Архив метки: salinity

BIODIVERSITY OF HYDROBIONTS IN SODA, CHLORIDE, AND SULPHATE LAKES (TRANSBAIKALIA, RUSSIA)

Arid Ecosystems

UDC 574.58 (571.54/55)

Bazarova B.B., Borzenko S.V., Tashlykova N.A., Afonina E.Yu., Matafonov P.V.,  Tsybekmitova G.Ts., Kuklin A.P. BIODIVERSITY OF HYDROBIONTS IN SODA, CHLORIDE, AND SULPHATE LAKES (TRANSBAIKALIA, RUSSIA) // Arid Ecosystems. 2023. Vol. 29. № 4 (97). P. 187-201. | PDF

The article presents the results of a comprehensive hydrochemical and hydrobiological study of 13 different lakes in Transbaikalia carried out in July 2022. Based on cluster analysis of the hydrochemical and hydrobiological indicators, the studied lakes were divided into three groups: 1) brackish soda lakes; 2) chloride and sulfate lakes and one salty soda lake, Lake Shvartsevskoye; and 3) soda brine lakes. It was found that the number of species of different groups of hydrobionts decreases with increasing salinity of water. At the same time, the number of species of different groups of hydrobionts does not depend on the chemical type of water. However, the dominant composition of primary producers in lakes of different types differs. Two new species of macroalgae (Stigeoclonium flagelliferum Kütz., Rhizoclonium riparium (Roth.) Harv.) were identified for Transbaikalia. After more than a 100-year hiatus, the presence of Ruppia maritime L. was confirmed in the aquatic flora of Siberian Baikal. Galotolerant species dominate in the zooplankton of the lakes. In the dominant structure of the zoobenthos of brine and salty lakes, Artemia shrimp and Ephydridae flies are prevalent. In deeper brackish lakes, representatives of the Chironomidae mosquito family are permanent dominants. Quantitative indicators of phytoplankton and zooplankton communities are characterized by an inverse relationship. For example, during the massive development of cryptophytic algae in brine water bodies, the numerical values and biomass of zooplankton are minimal. No specific tendencies were identified in the range of fluctuations in the biomass of zoobenthos and the phytomass of aquatic plants. The trophic structure of heterotrophs in sulfate and chloride lakes is presented in the zooplankton by a grazing chain, while detritivores dominate in the zoobenthos.

Keywords: salinity, phytoplankton, macrophytes, zoobenthos, zooplankton, primary production, chlorophyll a.

Funding. This work was carried out for the Grant No. 22-17-00035 of the Russian Science Foundation “Ecology and Evolution of Aquatic Ecosystems under Conditions of Climatic Fluctuations and Anthropogenic Pressure”.

DOI: 10.24412/1993-3916-2023-4-187-201

EDN: SWFILX

HARMONIZATION OF THE RESULTS OF SOIL SALINITY CHEMICAL STUDY

Arid Ecosystems

UDC 631.4

Prokopyeva K.O., Konyushkova M.V. HARMONIZATION OF THE RESULTS OF SOIL SALINITY CHEMICAL STUDY // Arid Ecosystems. 2023. Vol. 29. № 3 (96). P. 24-35. | PDF

