STOICA GODEANU, MARIOARA GODEANU, ADRIANA CIUREA, NICOLAE FĂTU
In the chain of natural lakes on the Romanian seashore of the Black Sea three new man-made lakes appeared in 1970, situated in the area between the Neptune – Jupiter resorts and the sand belt of the litoral. They were created by dredging the old swamp near the Comorova forest. The swamp covered an area of 44 acres and it used to stretch on a length of 1700 m and a width of approx. 380 m. After it was dredged, three lakes were created, two in the Neptune resort (called Neptune and Jupiter or Neptune 1 and Neptune 2) and one the Jupiter resort (called Tismana or Neptune 3) (Breier A., 1976, Gastescu, 1971)
RESERVOIR DEVELOPMENT VS. BIODIVERSITY: IS IT ALWAYS A REAL CONFLICT? A CASE STUDY – BISTRIÞA VALLEY, ROMANIA
IOAN CĂRĂUŞ, DAN TEODORESCU
An usual perception related to hydroelectric developments resulted in the hypothesis, even in the common opinion, that the construction of large dams produces – as a rule – an important, negative impact, not only on the local environment, but also, at the level of the biodiversity in the area. Of course, there are some certain and major environmental changes involved by hydroelectric developments. One of these is represented by the interruption of the river continuity and, subsequently, by some significant changes within the fish fauna of the aquatic ecosystem. Such modifications were recorded on Bistriþa River, after the finishing of the hydroelectric schemes. Based on the results of the relative numerous results of a long period of research carried out on different aspects of the environment and the biota within the upper, middle and lower sectors of Bistriþa River valley, the authors try to define the real impact of the hydroelectric developments – at the level of the whole river basin and referring to a long period of time – upon the general biodiversity.
HYDROGEOLOGICAL AND GEOMORPHOLOGIC ASPECTS IN SOMUZU MARE SUPERIOR BASIN
NECULAI ANDREIAŞI, CLAUDIA ANDREIAŞI, DANIELA JITARIU
Somuzu Mare river is a Siret affluent and its origin is in Liteni depression. It crosses the whole north-west depression area, and through first class affluents (Lãmãºanca, Graniþa, Stupca, Drãgoiasca and others), it develops a lot of ridges, due exclusevely to the subsequent nature of the stream system. Glacis microrelief, alluvial fans, special river flats represent a trully phreatic waters „store”, also related with lithologic constitution, on support clayey. Hydrogeological aspects in Somuzu Mare superior basin have been considered part of natural resources from Suceava' s tableland western area, near the contact with carpethians miocene unit. The attachment of phreatic waters map, with hydrocontourlines and hydroisobathes drawing, completes the information regarding hydrogeologic resources, their way of using and, related to this, the monitoring of other natural resources, like the soils and vegetation.
THE FAST TECHNOLOGIES FOR PROTECTION AGAINST FLOODS
DAN DĂSCĂLIŢA
The floods produce the damages with disastrous effects at population and the social economic objectives. The climatic changes from the last century and the human activities conducted to floods with high frequency, in the high risk areas as in the areas without this kind of phenomena. The existent measures of defence against floods (regularizations of rivers, banking protection zone of the of banks, etc.) could become inadequate in the extraordinary conditions. It is sufficient the exceed with several centimetres of the defence work quotas by the maximal calculated flow level, in order that the localities, in fields or socio – economic objectives to be flooded. The frequency of this phenomenon is increasing in Romania and in another areas of the World. In such of situations the existence of the measure intercession with the fast technologies of defence against floods, could represent concrete solutions which head off he damages. Such of technologies are especially useful in the situation of the producing of the maximal floods with historical character and fast propagation. The systems of fast protection (in real time) contain 2 distinct subsystems: - The informatical forecast and warning subsystem, which the function of warning the floods that exceed the flooding level and that establish automatically the risk areas , emplacements and the dimensions of the protection devices . - The technological subsystem of execution of the protection dimensional commanded work of the informatical forecast and warning subsystem . This paper proposes to present theoretically and succinct few examples of fast protection of the socio – economic objectives in the imminent cases of floods .
MODIFICATIONS OF PHYTOPLANKTON STRUCTURE IN THE CIRIC LAKE DETERMINED BY ALGAL BLOOM
MIHAI COSTICĂ, NAELA COSTICĂ
Algal bloom takes place in the eutriphized waters and represents the expression of industrial development and ecological perturbation in the context of a negligence concerning the environment protection. The waters bloom is followed by the degradation of the water quality and the impossibility of using it for drinking, agriculture and amusement. Some species of blue-green algae produce toxins (Collins 1978, Codd 2000) and require strict control of the phenomenon of algal bloom. In order to have control on the phenomenon of algal bloom, it is necessary to understand the mechanism that leads to this phenomenon. An explanation is that among the species of the phytoplankton there is competition for light and nutrients realized by biochemical, physiological and morphological mechanisms (Legrand Catherine 2003). It was noticed that Microcystis produces blooming more often in stagnant waters than in running waters (Pearl 1988). Thus, blooming is naturally controlled by water conditions and phytoplankton composition, and this implies classifying the existent species in phytoplankton before and after algal bloom (the objective of this study).
THE RAPPORT BETWEEN THE STRUCTURES OF GASTROPODS POPULATIONS AND THE TYPES OF CONTINENTAL AQUATIC ECOSYSTEMS
OLIVIA CIOBOIU
One of the decisive factors the distribution and location of Gastropods, as well as other organisms from the continental aquatic ecosystems depend on is the type of ecosystem they populate. Continental waters are grouped in springs, streams, mountain, hill and plain rivers, the Danube and the Danube Delta, lakes, pools, swamps, underground waters. As compared to other types of ecosystems, we shall identify the Gastropods specific to these ecosystems due to their ecophysiological features (CIOBOIU CODOBAN, 2003).
