122,109 research outputs found
Le Chott Tigri
No full textGautier E.-F. Le Chott Tigri. In: Annales de Géographie, t. 25, n°135, 1916. pp. 181-189
Le problème hydraulique du chott Ech Chergui (Algérie)
No full textLarnaude Marcel. Le problème hydraulique du chott Ech Chergui (Algérie). In: Annales de Géographie, t. 57, n°305, 1948. pp. 88-89
Le problème hydraulique du chott Ech Chergui (Algérie)
No full textLarnaude Marcel. Le problème hydraulique du chott Ech Chergui (Algérie). In: Annales de Géographie, t. 57, n°305, 1948. pp. 88-89
Essai de bilan hydrologique du chott d’Ouargla (Sahara occidental)
No full textExperimental "hydraulic balance" for Chott d Ouargla in the Western Sahara.
The purpose of an investigation during the past two years has been to find out whether the "chott" (which, like most other Algerian "chotts", can be compared to a complex evaporation mechanism) is fed by underground water, or whether it is part of the degraded Oued Mya hydrographical system in that it provides a return path for runoff from the Ouargla palm grove to the underflow water tables.
The "chott’s" hydraulic balance is based on three items : 1) a positive item expressing the inflow from the drains collecting surplus irrigation water from the palm grove, which is supplied both by an artesian well and runoff ; 2) a negative item relating to evaporation losses and 3) the quantity of water drawn off by pumping, also a negative item. If the "chott" is operating as a closed-circuit system, the algebraic sum of these three items should be the same as the change in the volume stored in the "chott". The repeated failure to get the two sides of the "balance sheet" to agree during the past two years appears to show that the "chott" is either feeding or boosting supplies to the underflow water table, especially a series of "sebkhets" in the N’Goussa depression 20 kms north of Ouargla. The existence of a pronounced pressure gradient towards this depression appears to substantiate this theory.
The "trial balance" drawn up by the Hydro-logical Section of the Scientific Research Department is presented and its pedological aspect discussed by Mr. P. Dutil, who is a member of the Pedological Section of that Department.L'étude entreprise depuis deux ans visait à s'assurer, soit de l'alimentation souterraine du chott qui fonctionnait alors comme la majeure partie des chotts algériens en machine évaporatoire complexe, soit de son appartenance à l'ensemble hydrographique dégénéré de l'Oued Mya en permettant aux eaux de ruissellement de la palmeraie d'Ouargla de retourner aux nappes d'inféro-flux.
Le rapport présente le bilan du chott à partir de trois postes : le premier, positif chiffre l'apport des drains recueillant le surplus des eaux d'irrigation de la palmeraie alimenté par un forage artésien et les eaux de ruissellement ; le second, négatif concerne les pertes par évaporation et le dernier, également négatif, est celui des prélèvements par pompage. La somme algébrique de ces trois postes du bilan doit, si le chott travaille en circuit fermé, correspondre à la variation du volume emmagasiné dans le chott. L'impossibilité où l'on se trouve depuis deux ans de fermer ce bilan par excès montre que le chott alimente, ou suralimente, la nappe d'inféro-flux et en particulier une série de sebkhet dans la dépression de N'Goussa à une vingtaine de kilomètres au N d'Ouargla ; l'existence d'une pente piézométrique importante vers cette dépression semble confirmer cette hypothèse.