Soil salinity is one of the main ecological factors that limits the growth and productivity of many plants. Its assessment in different countries is carried out by different methods. In Russia and some other countries, soil salinity is assessed using water extracts. Internationally, the method of electric conductivity of soil paste extracts is widely used. These methods are labor-consuming, and, therefore, the reduced methods are used to assess soil salinity for mass analysis. Thus, in Russia, salt surveys are often evaluated by the leading toxic ion (chlorine or sodium). In a number of foreign countries assessment is given by electrical conductivity at various ratios of soil to water (1: 1; 1: 2.5; 1: 5; 1: 10). In this study, comparisons of different methods for substantiation of possibility to use electrical conductivity measurement in 1: 5 suspension were carried out. The following methods were compared: 1 – method of determination of specific electric conductivity in water suspension (1: 5); 2 – method of determination of pNa and pCl measured in water suspension (1: 5) using ion-selective electrodes; 3 – determination of sodium in water suspension (1: 5) by atomic absorption spectrometry. Salinity was evaluated in samples of light clayey soils of the dry steppe zone of mainly chloride-sodium salinity type. The results showed that when determining the activity of ions, the greatest correlation was observed between measurements of specific conductivity (conductometer) and sodium activity (ion-selective electrodes). A sufficiently close correlation between specific conductivity and the content of sodium ions in the water extract was revealed and the function of recalculation of these indicators was obtained: ЕС1: 5 = 0.213Na1: 5 + 0.17 (with intercept); ЕС1: 5 = 0.23Na1: 5 (without intercept). For evaluation of salinity degree according to specific conductivity index (1: 5) the following criteria are suggested: 0-0.4 dS/m (non-saline), 0.4-0.6 dS/m (slightly saline), 0.6-1 dS/m (medium saline), 1-1.9 dS/m (strongly saline), > 1.9 dS/m (very strongly saline). When comparing different gradations of soil salinity with the help of contingency tables using chi-square and kappa index, the presence of statistically significant contingency was revealed, which allows us to use different methods of soil analysis to assess the degree of salinity.

Keywords: salinity, soil analysis, electrical conductivity, ion selective electrodes (ISE), sodium, Caspian Lowland.

Financing. The work was supported by the funds for the Eurasian Center for Food Security of Lomonosov Moscow State University (Decree No. 1736-r, dated 26/06/2021).

DOI: 10.24412/1993-3916-2023-3-24-35

EDN: WCVAFO

PECULIARITIES OF THE ANNUAL AND SEASONAL DYNAMICS OF THE ECOLOGICAL STATE OF THE SALINE LAKES LOCATED IN ARID CLIMATE IN CRIMEA

Arid Ecosystems

UDC 577.115.3+577.359

Rudneva I.I., Shaida V.G., Scherba А.V. PECULIARITIES OF THE ANNUAL AND SEASONAL DYNAMICS OF THE ECOLOGICAL STATE OF THE SALINE LAKES LOCATED IN ARID CLIMATE IN CRIMEA // Arid ecosystems. 2022. V.28. № 3 (92). P. 117-125. | PDF

On Crimea peninsula there are several unique lakes of different genesis, which characterize high quality recreational and balneological properties. These water bodies are impacted for anthropogenic activities, caused negative consequences for the  total ecosystem, including the lost of biological and hydromineralogical resources. At several cases, the water bodies located not far from each other greatly differ because of anthropogenic activity. For instance, Moinaky Lake is located at the west part of the Eupatoria city (Crimea), at present it is divided by the sand barrier in two parts namely Moinaky 1 (big part) and Moinaky 2 (small part). The aim of the present work was to study several physical and chemical characteristics of the water ( temperature, pH, Eh, salinity, oxygen  content) in both basins and the population state of brine shrimp Artemia salina at the period of 2018-2020. We studied the hydrochemical parameters of the water namely temperature, рН, oxygen concentration, salinity and Eh) monthly in both water bodies, divided by sand barrier. Seasonal dynamics of the tested parameters was characterized by the increase of salinity and Eh in summer period, accompanied with the increasing temperature of the air and water caused high insolation. Simultaneously, the concentration of the oxygen dropped and the insignificant decrease of pH was observed. The differences between the tested processes in both water bodies were shown, which were more clearly in Moinaky 2 as compared with Moinaky 1. Artemia cysts were found in both basins, while nauplia and adults were found only in Moinaky 2 at autumn and winter 2020, after dry period and restoration of the hydrological regime.

Keywords: hypersaline lakes, Crimea Peninsula, pH, Eh, salinity, oxygen content.

Financing. The work was carried out on the topic of the state assignment of the Moscow Hydrophysical Institute of the Russian Academy of Sciences 0555-2021-0004 «Fundamental research of oceanological processes that determine the state and evolution of the marine environment under the influence of natural and anthropogenic factors, based on observation and modeling methods» (cipher «Oceanological processes»).

