Determination of limited nutrients in the Turkish coastal waters of the Mediterranean and Aegean Seas

Increased human activities, rapid and uncontrolled industrial development, intensive urbanization have polluted and hence drastically modified the Turkish coastal water ecosystem of North East (NE) Mediterranean and Aegean Seas. Assessments of nutrient budgets and limiting nutrients in aquatic systems are of wide interest because of their fundamental importance in understanding carbon fixation, coastal eutrophication and wastewater management. In this study, the relative importance of nitrogen and phosphorus as potential limiting factors for primary producers during spring and summer seasons of 2009 was investigated in the near surface water along the Turkish coasts of the NE Mediterranean and Aegean Seas by using the 14C bioassay technique. The results of bioassays and nutrient concentrations (DIN, PO4, Si) indicate that phosphorus is primarily limiting factor in the less contaminated, nutrient-depleted coastal waters of NE Mediterranean (including the Aegean Sea). However, nitrogen appears to be potential limiting element in heavily polluted semi-closed coastal zones (Izmir and Edremit Bays of the Aegean Sea) due to large organic and nutrient loads from industrial and domestic sources in the last decades and consequent occurrence of intense denitrification in the elongated Izmir Bay, reducing the N/P ratio in the shallow water column

The effect of organic matters on manganese oxidation

11th International Symposium on Environmental Pollution and Its Impact on Life in the Mediterranean Region -- OCT 06-10, 2001 -- LIMASSOL, CYPRUSIn oxygen-free aquatic environments, such as ground water or hypolimnetic waters of eutrophic lakes, manganese predominantly as Mn(II) and natural organic compounds like humic materials occur. The effects of tannic acid and acetic acid as representatives of organic material on stabilizing the transformation of Mn(II) to Mn(IV) in a two-stage batch system have been examined. In the first stage, the catalytic effect of Mn(IV) linearly increased up to about 300 mg/l, keeping Mn(II) constant at 25 mg/l. In the second stage it has been studied how oxidation of Mn(H) and the catalytic effect of Mn(IV) are affected by tannic and acetic acids. Tannic acid completely inhibited the oxidation of manganese and acetic acid had no observable effect on the oxidation reaction