scholarly journals Assessment of Changes in the Structure of Zooplankton Communities to Infer Water Quality of the Caspian Sea

Diversity ◽  
2019 ◽  
Vol 11 (8) ◽  
pp. 122 ◽  
Author(s):  
Elena Krupa
Keyword(s):  
Water Quality ◽  
Deep Water ◽  
Caspian Sea ◽  
Size Structure ◽  
The Caspian Sea ◽  
Structural Variables ◽  
Zooplankton Communities ◽  
Average Individual ◽  
Individual Mass

The work aimed to study the structural variables of zooplankton to assess the water quality of the Caspian Sea. Studies of zooplankton were conducted in the spring and summer of 2008 and 2010. Abundance, biomass, an average individual mass of a specimen, Shannon Bi, Shannon Ab, Δ-Shannon indices, and Clarke’s W-statistic were calculated for zooplankton. Quantitative variables of zooplankton were the highest in the Northeastern and Northern Caspian, decreasing towards the Middle Caspian. In the Northeastern and Northern Caspian from spring to summer, the number of zooplankton, and the values of Shannon Bi and Shannon Ab indices decreased; the values of Δ-Shannon and Clarke’s W-statistic increased. In the Middle Caspian, the biomass of the community increased; the values of Δ-Shannon and Clarke’s W-statistic decreased. From spring to summer, the value of an average individual mass of a specimen decreased over the entire surveyed area. The jellyfish Blackfordia virginica and Moerisia pallasi significantly influenced the size structure of the holoplankton. Seasonal dynamics of structural variables of zooplankton as well as changes in water transparency showed that water quality improved from spring to summer in the shallow northern and northeastern areas of the sea, and decreased in the deep-water Middle Caspian.

scholarly journals Impact of the European Russia drought in 2010 on the Caspian Sea level

2012 ◽  
Vol 16 (1) ◽  
pp. 19-27 ◽  
Author(s):  
K. Arpe ◽  
S. A. G. Leroy ◽  
H. Lahijani ◽  
V. Khan
Keyword(s):  
Sea Level ◽  
Caspian Sea ◽  
Analysis Data ◽  
Reanalysis Data ◽  
European Russia ◽  
Severe Drought ◽  
The Caspian Sea ◽  
Volga River ◽  
The Impact

Abstract. The hydrological budgets of the Volga basin (VB) and the Caspian Sea (CS) have been analysed. The components of the water balance for the CS were calculated for the period 1993 to 2010 with emphasis on summer 2010 when a severe drought developed over European Russia. A drop in precipitation over the VB in July 2010 occurs simultaneously with a decrease in evaporation for the same area, an increase of evaporation over the CS itself and a drop of the Caspian Sea level (CSL). The drop in the precipitation over the VB cannot lead to an instantaneous drop of the CSL because the precipitated water needs some months to reach the CS. The delay is estimated here to be 1 to 3 months for excessive precipitation in summer, longer for deficient precipitation and for winter cases. However, the evaporation over the CS itself is considered to be responsible for a simultaneous drop of the CSL from July to September 2010. The impact on the CSL from the precipitation deficit over the VB occurs in the months following the drought. The water deficit from July to September 2010 calculated from the anomalous precipitation minus evaporation over the VB would decrease the CSL by 22 cm, of which only 2 cm had been observed until the end of September (observed Volga River discharge anomaly). So the remaining drop of 20 cm can be expected in the months to follow if no other anomalies happen. In previous studies the precipitation over the VB has been identified as the main cause for CSL changes, but here from a 10 cm drop from beginning of July to end of September, 6 cm can be directly assigned to the enhanced evaporation over the CS itself and 2 cm due to reduced precipitation over the CS. Further periods with strong changes of the CSL are also investigated, which provide some estimates concerning the accuracy of the analysis data. The investigation was possible due to the new ECMWF interim reanalysis data which are used to provide data also for sensitive quantities like surface evaporation and precipitation. The comparison with independent data and the consistency between such data for calculating the water budget over the CS gives a high confidence in the quality of the data used. This investigation provides some scope for making forecasts of the CSL few months ahead to allow for mitigating societal impacts.

