Izmir Bay is one of the most polluted estuaries in the whole Mediterranean Sea. The inner part of the Bay (Inner Bay) is heavily affected by domestic and industrial discharge. As a result of these loads, strong eutrophication occurs in the Inner Bay, which is temporally anaerobic. The ecologically sensitive approach of the local authorities during the last decade has given rise to a wide variety of monitoring and research studies on this bay. On the other hand, the municipality of Izmir started to operate wastewater treatment facilities since January 2000. The Institute of Marine Sciences and Technology -Izmir (IMST) with its research vessel R/V K Piri Reis has been conducting an intensive monitoring program since 1988 and especially during the recent few years. These investigations provide an opportunity for the evaluation of the performance of the wastewater treatment plant in terms of the change in the optical properties of Izmir Bay water in a positive manner. The turbidity values measured in these monitoring studies indicate that the values have changed drastically after January 2000. Their spatial variation indicates that the values decrease from the Inner Bay towards the Aegean Sea. The turbidity (light transmission) values are measured with an automatic CTD (conductivity, temperature and depth) system during each cruise. The seiche disc depth measurement is carried out only occasionally. The accuracy of the seiche disc depth is dependent on certain daylight conditions and depends on the operator. The seiche disc depth (D s ) is an important parameter to estimate primary production of organic matter (hereafter called production). A relation between light transmission (turbidity) value and seiche disc depth (D s ) is found with very good agreement. The correlations are very high (approximately 0.94) with slight seasonal variation.

A unicellular marine microalga, Entomoneis sp. was isolated and studied as had become the dominant species according to other bacillariophyta species in different environmental fluctuations in Izmir Bay. Because of our effort to better understand the dynamics of this microalga that facilitates unprecedented domination, we conducted on a monoculture isolation study.In this study, experiments were planned with the annual range of the Izmir Bay temperature, and the demonstrated behavior of the species in light and nutrient conditions. The stock culture medium was illuminated by approximately 50μmol photons m-2s-1 of illumination with 14/24 daylight. The temperature of the climate chamber was set on the summer (T1 (21±1oC)), spring (T2 (17±1oC)) and winter (T3 (13±1oC)) of Izmir Bay. Experiments were also applied with four different light intensities (L1 (50 μmol photons m-2s-1), L2 (25 μmol photons m-2s-1), L3 (5 μmol photons m-2s-1) and L4 (dark)). In this context, nutrient measurements were made on samples of the exponential, stationary and death phase of the culture and nutrient analyses were carried out. The results, which were designed according to ceteris paribus assumptions, were adapted to Michaelis-Menten kinetics. Consequently, considering the lifetime of the diatom at different temperature conditions, T3 was determined as an optimum temperature. Maximum growth rate and process time were observed at this temperature. This is the evidence why these diatoms are available in the winter. Once the light intensity was increased, the growth rate was increased at the T1 and T2 temperatures. However, T3 had a high growth rate in the nearly L1 light intensity. Considering the consumption and transformation of different nutrient conditions, different results for both types of microalgae were obtained.