ALPHA AND BETA DIVERSITIES OF LATE QUATERNARY BATHYAL BENTHONIC FORAMINIFERAL COMMUNITIES IN THE NE CARIBBEAN SEA

Abstract

The 3.85 m-long piston core En20-10, from the NE Caribbean Sea (17°02.2′N, 63°03.3′W, 885 m water depth) comprises hemipelagic sediment interrupted by calcareous turbidites at ~160–200 cm. SHE Analysis for Biozone Identification (SHEBI) revealed four abundance biozones (ABs), one of which (AB2) was coincident with the turbidites. The AB3/AB4 boundary may be coincident with the Pleistocene/Holocene boundary. The α diversities ranged 22.6–36.0 effective species, being lowest in AB2 and highest in the succeeding AB3. The β diversities were 0.728–1.593. However, only the β diversity across the AB2/AB3 boundary was significant. This indicates that the major control of α diversity was sedimentological, low α being associated with the turbidites. The β diversity across the AB3/AB4 boundary was not significant, which implies that the environmental change at the end of the Pleistocene that impacted the composition of the bathyal fauna did not influence α diversity.