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The saline water intrusion to aquifers in arid regions is one of the major challenges in the development of water resources. In this research, the risk of saline water intrusion near a salt playa in Sirjan plain was evaluated by modifying and optimizing the GALDIT model. Parameters such as aquifer type, aquifer hydraulic conductivity, groundwater level, distance to salt playa, current status of saline water intrusion and aquifer thickness were used to zoning the risk of saline water intrusion. To modify and optimize the GALDIT model, single parameter sensitivity analysis method, analytical hierarchy process and fuzzy logic were used. According to the different models results, the Sirjan plain has been classified into three saline water intrusion risk zones namely: low, moderate and high. Groundwater electrical conductivity and chloride ion concentration were employed for the validation of the results of the models. Achieving results show that the fuzzy logic is the best method for optimizing the GALDIT model. So that the correlation coefficients between the results of Fuzzy GALDIT model results and parameters of electrical conductivity and chloride ion concentration are equal to 0.88 and 0.90 respectively

Abstract Salicornia rubra is a commonly occurring annual species of the salt playas of the Great Basin Desert of the western United States. In such habitats, plants experience high levels of ultraviolet radiation, which could potentially damage DNA. As a member of the Amaranthaceae (Caryophyllales), S. rubra shoots typically contain high concentrations of the red‐violet pigments called betacyanins, which are ultraviolet‐absorbing compounds. Nevertheless, some specimens of S. rubra are green even when growing with full exposure to the sun. We, therefore, tested several hypotheses regarding the causes of variation among S. rubra plants in betacyanin concentration and the role of betacyanins in the absorption of ultraviolet radiation. We measured ultraviolet radiation absorption and the concentrations of betacyanins and phenolic compounds of the cell sap expressed from red and green plants growing in full sun, as well as plants grown under various levels of shade. We found that while betacyanin concentrations were predictable from plant color (red plants contained more betacyanins than green plants), the ability to absorb ultraviolet radiation was determined primarily by the concentration of phenolic compounds, which was determined by the level of exposure to the sun. Therefore, the DNA of green plants growing in full sun appears to be at no greater risk than the DNA of red plants.

Salicornia rubra is a commonly occurring annual species of the salt playas of the Great Basin Desert of the western United States. In such habitats, plants experience high levels of ultraviolet radiation, which could potentially damage DNA. As a member of the Amaranthaceae (Caryophyllales), S. rubra shoots typically contain high concentrations of the red‐violet pigments called betacyanins, which are ultraviolet‐absorbing compounds. Nevertheless, some specimens of S. rubra are green even when growing with full exposure to the sun. We, therefore, tested several hypotheses regarding the causes of variation among S. rubra plants in betacyanin concentration and the role of betacyanins in the absorption of ultraviolet radiation. We measured ultraviolet radiation absorption and the concentrations of betacyanins and phenolic compounds of the cell sap expressed from red and green plants growing in full sun, as well as plants grown under various levels of shade. We found that while betacyanin concentrations were predictable from plant color (red plants contained more betacyanins than green plants), the ability to absorb ultraviolet radiation was determined primarily by the concentration of phenolic compounds, which was determined by the level of exposure to the sun. Therefore, the DNA of green plants growing in full sun appears to be at no greater risk than the DNA of red plants. [ABSTRACT FROM AUTHOR]

We used Landsat imagery to examine surface-water dynamics over the past 27 years in 39 salt lakes (salinas) of the Southern High Plains of the U.S. These groundwater- and precipitation-fed wetlands are regionally unique habitats with high salt concentrations and halophytic biota that may be vulnerable to hydrological changes from groundwater extraction for agriculture coupled with drought. We documented amounts and occurrences of water within the 39 salinas, comparing summer and winter (representing periods of high and low groundwater demand, respectively) in 1986-2013. During this span in our study area, total and irrigated cropland acreage increased, and the saturated thickness of the Ogallala Aquifer decreased by ~18.3%. There was variation in inundation frequency by salina, with two never holding water during our study. A third of the salinas went dry at least once, slightly more in summer than winter. Occurrence of water was not simply a function of basin size or to depth to the aquifer. These wetlands are being impacted by human changes to the landscape that are diminishing groundwater inputs, effectively creating novel wetlands that are now primarily supplied by precipitation rather than groundwater, with altered hydrological and ecological traits that may exacerbate regional vulnerability to climate change. [ABSTRACT FROM AUTHOR]