Wadi El-Natrun Research Articles

Osmoregulation in a New Haloalkaliphilic Bacillus from the Wadi Natrun (Egypt)

Summary A new haloalkaliphilic Bacillus strain was isolated from an alkaline, sodium chloride, sulfate and carbonate containing lake of the Wadi Natrun (Egypt). The organism only grows between pH 8.5 and pH 10 and is extremely halotolerant, growing in media with up to 200 g/l NaCl. In its morphology and its utilization of various substrates, it differs remarkably from previously described alkaliphilic bacilli. Determination of the intracellular concentration of Na + , K + , Cl - , amino acids and polyols showed that these ions were responsible for osmoregulation. The sodium chloride concentrations within the cells were similar to those in the medium. In contrast, the enzymatic apparatus of the organism does not seem to be adapted to the high intracellular ion concentrations. All tested enzymes were inhibited by high concentrations of NaCl.

Paleozoic and Mesozoic Stratigraphy and Oil Potential of Western Desert: ABSTRACT

The depocenter of the Paleozoic basin in western Egypt lies in the northwestern part of the Western Desert. The sediments are primarily terrigenous (with two minor phases of vulcanicity) laid down in an epicontinental sea. The depositional axis of the basin, where thicknesses in excess of 2,800 m (9,200 ft) have been recorded, has a northwesterly trend to the vicinity of the Siwa Oasis. A less well-defined shallower basin with a northerly trend lies to the southwest. The facies show such similarities to those found in the Ghadames and Murzuq basins that the same formational names are applied. Farther east, a possible Paleozoic basin lies in the Abu Gharadig area where 1,300 m (4,265 ft) of sediments were drilled. The limits of this presumed basin are questionable since ba ement was not reached. Following the deposition of the Paleozoic section, there was a marked hiatus; the time of Hercynian movements for Permian and Triassic beds is absent. Uplift and the presence of volcanics dated in Permian-Carboniferous time are indicative of Hercynian tectonic activity. Only in Early Jurassic time did the seas again begin to encroach upon the Western Desert area from the Salum basin in the northwest and the Wadi Natrun basin to the east and northeast. This process continued, until by the time of the Oxfordian transgression maximum there was a relatively uniform carbonate cover to about lat. 29°N over the Western Desert. Further tectonic uplift accompanied by faulting and marine regression is dated from late Kimmeridgian time to the beginning of the Cretaceous, when transgression began once again. The pattern of transgression, however, differs from that of the Jurassic; the two basins, the more westerly Matru basin and the easterly Alamein basin, both have north-northeasterly trends, although by Aptian times they are less clearly distinguishable. The dominant feature, new in the Western Desert, was the development of an east-west extensional basin, the Abu Gharadig basin, in Cretaceous time. It was bounded on the north (30°N) by the Rabat Abu Rivash ridge, which persisted through the Cretaceous. The trough became less distinctive in Cenozoic times when a further trough, the Tiba basin, developed north of the ridge. Production from the northern Western Desert until recently has been disappointing. Exploration results from the Paleozoic Section have yielded little, but the existence of a marine section suggests that the area northeast of Siwa still has potential. The thick deeply buried Jurassic marine sequence in the Western Desert may be the source for at least part of the production from Cretaceous horizons in the Abu Ghradig, Alamein, and Razzak oil and gas fields. End_of_Article - Last_Page 495------------

Halobacterium pharaonis sp. nov., a New, Extremely Haloalkaliphilic Archaebacterium with Low Magnesium Requirement

Halobacterium pharaonis sp. nov. was isolated from the alkaline brines of eutrophic desert lakes of Wadi Natrun, Egypt. The new species differs from the Halobacterium species so far described in being alkaliphilic, in its extremely low Mg2+ requirement for growth, and in its DNA base composition (64.3 mol% guanine + cytosine, determined by thermal decomposition; no satellite DNA). Magnesium in concentrations above 0.01 mol/1 (≈ 0.25% w/v MgSO4·7H2O) inhibits growth. Good growth occurs between pH 7.7 and 9.3, optimal growth at pH 8.5.

Ectothiorhodospira abdelmalekii sp. nov., a New Halophilic and Alkaliphilic Phototrophic Bacterium

A new species of the genus Ectothiorhodospira is described isolated from alkaline soda lakes of the Wadi Natrun in Egypt. In most of its properties it resembles the recently described Ectothiorhodospira halochloris, which had been isolated from similar lakes of the same area. The new species, Ectothiorhodospira abdelmalekii, has spiral-shaped cells with 0.9-1.2 μm diameter, it is polarly flagellated with sheated flagella, has lamellar photosynthetic membrane stacks, possesses bacteriochlorophyll b as the main photosynthetic pigment, and has a DNA base composition of 63.3–63.8 mol% G + C. Photolithotrophic growth with sulfide or elemental sulfur as electron donors is the predominant mode of life. During sulfide oxidation to sulfate, elemental sulfur is accumulated outside the cells. Acetate, pyruvate, fumarate and succinate are photoassimilated. The properties of E. halochloris and E. abdelmalekii are compared.

