salt balance
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AbstractThough subthermocline eddies (STEs) have often been observed in the world oceans, characteristics of STEs such as their patterns of generation and propagation are less understood. Here, the across-shore propagation of STEs in the California Current System (CCS) is observed and described using 13 years of sustained coastal glider measurements on three glider transect lines off central and southern California as part of the California Underwater Glider Network (CUGN). The across-shore propagation speed of anticyclonic STEs is estimated as 1.35-1.49 ± 0.33 cm s−1 over the three transects, Line 66.7, Line 80.0, and Line 90.0, close to the westward long first baroclinic Rossby wave speed in the region. Anticyclonic STEs are found with high salinity, high temperature, and low dissolved oxygen anomalies in their cores, consistent with transporting California Undercurrent water from the coast to offshore. Comparisons to satellite sea-level anomaly indicate that STEs are only weakly correlated to a sea surface height expression. The observations suggest that STEs are important for the salt balance and mixing of water masses across-shore in the CCS.


2021 ◽  
Author(s):  
Tong Heng ◽  
Gary Feng ◽  
Xin‐Lin He ◽  
Guang Yang ◽  
Fa‐Dong Li ◽  
...  

Author(s):  
Adrian Mikhail P. Garcia ◽  
W. Rockwell Geyer ◽  
Noa Randall

Abstract The North River estuary (Massachusetts, USA) is a tidal marsh creek network where tidal dispersion processes dominate the salt balance. A field study using moorings, shipboard measurements, and drone surveys was conducted to characterize and quantify tidal trapping due to tributary creeks. During flood tide, saltwater propagates up the main channel and gets “trapped” in the creeks. The creeks inherit an axial salinity gradient from the time-varying salinity at their boundary with the main channel, but it is stronger than the salinity gradient of the main channel because of relatively weaker currents. The stronger salinity gradient drives a baroclinic circulation that stratifies the creeks, while the main channel remains well-mixed. Because of the creeks’ shorter geometries, tidal currents in the creeks lead those in the main channel; therefore, the creeks never fill with the saltiest water which passes the main channel junction. This velocity phase difference is enhanced by the exchange flow in the creeks, which fast-tracks the fresher surface layer in the creeks back to the main channel. Through ebb tide, the relatively fresh creek outflows introduce a negative salinity anomaly into the main channel, where it is advected downstream by the tide. Using high-resolution measurements, we empirically determine the salinity anomaly in the main channel resulting from its exchange with the creeks to calculate a dispersion rate due to trapping. Our dispersion rate is larger than theoretical estimates that neglect the exchange flow in the creeks. Trapping contributes more than half the landward salt flux in this region.


2021 ◽  
pp. 199-206
Author(s):  
Arzu Rivera Garcia ◽  
Géza Tuba ◽  
Györgyi Kovács ◽  
Lúcia Sinka ◽  
József Zsembeli

The effect of irrigation with saline water (above 500 mg L-1) is considered a problem of small-scale farmers growing vegetable crops with high water demand in the hobby gardens characteristic of the Hungarian Great Plain. In order to simulate the circumstances of such hobby garden, we set up an experiment including five simple drainage lysimeters irrigated with saline water in the Research Institute of Karcag IAREF UD in 2019. We regularly measured the electric conductivity (EC) of the soil referring to its salt content and the soil moisture content with mobile sensors. Before and after the irrigation season, soil samples from the upper soil layer (0-0.6 m) were taken for laboratory analysis and the soil salt balance (SB) was calculated. The actual salt balance (SBact) was calculated of the upper soil layer (0-0.6 m) based on the salt content of the obtained soil samples. The theoretical salt balance (SBth) was calculated by the total soluble salt content of the irrigation water and leachates. During the irrigation season, we experienced fluctuating EC in the topsoil in close correlation with the soil moisture content. Based on the performed in-situ EC measurements, salts were leached from the upper soil layer resulting in a negative SB. Combining SBact and SBth of the soil columns of the lysimeters, we estimated the SB of the deeper (0.6-1.0 m) soil layer. We quantified 12% increase of the initial salt mass due to accumulation. We consider this methodology to be suitable for deeper understanding secondary salinization, which can contribute to mitigating its harmful effect. By repeating our measurements, we expect similar results proving that saline irrigation waters gained from the aquifers through drilled wells in Karcag are potentially suitable for irrigation if proper irrigation and soil management are applied.  


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Mohammed Mainuddin ◽  
Fazlul Karim ◽  
Donald S. Gaydon ◽  
John M. Kirby

AbstractEnhancing crop production, particularly by growing a crop in the typically-fallow dry season is a key strategy for alleviating poverty in the Ganges delta region. We used a polder water and salt balance model to examine the impact of several crop management, salt management and climate change scenarios on salinity and crop evapotranspiration at Dacope and Amtali in Bangladesh and Gosaba in India. A key (and unsurprising) finding is that salt management is very important, particularly at the two drier sites, Dacope and Gosaba. Good salt management lowers salinity in the shallow groundwater, soil and water storage ponds, and leads to more irrigation. Climate change is projected to alter rainfall, and this in turn leads to modelled increases or decreases in runoff from the polders, and thence affect salt concentrations in the soil and ponds and canals. Thus, the main impacts of climate change are through the indirect impacts on salt concentrations, rather than the direct impacts of the amount of water supplied as rainfall. Management practices to remove salt from polders are therefore likely to be effective in combatting the impacts of projected climate change particularly at Dacope and Gosaba.


