Assessment the Ecological and Physiological Status of Seagrasses in Representative Habitats at Hurghada and Safaga Provinces, Red Sea Coast, Egypt | ||||
| Egyptian Journal of Botany | ||||
| Article 10, Volume 56, Issue 1, September 2016, Page 173-201 PDF (961.5 K) | ||||
| Document Type: Regular issue (Original Article) | ||||
| DOI: 10.21608/ejbo.2016.382 | ||||
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| Abstract | ||||
| EAGRASS communities represent spatially complex and ……biomass producing systems. The present study investigated shallow water seagrass communities from four sites; two sites located at Hurghada (Abu Shaar and NIOF) and two sites located at Safaga (GeneralBeach and Aza'at). Five seagrasses were identified in the studied sites; Halophila stipulacea (Forssk.) Asch., Halodule uninervis (Forssk.) Boiss., Halophila ovals (R.Br.) Hook. f., Thalassodendron ciliatum (Forssk.) Hartog and Syringodium isoetifolium (Forssk.) Hartog. Distribution of the recorded species and sediment texture explained the relation between species and sediment type, where Th. ciliatum prefers conglomerate sediments from coarse sand, H. uninervis prefers fine sandy sediments while H. stipulacea and H. ovalis prefer disjointed coarse sandy sediments. The soils of fine particles have high organic matter content than those constructed from conglomerate or disjointed coarse sand. Abu Shaar and NIOF sites contain a low concentration of calcium carbonate compared to General Beach and Aza'at sites. Shoot biomass and density of the four seagrasses were highly affected by seasonality; where they were increased in summer season than in winter. Photosynthetic pigments of H. stipulacea and H. uninervis significantly increased in winter than in summer, while those of H. ovalis and Th. ciliatum showed the reverse. Total carbohydrates and crude protein of the four seagrasses in the four sites increased in winter than in summer. Soluble compounds (Total soluble sugars, total soluble amino acids and protein) significantly increased in the four species in summer season than in winter and increased in seagrasses growing in low depth than deepest locations. Nitrogen and phosphorus didn't show significant variation in seagrasses tissues in the two seasons or sites. Na+, K+, Mg++ and Ca++ cations significantly increased in the four studied seagrasses in summer than in winter and in seagrasses growing in shallow habitats than the deepest ones. The current study indicated that the most important factors affecting the distribution of seagrasses in the study area are the quality of the sediments, while climatic factors and water depth affecting on productivity and metabolic processes of seagrasses. Recording H. uninervis at NIOF site and Syringodium isoetifolium at GeneralBeach site for the first time indicated that changes have been occurred in these environments to become suitable for the appearance of these species. | ||||
| Keywords | ||||
| Seagrasses; Distribution; Sediment; Biomass; physiology; Hurghada; Red Sea | ||||
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