Thermal studies on thenardite

Two natural thenardite (Na 2SO 4) single crystals, e.g. from Wadi El-Natron and Searles Lake, and one synthetic thenardite were studied by combined thermal techniques (e.g. DTA, TG, TMA, TOA and MS) mainly with regard to the occurring phase transitions and in order to determine the reason for the observed differences in the transition behaviour of the studied samples. The synthetic thenardite which was chemically very pure (especially free of water) showed its phase transitions during heating and cooling for be much closer together and (1st heating) a little shifted to higher temperatures compared with the natural samples which contained remarkable amounts of water and carbon, respectively. Simultaneously with the phase transitions, both natural samples lost some weight, showed very sharp, clear changes in the TMA curves and released water and CO 2 during the first heating. The thermal transitions started at distincts spots within the single crystals, easily recognizable at different interference colours when using crossed nicols in the thermomicroscope. These spots were interpreted as domains with a certain crystal physical defect character which partly enables earlier phase transitions at the defect domains. The spots seem to include very small particles of mirabilite, Na 2SO 4 10 H 2O, or carbon flakes which are the reason for the defect domains and the observed release of water and CO 2.

The Wadi Natrun: Chemical composition and microbial mass developments in alkaline brines of Eutrophic Desert Lakes

Six lakes of the Wadi Natrun, Egypt, were studied with respect to the chemical composition of their brines and the occurrence of microbial mass developments. All investigated lakes showed pH values of approximately 11 and a total salt content of generally more than 30%. The main components were sulfate, carbonate, chloride, sodium, and minor amounts of potassium. Only traces of magnesium and calcium were present, but unusually high concentrations of organic carbon compounds, nitrogen compounds, and phosphate were found. Mass developments of phototrophic sulfur bacteria, halobacteria, cyanobacteria, and green algae were observed. The functions of complete nitrogen and sulfur cycles in the alkaline brines are discussed. The properties of the lakes and their ecology are compared with data on the Dead Sea and Great Salt Lake, Utah.

Geochemistry of ground waters from some localities West of the Nile Delta

The geochemistry of ground waters from Tahrir Province and Wadi El-Natrun, both West of the Nile Delta, has been studied in detail. The distribution of cations and anions in the water shows that the concentration of calcium and magnesium is lower in Wadi El-Natrun than in Tahrir, while sodium, carbonate and bicarbonate and chloride ions are higher. The concentration of potassium and sulphate ions is identical.

New fish fossils from the Pliocene of Wadi Natrun, Egypt

New material from the Pliocene fish beds of Wadi Natrun, Egypt, is described, including a new species of Alestes (Characidae). A total of 15 freshwater and at least four marine genera are now known from the site. This fauna is reviewed with particular regard to the fossil history and zoogeographical relationships of its component taxa.

Study of Glass and Glass-Making Processes at Wadi el-Natrun, Egypt in the Roman Period 30 B.C. to 359 A.D. Part 1. Fritting Crucibles, Their Technical Features and Temperature Employed

Study of Glass and Glass-Making Processes at Wadi el-Natrun, Egypt in the Roman Period 30 B.C. to 359 A.D. Part 1. Fritting Crucibles, Their Technical Features and Temperature Employed

STUDY OF GLASS AND GLASS-MAKING PROCESSES AT WADI EL-NATRUN, EGYPT IN THE ROMAN PERIOD 30 B.C. TO 359 A.D.

AbstractIn the Roman period, from about 30 B.C. to about A.D. 359, Wadi el-Natrun was probably one of the main centres of the glass industry in Egypt. In this district, the essential materials for glass-making processes, mainly silica and natron, were and are still quite abundant. Two kinds of crucibles were in use: fritting and melting. The first kind was used for fritting the raw materials of glass to produce glass frit blocks. Such fritting crucibles had a rectangular form which is not usually encountered in other places. Probably this was intended to facilitate the transport of the glass frit blocks produced to glass factories in different places where raw materials were not available. Dimensions for two fritting crucibles are proposed. The body texture is coarse, highly porous and almost loose. These features were intended by the ancient glassmaker to release the frit block easily by fracturing the crucible, which was thus used only once. The chemical composition is distinguished by a high content of...

