Biogeochemical behavior and distribution of biogenic silica in marine sediments from Izmir Bay, Aegean Sea (Turkey)

WOS: 000340977900001The distribution of BSi (biogenic silica) in surface sediment and pore water from Izmir Bay was investigated using Si-only and Si/Al methods for determining the appropriate methods. Surface sediment samples were collected using a box core from 15 stations in the inner Izmir Bay from March to May 2008. The relationships between biogenic silica, heavy metals and geochemical data were investigated. Si/Al ratios (weight/weight) ranged between 0.88-1.39 for positive BSi values and 1.21-12.409 for negative BSi values. The silica dissolution values showed a rapid increase in Al concentrations during the first 5 h of the experiment when the silica dissolved, followed by constant silica level at all stations. The dissolution curves in all stations have been stable in a maximum DSi (dissolved silica) value after 5 h. The linear curve of Al against the silica dissolution explained the biogenic silica content from intercept. The BSi measurements for this study give more accurate results according to the method of Si/Al. Factor analysis was used to determine the relationships between silica and geochemical data. BSi and Si-pore have a strong association with manganese. The diatomeae productivity in the water column has a significant importance on the stability of Mn in the sediment. Carbonate content of sediments controls the Mn anomalies from terrestrial sources in the bay. Maximum values of BSi at inner parts of the bay are due to the freshwater source at the deep. (C) 2014 Elsevier B.V. All rights reserved

A PRELIMINARY RESEARCH ON HEAVY METALS ACCUMULATED IN LIVER AND MUSCLE TISSUE OF SEAHORSE (Hippocampus hippocampus) CATCHED FROM TIREBOLU COASTS (GIRESUN, EASTERN BLACK SEA)

6th International Symposium on Ecology and Environmental Problems -- NOV 17-20, 2011 -- Antalya, TURKEYWOS: 000313458600012The aim of this research was to determine the accumulation levels of heavy metals (Zn,Pb,Cu,Cd) in livers and muscles tissue of seahorse (Hippocampus hippocampus). The 20 died seahorse individuals were collected from regional fishermen at the Tirebolu coast in November 2010. In all fish samples, mean of standard length was calculated as 78 +/- 19.68 mm, mean weight was 2.02 +/- 0.34 g. The highest levels of Pb, Zn, Cu, Cd were found in muscle tissue in descending order and their values were 1750,6; 197,4;121,32;1,568 ppm respectively. Causes of metal concentrations levels in tissues of seahorse were attributed to atmospheric sources like fossil fuel oil consumption and to territorial sources as mine reservoirs (Cu, Pb,Zn).Hacettepe Uni

Development of biosotption-based algal biosensor for Cu(II) using Tetraselmis chuii

WOS: 000251465000037A new biosorption-based biosensor using Tetraselmis chuii microalgae was developed for the voltammetric measurement of copper(II). Biosensor was prepared by incorporating non-living biomass in carbon paste. T chuii incorporated in carbon paste electrodes (CPE) in weight percentages ranging from 2.5 to 20 accumulate copper(II) from solution through passive adsorption. Copper(II) was accumulated, at open circuit, on the algal biosensor and the voltammetric measurements were carried out by differential pulse cathodic stripping voltammetry. The biosensor performance was optimized with respect to the operating conditions. Under the optimal conditions, a detection limit of 4.6 x 10(-10) M was obtained with a good precision (R.S.D. = 3.4%, n = 6). The cathodic peak current was linear with concentration in the range of 5.0 x 10(-8)-1.0 X 10(-6) M (r=0.9981). The developed biosensor was also applied for the determination of copper(II) in real sample. Such an excellent performance of the algal biosensor toward copper(II), represents a very good alternative for developing other sensors. (c) 2007 Elsevier B.V. All rights reserved

Comparison of growth kinetics of chaetoceros gracilis Isolated from two different areas in the aegean sea (the bay of Izmir and the Homa Lagoon)

In this study, the species Chaetoceros gracilis was isolated from two different ecosystems (sea-lagoon) in the Bay of Izmir with very different physico-chemical environmental parameters. With the batch culture experiments carried out using the small diatom C. gracilis, it is aimed to determine the physiological properties of this species and also to form a basis for model studies by parameterizing its exponential growth rates, its nutrient limiting growth rates and the Michealis-Menten curves that indicate its dependence on nutrients. The fact that it is spread in a wide variety of areas from oligotrophic regions to eutrophic regions shows that this species environmental adaptation is quite interestin