Variations in copepod composition and diversity in relation to eutrophication and hydrology in Izmir Bay, Aegean Sea.

Hyrographic and trophic gradient along Izmir Bay used to assess their effects on the copepod composition and diversity. Trophic state of the bay varied from oligotrophic in the outer region to hypertrophic condition in the inner region as stated by trophic index (TRIX). Aegean Sea water entrance and trophic conditions of the bay affected species assemblages. Oithona davisae, Oithona nana and Acartia clausi were associated with hyper-eutrophic conditions whereas the typical Aegean Sea species, such as Oncaea media group, Oithona similis, Paracalanus parvus, A. clausi, Farranula rostrata and Calocalanus styliremis were related to oligotrophic condition. Copepod diversity indices decreased linearly along the trophic gradient, from oligotrophic to hyper-eutrophic conditions, highlighting the substantial impact of eutrophication on the copepod community structure in the inner region. These findings emphasize TRIX's value in assessing eutrophication in anthropized systems, and immense potential for using copepod composition and diversity in monitoring programs for ecological assessments studies.

The impact of fish farming on the water column and marine sediments in three coastal regions from eastern Aegean coast.

The impacts of mariculture activities in the water and sediments were comprehensively evaluated for the first time in this study. Lower dissolved oxygen was detected near the cages during summer due to aquacultural activities and bacterial degradation of organic compounds. However, DO levels were not below the 5 mg L-1 limit recommended for aquatic growth, survival and metabolic processes. Different eutrophication assessment methods showed that Güllük Bay, where intensive aquaculture activities occurred, was characterized by poor status. Assessment of different eutrophication tools for Akköy and Ildir Bay indicated that water quality status was not similar to each other. The most noticeable effect of aquaculture activities is the sedimentation of faeces and uneaten food under the cages. Nutrients in the water indicated gradual decrease with distance from the cages. Comparison of total phosphorus in sediments showed that the most affected area is Güllük Bay owing to cumulative impact of aquaculture. The higher total organic carbon (TOC) in sediments was measured near and under the cages. TOC was a useful indicator to show benthic health, less than 10 mg g-1 corresponded to low risk deteriorations for all aquaculture sites. Sediment monitoring studies should be carried out to provide sustainable use of the aquaculture areas.

Modeling wastewater discharge at the planning stage of a marine outfall system.

The possibility of marine discharge of a negatively buoyant industrial waste was evaluated by a modeling study using Killworth 3-D, which is the first version of the Modular Ocean Model (MOM). The Model was run with the recorded wind direction and speed on the cruise dates and the circulation patterns for surface and subsurface were found to be similar with the current meter measurements. Model scenarios have been set-up in order to estimate the intensity and direction of the currents in the Nemrut Bay under the condition of wind blowing from a definite direction for a long time. MOM model has been run for four major wind directions, each having duration of 10 days and the behavior of the discharge plume in the worst case has been traced. Also, the behavior of the discharge plume in the real case has been estimated by using the wind data of the region. According to the model results, impact of trace elements that compose the discharge effluent is limited both in time and space. It is concluded that trace elements will leave the Bay in a short time due to the short residence times.