Study of the applicability of different radioisotopes for determination of the porosity of ground-water aquifers

Field experiments have been made to study the effective porosity of the ground-water aquifers in three localities in Wadi El-Natrun area by the use of γ-emitting tracers and tritiated water with the aim of examining the influence of the adsorption of tracers on to the water bearing formation particles on the velocity in aquifers under pumping conditions. Each of the tracers: I 131, Br 82 and Cr 151 (EDTA) was injected simultaneously with H 3, as a reference, in every locality. The experiments show that the adsorption phenomenon has no influence on the results. It is also concluded that I 131 may be considered the most suitable and convenient tracer for such experiments.

Psalm-Fragments from the Monastery of Saint Macarius in Scetis

Psalm-Fragments from the Monastery of Saint Macarius in Scetis

Plant growth and mineral content of barley as related to irrigation with bicarbonate Waters

In lysimeters filled with sand from the Wadi el Natrun Area, the effect of varying levels of bicarbonate in irrigation solutions on the growth and mineral content of barley, var. Maryut, was investigated.

A method for the determination of aquifer parameters using radioactive isotopes

A new method for measuring the lowering of the water level in wells during pumping has been developed. A γ-source is arranged to float on the water surface in the piezometer well and the variation of the counting rate obtained by a G.M. detector caused by the lowering of the source due to pumping from a nearby well is registered. A calibration is made to give the dependence of the counting rate on the vertical distance between the source and the detector in the piezometer. In this way a (drawdown—time) curve for a constant pumping rate could be constructed. From this curve, the aquifer parameters: coefficients of: transmissibility, T, permeability, P, and storage S are obtained. This method gives an instantaneous response for the variation in the water level. It has been applied on a pumped well with a 50-m distant piezometer in the Wadi El Natrun area. The results were compared with those obtained by the conventional hydrologic method.

Medieval Cairo and the Monasteries of the Wadi Natrun. A Historical Guide

Medieval Cairo and the Monasteries of the Wadi Natrun. A Historical Guide

The First Monasteries

In the ‘Era of Martyrs’ at the end of the third century the persecuted Copts, the Christians of Egypt, suffered death or fled into the desert; but they found life possible only where there was water. The most favourable of these few oases was Nitria, today called ‘Wadi Natrun’ or Valley of Soda, a shallow depression of twenty-two miles by five in the Libyan desert surface. It is situated a camel journey of a day and a half along the ancient track which leaves the Delta near Terenthus, the modern El Tarrana. In it there are eight small lakes, some of whose waters contain soda, others salt. They lie about seventyfive feet below sea-level and are fed not by the Nile, but, as Dr Ball has recently shown, by desert subsoil water flowing from the southwest. Wells dug in their vicinity yield water, brackish but drinkable, and on the shore of one was the town of Nitriotis, the habitation of the sodaworkers and glass-blowers, existing since ancient Egyptian times, Now the desert is crossed by a light railway, run by a company that exploits the salt and sodium carbonate.

Three Liturgical Fragments from the Wadi Natrun

Three Liturgical Fragments from the Wadi Natrun

VI.—Professor Walther's Erosion in the Desert Considered

In the Cairo Scientific Journal the first chapter of Professor Walther's new edition of Das Gosetz der Wüstenbildung was considered in some detail. His second chapter, “Die Abtragung in der Wüste” (pp. 111–218), is no less stimulating to thought and replete in observation. He opens this section of his work with a statement of the facts which point to great climatic stability in Egypt during historical times. Two of these are specially mentioned. First, the presence of a small sack of salt in a grave of the Eighteenth Dynasty, the analysis of which agreed absolutely with that of the salt at present obtained from the lakes of the Wadi Natrun. This occurrence, according to him, proves that the same salt mixtures were being formed at periods 3,500 years apart. A statement as to the nature of the resemblances which lead to so wide a conclusion would have been of interest. Secondly, attention is also called to the total absence of water in the Tombs of the Kings since they were first excavated, pointing to the underground water having stood for many thousands of years at more than 50 metres below present valley level.

Egyptian Soda

A REPORT by Mr. A. Lucas on “Natural Soda Deposits in Egypt” has been issued by the Ministry of Finance as “Survey Department Paper, No. 22.” Natural soda occurs'in Egypt principally in the Wadi Natrun in the Libyan desert, but it is also found some fifty kilometres due north of this, at El Barnugi, in Lower Egypt, and at Mahamid, in Upper Egypt. The principal soda-lakes are in a valley the bottom of which is about 27 metres below sea-level; the lakes extend over a range of 30 kilometres, the nearest being about 38 kilometres from the Nile. In ancient times there were two lakes, which became united when water was most abundant, but at the present time they are divided into about a dozen separate areas, the smaller of which dry up almost entirely in summer, leaving only a few pools of water. The soda is found in solution in the water of the lakes, in a solid form at the bottom of some of the lakes and as an incrustation on the adjoining ground.