Morphometry, migration rates, and environmental hazards of barchan dunes in the Kharga Depression, Western Desert, Egypt

On the crescentic shape of barchan dunes

Aeolian sand dunes originate from wind flow and sand bed interactions. According to wind properties and sand availability, they can adopt different shapes, ranging from huge motion-less star dunes to small and mobile barchan dunes. The latter are crescentic and emerge under a unidirectional wind, with a low sand supply. Here, a 3d model for barchan based on existing 2d model is proposed. After ...

On the shape of barchan dunes

Barchans are crescent-shaped sand dunes forming in aride regions with unidirectional wind and limited sand supply. We report analytical and numerical results for dune shapes under different environmental conditions as obtained from the so-called ‘minimal model’ of aeolian sand dunes. The profiles of longitudinal vertical slices (i.e. along the wind direction) are analyzed as a function of wind ...

Vegetated dunes and barchan dune fields

Migration and Environmental Hazards.

Losses due to natural hazards (e.g., earthquakes, hurricanes) and technological hazards (e.g., nuclear waste facilities, chemical spills) are both on the rise. One response to hazard-related losses is migration, with this paper offering a review of research examining the association between migration and environmental hazards. Using examples from both developed and developing regional contexts,...

Microbial Characterization of Qatari Barchan Sand Dunes

This study represents the first characterization of sand microbiota in migrating barchan sand dunes. Bacterial communities were studied through direct counts and cultivation, as well as 16S rRNA gene and metagenomic sequence analysis to gain an understanding of microbial abundance, diversity, and potential metabolic capabilities. Direct on-grain cell counts gave an average of 5.3 ± 0.4 x 105 ce...