Papers in Marine Biology and Oceanography, Suppl. to vol. 3 of DeefvSea Research, pp. 204-211. 



Distribution of planktonic Foraminifera in some Mediterranean 



sediments* 



By Frances L. Parker 

 Scripps Institution of Oceanography, La Jolla 



Summary — The planktonic foraminiferal populations of the Mediterranean Sea may be differentiated 

 from those of the adjacent Atlantic Ocean. 



Three distinct populations are found located in the western and eastern Mediterranean and the 

 Aegean Sea, and additional discrete populations may occur in the unsampled areas. 



Populations probably are derived from the Atlantic and from indigenous ancestral stock. 



The direction of coiling of Globorotalia truncatulinoides shows a shift to left coiling dominance 

 within the Mediterranean. Additional statistical analysis may give further evidence concerning 

 derivation of species in the area. 



INTRODUCTION 

 The planktonic Foraminifera in sediment-surface samples from forty-six stations 

 throughout the Mediterranean Sea have been studied and compared with planktonic 

 assemblages in the adjacent Atlantic. These populations show some regional variation 

 and the Mediterranean faunas as a whole differ from those of the Atlantic. The 

 samples were collected, in 1947-48, by members of the Woods Hole Oceanographic 

 Institution on KlV Atlantis Cruise 151. This study was supported by the Office of 

 Naval Research (Project NR 081-050, Contract Nonr— 233 Task 1). The drafting 

 was done by Miss J. F. Peirson and R. R. Lankford. 



Much has been published on the description and taxonomy of Mediterranean 

 faunas but few quantitative studies have been made. Phleger (1947) gives quantitative 

 lists of planktonic species in top samples of three long cores from the Tyrrhenian Sea, 

 but suggests that at least one of these does not represent the modern fauna. Muraour 

 (1954 A, b) gives quantitative data for two stations near Algiers. Di Napoli-Alliata 

 (1952) gives a very useful resume of the literature on Mediterranean planktonic 

 faunas. 



The stations (Fig. 1, Table I) are scattered throughout most of the area south of 

 North Latitude 38° 51' with the exception of four in the northern part of the Aegean 

 Sea. No samples were obtained from the Adriatic Sea, where many of the previous 

 studies have been made, nor from the northern part of the western Mediterranean, 

 The samples were collected with a gravity corer or with a coring tube attached to a 

 camera and are believed to contain material from the surface of the sediment. Three 

 hundred to five hundred planktonic specimens larger than 0-149 mm were counted 

 from each and the relative abundances of the species calculated. Samples having 

 fewer specimens are omitted ; the majority contain many more. 



SURFACE TEMPERATURE AND SALINITY DISTRIBUTION 



For convenience in the later discussion of the planktonic populations, the area may 

 be divided into three parts: western Mediterranean, eastern Mediterranean, and the 



* Contribution No. 20, Marine Foraminifera Laboratory; Contribution No. 803, Scripps Institu- 

 tion of Oceanography. 



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