scholarly journals Microelement Structure of the Cherek-Bezengiysky River Water

2017 ◽  
Author(s):  
Keyword(s):  
Water Quality ◽  
River Water ◽  
River Basin ◽  
Caspian Sea ◽  
High Mountain ◽  
Clean Water ◽  
Mountain Regions ◽  
The Caspian Sea ◽  
The Caucasus ◽  
River Waters

Urgency of the issues concerning studying water quality in mountain-glacial high-mountain regions of the Caucasus where the rivers feeding the Kabardino-Balkar Republic lowland parts originate has been highlighted. The Bezengiysky Canyon river waters have been investigated for Mn, Zn, Cu, Pb, Ag, Ni, Cr, and Cd content. The high-mountain glacial/mountain fed Cherek Bezengiysky River microelements’ concentration values have been compared from the source to the mouth both during winter low-water and glacial flood periods. It has been stated that river water microelements contamination in the high-mountain region is caused by natural geochemical and geo/morphological background and is connected with the microelements washing out mountain rocks. Earlier investigations have shown that the microelements concentration significantly drops in comparison with the upper reach when the river enters the lowlands. It was found that the Cherek Bezengiysky River waters under study in terms of Mn, Pb, Cr, Cd, Ni, Cu, and Ag content could be classified as clean water excluding Zn which made the water very polluted. Minimal, maximal and average values of the main ion and nitrogen-containing substances concentrations during winter low-water and glacial flood periods have been presented. The value of the conducted investigation is determined by the fact that the Cherek Bezengiysky River inflows to the Terek River and forms the Caspian Sea river basin.

Hydrochemical Studies of Deep-Water Basins of the Caspian Sea in August–September 2013 Onboard the R/V “Nikifor Shurekov”

2015 ◽  
Vol 55 (1) ◽  
pp. 162-164
Author(s):  
L. A. Dukhova ◽  
E. A. Serebrennikova ◽  
A. K. Ambrosimov ◽  
A. A. Klyuvitkin
Keyword(s):  
Deep Water ◽  
Caspian Sea ◽  
The Caspian Sea ◽  
Hydrochemical Studies

scholarly journals Analysis of deep-water exchange in the Caspian Sea based on environmental tracers

2000 ◽  
Vol 47 (4) ◽  
pp. 621-654 ◽  
Author(s):  
F. Peeters ◽  
R. Kipfer ◽  
D. Achermann ◽  
M. Hofer ◽  
W. Aeschbach-Hertig ◽  
...  
Keyword(s):  
Deep Water ◽  
Caspian Sea ◽  
Water Exchange ◽  
Environmental Tracers ◽  
The Caspian Sea

scholarly journals Factors Influencing Abundances and Population Size Structure of the Threatened and Endemic Cyprinodont Aphanius iberus in Mediterranean Brackish Ponds

Water ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 3264
Author(s):  
Serena Sgarzi ◽  
Sandra Brucet ◽  
Mireia Bartrons ◽  
Ignasi Arranz ◽  
Lluís Benejam ◽  
...  
Keyword(s):  
Water Quality ◽  
Total Nitrogen ◽  
Size Structure ◽  
Ecological Status ◽  
Maximum Size ◽  
Structured Populations ◽  
Negative Effect ◽  
The Mean ◽  
Abiotic And Biotic Factors

Aphanius iberus is an endemic cyprinodontoid fish species of Mediterranean ponds in danger of extinction. In this study, we studied some abiotic and biotic factors that can influence A. iberus’s size structure and density in Mediterranean brackish ponds. We sampled fish using fyke nets in 10 ponds of Empordà (Spain) during the spring season. Our results showed that a better ecological status (according to the Water Quality of Lentic and Shallow Ecosystems (QAELS) index), pond’s depth and pond’s isolation (reflected by an increase in total nitrogen) were related to larger individual sizes and more size-diverse populations. Increasing the salinity is known to help the euryhaline A. iberus acting as a refuge from competitors. Nevertheless, our results showed that higher conductivities had a negative effect on A. iberus’s size structure, leading to a decrease in the mean and maximum size of the fish. Fish abundance (expressed as captures per unit of effort (CPUE)) seemed to increase with increasing the pond’s depth and total nitrogen (the latter reflecting pond isolation). In conclusion, our results suggest that achieving a better pond ecological status may be important for the conservation of endangered A. iberus, because better size-structured populations (i.e., larger mean and average lengths) were found at higher water quality conditions.

