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DOI

10.19111/bmre.87557

Abstract

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 Ayval›k-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 Ayval›k 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 Ayval›k,
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.

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