DOI: 10.24412/1993-3916-2022-3-117-125

 

VARIABILITY OF SOIL SALINITY AND PHYTODIVERSITY OF HETEROCHRONOUS REGIONS OF THE CASPIAN LITTORAL PLAIN

Arid Ecosystems

Konyushkova M.V.,  Nukhimovskaya Yu.D.,  Gasanova Z.U.,  Stepanova N.Yu. VARIABILITY OF SOIL SALINITY AND PHYTODIVERSITY OF HETEROCHRONOUS REGIONS OF THE CASPIAN LITTORAL PLAIN // Arid ecosystems. 2020. V. 26. № 4 (85). P. 66-75. | PDF

The article discusses the results of soil and geobotanical studies at the plots on the coastal plain of the Caspian Sea (Northern Dagestan) of different ages: 1340 ± 36 years calBP (Kaspii-1) and 293 ± 13 years calBP (Kaspii-2). Changes in the biodiversity of the vegetation cover and the soil-salinity variation over time are assessed. It is shown that the variability of soil salinity (range, quartile scale, and standard deviation) at the local level (areas of nonuniformity with linear dimensions of meters or tens of meters) has increased, while the parameters of vegetation biodiversity (floristic richness, the species number, the families number, the number of long-vegetating herbaceous perennials and ephemers, the presence of species with different salinity tolerance, and differentiation of the intracoenotic diversity) have decreased. The plot with a Tamarisk community (Kaspii-2) is characterized by a statistically significant, moderate correlation (R2 = 0.29) between soil salinity and vegetation based on data on the distribution of dominant species, whereas this correlation is not significant on the older plot with a saltwort—suaeda community (Kaspii-1). The data show that, when the area dries up after sea regression, the variation in soil properties (salinity) and vegetation changes in different directions: the variation in soil salinity (functional pedodiversity) increases with age, while the variation in vegetation (phytodiversity) decreases. Moisture availability is obviously the main factor limiting the biodiversity on the older plot on the background of high salinization of soils on the both plots as evidenced with the smaller moisture reserve in the top 1-m soil layer on the older plot.

Keywords: solonchaks, biodiversity, functional pedodiversity, sea plain, Caspian Sea Region, nonuniformity, salinity.

DOI: 10.24411/1993-3916-2020-10120

EVALUATION OF ECOLOGICAL CONDITION AND PRODUCTIVITY LOSSES OF ARID PASTURES ECOSYSTEMS OF SARPINSKY LOWLAND

Arid Ecosystems

Vlasenko M.V., Kulik A.K., Salugin A.N. EVALUATION OF ECOLOGICAL CONDITION AND PRODUCTIVITY LOSSES OF ARID PASTURES ECOSYSTEMS OF SARPINSKY LOWLAND // Arid ecosystems. 2019. V. 25. № 4 (81). P. 71-81. | PDF

We monitored the pastures ecosystems of the semi-arid zone in Sarpinsky Lowland of Russia and registered some local problems. The experimental data was collected through 1999-2017. It is stated that the present agro-landscape conditions are critical. The degraded pastures account for more than 600 thousands ha (34%), more than the half of which are highly degraded. 35-40%, of the total area of the regional forage grounds (about 1870 thousands ha) are moderately overgrazed, 30-40% are highly overgrazed, and 15-20% are excluded from the agricultural management and have turned into broken sands and abandoned territories. The digression is severely high on the winter (year-round) pastures. The area of open and drift sands has increased to 20-30%. In some districts the pressure on the pastures exceeds the optimal index 5-7 times. Almost all pastures need resting periods and agricultural restoration. Desertification (salinity, erosion and deflation) is a severe problem of the region. As the result of it the productivity loss of the pastures is 1052.7 thousands hwt of feed-units per year. Agroforestry measures have a significant value for preventing of soil erosion and deflation and are considered to be the many-functional, long-term protection factor. A map of forest conditions was composed to achieve the maximal ecological- and economical result of agroforestation; it was based on the agroforestry classification which represents the natural characteristics of the territory and features of its agroforestry developing

Keywords: desertification, deflation, eroding, salinity, pastures, annual productivity loss.

DOI: 10.24411/1993-3916-2019-10075