Bardawil is a coastal lake/lagoon that stretches across most of the Mediterranean coastline of Egypt's Sinai Peninsula. The surrounding area is known as the eastern gate to Egypt, and has a long history of being a bridge between Africa and Asia. The lake's length is 76.37 km (extending from (31°03`N to 31°14`N, and 32°40`E to 33°30`E) and has a maximum width of 16.65 km, occupying a total surface of 518.99 km2. Before 2011 the basic dominants flora in the lagoon were Ruppia cirrhosa and Cymodocea nodosa. In 2011, Halophila stipulacea became the most prominent species in the lake
The aim of this study was to determine changes in the bacterial population of aquatic macrophytes, sediment and water samples of Bardawila lake and changes in the macro-vegetation and their possible reasons. For bacteriological analyses Samples of water, sediments and two seagrass roots were collected from two sectors of Lake Bardawil, Sector I at the eastern side with plant cover of Halophila stipulacea and Sector II at the water- circulated area in the northern middle and with plant cover of Cymodocea nodosa. Total bacteria and total diazotrophs were present in high densities in all samples. ANOVA analysis indicated significant differences attributed to the environmental niches. Halophila stipulacea roots support higher populations of diazotrophs (up to 1010 cfu g-1).
This study demonstrates that diazotrophs are not randomly distributed in the lake and are either distributed by the host plant or adapted to different environmental niches. The reduction in the distribution of Cymodocea nodosa is a result of competitive displacement by Halophila stipulacea