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Nutrient Fluxes and Their Dynamics in the Inner Izmir Bay Sediments (Eastern Aegean Sea)

Nitrogen, which is the most limiting nutrient for marine productivity of the ecosystem, is an essential element contributing to the biological process of all organisms (Capone and Knapp 2007; Bertics et al. 2012). Nitrification, the sequential oxidation of amonia to nitrite and then nitrate by nitrifiers, is also a critical step in the biological removal of nitrogen from the waste‐ water treatment process. In coastal ecosystems, nitrification is often coupled to denitrifica‐ tion (Jenkins and Kemp 1984; Sebilo et al. 2006), ultimately resulting in nitrogen being returned to the atmosphere (Bernhard and Bollmann 2010). Most transformation reactions recog‐ nized so far in the benthic N cycle are catalyzed by a suite bacteria and include the release of ammonium during the degradation of organic matter, the aerobic oxidation of ammonium to nitrite and nitrate(nitrification) and the bacterial denitrification of nitrite and nitrate to N2 un‐ der anaerobic conditions. Denitrification and nitrification are two of the main bacterial path‐ ways responsible for inorganic nitrogen removal and speciation in estuaries (Rao et al. 2007). Denitrification, dissimilatory reduction of NO3 and NO2 to N2 and N2O, is recognized as the key process to maintain nitrogen limitation for primary production in marine environ‐ ments. As a consequence, denitrification is important in controlling the eutrophication level in coastal environments that are increasingly affected by nutrient inputs (Cloern 2001; Pou‐ lin et al. 2007). The exposure of nutrient inputs removed by denitrification in sediments of continental margins leads to high bacterial mineralization. In addition, microbially mediat‐ ed nitrogen transformations have a potential impact on coastal eutrophication and estuar‐ ine oxygen status (Balls et al. 1996; Sanders et al. 1997; Barnes and Owens 1998).

Effects of Wastewater Treatment Plant on Water Column and Sediment Quality in Izmir Bay (Eastearn Aegean Sea)

Economic and social consequences of damage to the marine environment are becoming increasingly evident. Unless seas and oceans are carefully protected, their economic potential can not be sustainable. The marine environment is one of humanity’s most precious assets. Oceans and seas cover 71% of the earth’s surface and are the greatest sources of biodiversity, containing 90% of the biosphere. Marine ecosystems play a key role in climate and weather patterns. They also contribute to economic prosperity, social wellbeing and quality of life and are literally a source of survival for coastal communities. However, this environment is under intense pressure. The pace of degradation of biodiversity and habitats; the level of contamination by dangerous substances and the emerging consequences of climate change are some of the most visible warning signals (Environment for Europeans 2005). Only recently marine eutrophication is being regarded as pollution, particularly in near shore environments where more often low water transparency, oxygen depletion and algal blooms occur. Nutrient concentrations in sea water and sediment increase remarkably going from offshore to inshore, due to the proximity of terrestrial and domestic inputs and to the increase of biotic and abiotic processes strictly related to the progressive decrease of water depth. The Bay of Izmir is in a state of pollution centre in Turkish Aegean coast region in respect of aesthetic and welfare where pollution increased in the course of time from what it used to be in 1960s. The most important factors of this current status are; domestic wastes of more than 3 million people; industrial wastes from 1,500 factories; wastewater discharge during maritime transportation and shipyard services filling materials arisen from the recreation of seaside alluvions carried with rivers and valleys. Izmir Bay is surrounded by major agricultural plateau. Menemen plateau in the North–North West of Izmir is one of the most important production fields where agricultural irrigation is utilized. The Bay is also influenced by the pollution caused by the agricultural activities in the Gediz River water shed and erosion of a large area by Gediz River. The bay of Izmir, which is the biggest harbour on the Aegean Sea, is of economical importance for Izmir, the third largest city in Turkey. The Bay is divided into inner, middle and outer bays in terms of topographical and hydrographical characteristics. The inner bay

Nanoplankton population dynamics and dissolved oxygen change across the bay of Izmir by neural networks

The bay of Izmir, which is the biggest harbor on the Aegean Sea, is of upmost economical importance for Izmir, the third largest city in Turkey. Most of the studies carried out focused on the effects of intensive industrial activity and agricultural production on the bay pollution within the region. These studies, most of the time, are limited to monitoring the level of pollution. However, it is believed that these studies should be supported with models and statistical analysis techniques, as the models, especially the prediction ones, provide an important approach to assessing risk and assessment. In this study, neural network analysis was used to construct prediction models for nanoplankton population change with nutrients and other environmentally important parameters. The results indicated that, using data over a 52 week period, it is possible to predict nanoplankton population dynamics and dissolved oxygen change for the future.