The Effect of Heavy Metals (Cu, Cd, Zn, Cr , Ni) onDiversity and Density of Benthic Foraminifera in the Sediments of the Southern Coast of Caspian Sea (From Abbas-Abad to Ramsar)
Subject Areas :Mona Eghbali 1 , Setareh Piroozmanesh 2 , Babak Moghaddasi 3 , Masomeh Sohrabi 4 , Pargol Ghavam Mostafavi 5
1 - M.Sc. Holder, Marine Science and Technology Department, Science and Research Branch, Islamic Azad
University, Tehran
2 - M.Sc. Holder, Marine Science and Technology Department, Science and Research Branch, Islamic Azad
University, Tehran
3 - Assistant Professor, Natural Resources Department ,Savadkooh Branch , Islamic Azad University
4 - Assistant Professor, Geology Department, Islam Shahr Branch, Islamic Azad University
5 - Assistant Professor, Marine Science and Technology Department, Science and Research Branch, Islamic
Azad University, Tehran
Keywords: Heavy metals, Caspian Sea, sediments, benthic foraminifera,
Abstract :
In order to identify and assess the relationship between Benthic Foraminifera with environmental factors andheavy metals (Pb, Cd, Zn, Ni, Cr and Cu) the effects of these metals on the variety and condensation of BenthicForaminifera on the southern coast of the Caspian Sea (between Abas Abad and Ramsar) were studied. Sampleswere gathered in May 2012 from 5 transects at four depths (5, 10, 15 and 20 meters). The extent ofenvironmental factors of sea floor adjacent waters such as electrical conductivity (EC), salinity, temperature,acidity (pH), dissolved oxygen during sampling and concentration of heavy metals, total organic matters(T.O.M) and the diameter of sediment particles were determined through laboratory procedures. Averageconcentration for the heavy metals were Pb 48/08, Cd 3/30 and Cu 20/86,Zn 64/76, Ni 36/50 and Cr 36/92 partsper million (ppm), also the mean diameter of the sediment particles was 0/21 mm and the average percentage ofthe total organic matter was 3/59. Average water temperature near the sea floor was 26/09 ° C, EC 18/62 µs/cm,salinity 13 parts per thousand, acidity 8/34 and dissolved oxygen 9/98 milligrams per liter. Results from thedensity and diversity of Foraminifera show a dominant species of Ammonia beccarii from the four species ofbenthic. It shows that this species belongs to three genera of 3 families coming from the same line. Most of thedeposits in this region were fine sand, very fine sand, silt, and clay. Results show an increase in the frequencyand density of Foraminifera with the increase of silt and clay. Positive correlation between the diversity ofForaminifera and environmental factors like dissolved oxygen, organic matters, depth and electricalconductivity in the region under study shows an increase of condensation of this group with an increase in theextent of the factors pre-mentioned. Also a negative correlation between the diversity of Foraminifera, Zn andCr shows a decrease of condensation when these metals increase. Finally no significant difference or correlationwas seen regarding the diversity of Foraminifera, environmental factors and heavy metals. . Also Chromiumshowed noticeable difference in the depths under study as in deeper depths the amount of Cr decreased.. Finally,the existence of Benthic Foraminifera with morphological abnormalities in the structure of the crust in thisregion indicates the presence of pollution in the sea floor.