This study focuses on the synchronous blooms of the coccolithophore Emiliania huxleyi and three dinoflagellates Prorocentrum micans, Ceratium furca var. furca and Ceratium fusus var. seta observed between 7 June and 11 July 2003 in the Dardanelles. An analysis of the vertical distribution of the E. huxleyi population size with respect to various environmental parameters was discussed. Additionally, inorganic nutrients and phytoplankton interactions were investigated in relation to the bloom conditions and hydrography of the Dardanelles. The algal bloom started in nearby Izmit Bay (eastern end of the Sea of Marmara) in early June, then quickly spread through the Sea of Marmara and continued until mid-July. Thermal stratification was observed between different water masses at the time of sampling. During the bloom period, cell density of E. huxleyi ranged from 3.58 × 107 to 2.55 × 108 cells l−1 in the superficial layer. Prorocentrum micans was the second most-abundant species and the cell numbers ranged from 1.0 × 106 cells l−1 to 3.3 × 106 cells l−1. Other abundant species in this area included C. furca var. furca and C. fusus var. seta.

This study focuses on spatial and temporal distribution and species composition of phytoplankton in the south-western Caspian Sea between July 2009 and March 2010. Samples were collected from 11 stations along three transects: Lisar, Anzali and Sefidrood. Among 44 identified phytoplankton species, diatoms (70.2%) and cyanophytes (25.0%) were dominant. The average phytoplankton abundance was calculated as 1.085E + 05 cells l−1. Among the phytoplankton groups, diatom density was higher (70.2%) than two out of three of total abundance in density of 1.085E + 05 cells l−1. Cyanophytes were the second important group (25.0%) contributing to total phytoplankton. Dinoflagellates, chlorophytes and euglenoids were other contributors to total phytoplankton. Diatoms Dactyliosolen fragilissimus and Skeletonema costatum and cyanophyte Oscillatoria sp. numerically dominated in the system. There were major changes in phytoplankton composition and average phytoplankton density was higher than those documented in 1996–1997 and 2005. The average concentrations of dissolved inorganic nitrogen (DIN), dissolved inorganic phosphorus (DIP) and dissolved inorganic silicate were 14.5 ± 6.32, 1.14 ± 0.44 and 5.10 ± 3.98 μM, respectively, and these concentrations were strikingly high. Increases in DIN and DIP concentrations were more than twofold compared to recorded values during the last 2 decades due to the eutrophication. Fluctuations in nutrients played an important role in the variation of phytoplankton composition and abundance. Chlorophyll-a concentrations varied between 3.22 and 16.1 μg l−1 and there was a significant increase in chlorophyll-a (8.13 ± 5.72 μg l−1) compared to the values in 1996–1997 (1.44 ± 1.48 μg l−1), 2001 (2.62 ± 1.48 μg l−1) and 2005 (2.14 ±1.94 μg l−1).

Cadmium and lead were determined simultaneously in seawater by differential pulse stripping voltammetry (DPSV) preceded by adsoptive collection of complexes with 8-hydroxyquinoline (oxine) on to a hanging mercury drop electrode (HMDE). In preliminary experiments the optimal analytical condition for oxine concentration was found to be 2.10(-5) M, at pH 7.7, the accumulation potential was -1.1 V, and the initial scannig potential was -0.8 V. The peak potentials were found -0.652 V for Cd and -0.463 V for Pb At the 60 s accumalation time. The limit of detection (LOD) and limit of quantitatification (LOQ) were found to be by voltammetry as 0.588 and 1.959 microg l(-1) (RSD, 5.50%) for Cd and 0.931 and 3.104 microg l(-1) (RSD, 4.10%) for Pb at 60 s stirred accumulation time respectively. In these conditions the most of the seawater samples are amenable for direct voltammetric determination of cadmium and lead using a HMDE. An adsorptive stripping mechanism of the electrode reaction was proposed. For the comparison, seawater samples were also analysed by ICP-atomic emission spectrometry method (ICP-AES). The applied voltammetric technique was validated and good recoveries were obtained.

Following a summer bloom of coccolithophore Emiliania huxleyi (Lohmann) Hay & Mohler, 1967, in 2003, a winter bloom was observed for the first time between late December 2003 and early January 2004 in the Dardanelles. Microscopic observations showed that the cell dimensions of E. huxleyi (Ehux) varied from 9.85 to 13.50 μm in diameter (mean: 11.20±1.38 μm). While Ehux revealed a relatively small population density (1.60 × 104 cells L−1) in early December 2003, the bloom started in middle December 2003 (7.86 × 106 cells L−1) and then peaked in early January 2004 (5.03 × 107 cells L−1) in the superficial layer. The peak dramatically decreased in late January 2004 (7.50 × 106 cells L−1). Ehux was the dominant species and represented about 90.0% of the phytoplankton assemblage. The bloom started flourishing after the diatom and dinoflagellate blooms under nitrogen depletion and moderate light, temperature and salinity conditions. Water temperature (10.31±1.14°C) and salinity values (27.05±0.88 ppt) were usually stabile. Surface chlorophyll-a concentrations ranged from 1.23 to 2.32 μg L−1 during the bloom. The ratios of N:P (mean: 4.12±2.22) and Si:P (40.35±16.25) of the bloom period were lower than those of the non-bloom periods.

Waste water pollution of industrial areas can answer for the serious consequences of one of the most important environmental threats to the future. In this study, inductively coupled plasma-atomic emission spectrometry method (ICP-AES) is proposed to determine heavy metals (Pb, Cu, Cd, Cr, Zn, Al, Fe, Ni, Co, Mn) and major elements (Ca, Mg) in waste water of Kocabas Stream. The concentration of metals in the waste water samples taken from 9 different stations (St.) in Biga-Kocabas Stream in November 2004 (autumn period) were determined after simple pretreatment of samples by the proposed ICP-AES method. An analysis of a given sample is completed in about 15 min for ICP-AES the method. The results of heavy metals concentrations in waste water were found between 0.00001-77.69610 mg l(-1) by the ICP-AES technique. The concentrations of Pb, Cd, Cu, Zn, Cr, Al, Fe, Mn, Ni, Co, Mg and Ca 0.00001 (St.3,6,7) - 0.0087 mg l(-1) (St.9), 0.00001 (St.4-7) - 0.0020 mg l(-1) (St.8), 0.00001 (St.1,3-7,9) - 0.0041 mg l(-1) (St.2), 0.0620 (St.2) - 0.2080 mg l(-1) (St.3), 0.0082 (St.6) - 0.2290 mg l(-1) (St.8), 0.3580 (St.2) - 1.7400 mg l(-1) (St.3), 0.2240 (St.1) - 0.6790 mg l(-1) (St.3), 0.0080 (St.1) - 1.5840 mg l(-1) (St.3), 0.0170 (St.3) - 0.0640 mg l(-1) (St.2), 0.0010 (St.1,4,5,8) - 0.0080 mg l(-1) (St.3), 5.0640 (St.9) - 5.2140 mg l(-1) (St.1) and 43.3600 (St.2) - 77.6961 mg l(-1) (St.9), respectively. Also we measured environmental physicochemical parameters such as temperature, salinity, specific conductivity, total dissolved solid (TDS), pH, oxidation and reduction potential (ORP), and dissolved oxygen (DO) in the waste water at sampling stations.