THE IMPORTANCE OF BENTHIC FORAMINIFERASIN DETECTING FEATURES OF ECOLOGICAL AND GEOLOGICAL STRUCTURES IN EDREMIT BAY AND ON COASTAL AREAS OF DİKİLİ CHANNEL (NE AEGEAN SEA)

Abstract

Benthic foraminiferal assemblages from the Gulf of Edremit, Lesbos Island, Alibey andMaden islands and Dikili Bay have been investigated and various morphologicalabnormalities, as well as, colored tests and large sizes have been observed. Besides,abundance of alien species originating from tropical seas attracts attention. Interestingtogethernesses were found between different genera and species. Significant differences wereobserved between the assemblages from the northwest and southeast coasts of the Gulf ofEdremit. 57 genera and 97 species were identified in the samples from the northwest coast,where as only 32 genera and 48 species were found on the southeast coast. A diverseforaminifer assemblage were observed around the Ayvalik-Alibey and Maden islands, withlarge individual sizes, colored tests and morphological abnomalities. Abnormaltogethernesses between different genera and species were also observed in this locality.Togethernesses between Peneroplis pertusus (Forskal)-Coscinaspira hemprichii Ehrenbergand Peneroplis planatus (Fichtel and Moll)- Coscinaspira hemprichii Ehrenberg areimportant findings in the benthic foraminiferal assemblages of Ayvalik Alibey and Madenislands. Orange and brown coloration observed on many Peneroplis pertusus (Forskal) andP. planatus (Fichtel and Moll) individuals is another important finding in this region.Besides, many individuals of Peneroplis pertusus (Forskal), P. planatus (Fichtel and Moll),Lobatula lobatula (Walker and Jacob), Cibicidella variabilis (d’Orbigny), Ammoniacompacta Hofker, A. parkinsoniana (d’Orbigny), Challengerella bradyi Billman, Hottingerand Oesterle, Elphidium complanatum (d’Orbigny) and E. crispum (Linne) were found. Thepresence of Laevipeneroplis karreri (Wiesner), Peneroplis pertusus (Forskal) and P.planatus (Fichtel and Moll) and Sorites orbiculus Ehrenberg on the east coast of LesbosIsland indicates the presence of hotwater springs. An abnormally large Peneroplis planatus(Fichtel and Moll) individual were found. Besides, many Peneroplis pertusus (Forskal) andP. planatus (Fichtel and Moll) individuals with orange-yellow tests, like the ones in Ayvalik,were found, suggesting the presence of submarine springs with Fe content. An abnormalPeneroplis planatus (Fichtel and Moll) individual with three different apertures was foundin Dikili samples. One of the apertures was typical of the species, whereas the other two havethe aperture characteristics of Coscinospira hemprichii Ehrenberg. The aim of our study isto figure out the factors leading to abnormal test morphologies. It is suggested that thebenthic foraminiferal assemblages found in the study area are affected by the physicalenvironmental conditions such as, temperature and salinity, as well as the chemical factors,such as radioactivity