LONGITUDINAL DITRIBUTION OF THE MAYFLIES (EPHEMEROPTERA) COMMUNITIES IN BUZÃU RIVER
OANA RISTEA, ANCA NEAGU, IONEL MIRON
According to Water Framework Directive 60/2000/EC, benthic macroinvertebrates become a priority in establishing of the surface water status. Among these, the mayflies (Ephemeroptera) have an important role in the evaluation of the physical, chemical and hydromorphological conditions of water flows. Mayfly taxa are widely accepted as bioindicators for water quality and ecological integrity (Bauernfeind & Moog, 2000). In the course of their evolution, mayflies have adapted to certain hydromorphological conditions, therefore, knowing these conditions we can appreciate the population structure and vice versa, knowing the population structure we can appreciate their environmental conditions. That`s why, the mayflies as all macroinvertebrates are the most used indicators for the determination of the water quality, because they respond to a great number of characteristics such as altitude, bottom, velocity and physical-chemical parameters. The Buzãu River represents one of the most important tributary of the Siret River, with a length of 302 km (Fig 1). The surface of the Buzãu river basin contains three kinds of relief: mountains, hills and field, from the peaks of Penteleu to the Bãrãgan plain. The prevailing geological structure is a siliceous one, followed by an organic and a reduced calcareous structure. The distribution of the precipitations and the temperature follow the great forms of relief. Thus, the annual mean precipitations vary from 400 mm/year to 1200 mm/year and the annual mean temperature from – 4 oC in the mountain to 10C in the plain.
PRELIMINARY RESULTS OF USING EXTERNAL ATTACHED RADIO-TRANSMITTERS TO TRACK THE MOVEMENTS OF ROMANICHTHYS VALSANICOLA DUMITRESCU, BANARESCU & STOICA, 1957
ADRIAN IONAŞCU, NICOLAE CRĂCIUN
The asprete, (Romanichthys valsanicola Dumitrescu, Banarescu & Stoica, 1957) is an extremely endangered species, endemic to a Romanian river: Valsan. Romanichthys valsanicola is the fish genus having the smallest range in Eurasia and was considered by Maitland (1991) the most endangered freshwater fish species in Europe. Once Palearctic the asprete is now a preglaciar relict, which can be found in our days only in the river Valsan. Found in cold, clear, fast-flowing areas, hidden under rocks. Territorial. The asprete is a predator feeding exclusively on aquatic invertebrates: larvae of rheophilic insects, mainly mayflies and stoneflies. As part of an ongoing study into the behaviour and ecology of asprete, eight radio-tagged asprete were tracked in the River Valsan, a central roumanian stream, from august 2004 to December 2004. Unfortunately two of them had been lost, and one was released, and his tracking was cancelled, due to his small size. The radio-tracking procedures were obstruct during July, August and November because of high rainfall who caused the River Valsan to flood repeatedly, with these floods being of unusual duration and severity.
MAIN CHEMICAL PARAMETER WITH PATHOLOGICAL INFLUENCE CONDITION IN FISH
AIDA VASILE, GEORGE VASILESCU, VALERIU GHEORGHE
Fish population from various breeding systems, may be affected by diseases other than those infection or parasitical, namely unspecific diseases. Physical and chemical ambient, nutritional and constitutional agent causes these. Water chemistry is defined by a multitude of parameters, from which more important for fishes' life are pH, dissolved gasses (oxygen and carbon dioxide), organic mater in suspension, its concentration in ammonia, nitrites, nitrates, phosphates, chlorides, sulfates, hydrogen, sulfides, metals, detergents, pesticides and phenols. Starting from this reason, in the present work it is shown the evolution of the main chemical parameters in the pond water for breeding cyprinids of first year EC3A from Brates farm during the year 2004. There were examined water pH, dissolved oxygen content (mg/l), decomposing organic matter (mg of KMnO4/l of water), ammonia (mg of NH3/l of water) and nitrites (mg of NO2/l of water), parameters which indicate, in the situation of exceeding of the admissible limits for culture cyprinids, which may cause pathological conditions in fish. From May to October 2004, as a result of the conducted research, there have been 7 parasitic diseases registered on the cyprinids of the first summer from the EC3A growth pond.
ASPECTS ON THE QUANTITATIVE AND QUALITATIVE COMPOSITION OF BICAZ LAKE ICHTHYOFAUNA
ALINA CIUCANU
The purpose of this study was the determination of quantitative and qualitative composition, the ecological state of the original species and of those introduced by man in Bicaz Lake, which, undergo continuous transformations because of annual variations of water level and of the position of the mid-altitude lake in a mountainous area. Previous investigations on the different aspects of the composition and evolution of the ichthyofauna of Bicaz Lake allow us the realization of a comparative study to point out the modifications occurred from the origins of the lake until now. Thus, during the first years from its formation, the ichthyofauna was represented by a number of 25 species (Matei D. and Dimitriu M., 1963); after about 15 years of existence were recorded only 19 species (Battes K., 1974); after about 37 years of existence were mentioned 14 species (Miron L. and Simionescu C., 1997). Because of the diminution of the number of species it becomes necessary a periodical surveillance of quantitative and qualitative reports between the different ichthyofaunistic species.