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First record of straight-needle pteropod Creseis acicula Rang, 1828 bloom in the Çanakkale Strait (NE Aegean Sea, Turkey)

Tunçer Sezginer, Öğretmen Nazik, Çakır Fikret, Öztekin Alkan, Oral Ayhan, Suner Salih Can

Oceanological and Hydrobiological Studies

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2021

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Vol. 50, No. 3

310--324

EN

Pteropods are marine pelagic calcifier mollusks sensitive to chemical changes in seawater due to their highly soluble aragonite shells. Increased acidity (reduced pH) of seawater causes difficulties in precipitating their shells and/or results in their dissolution, which is related to increased atmospheric CO2 concentrations and warming of seawater. They are therefore indicators of environmental changes. In this paper, we present the first record of the straight-needle pteropod Creseis acicula Rang, 1828 bloom in the surface waters of the Ҫanakkale Strait, Turkey (NE Aegean Sea), encountered in July 2020, when the highest sea surface temperatures and pH levels since 2007 were recorded. In coastal zones, such as the Ҫanakkale Strait, anthropogenic activity contributes significantly to environmental changes. Consequently, the increase in pH at elevated temperatures indicates an auxiliary factor (i.e. anthropogenic activity) that triggered the C. acicula bloom, rather than global atmospheric CO2 levels.

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Optical properties of crude oil detected in seawater

Haule K., Toczek H.

Journal of KONES

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2014

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Vol. 21, No. 3

127--132

EN

The effects of crude oils entering marine environment have been investigated since early 1960s when oil pollution became a subject of global environmental concern. Extraction and transportation of crude oils have been contributing to water pollution especially in closed water basins, such as the Baltic Sea. It was estimated that yearly oil input to the Baltic Sea amounts to 21-70 thousands of tons, which is twice higher than in the North Sea and three times higher than in the North Atlantic. Growing pollution loads into the Baltic Sea created a demand for multifarious studies on the environmental effects of oil products. In this study, we focus on bio-optical and ecological aspects of the presence of crude oil in seawater. Dispersed oil droplets occur in seawater as the result of contaminated river inflows, bilge water discharges and as the consequence of mechanical and chemical dispersion of oil spills. Their optical properties depend on oil type, concentration and size distribution. We present further results obtained from the developed fluorescence-based method for determination of the crude oil concentration in natural Baltic seawater and for evaluation of the oil droplets size by applying vacuum filtering. The results have been measured for the samples collected in Southern Baltic Sea during several ship cruises in 2012. We discuss the application of vacuum filtering in the fluorescence analyses in the context of laboratory, in situ and remote detection of dispersed oil.

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Fluorescence properties of mechanically dispersed crude oil

Haule K., Toczek H.

Journal of KONES

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2014

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Vol. 21, No. 4

161--167

EN

Despite of numerous actions undertook by the global and local authorities towards protection of marine environment, oil pollution loads into the Baltic Sea still tend to increase and need to be continuously estimated in order to apply the legal regulations. There is a demand for multifarious studies on the environmental effects of oil products. Dispersed oil droplets occur in seawater as the result of contaminated river inflows, bilge water discharges and as the consequence of mechanical and chemical dispersion of oil spills. Their optical properties depend on oil type, concentration and size distribution. Oil content influences many environmental factors, like water quality and bio-optical parameters (e.g. water-leaving radiance, inherent optical properties, seawater fluorescence). We present a unique study of the collected database of crude oil fluorescence spectra for better understanding the correlations between oil optical properties and its concentration, as well as for evaluation of the oil droplets size by the application of vacuum filtering using three filters of different permeability. Fluorescence spectra have been registered for oil-in-water emulsion samples prepared in the laboratory by mechanical dispersion. We discuss the optical properties of crude oil and the relationships between them in the context of potential remote detection of dispersed oil in seawater.