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Atanasovsko Lake (7.200 ha, Southeast Bulgaria) incorporates diverse habitats and lies along the Europe's second largest migration route, Via Pontica. The dynamics of environmental conditions, factors controlling water quality and ecological status (water chemical parameters and biological quality elements) were studied for three years. The key fac...
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Context 1
... final evaluation during 2013 was deter- mined as moderate in North and South salterns, and good for Azmaka (Figure 2). Data from 2014 showed that the ecological status of North Saltern was moderate, while of South Saltern and Azmaka was good. ...
Context 2
... still under development for the national L10 lake type. Thus the integrated assessment represented the aver- age value of scoring assessment both of applied met- rics (phytoplankton and benthic invertebrates) and of the four key BQEs. Relative improvement through- out the three years could be recognized for the site located at the North Saltern (Fig. 2), with moderate to good potential in the last year. Both South Saltern and Azmaka were in moderate ...
Citations
... In Bulgaria, there are several large saline lakes with varying salinity between 1 and 7%. Three limans with salinity of 3-5% (Vaya, Mandrensko and Atanasovsko) are connected with the Black sea (0.17-0.18% salinity) coast near Burgas town (Gecheva et al. 2017). The lagoon Pomorie Lake (7%) situated near Pomorie town is separated from the Black sea by a man-made dike and a sand bar (Ivanova et al. 2006). ...
Halophilic bacteria are recognized as a promising source of novel enzymes and biopolymers with various applications in biotechnology and the industry. In comparison with their mesophilic analogues, halophilic metabolites are stable under extreme conditions typically encountered in the industrial processes. In this study, the biotechnological potential of twenty strains of halophilic bacteria isolated from the Provadia salt deposit, Bulgaria was investigated for the first time. The strains were identified based on the sequencing of the 16S rRNA gene and were assigned to 13 different species falling in the Bacillota and Pseudomonadota phyla. The majority (90%) of them showed single or combined hydrolytic enzyme activity. Half of the strains (55%) were able to produce between three and eight extracellular hydrolytic enzymes—arabinase, cellulase, gelatinase, glucanase, L-glutaminase, pectinase, and xylanase. Ten strains were able to synthesise exopolysaccharides (EPS) in concentration between 32 and 227 μg/ml. The optimal EPS production kinetics (1.6 ± 0.15 g/l) by Virgibacillus halodenitrificans PSZ-34 was systematically investigated for the first time. Three strains also exhibited antimicrobial activity. The present study involved culture-dependant isolation of halophilic bacteria from the Provadia salt deposit and shed more light on their capability to synthesise hydrolytic enzymes and EPS with potential industrial exploitation.
... (Hammer, 1986) (Last, 1993;Jellison et al., 1996;Shadrin, 2009) به سابقه از شور فوق های آب پالنکتونی اجتماعات مطالعه این . (Ruinen, 1938) (Elloumi et al., 2009) واحد 54 شوری بیشینه با بلغارستان در Atanasovsko ثبت فیتوپالنکتونی گونه 14 حداکثر حضور هزار در شهر های حوضچه در و (Gecheva et al., 2017) ...
Hypersaline ecosystems provide excellent conditions for ecological studies of aquatic ecosystems. Lipar Lagoon is an understudied hypersaline lagoon located in southeasternmost Iran (northern Gulf of Oman). Knowledge about the biotic and abiotic characteristics of this hypersaline water system is limited. This research thus investigated the plankton community composition and abundance, and also its variability under variable environmental conditions over one year. Monthly (five replicates each month) water samplings were performed from 2017 to 2018, during pre-monsoon, monsoon, and post-monsoon seasons. Physicochemical properties of water were measured at the site using a portable multi-meter, while other parameters such as silicate, nitrate, and phosphate were analyzed by spectrophotometry. For plankton identification and density measurements, each sample was fixed by adding 3ml of acidic Lugol’s solution, and transferred to the laboratory for further analysis. The plankton community observed during the study period included Fabrea salina, Dunaliella salina, Pseudo-nitzschia sp., and Spirulina sp. Temporal variations in plankton abundance were evident, mostly in September and November, most of which occurred due to the difference in the abundance of D. salina and F. salina. The impact of environmental parameters including salinity and the concentration of dissolved oxygen, nitrite, silicate, and phosphate on the community structure of planktons was significant. The combination of high salinity, high evaporation rate, low freshwater input, and consequently, low nutrient levels may be the main factors behind the low biodiversity in the lagoon. Being under pronounced anthropogenic pressure due to salt extraction activities, it is evident that further hydrobiological monitoring is crucial for the long-term preservation of the lagoon.
... (Hammer, 1986) (Last, 1993;Jellison et al., 1996;Shadrin, 2009) به سابقه از شور فوق های آب پالنکتونی اجتماعات مطالعه این . (Ruinen, 1938) (Elloumi et al., 2009) واحد 54 شوری بیشینه با بلغارستان در Atanasovsko ثبت فیتوپالنکتونی گونه 14 حداکثر حضور هزار در شهر های حوضچه در و (Gecheva et al., 2017) ...
