Benthic foramınıferal assemblages of the surface sediments of Sinop coasts

The present study was conducted in order to determine the recent benthic foraminiferal species distributed in the Sinop coasts. Samplings were carried out between August 2009 and July 2010 at eight stations with depths of 3 and 10 m. Water and sediment analyzed for each station using spectroscobic and sedimentologic methods. Additionally several physicochemical parameters were measured in situ by a CTD probe. Biological samplings were done as three replicates from soft substrata through the use of 30-40 mm wide and 10 cm length tube sediment corers. Rose bengal staining method was used to easily determine the living benthic foraminifers. As a result of the study a total of 36 benthic foraminifer species belonging to 24 genera, 15 families and 7 orders were found to distribute along Sinop coasts. When the species obtained were classified according to frequency index 21 species (58%) were classified as constant,7 species (21%) as common and 8 species (21 %) as rare. As to the evaluations in terms of mean abundance values Ammonia compacta (43%) was found to be the most dominant with 34626 indiv./m2 followed by A. tepida (5%) with 3184 indiv./m2, species of the family Hauerinidae (5%) with 3980 indiv./m2, A. parasovica (2%) with 1592 indiv./m2 and Massilina secans (2%) with 1592 indiv./m2. When the stations were examined according to the Bray-Curtis similarity index, 2 main foraminiferal groups were observed. SIMPER analysis demonstrated that A. compacta (56.68%), Ammonia sp. (7.69%) and A. tepida (6.51%) made the highest contribution to the formation of group A whereas in group B, the highest contributions were by A. compacta (11.79%), Ammonia sp. (9.52%) and Hauerinidae spp., respectively. As a result of Bio-Env analysis, particle size of the sediment, temperature, phosphate (PO4), nitrite (NO2), nitrate (NO3), silica, pH, % water content and organic matter were detected to be the influencing factors for the distribution of foraminiferal species along Sinop coasts.