Saline Bodies Of Water Research Articles

Lithium enrichment optimization from Dead Sea end brine by chemical precipitation technique

Lithium and its compounds are widely utilized in many applications like batteries, aircraft alloys, ceramics, nuclear reactors, medicine, and metallurgy additives due to its exceptional physical and chemical properties. The Dead Sea is known to be rich in several minerals and is considered as a saturated lake for many valuable elements like potassium and magnesium and a trace amounts of precious elements including lithium. Though, the high ratio of Mg2+ to Li+ in the Dead Sea water is one of the main challenges to extract lithium. This paper presents a promising approach for optimizing chemical precipitation from Dead Sea evaporation End Brine containing high Mg2+/Li+ ratio. The process can be carried out in the presence of magnesium, calcium, sodium and potassium chlorides. By comparing the effect of different precipitating reagents on the percentage of lithium extracted, tri-sodium phosphate (TSP) was found to be a promising Li precipitating reagent. The effects of operating conditions on the lithium phosphate (Li3PO4) precipitation behaviours were evaluated. The highest percentage of lithium extracted was reached when seven grams of TSP were added to 1-liter samples of the Dead Sea evaporated end brine at 450 rpm stirring speed. Statistically, temperature and stirring time, were found to have a negligible effect on the percentage of lithium extracted. The optimization process enriched lithium concentrations from 30 −40 mg/L in the brine to 1000–1700 mg/kg in the obtained solid precipitate and more than 40% of the lithium present in the brine was extracted. The effectiveness of the followed procedure and conditions was proven by testing on synthetic brine. The average percentage of lithium extracted from the synthetic brine was 55% and Li concentration was enriched over 50 times larger than its initial concentration. The novelty of the current work is not only by the results obtained but also the successful application of the method on an environmental complex brine that is considered among the most saline bodies of water on earth.

The genome of a novel isolate of Prochlorococcus from the Red Sea contains transcribed genes for compatible solute biosynthesis.

Marine microbes possess genomic and physiological adaptations to cope with varying environmental conditions. So far, the effects of high salinity on the most abundant marine photoautotrophic organism, Prochlorococcus, in marine oligotrophic environments, are mostly unknown. Here, we report the isolation of a new Prochlorococcus strain (RSP50) belonging to high-light (HL) clade II from the Red Sea, one of the warmest and most saline bodies of water in the global oceans. A comparative genomic analysis identified a set of 59 genes that were exclusive to RSP50 relative to currently available Prochlorococcus genomes, the majority of which (70%) encode for hypothetical proteins of unknown function. However, three of the unique genes encode for a complete pathway for the biosynthesis of the compatible solute glucosylglycerol, and are homologous to enzymes found in the sister lineage Synechococcus. Metatranscriptomic analyses of this metabolic pathway in the water column of the Red Sea revealed that the corresponding genes were constitutively transcribed, independent of depth and light, suggesting that osmoregulation using glucosylglycerol is a general feature of HL II Prochlorococcus in the Red Sea.

Palaeoenvironmental evolution of the ancient lagoon of Ostia Antica (Tiber delta, Italy)

The ancient lagoon of Ostia played a key role in the development of the cultures of central Italy and especially that of Rome. The evolution of its environmental history and its partial transformation into a saline body of water during Antiquity remain as poorly known to archaeologists and historians as to geologists and geographers. A high chronostratigraphical resolution palaeoenvironmental study has been carried out on a sediment core. It is based on multi-proxy analysis and pays particular attention to ostracods, which are very useful palaeoenvironmental indicators in marginal marine environments. Our study has unveiled five evolution phases of the landscapes in the countryside of Ostia: (1) between the 6th and the middle of the 2nd millennia BC a lagoon open to the sea was formed; (2) the lagoon was then subject to marine and fluvial influences,; (3) between the middle of the 2nd and the beginning of the 1st millennia BC, a marshland formed, indicating either a period of limited flooding or a shifting of the branch of the Tiber; (4) during the first part of the 1st millennium BC, the lagoon became again connected to the sea. In this area, its depth at the time of the founding of Ostia varied between 3.5 m and 4.5 m (below ancient sea level), which suggests that it could have served as a naturally sheltered place on the coast; (5) from the middle of the 1st millennia BC to the 19th century AD, the lagoon probably remained connected to the sea and progressively silted, until it disappeared in the 19th century.