2021 ◽  
pp. 47-54
Author(s):  
Buket GÜNGÖR ◽  
Afet Seçil AKDUR ◽  
Coskun SILAN ◽  
Hakki Engin AKSULU ◽  
Orhan ŞAHİN

In the study which was prepared based on the factors that can take place in essential hypertension pathology; We aimed to investigate the interactions of intensive exercise, high salt and partial NOS inhibition applications with each other, the effects on water-salt balance and blood pressure, changes in the intrarenal dopaminergic system, which is an important natriuretic system, and the participation of oxidative stress. The rats were given intensive exercise on a treadmill at a speed of 25 m / min at 5% inclination for 30 minutes a day, LNNA at a concentration of 50 mg / L and a high salt diet of 4% for 7 days either separately or together. Blood pressures of the rats were measured on the first and last days of the experiment, and the rats were taken into metabolic cages; 24-hour water intake and urinevolume were measured. Dopamine levels were measured in 24-hour urine to detect intrarenal dopamine synthesis. In addition, oxidative stress parameters in the serums of rats; TAS, TOS and OSI levels were measured. Blood pressure was found to be high in the groups in which intensive exercise was applied together with LNNA and high salt diet. While there was no change in the water balance of this group, it was found that sodium excretion and dopamine levels increased in 24-hour urine. In addition, it was found that the total oxidant status increased in this group, and oxidative stress developed as a result of insufficient antioxidant system. It suggests that the reason of hypertension that develops with the application of intensive exercise together with LNNA and high salt diet may be due to the vascular resistance increasing effect of oxidative stress rather than water-salt retention and it points out the necessity of studies to fully detect vascular tissue oxidative stress markers and vascular oxidative damage.


2021 ◽  
Vol 264 ◽  
pp. 01015
Author(s):  
Zulfiya Mirkhasilova ◽  
Мurat Yakubov ◽  
Lyudmila Irmuhamedova

In recent years, there has been a shortage of water resources in the basins of the Amu Darya and Syrdarya rivers, which is the result of the development of new lands for irrigation and the inappropriate use of water and land resources. A side effect of irrigation and land reclamation is the increasing flow of collector-drainage waters every year, which leads to a deterioration in the land reclamation state and pollution of water resources, which can lead to the ecological disaster of land and water resources. Currently, in the Republic of Uzbekistan, from the total volume of water resources of the Amu Darya and Syrdarya rivers, up to 68% is used for irrigation. Of this volume on the Republic territory, about 12% of collector-drainage waters of deteriorated quality are formed. With a shortage of water resources, they are used for irrigation. But irrigation with saline waters can lead to a deterioration in the land reclamation state. In this regard, new irrigation technologies are proposed, which can save both irrigation water and it is advisable to use underground pumped water for irrigation. Field experiments were carried out in the farm "Khozhilkhon-hozhi" in the farm named after A. Niyazov, Kuva district, Fergana region. A feature of the soil conditions in this farm is the small thickness of the covered fine earth, underlain by highly permeable gravel, strong and increased water permeability, with a deep groundwater level (GWL> 3 m). Large water losses are observed during irrigation. The calculation task was to determine how many hectares of land can be irrigated from one vertical drainage well, taking into account the irrigation time, inter-irrigation period, etc. The water-salt balance of the reclaimed lands for 2017-2019 was compiled. The water-salt balance showed that water supply and filtration from canals and atmospheric precipitation play the main role in the inlet part. In the consumable part, the main place is occupied by evapotranspiration and drainage flow. In general, a negative balance is formed on the territory annually by the type of a small salt carryover within 2.85 t / ha. On the territory of the farm and the experimental plot, cotton of the S-6524 variety was sown, the flow rate of the well is 30 l / s, the furrow consumption is 0.5 l / s. The composition of hypothetical salts in the pumped-out waters is calculated After the first irrigation of our field, the pumped-out water is diverted to the neighboring fields, while the first inter-irrigation period is 20 days. In the interval of these 20 days until the second irrigation of the cotton of the original field, it is possible to irrigate the same fields 5 hectares 8 times, in total 40 hectares of land. The experiments showed that irrigation with pumped water from vertical drainage wells did not have a negative impact on the yield of cotton. And the use of the recommended irrigation technology will reduce the shortage of irrigation water and improve the ecological situation of water resources.


2021 ◽  
Vol 280 ◽  
pp. 10008
Author(s):  
Vasyl Turchenyuk ◽  
Anatoliy Rokochinskiy ◽  
Nataliia Prykhodko ◽  
Pavlo Volk ◽  
Oleh Meshyk

Ecological-reclamation state of rice irrigation systems harvest of cultivated crops determined by a number of factors, including natural (soil, topographical, hydrogeological, climatic factors) and technological (irrigation norm, designs and parameters of irrigation and drainage networks, etc.) factors. One of the main factors influencing the formation of rice yield which is traditionally grown by flooding technology is the efficiency of the rice irrigation system’s design. Construction features of irrigation fields and their parameters (distances between the drains, depth of the drainage network) affect the intensity of the processes of salinization of soils and groundwater. Analysis of the components of salt balances of rice fields with different parameters and designs on example of the Danube rice irrigation systems showed that fields with the distances between the drains from 200 to 250 m have significant advantages over Krasnodar-type fields with the same parameters and over fields with 500 m distance between the drains creating optimal salt regime for rice and, accordingly, obtaining higher yields of rice. As on the card-checks with drainage with the distances between the drains 500 m uniform desalinization of soils on all area cannot be reached and yield of rice on them is close to 20 c/ha such card-checks with drainage must be converted into card-checks with drainage with the distances between the drains 250 m.


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