The importance of benthic foraminiferas in detecting features of ecological and geological structures in Edremit Bay and on coastal areas of Dikili Channel (NE Aegean Sea)

Benthic foraminiferal assemblages from the Gulf of Edremit, Lesbos Island, Alibey and Maden islands and Dikili Bay have been investigated and various morphological abnormalities, as well as, colored tests and large sizes have been observed. Besides, abundance of alien species originating from tropical seas attracts attention. Interesting togethernesses were found between different genera and species. Significant differences were observed between the assemblages from the northwest and southeast coasts of the Gulf of Edremit. 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 diverse foraminifer assemblage were observed around the Ayvalik-Alibey and Maden islands, with large individual sizes, colored tests and morphological abnomalities. Abnormal togethernesses between different genera and species were also observed in this locality. Togethernesses between Peneroplis pertusus (Forskal)-Coscinaspira hemprichii Ehrenberg and Peneroplis planatus (Fichtel and Moll)- Coscinaspira hemprichii Ehrenberg are important findings in the benthic foraminiferal assemblages of Ayvalik Alibey and Maden islands. Orange and brown coloration observed on many Peneroplis pertusus (Forskal) and P. 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), Ammonia compacta Hofker, A. parkinsoniana (d'Orbigny), Challengerella bradyi Billman, Hottinger and Oesterle, Elphidium complanatum (d'Orbigny) and E. crispum (Linné) were found. The presence of Laevipeneroplis karreri (Wiesner), Peneroplis pertusus (Forskal) and P. planatus (Fichtel and Moll) and Sorites orbiculus Ehrenberg on the east coast of Lesbos Island indicates the presence of hotwater springs. An abnormally large Peneroplis planatus (Fichtel and Moll) individual were found. Besides, many Peneroplis pertusus (Forskal) and P. 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 abnormal Peneroplis planatus (Fichtel and Moll) individual with three different apertures was found in Dikili samples. One of the apertures was typical of the species, whereas the other two have the aperture characteristics of Coscinospira hemprichii Ehrenberg. The aim of our study is to figure out the factors leading to abnormal test morphologies. It is suggested that the benthic foraminiferal assemblages found in the study area are affected by the physical environmental conditions such as, temperature and salinity, as well as the chemical factors, such as radioactivity