PENGARUH SALINITAS TERHADAP PERKEMBANGAN STADIUM AKUATIK Aedes aegypti DI LABORATORIUM

Aedes aegypti is known as the species of mosquito that breeds in fresh water, but due to the nature of adaptive this species found in habitats containing salt. This laboratory experiment aims to find out how different concentration of salinity will affect aquatic stages of Aedes aegypti. Salinity concentrations or treatment used in this study were 0‰, 2‰, 4‰, 6‰, 8‰ and 10‰ with five replicates. The observed parameters is the number of hatched eggs and number of surviving larvae or pupa after exposed to media containing salt. The results show that salinity influence both the number of hatced eggs and surviving larvae or pupae. There were decrease of number of hatched eggs and also the surviving larva or pupa as salinity increase. Analysis of variance showed significant relationship between salinity and the number of larvae or pupae survived but not with number of hatched eggs. Dengue vector adaptation against salinity become a phenomenon that needs to be examined and related to the spread of vector in habitats containing salt as well as transmission of the virus.

Cellular Stress Responses of the Endemic Freshwater Fish Species Alburnus vistonicus Freyhof & Kottelat, 2007 in a Constantly Changing Environment

Herein we investigated the cellular responses of the endemic fish species Alburnus vistonicus Freyhof & Kottelat, 2007, under the variation of several physico-chemical parameters including temperature (°C), salinity (psu), dissolved oxygen (mg/L), pH and conductivity (μS/cm), which were measured in situ. Monthly fish samplings (October 2014–September 2015) were conducted in Vistonis Lake in northern Greece, a peculiar ecosystem with brackish waters in its southern part and high salinity fluctuations in its northern part. Fish gills and liver responses to the changes of the physico-chemical parameters were tested biochemically and histologically. Heat shock protein levels appeared to be correlated with salinity fluctuations, indicating the adaptation of A. vistonicus to the particular environment. The latter is also enhanced by increased Na+-K+ ATPase levels, in response to salinity increase during summer. The highest mitogen activated protein kinases phosphorylation levels were observed along with the maximum mean salinity values. A variety of histological lesions were also detected in the majority of the gill samples, without however securing salinity as the sole stress factor. A. vistonicus cellular stress responses are versatile and shifting according to the examined tissue, biomarker and season, in order for this species to adapt to its shifting habitat.

Increase of Temperature and Salinity in the Active Layer of the North-Eastern Black Sea from 2010 to 2020

Purpose. The paper is aimed at assessing salinity and temperature variability in the upper 300-meter layer of the northeastern part of the Black Sea based on the analysis of the archival and modern expeditionary data. Methods and Results. The data on the cross-sections “coast – sea center” (with the length of 70–110 nautical miles) performed from 1999 to 2009, as well as the results of regular ship monitoring in the shelf-slope zone of the northeastern part of the Black Sea carried out in 2010–2020 were used. It was found that salinity was progressively increasing in the upper 200-meter layer during the last decade. Salinity increase, on the average, constituted annually about 0.05–0.06 PSU. An increase of temperature was also observed below the layer of temperature minimum (core of the cold intermediate layer). In particular, the lower 8.7 °C isotherm rose annually, on the average, by 11 m from its annual average depth 242 m in 2010 up to 121 m in 2020. Salinity growth led to the corresponding changes in water density that resulted in elevation of the lower boundary of the oxygen-containing layer (potential density is 15.8) from the depth of 143 m in 2010 to 124 m in 2020. Conclusions. Climatic changes have led to a noticeable salinity increase in the upper 200-meter layer of the northeastern Black Sea, as well as to a temperature increase in the layers situated below the temperature minimum layer. Though the measurements were carried out in a certain area of the shelf-slope zone, there are reasons to assume that the observed dynamics can be attributed to the entire Black Sea. Physical reasons for the observed changes require a detailed research.

Microphytobenthos in the Hypersaline Water Bodies, the Case of Bay Sivash (Crimea): Is Salinity the Main Determinant of Species Composition?

