Date of Award

12-1994

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Environmental Science

First Advisor

Mohamed Nabih El-Shourbagy

Second Advisor

Abdul-Rahman Saghir,

Third Advisor

Dr. M.H. El-Deeb,

Abstract

Seedling emergence, survival and growth of gray mangrove Avicennia marina (Forssk.) vierh. were studied in relation to different environmental factors through a series of experiments conducted at indoor low temperature, outdoor shaded and field areas at the Marine Resources Research Center, Umm Al Qaiwain. No emergence occurred when seeds were sowed in salinities equal to or higher than 60 ppt. Seedling survival rate decreased with increasing salinity at both indoor and outdoor experimental sites . Faster seedling growth rates were observed under outdoor shaded conditions than under indoor low temperatures. Results of field studies on a sloping beach indicated that the seedling survival was limited to a landward distance of about 5 meters from seawater line, whereas on a flat beach the survival of seedlings was observed up to about 19 meters from seawater line. Mangrove seedling survival growth rates decreased with distance from the seawater line in sloping and flat beaches due to the increase in salinity and depth of ground water. Higher chlorophyll content of the mangrove leaves were encountered in outdoor location than in indoor low temperature area. In the field, the leaf chlorophyll content of mangrove seedlings decreased in the outward direction from the seawater line. Roots contained more moisture than sterns or leaves. Moisture content of roots, sterns, and leaves decreased with an increase in salinity of the seedling growing media in indoor areas and with increasing distance from seawater line in the field. In all analysed soil samples, more than 93 % sand was found in the field study area; whereas sodium, potassium and calcium carbonate were the dominant chemical constituents of the sediment.

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