L'essai de bilan de la Section Hydrologie du S.E.S. est présenté et commenté du point de vue pédologique par M. P. Dutil (Section Pédologie du S.E.S.).Dutil Pierre, Samie C. Essai de bilan hydrologique du chott d’Ouargla (Sahara occidental). In: L'hydraulique souterraine. Compte rendu des sixièmes journées de l'hydraulique, Nancy, 28-30 juin 1960. Tome 2, 1961
P. Trousset, Recherches sur le Limes Tripolitanus du Chott el-Djerid à la frontière tuniso-libyenne
No full textChevallier Raymond. P. Trousset, Recherches sur le Limes Tripolitanus du Chott el-Djerid à la frontière tuniso-libyenne. In: Annales. Économies, Sociétés, Civilisations. 31ᵉ année, N. 6, 1976. pp. 1110-1111
Prokaryotic diversity in a Tunisian hypersaline lake, Chott El Jerid
No full textProkaryotic diversity was investigated in a Tunisian salt lake, Chott El Jerid, by quantitative real-time PCR, denaturing gradient gel electrophoresis (DGGE) fingerprinting methods targeting the 16S rRNA gene and culture-dependent methods. Two different samples S1-10 and S2-10 were taken from under the salt crust of Chott El Jerid in the dry season. DGGE analysis revealed that bacterial sequences were related to Firmicutes, Proteobacteria, unclassified bacteria, and Deinococcus-Thermus phyla. Anaerobic fermentative and sulfate-reducing bacteria were also detected in this ecosystem. Within the domain archaea, all sequences were affiliated to Euryarchaeota phylum. Quantitative real-time PCR showed that 16S rRNA gene copy numbers of bacteria was 5 x 10(6) DNA copies g(-1) whereas archaea varied between 5 x 10(5) and 10(6) DNA copies g(-1) in these samples. Eight anaerobic halophilic fermentative bacterial strains were isolated and affiliated with the species Halanaerobium alcaliphilum, Halanaerobium saccharolyticum, and Sporohalobacter salinus. These data showed an abundant and diverse microbial community detected in the hypersaline thalassohaline environment of Chott El Jerid
Trousset (Pol) : Recherches sur le limes tripolitanus du Chott el-Djerid à la frontière tuniso-libyenne
No full textCamps Gabriel. Trousset (Pol) : Recherches sur le limes tripolitanus du Chott el-Djerid à la frontière tuniso-libyenne. In: Revue de l'Occident musulman et de la Méditerranée, n°20, 1975. pp. 181-183
Fouilles sur l'emplacement d'une basilique près de Douar-ech-Chott à Carthage
No full textDelattre Alfred-Louis. Fouilles sur l'emplacement d'une basilique près de Douar-ech-Chott à Carthage. In: Comptes rendus des séances de l'Académie des Inscriptions et Belles-Lettres, 66ᵉ année, N. 4, 1922. pp. 302-307
Taxonomy, phylogeny and biostratigraphy of the upper Aptian–lower Albian ammonites of the Chott area, southern Central Tunisia
No full textInternational audienceFour sections were measured and studied in the uppermost Aptian and lower Albian of the Chott Basin (southern Central Tunisia), providing an abundant, bed-by-bed collected paleontological material. The ammonite succession allows precise correlations with the ammonite biozonation established in Central Tunisia. The phylogeny of knemiceratids and acanthohoplitinids of the Chott Basin is investigated and the alleged extreme variability of knemiceratids is questioned. Five new ammonite species are herein described: Knemiceras sagetae sp. nov., Knemiceras lanceolatum sp. nov., Knemiceras multicostatum sp. nov., Knemiceras tunisiense sp. nov., Parengonoceras chottensis sp. nov., highlighting the highly endemic character of the Chott Basin ammonite faunas
Spatio-temporal monitoring of evaporitic processes using multi-resolution C band radar remote sensing data: example over the Chott el Djerid
No full textCanadian Journal of Remote Sensing, 2013, in pressInternational audienceThis paper gives an illustration of the contribution of spatio-temporal multi-resolution of spaceborne radar data for the monitoring of land surfaces. More precisely, it illustrates the potential of C band spaceborne radar data, by using in synergy scatterometer and SAR (Synthetic Aperture Radar) sensors, for the spatio-temporal monitoring of evaporitic processes over a vast playa, the Chott el Djerid, located in central Tunisia. Scatterometer data from the ASCAT (Advanced Scatterometer) instrument are characterized by a high temporal frequency of acquisition, about 3 days over the Chott, with a spatial resolution of 25 km. It is well suited for an interpretation of radar temporal signatures in relationship with seasonal variations of surface states. SAR images obtained from both ASAR (Advanced SAR) and RADARSAT-2 sensors are less frequent (about 20 days) but provide a higher spatial resolution, allowing the discrimination of spatial patterns related to evaporitic processes. ASAR Wide Swath mode, associated to 150m of spatial resolution, allows for the monitoring of the whole Chott area, while RADARSAT-2, realizing full polarimetric acquisitions with a spatial resolution of 8 m over, allows for the discrimination of finer spatial patterns over a sub-area within the Chott. Both scatterometer and SAR data show an overall good agreement in radiometry. Polarimetry, available for the RADARSAT-2 data, allows to highlight striking spatial patterns in relation with the various sedimentation processes within the saline deposit over the chott
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