In hypersaline water bodies, the microphytobenthos plays a very important ecosystem role and demonstrates variability along with a salinity change. Due to anthropogenic activity, the sharp salinity increase in Bay Sivash occurred after 2014. To assess the changes in the microalgae community during the bay ecosystem transformation, the study was conducted four times in 2018 and 2019. At every sampling period, the samples were taken in a salinity gradient (from 7 to 10 sites). A total of 40 species of microalgae were identified during all research, including Cyanobacteria (Cyanophyceae, 2 species), Ochrophyta (Bacillariophyceae, 35 species), Haptophyta (Prymnesiophyceae, 2 species), and Miozoa (Dinophyceae, 1 species). According to the calculated similarity indices of Jaccard and Czekanowski–Sørensen–Dice, the species composition significantly differed during sampling periods. A total of 15 species were recorded at salinities of 80–90 psu, and 10 species at higher salinities, which contribute 64% of all species found in this study. The microalgae abundance was two times more in the floating green algae mat than on the bottom. There was no significant correlation between the number of species and salinity in all sampling periods. In November 2018, a significant positive correlation between the number of species in the sample and total suspended solids (TSS) and dissolved organic matter (DOM) was revealed. A significant correlation between the cell length in different species and salinity and DOM concentration was noted. Before the onset of the salinity increase, 61 species of microalgae were found in Eastern Sivash, of which only 12 have now been recorded, 31% of the currently found species. The characteristics of the total microphytobenthos abundance also significantly changed during all studies. Many characteristics have changed in the bay: the concentration of total suspended matter and dissolved organic matter, the temperature regime, composition of zoobenthos and plankton, and oxygen concentration. Due to this, it is unlikely that only the salinity increase caused the microphytobenthos changes in the lagoon.

Individual and Combined Effects of Salinity and Nanoparticles (Al2O3, TiO2) on the Activity of Antioxidant Enzymes in Freshwater Fish (Oreochromis niloticus)

Salinity increase in freshwaters affects the physiology and metal uptake in fish, though there is no enough evidence on the influence of salinity on metal-oxide nanoparticle (NPs) toxicity. Therefore, the effects of salinity and NPs (Al2O3, TiO2) were tested in acute (2 days and 10 mg NPs/L) and chronic (20 days and 1 mg NP/L) exposures at different salinities (0 and 10 ppt). Following the exposures, the activities of CAT (catalase), SOD (superoxide dismutase), GPX (glutathione peroxidase), GR (glutathione reductase) and GST (glutathione S-transferase) were determined in the liver of O. niloticus. Data showed that CAT and SOD activities did not change significantly (P>0.05) in acute exposures, though their activities significantly (P<0.05) decreased in chronic exposures at both salinities. Similarly, GPX and GR activities did not respond to acute NP exposures, but their activities decreased significantly in chronic exposures. However, GST showed the opposite response in acute and chronic exposures following NP and salinity exposures. Data showed that chronic exposures were more effective than acute exposures in regard to the response of the enzymes. Data also revealed that salinity did not have a predominant effect on the antioxidant enzymes, and also did not influence NPs toxicity.

Increase of Temperature and Salinity in the Active Layer of the North-Eastern Black Sea from 2010 to 2020

