A new type of submarine chimneys built of halite.

In contrast to the subaquatic sulphide and carbonate chimneys, which are known from Mid Ocean Ridges and abyssal submarine volcanoes, chimneys built of salts have not been described yet. Here we present such halite chimneys as a new form of cold-water smokers in hypersaline environments. The here described structures rise up from the bottom of the Dead Sea and result from the submarine discharge of saturated halite-dissolution brines into the salt lake, which is at halite saturation and holds remarkable chloride excess.

Deep desert aquifers as an archive for Mid- to Late Pleistocene hydroclimate: An example from the southeastern Mediterranean.

Many efforts have been made to illuminate the nature of past hydroclimates in semi-arid and arid regions, where current and future shifts in water availability have enormous consequences on human subsistence. Deep desert aquifers, where groundwater is stored for prolonged periods, might serve as a direct record of major paleo-recharge events. To date, groundwater-based paleoclimate reconstructions have mainly focused on a relatively narrow timescale (up to ∼40 kyr), limited by the relatively short half-life of the widely used radiocarbon (5.

Controls on the Cl/Cl input ratio of paleo-groundwater in arid environments: New evidence from Kr/Kr data.

Measurements of the long-lived Kr and Cl radioisotopes in groundwater from the Negev Desert (Israel) were used to assess the Cl/Cl input ratios and Cl contents for paleorecharge into the Nubian Sandstone Aquifer (NSA). The reconstructed Cl content of the recharge flux was on the order of 300-400 mg/L. An initial Cl/Cl ratio of 50 × 10 was assessed for the groundwater replenishment in the Negev Desert since the late Pleistocene, in agreement with the Cl/Cl ratios in recent local rainwater.

Redox condition of saline groundwater from coastal aquifers influences reverse osmosis desalination process.

Reverse osmosis (RO) seawater desalination is a widely applied technological process to supply potable water worldwide. Recently, saline groundwater (SGW) pumped from beach wells in coastal aquifers that penetrate beneath the freshwater-seawater interface is considered as a better alternative water source to RO seawater desalination as it is naturally filtered within the sediments which reduces membrane fouling and pre-treatment costs. The SGW of many coastal aquifers is anoxic - and thus, in a low redox stage - has elevated concentrations of dissolved manganese, iron and sulfides.

The effects of long-term saline groundwater pumping for desalination on the fresh-saline water interface: Field observations and numerical modeling.

This study tests for the first time the long-term effects of pumping saline groundwater (SGW) as feed for a desalination plant on a coastal aquifer. Field measurements combined with 3D modeling of the hydrological conditions were conducted to examine the effects of SGW pumping on the aquifer system. The plant is next to the city of Almeria (South East Spain) and has been operating since 2006.

Harnessing Paleohydrologic Modeling to Solve a Prehistoric Mystery.

A riddle arises at the Epipaleolithic and Neolithic sites that dot the lower Jordan Valley. The area has no water resources yet it has long been a focus of inquiry into the transition from mobile hunter-gatherer to sedentary agriculture-based cultures. How then is there such clear evidence of life here, and particularly at such a critical moment in human evolution? Keen to unravel this conundrum, a numerical hydrological model was devised to simulate the groundwater flow field within the Eastern Aquifer of the Judea and Samaria Mountains during the transition from the last glacial to the current interglacial.

Radiokrypton unveils dual moisture sources of a deep desert aquifer.

In arid regions, groundwater is a vital resource that can also provide a long-term record of the regional water cycle. However, the use of groundwater as a paleoclimate proxy has been limited by the complex hydrology and the lack of appropriate chronometers to determine the recharge time without complication. Applying Kr, a long-lived radioisotope tracer, we investigate the paleohydroclimate and subsurface water storage properties of the Nubian Sandstone Aquifer in the Negev Desert, Israel.

The effect of pumping saline groundwater for desalination on the fresh-saline water interface dynamics.

