Taxonomy and distribution of the benthic foraminifera in the gulf of İskenderun, Eastern Mediterranean


Thesis Type: Postgraduate

Institution Of The Thesis: Middle East Technical University, Faculty of Engineering, Department of Geological Engineering, Turkey

Approval Date: 2006

Thesis Language: English

Student: Sabire Aslı Oflaz

Supervisor: SEVİNÇ ALTINER

Abstract:

The present study aims to investigate the foraminiferal assemblages of the recent samples in terms of abundance and diversity, to determine the bathymetrical and the geographical distributions of the foraminiferal assemblages. This study further intends to put forward the responses of foraminifers to environmental factors (e.g. bathymetry, salinity, substrate, pollution, water currents, etc.) on the distribution of foraminifers. In this manner, foraminiferal fauna has been taxonomically identified and quantitatively analyzed in the 34 grab samples distributed at depths from 18 m. to 190 m. collected from the Gulf of İskenderun. Counting 300 individuals from each sample, the relative abundances of 151 benthic foraminiferal species belonging to suborders of Rotaliina, Miliolina, Textulariina, Spirillinina and Lagenina have been determined. The relative abundances of samples are dominated by Ammonia tepida; Adelosina cliarensis, Nonion sp.A, Textularia bocki, Reussella spinulosa, Cribroelphidium poeyanum, Adelosina pulchella, Buccella granulata, Elphidium advenum and Nonion depressulum that are also common in the western Mediterranean. Furthermore, the Lessepsian migrants; Peneroplis pertusus, Septoloculina angulata, Septloculina rotunda, Septoloculina tortuosa, Vertebralina striata and Amphistegina lobifera are abundant in only southeastern part of the gulf. Because of complex distribution scheme of benthic foraminifers, some statistical analysis (Cluster Analysis, DCA and CCA) have been applied to relative abundance (percentage) of the most abundant, ecologically important taxa in order to visualize assemblages and their representative species. Two main clusters, mainly controlled by CaCO3 and substrate, have been obtained. It is recognized that the distribution of benthic foraminiferal assemblages are not strongly depend on depth as it expected.