Purpose. The paper is aimed at assessing salinity and temperature variability in the upper 300-meter layer of the northeastern part of the Black Sea based on the analysis of the archival and modern expeditionary data. Methods and Results. The data on the cross-sections “coast – sea center” (with the length of 70–110 nautical miles) performed from 1999 to 2009, as well as the results of regular ship monitoring in the shelf-slope zone of the northeastern part of the Black Sea carried out in 2010–2020 were used. It was found that salinity was progressively increasing in the upper 200-meter layer during the last decade. Salinity increase, on the average, constituted annually about 0.05–0.06 PSU. An increase of temperature was also observed below the layer of temperature minimum (core of the cold intermediate layer). In particular, the lower 8.7 °C isotherm rose annually, on the average, by 11 m from its annual average depth 242 m in 2010 up to 121 m in 2020. Salinity growth led to the corresponding changes in water density that resulted in elevation of the lower boundary of oxygen-containing layer (potential density 15.8) from the depth 143 m in 2010 to 124 m in 2020. Conclusions. Climatic changes have led to a noticeable salinity increase in the upper 200-meter layer of the northeastern Black Sea, as well as to a temperature increase in the layers situated below the temperature minimum layer. Though the measurements were carried out in a certain area of the shelfslope zone, there are the reasons to assume that the observed dynamics can be attributed to the entire Black Sea. Physical reasons for the observed changes require a detailed research

Different Levels Of Addition Of Salinity To Survival, Growth And Conversion-Efficiency Feed’s Tilapia (Oreochromis sp.)

<em>Tilapia is one of the consumption fish commodities that was very popular with the public. The development of tilapia aquaculture was growing rapidly, especially saline tilapia. The high potential of saline tilapia development causes the demand for fingerlings to increase. This research aimed to determine the best dose of salinity increase in the effort to adapt freshwater tilapia to saline tilapia. In addition, it also observed survival, growth and feed efficiency. The method used was experimental method with completely randomized design and data were analyzed using SPSS16 and Tukey's test. The research treatments included the levels of addition of salinity by 1 ‰/day, 2 ‰/day, 3/day and 4 ‰/day. The difference in salinity had a significant effect on Survival Rate (SR), Growth Rate (GR), Specific Growth Rate (SGR), Feed Conversion Ratio (FCR) and Feed Utilization Efficiency (FUE). The best treatment in this research was the addition of salinity of 1 ‰/day with SR of 96%, GR of 35.1 g / t, SGR 1.22% w / day, FCR of 1.04 and FUE of 96%.</em>

Possible Sources of Salinity in the Upper Dibdibba Aquifer, Basrah, Iraq

Salinity increase in groundwater was investigated in the area between Al-Zubair and Safwan, and close to the Khor Al-Zubair Channel of southern Iraq. Thirty-nine groundwater samples from the shallow aquifer and one sample from the Khor Al-Zubair Channel were analyzed. The mean total dissolved solids are 7556 mg/L. The δ2H and δ18O plot in two groups are below the global meteoric water line. Group A indicates the evaporation effect of irrigation return-flow, while group B is characterized by depleted δ18O values due to recharge under colder climate. Deuterium excess values plot within the region of modern precipitation and dilution of groundwater by precipitating water. The groundwater residence time is between 1000 and 2000 years and combining 14C -age with SO42− shows a contrasting effect on groundwater on both sides of Khedr Almai Fault and the Zubair anticline, which indicates the role of these geological structures on the hydrochemical evolution in the western part. Jabal Sanam shows no clear effect in this regard. The ratio Cl−/Br− and sulfate in groundwater showed that the measured salinity in groundwater is the result of a mixing process between groundwater, seawater intruding from Khor Al-Zubair Channel, and water from septic tanks in addition to dry and wet sea spray, and irrigation return-flow.

The role of tides in bottom water export from the western Ross Sea

Approximately 25% of Antarctic Bottom Water has its origin as dense water exiting the western Ross Sea, but little is known about what controls the release of dense water plumes from the Drygalski Trough. We deployed two moorings on the slope to investigate the water properties of the bottom water exiting the region at Cape Adare. Salinity of the bottom water has increased in 2018 from the previous measurements in 2008–2010, consistent with the observed salinity increase in the Ross Sea. We find High Salinity Shelf Water from the Drygalski Trough contributes to two pulses of dense water at Cape Adare. The timing and magnitude of the pulses is largely explained by an inverse relationship with the tidal velocity in the Ross Sea. We suggest that the diurnal and low frequency tides in the western Ross Sea may control the magnitude and timing of the dense water outflow.