Over the past few decades, seawater desalination has become a necessity for freshwater supply in many countries worldwide, particularly in arid and semi-arid regions. One potentially high-quality feed water for desalination is saline groundwater (SGW) from coastal aquifers, which has lower fouling propensity than seawater. This study examines the effect of pumping SGW from a phreatic coastal aquifer on fresh groundwater, particularly on the dynamics of the fresh-saline water interface (FSI).

Saline Groundwater from Coastal Aquifers As a Source for Desalination.

Reverse osmosis (RO) seawater desalination is currently a widespread means of closing the gap between supply and demand for potable water in arid regions. Currently, one of the main setbacks of RO operation is fouling, which hinders membrane performance and induces pressure loss, thereby reducing system efficiency. An alternative water source is saline groundwater with salinity close to seawater, pumped from beach wells in coastal aquifers which penetrate beneath the freshwater-seawater interface.

Anaerobic oxidation of methane by sulfate in hypersaline groundwater of the Dead Sea aquifer.

Geochemical and microbial evidence points to anaerobic oxidation of methane (AOM) likely coupled with bacterial sulfate reduction in the hypersaline groundwater of the Dead Sea (DS) alluvial aquifer. Groundwater was sampled from nine boreholes drilled along the Arugot alluvial fan next to the DS. The groundwater samples were highly saline (up to 6300 mm chlorine), anoxic, and contained methane.

Determination of pollution and recovery time of karst springs, an example from a carbonate aquifer in Israel.

This work combines the monitoring of two incidents of spring water pollution in the Western Galilee region of Israel, together with artificial tracer tests that provided valuable information regarding karst system connections and direct estimation of groundwater velocities. Almost simultaneous contamination of seven springs endangered the water supply for the region. The variations over time in contaminant concentration in the different springs were not similar, indicating more than one contamination source.

What is the role of fresh groundwater and recirculated seawater in conveying nutrients to the coastal ocean?

Submarine groundwater discharge (SGD) is a major process operating at the land-sea interface. Quantifying the SGD nutrient loads and the marine/terrestrial controls of this transport is of high importance, especially in oligotrophic seas such as the eastern Mediterranean. The fluxes of nutrients in groundwater discharging from the seafloor at Dor Bay (southeastern Mediterranean) were studied in detail using seepage meters.

Colloid transport in porous media: impact of hyper-saline solutions.

The transport of colloids suspended in natural saline solutions with a wide range of ionic strengths, up to that of Dead Sea brines (10(0.9) M) was explored. Migration of microspheres through saturated sand columns of different sizes was studied in laboratory experiments and simulated with mathematical models.

Line-source multi-tracer test for assessing high groundwater velocity.

Segmented line-source multi-tracer injection is suggested as an effective method for assessing groundwater velocities and flow directions in subsurfaces characterized by high water flux. Modifying the common techniques of injecting a tracer into a well became necessary after point-source natural and forced gradient tracer tests ended with no reliable information on the local groundwater flow. The tracer's line-source increases the likelihood of success of the test and could provide additional information regarding the lateral heterogeneity of the aquifer.

Biased monitoring of fresh water-salt water mixing zone in coastal aquifers.

In coastal aquifers, significant vertical hydraulic gradients are formed where fresh water and underlying salt water discharge together upward to the seafloor. Monitoring boreholes may act as "short circuits" along these vertical gradients, connecting between the higher and the lower hydraulic head zones. When a sea tide is introduced, the fluctuations of both the water table and the depth of the mixing zone are also biased due to this effect.

On the relation between steep monoclinal flexure zones and steep hydraulic gradients.

Steep hydraulic gradients are found in association with steep monoclinal flexures. However, the physics of the reduction of the hydraulic conductivity, which is responsible for the steep gradients, has seldom been studied. We present results of hydrological and mechanical modeling aiming to study the effect of such steep hydraulic gradients demonstrated in the Judea Group Aquifer system, Israel.