... In Bulgaria, experimental metrics on different types of lakes and reservoirs were tested (CHESHMEDJIEV et al. 2010;VARADINOVA 2012;VARADINOVA 2013;TRICHKOVA et al. 2013;GECHEVA et al., 2013;BORISOVA et al., 2014;GECHEVA et al., 2017;VARADINOVA et al., 2019). Nevertheless, at this stage in the national water legislation there is no appropriate metric for evaluation of the status of freshwater standing water bodies based on macrozoobenthos. ...
Surveys on benthic macroinvertebrate communities of ten standing water bodies (Bezbog,
Kalin, Choklyovo marsh, Bistraka, Dospat, Stoykovtsi, Drenov dol, Pchelina, Dolna Dikanya,
Dyakovo) were conducted in the period July-August 2018. They were chosen to represent natural
(lakes) characterized with reference conditions as well as artificial and heavily modified water bodies
(dams). They were associated with earlier data for three dams (Studena, Pyasachnik, Ovchi
kladenets), studied over the period 2013-2017. The standing waters fall into the West and East Aegean
Basin districts and belong to all types of water bodies (identified according to the Bulgarian typology)
located in the Ecoregion 7 (L1-Glacial high-mountain lakes/Alpine lakes, L3-Mountain lakes, L4-
Lowland and semi-mountain lakes and swamps, L6-Riverside wetlands, L11-Large deep reservoirs,
L13-Medium-size and small semi-mountain reservoirs, L15 Large lowland reservoirs up to middle
depth, L17-Small and medium size reservoirs). A current evaluation based on the values of the
measured physicochemical parameters, regulated by the national water legislation was made. Four
experimental biological metrics - Total number of taxa, Biotic index for slow-flowing river stretches,
percentage of Oligocheata and PETI were applied to assess the ecological status of the studied water
bodies. The Biotic index is leading in the evaluation, others metrics have a supportive role. The lack of
type-specific scales of the indices used, insufficiently long ranges of data sets on which to test the
methods as well as the anthropogenically induced fluctuations at the water level which affects the
distribution of macrozoobenthos in the sampling littoral zone are the main difficulties for a more
precise assessment of the ecological status/potential of standing water bodies in Bulgaria.
Marine coastal shallow lagoons are widespread worldwide; macroalgae and seagrasses often play a key role in their ecosystem functioning. The world's largest hypersaline lagoon Bay Sivash (the Sea of Azov) plays a vital role in maintaining the landscape connectivity and sustainability of the region. The green macroalga Cladophora sivashensis occupies hundreds of km-2 in the lagoon, forming the bottom and floating mats with wet biomass over 20 kg m-2. Data was obtained during expeditions to the lagoon. Sampling of mats was carried out at 15 stations on July 16–17, 2020, one site of these on May 27–29, 2022 (every four hours during the day), and June 21, 2022 (every four hours during three days). Measurements of environmental parameters (water temperature, photosynthetically active radiation, oxygen content, wind speed and direction, turbidity, etc.) were also done. Mats distribution is directly related to the direction and speed of the wind. Cladophora mats influenced the daily dynamics and the vertical distribution of most studied water parameters. In Bay Sivash, the average dry biomass of Cladophora mats was 2.25 kg (dry weight) m-2, and its total biomass in the lagoon can reach from 524 to 1573 thousand tons of dry weight. Obtained data allowed an assessment of the total biomass of Cladophora in the entire bay and quantify the influence of mats on the abiotic water parameters in the lagoon for the first time. The high Cladophora total biomass and productivity, a variety of valuable compounds in its biomass indicate that it can be considered as a potential resource in the lagoon for large-scale use in medicine, agriculture, and industry. may suggest such perspective areas as long-term monitoring of Cladophora development in lagoon
The Water Framework Directive (WFD, 2000/60/EC) determines that all water bodies must achieve a good ecological status. The solar salterns system of Mata-Torrevieja (Spain) has been designated as Heavily Modified Water Bodies (HMWB). This ecosystem is a transitional water body (TW) largely conditioned by socio-economic management plan and the related human activities that take place. Thus, WFD establishes as obligatory the determination of their ecological potential, and not their ecological status. In order to define the ecological potential, it is necessary to determine previously the chemical and biological conditions of the water body. This paper is focused on the analysis of physical-chemical parameters of a saltern system during 2008-2016, in order to establish a starting point for the implementation process of the WFD in this type of ecosystem (TW-HMWB). The behavior of salinity and physical-chemical parameters (temperature, pH, nutrients) has been studied. Salinity was the most relevant parameter studied to define pressures for these water bodies. However, total phosphorus turned out to be a good potential status indicator. It would be one of the most suitable chemical parameters to propose a methodology for the determination of the ecological potential in the salterns.
