الفهرس 
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Abstract
TheRed Sea is a natural laboratory for investigating relatively rapid changes of short
durationin a restricted marine environment. It covers a wide range of conditions, from
normalmarine, highly productive to external hypersaline and oligotrophic. It has shown
itselfto be an excellent laboratory for the study of relatively rapid changes of short
duration in the marine environment. Thus correlation in space and time between
ecologicalgradients and assemblages of organisms is facilitated.
The geographical position of the Red Sea (Fig., 1) amidst the deserts of North
Africaand Arabia and its unique hydro graphical properties made it a most valuable
archivefor paleo-climatic studies. The current knowledge of the Red Sea such as
geology,development, hydrography, and pal eo-oceanography have been summarized
andpresented in Chapter I.
Paleo-ecology is concerned with the fossil organisms in relation to their
environmentat the time of their life, death, and burial in the sediment. Acknow ’edge of
past oceanic conditions is fundamental to many aspects of oceanography, it was
inevitable that natural historians should attempt to deduce past environmental
conditionsthrough investigation of fossil assemblage. Foraminifera can be very useful
forreconstructing ancient marine environments; they are uni-cellular testate marine
organismswith a long strati graphic history. They produce four basic test (shell) types:
1)Organicwalled forms (allogromiids), 2) Agglutinated or arenaceous (made of foreign
particles, usually sand, cemented together by the organisms), 3) Porcelaneous
(combinationof organic and calcareous material) and 4) Calcareous (secreted by the
organisms).The first three types fossilize readily whereas the last one rarely does
(Loeblich& Tappan, 1964). The function of the test is probably multiple, as pointed out
by Marzaleket. al. (1969), including protection from predation and unfavorable.