Multivariate statistical analyses of recent deep-water benthic foraminifera of the Mediterranean reveal a bathymetric and geographic distribution that can be ascribed to water-mass distribution and bottom topography. Three bathyal zones were detected: upper (500 to 1,300 m), intermediate (1,300 to 2,800 m), and lower (> 2,800 m). The eastern Mediterranean (Ionian and Levantine Basins) displays significantly fewer species, fewer individuals, and shows lower species equitability than does the western Mediterranean. The Holocene foraminiferal distribution patterns provide a framework against which late Miocene and Pliocene foraminiferal dynamics were evaluated.

The late Miocene (Messinian) salinity crises eliminated bathyal faunas from the Mediterranean. Pliocene foraminifera which repopulated the Mediterranean (1) are remarkably similar to pre-Messinian faunas of the middle upper Miocene Mediterranean sediments; (2) appear in the sedimentary record very soon after initiation of Pliocene sedimentation and attain population stability within 0.5 million years; (3) were derived predominantly from the Atlantic Ocean; and (4) migrated across the Mediterranean from the west to east. Population differences between the eastern and western Mediterranean faunas suggest the presence of Pliocene sills, especially in the Sicilian area. The geographic differences between Pliocene population structures were less significant than they are today. This phenom non can be explained by Pleistocene tectonism which further restricted water circulation.

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