oa Halting the Erosion of Qatars' Barchan Dunes: A Study on the Synergy Between Ripple Motion, Moisture Retention and Microbial Growth within Barchans and How it Can be Exploited to Stop the Erosion of an Active Dune

Barchan dunes in Qatar are restricted to the southeastern region of the country. They are currently a disappearing natural habitat due to the northwesterly Al Shamal winds, which are scouring the landscape and spreading desertification, as they pass. This research aims to understand whether the synergy between the physical transport of dust, moisture retention and microbial growth beneath the dune surface, could be exploited to stop erosion of an active dune. Microbial communities at the surface down to 30cm below have been quantified using direct counts of live/dead cells through fluorescent stains, culturing sand microbes in media selective for general heterotrophs, fungi and/or cyanobacteria, and by conducting culture-independent phylogenetic characterization based on 16S/18S rRNA analysis. Current results show that there is more genetic material found in barchans at depths between 15 to 30 cm deep than at the surface, due to the cooler, moister, and UV-protected sand below the surface. Isolated colonies sequenced from barchans include Arthrobacter and Marmonicola sp., which are typical of bacteria associated with soils. Capacitance and thermal probes recording the humidity and temperature were deployed just beneath the sand surface. For the first time, diurnal variations of temperature and humidity profiles below a dune surface have been recorded. A correlation for migration velocity of Qatar dunes west of Umm Said was established. We anticipate that greater understanding of dune biology will lead to the development of new engineering technology to stabilize Barchans.