scholarly journals “Hand Drawn Portolan of the Caspian Sea of 1519” by Vesconte Maggiolo: A Source of Historical Geography for the Caspian Region

2021 ◽  
Vol 9 (4) ◽  
pp. 768-790
Author(s):  
Yusup M. Idrisov ◽  
◽  
Ismail I. Khanmurzaev ◽  
Keyword(s):  
Fifteenth Century ◽  
Caspian Sea ◽  
Historical Analysis ◽  
Caspian Region ◽  
The Caspian Sea ◽  
Military Campaigns ◽  
High Level ◽  
The Military ◽  
First Time

Research objectives: To conduct a detailed comparative analysis of the toponymic source known as “Hand Drawn Portolan of the Caspian Sea (1519)” by Vesconte Maggiolo, and ascertain the range and chronology of its sources. Research materials: At the turn of the fifteenth and sixteenth centuries, there were a few navigational maps – portolan charts – created in Italy which contained rather precise outlines of the coastline of the Caspian Sea. The present Portolan excels all earlier items in terms of precision of the depicted topographical realities of the region. The quality of the map we are examining was surpassed only in the seventeenth century after Peter I’s hydrographic expeditions. The high level of shoreline’s precision also strongly suggests that the map was based on authentic topographic input. Maggiolo’s map contains 136 geographical names. Results and novelty of the research: For the first time ever in domestic scholarship, we conducted a comparative historical analysis of the hand drawn portolan chart of the Caspian Sea. We also proved the correlation of some toponyms of the West Caspian region with the Timurid and local sources that covered the military campaigns of Amir Timur in the region. In our view, the “Hand Drawn Portolan Chart of the Caspian Sea (1519)” created by Vesconte Maggiolo is one of the most notable among similar works. It finds many common features with the portolan from the island of Lesina, but also contains some common elements with the Mallorca cartographic school and Fra Mauro, Egerton MS 73, and Egerton MS 2083. This research allows us to extend and systematize our understanding of Italian cartography in relation to the Caspian region. It also details or adds some facts about the presence of Europeans in this region during the Golden Horde era. Based on this topographic and toponymic analysis, we furthermore come to a conclusion that the portolan in question is derived from a protograph created in the first half of fifteenth century, reflecting the realities of the turn of the fourteenth and fifteenth centuries.

scholarly journals Zooplankton communities and their relationship with water quality in eight reservoirs from the midwestern and southeastern regions of Brazil

2020 ◽  
Author(s):  
P. H. S. Picapedra ◽  
C. Fernandes ◽  
G. Baumgartner ◽  
P. V. Sanches
Keyword(s):  
Water Quality ◽  
Food Availability ◽  
Suspended Solids ◽  
Ecosystem Processes ◽  
Hydroelectric Reservoirs ◽  
Kellicottia Bostoniensis ◽  
Quality Of Food ◽  
Zooplankton Communities ◽  
The Relationship

Abstract Zooplankton are widely recognised as being regulated primarily by predators and food availability. In reservoirs, the quantity and quality of food resources are generally affected by the characteristics of the water, which in turn are controlled by the flow pulse generated by operation of the dams. In this study, we investigated the relationship between zooplankton, water quality and food availability (phytoplankton) in eight hydroelectric reservoirs located in Brazil. Samples were collected during the rainy and dry periods between 2008 and 2009. In general, the reservoirs exhibited mesotrophic conditions and Cyanobacteria were the predominant phytoplankton. The results showed that the rotifers Kellicottia bostoniensis, Hexarthra mira, Keratella spp., and Polyarthra vulgaris were present, indicating nutrient-rich environments. In addition, the copepod Thermocyclops decipiens occurred in eutrophic environments. In contrast, the cladoceran Daphnia gessneri and copepod Notodiaptomus henseni were considered indicators of more desirable water quality, owing to their relationship with waters with lower levels of nutrients and suspended solids. The results support the use of these organisms as a useful tool for understanding changes in water quality and in the ecosystem processes involved.

Sign in / Sign up

Export Citation Format

Share Document