International Geologiical Congress - Oslo 2008

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HPF-12 Environmental micropaleontology: Past, Present, future

 

Effects of heavy metals on benthic foraminiferal tests with abnormal morphological deformities observed in Alibey and Maden islands (NW Ayvalik-NW Turkey)

 

Engin Meric, Moda, Hüseyin Bey Sokak No: 15/4 (Turkey)
Niyazi Avsar, Cukurova University (Turkey)
Atike Nazik, Cukurova University (Turkey)
Figen Mekik, Grand Valley State University (United States)
M.Baki Yokes, Halic University (Turkey)
Fikret Suner, Istanbul Technical University (Turkey)
Erol Sari, Istanbul University (Turkey)
Ipek F. Barut, Istanbul University (Turkey)
Mustafa Eryilmaz, Mersin University (Turkey)
Fulya Yucesoy-Eryilmaz, Mersin University (Turkey)
Ozcan Dora, 156. Sokak, No: 23/2 (Turkey)
Feyza Dincer, Cukurova University (Turkey)
 

 

The coastal underground water systems carry the heavy metals to marine environment via faults and other similar structures. The heavy metals adversely affect the biota and cause morphological abnormalities in individuals. Being found in abundance, benthic foraminifera constitute one of the important groups in investigating such effects. It is known that benthic foraminifera show great sensitivity to environmental changes. The foraminifera test remain in the sediment for a long time without any deterioration. Thus, they are good biomarkers for environmental pollution of natural or artificial causes. Petroleum wastes, agricultural chemicals and heavy metals are known to be responsible for these anomalies.

In the framework of this study, core samples were collected from four different stations on the coasts of Alibey, Maden and Kçk Maden islands (NW Ayvalik). Of the three core samples obtained from each station, only one was analysed for its foraminiferal content. Small reserves of lead, manganese, hematite and limonite are found around the stations on Alibey, Maden and Kçk Maden Islands.
A part of recent sediments were found to be redish brown in color and contained redish brown, yellow, orange and dark gray colored (or in combination of them) foraminifera in large quantities, mainly Peneroplis pertusus (Forskal) and P. planatus (Fichtel ve Moll). Morphologically abnormal Peneroplis individuals were highly observed. In the other areas investigated, the sediments were found to be composed of light gray sand and very small amount of partially colored or uncolored indivuals. Ammonia compacta Hofker, A. parkinsoniana (d'Orbigny), Challengerella bradyi Billman, Hottinger and Oesterle, Elphidium complanatum (d'Orbigny) and E. crispum (Linné) were dominant species in these sediments. Although, morphologicaly abnormal individuals were observed in these sediments, they were less attractive compared to the samples from other locations.

The ostracod fauna of the recent sediments also varied between stations. The redish brown sediments included less number of genus and species, however, the gray sediments contained a diverse and rich fauna. The diversity of the mollusc fauna was in accordance with the foraminifer and ostracod faunas. Only a few species were found in redish brown sediments, but the gray sediments were rich in mollusc species.

In conclusion, morphological abnormalities observed in different genera and species of benthic foraminifera in four core samples are suggested to be caused by the mine reserves located around Alibey and Maden Islands, as well as the thermal springs found in the vicinity. The core sample 4A was found to contain higher concentrations of Fe and Mn compared to the other core samples. The Fe concentration of 4A was 2.3%, whereas the mean Fe concentration of the other cores was 1.5%, indicating that different factors play a role in sediment deposition in this region.

 

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