Numerical Simulation of the Movement of Saltwater under Skimming and Scavenger Pumping in the Pleistocene Aquifer of Gaza and Jericho Areas, Palestine

The Pleistocene aquifers are important sources of water supply in both the Gaza and Jericho areas of Palestine. The aquifers are saline with freshwater lenses floating on saline bodies of water. It is important to investigate how to exploit these freshwater lenses without causing unnecessary mixing of the fresh and saline waters. The objective of this research is to investigate the feasibility of applying skimming and scavenger pumping as a means to exploit the freshwater lenses and to control saline water upconing in the aquifers. This study is the first to examine the movement of fresh and saline waters underneath skimming and scavenger wells in the aquifers of Gaza and Jericho. Two simulation models that couple density-dependent fluid flow and solute transport have been used to simulate and predict the movement of saltwater under different hydrogeological and operational conditions of skimming and scavenger wells in the two aquifers. The results show (for the Jericho Aquifer) that: the location of well screen has a strong control on the steady-state position of the fresh/saline water transition zone; the upconing mechanism appears to continue under skimming pumping until saline water enters the well screen even when the pumping rate is reduced; and for better salinity control it is necessary to place well screen against the gravel layers only and locate one screen segment in the saline water zone. The study shows (for the Gaza coastal aquifer) that the most important parameters affecting the movement of saline water under scavenger pumping are the relationship between recharge and pumping rates, the location of the well screen within the saturated thickness, the vertical permeability; and the transverse dispersivity. This study shows that saltwater upconing in Gaza aquifer can be controlled by operating a second well in the saline water zone so that the optimal ratio between saline water and freshwater pumping is 1:2 respectively.

A salt-sensitive Dunaliella mutant I. Growth and osmoregulatory responses to increases in salt concentration

Dunaliella is a genus of green unicellular algae distributed in all the oceans and saline bodies of water throughout the world and distinguished by unusual tolerance to salt. Since the cells of this genus do not success a rigid cell-wall, they respond to changes in salt concentration by rapid alterations in cell volume and then return to their original volume as a result of adjustments in the amounts of intracellular ions and glycerol, this latter being the major organic osmoticum. The paper describes the behaviour of a mutant of D. parva 19/9 with reduced capabilities of growth above 0.5 kmol m -3 NaCl. The mutant is unusual in that its abilities to synthesize glycerol and pump out Na + and Cl - do not appear to be impaired; volume changes in the hyperosmotic range also appear to be roughly the same as in D. parva. The average and volume of mutant cells is reduced (206 μm 3 as opposed to 255 μm 3 in D. parva) and their rate of change of cell volume after an increase in salt concentration is lower; it took about 10 min for mutant cells in the light to reach a new cell volume whereas D. parva cells reached their new volume in less than 1 min. Both factors may be dependent on components of the cyto-skeleton. The mutant throws light on adaptations necessary to allow Dunaliella cells to grow at high salt concentrations and demonstrates that halotolerance includes, but is not equivalent to, osmoregulation.

Antarctic Interglacial Features

Abstract The upper 180 ft. (55 m.) of Lake Vanda in Wright Valley, south Victoria Land, is essentially potable, whereas that part below 200 ft. (61 m.) is more than three times as saline as sea-water. The salinity below 200 ft. (61 in.) resulted from the evaporation and freezing, mainly during interglacial (Loop-Trilogy) time, of a larger, less saline body of water. An alluvial fan in Wright Valley has been dated as interglacial on the basis of (1) ice-marginal channels formed in Loop time that cut across it, and (2) the fjord-like longitudinal cross-section of the valley formed by the ice of the oldest glaciation or glaciations. Fossils found in till and glacio-fluvial deposits in the McMurdo Sound region, south Victoria Land, date from both early and late Pleistocene interglacial time. An ocean-bottom core sample obtained in the Ross Sea contained interglacial material. The presence in the sample of glacial marine sediments deposited in interglacial time suggests that the Antarctic Ice Sheet maintained itself throughout the Pleistocene. Sub-surface efflorescences consisting of a layer of pure salts as much as 3 in, (7.6 cm.) thick are found 2−5 in. (5−13 cm.) below the surface in Loop deposits in Wright Valley. The absence of similar thick occurrences in Trilogy deposits indicates that the efflorescences are, in part at least, interglacial. Interglacial cinder cones and lava flows are found in the McMurdo Sound area, and some of the widespread scoria present in moraines, glacio-fluvial deposits and beaches dates from interglacial time.

BIOLOGICAL AND OCEANOGRAPHIC CONDITIONS IN HUDSON BAY: 6. THE GENERAL HYDROGRAPHY AND HYDRODYNAMICS OF THE WATERS OF THE HUDSON BAY REGION

The waters of Hudson bay differ markedly from the waters of Hudson strait and the waters of the open ocean. Intense stratification in the upper twenty-five metres, decreasing as the waters of the open ocean are approached, gives Hudson bay the character of a large estuary. Below fifty metres the waters are for all purposes dynamically dead, thus resulting in a cold saline body of water which probably undergoes very little change from season to season. The movements of the waters at various levels are dealt with to show that the inflow of waters from Fox channel and the many fresh-water drainage areas control the hydrographic conditions as found. The main water movement is from the James bay area to Hudson strait and thence to the open ocean.