TEMPORAL VARIATIONS IN 4 SPECIES OF INTERTIDAL FORAMINIFERA, BAHRAIN, ARABIAN GULF

This study deals with the temporal variations in four infaunal foraminiferal taxa sampled monthly over a 25-month period (February 1991 - February 1993 inclusive) from the lower intertidal zone on the east coast of Bahrain, Arabian Gulf. Standing crop, relative abundance and changes in species diversity and annual production of tests were measured for Ammonia beccarii, Elphidium advenum, Brizalina pacifica and Nonion sp.. Additionally the greatest diameter of each individual of A. beccarii was measured to determine monthly size changes and periods of reproduction. An attempt was made, through the use of replicate sampling, to determine homogeneity or patchiness (similarity) in species distributions and abundance patterns. Major changes are noted in species diversity and abundance between July and August 1992. The standing crop of the whole assemblage and of A. beccarii doubled, that of E. advenum increased three to four times and, for B. pacifica and Nonion sp., the increase varied between 30 and 100 times. Overall, standing crop varied from 1-118 per 10cm(3) and annual production of tests ranged from 2 to 2550 per 10cm(3). A beccarii is thought to reproduce throughout the year. Species diversity is characteristically low in this hypersaline habitat. Whereas the living assemblage is dominated by infaunal taxa, the dead assemblage is composed largely of transported epiphytic taxa, so the two are very different.