İNŞaat mühendiSLİĞİ anabiLİm dali

Investigation of The Level and Diversity of Culturable Bacteria Around Gökçeada Island (Northern Aegean Sea)
In this study with an aim to describe "bacteriological structure of the study area" and to identify the ecosytem "at micro level", diversity and the levels of culturable heterotrophic aerobic bacteria, frequency of metabolically active bacteria and the levels of indicator bacteria were investigated. The sea water samples which were taken from coastal areas of Gökçeada and offshore area of the Northern Aegean Sea were used in the analyses. The obtained results were associated with variable environmental parameters.
The sea water samples were collected seasonally for the autumn, winter, spring as monthly for the summer in 12 times in total between March 2012 - November 2013. The samples which were taken to the sterile bottles under the aseptic conditions were transported to the Aquatic Microbial Ecology and Marine Biology Laboratory of Istanbul University, Fisheries Faculty. Marine Agar 2216 and the spread plate method were used for the enumeration of the total culturable heterotrophic aerobic bacteria. The bacterial isolates were identified with the automated micro identification system VITEK 2 Compact 30 (bioMerieux, France).
The frequency of the metabolically active bacteria was determined with modified staining technique of DAPI-CTC and epifluorescence microscope, comparing the number of the intact cells to the total (live and dead bacterial cells) number of bacteria.
The levels of indicator bacteria were determined by using membrane filtration technique. The nutrients and chlorophyll-a analyses were carried out by spectrophotometric method.
As a result, twenty-four bacteria species belonging to 8 classes (48% Bacilli, 24% Alpha Proteobacteria, 17% Gamma Proteobacteria, 8% Beta Proteobacteria, 1% Actinobacteria, 1% Lactobacillales, 1% of Sphingobacteria and 1% Cocci) were recorded in this study as the first records for the Gökçeada region. Sphingomonas paucimobilis was recorded as the most common (20.6%) species of the region. The isolates that have lipolytic and proteolytic enzym activities were detected to be the most abundant bacteria in the sea water. The highest metabolically active bacteria percentage was determined to be 33.12% in the seawater samples which were taken from Aydıncık Bay in 2012 summer. The levels of indicator bacteria were recorded above the limit values in the summer period. The highest bacteria count were recorded in the samples which were taken from Kaleköy Port.

Nutrients and chlorophyll-a values were found between class I. and class IV according to "Water Pollution and Control Regulation (2004)". Water quality values of the Kaleköy Port were recorded to be class IV. In this study that were detailed bacteriological structure around Gökçeada, were recorded an increase in the level of metabolically active bacteria during the summer period which there was also an increase in human activity. When the percentage of bacterial enzymatic activity is associated with the positive correlation between heterotrophic bacteria and nutrients levels, it showed that the possible increases of pollution inputs disturb the enzyme activities and the current state should be protected.