Distribution of planktonic foraminifera in surface sediments of the Mediterranean Sea

• Main Author: Thunell, Robert C
• Format: Dataset
• Language: English
• Published: PANGAEA 1978
• Subjects: ATL4647; ATL4648; ATL4650; ATL4654; ATL4655; ATL4656; ATL4657B; ATL4659; ATL4660; ATL4665; ATL4670; ATL4673; ATL4675; ATL4687; ATL4693; ATL4694; ATLB520; ATLB529; Barcelona Coast; Climatic Variability of the Mediterranean Paleo-circulation; CLIVAMP; CLIVAMPcruises; Counting >250 µm fraction; DEPTH; sediment/rock; Elevation of event; Event label; Globigerina bulloides; Globigerina calida; Globigerina digitata; Globigerina falconensis; Globigerinella aequilateralis; Globigerinita glutinata; Globigerinoides conglobatus; Globigerinoides ruber; Globigerinoides sacculifer; Globorotalia inflata; Globorotalia scitula; Globorotalia truncatulinoides; Globorotalia truncatulinoides sinistral; Globoturborotalita rubescens; Globoturborotalita tenella; Hastigerina pelagica; Izmit Bay; Latitude of event; Longitude of event; Neogloboquadrina dutertrei; Neogloboquadrina pachyderma dextral; Neogloboquadrina pachyderma sinistral; Neogloboquadrina sp.; Western Basin; Neogloboquadrina pachyderma; Planktonic foraminifera
• Online Access: https://doi.pangaea.de/10.1594/PANGAEA.55624; https://doi.org/10.1594/PANGAEA.55624

The Mediterranean Sea is a partillay isolated ocean where excess evaporation over precipitation results in large east to west gradients in temperature and salinity. Recent planktonic foraminiferal distributions have been examined in 66 surface sediment samples from the Mediterranean Sea. In addition to mapping the frequency distribution of 16 species, the faunal data has been subjected to cluster analysis, factor analysis and species diversity analysis. The clustering of species yields assemblages that are clearly temperature related. A warm assemblage contains both tropical and subtropical elements, while the cool assemblage can be subdivided into cool-subtropical, transitional and polar-subpolar groupings. Factor analysis is used to delineate the geographic distribution of four faunal assemblages. Factor 1 is a tropical-subtropical assemblage dominated by Globigerinoiden ruber. It has its highest values in the warmer eastern basin. Transitional species (Globorotalia inflata and Globigerina bulloides) dominate factor 2 with highest values occurring in the cooler western basin. Factor 3 reflects the distribution of Neogloboquadrina dutertrei and is considered to be salinity dependent. Subpolar species dominate factor 4 (Neoglobuquadrina pachyderma and G. bulloides), with highest values occurring in the northern part of the western basin where cold bottom water is presently being formed. The Shannon-Weiner index of species diversity shows that high diversity exists over much of the western basin and immediately east of the Strait of Sicily. This region is marked by equitable environmental conditions and relatively even distribution of individuals among the species. Conversely, in areas where temperature and salinity values are more extreme, diversity values are lower and the assemblages are dominated by one or two species.