Phytoplankton composition and environmental conditions of a mucilage event in the Sea of Marmara

The composition and abundance of phytoplankton and the corresponding environmental conditions were investigated during a mucilage event (October 2007-February 2008) in the Sea of Marmara. The mucilage producers Gonyaulax fragilis, Skeletonema costatum, and Cylindrotheca closterium were identified as abundant species. Thallassiosira rotula was also identified in large numbers. The maximum number of G. fragilis was observed at 83,600 cells L(-1) in November 2007 during the first sampling occasion on the surface layer of Izmit Bay, and T rotula was the most abundant diatom species, with 131,040 cells L(-1) in the same period. G. fragilis was recorded at 96,250 cells L(-1) in the dense mucilage-containing water samples collected from Degirmendere (Izmit Bay) in January 2008, and C. closterium was the dominant (161,250 cells L(-1)) diatom species in the same sample. Species diversity values (H'(log2)) increased from November to February, displaying maximum values of 2.5-3.5 in February at almost all stations (depths of 0.5 and 10 m), caused by the balanced increase of diatom species and their individual numbers in the total phytoplankton abundance. The surface layer waters of Izmit Bay exhibited severely low nitrogen to phosphorus ratio (N:P) values (0.1-14.4) compared to the Redfield ratio (16), which could be supported by the fact that the limiting nutrient for the Sea of Marmara is nitrogen. Even though there is a lack of data from before the mucilage period, the data obtained during the lifespan of the event indicated that a mixture of several phytoplankton species might have played a key role in the mucilage formation. The high organic carbon content of the mucilage (24% org-C) and the surrounding waters support the possibility that the event could have been related to organically rich cellular exudates of phytoplankton

Establishing Boundary Classes for the Quality Classification of Southeastern Black Sea Using Phytoplankton Biomass

Benthic macroinvertebrates, macroalgae and phytoplankton constitute the Biological Quality Elements (BQE) proposed in the Water Framework Directive (WFD, 2000/60/EC) to be used for the classification of the ecological status of a water body. Chlorophyll-a is a usefull expression of phytoplankton biomass and this indicator is an effective and relevant BQE for coastal ecosystems which is universally accepted. In the present study, interpretations of the class boundaries according to normative definitions of WFD, are presented for chlorophyll-a in South Eastern (SE) Black Sea. Water quality classification was determined in five different categories as "high, good, moderate, poor and bad". The coastal waters of SE Black Sea were classified in 8 different typologies (K1-K8) based on depth, salinity and substratum types. In this study, types K1 and K2 (>17,5 salinity, >30m depth) were considered because of availability of time-series data for those typologies. Sinop and Surmene sites were selected due to the best available long-term chlorophyll-a data set, respectively over the period of 2002-2010 and 2001-2011 for chlorophyll-a respectively. Type specific chlorophyll-a (Chl-a) reference and threshold values were determined based on the 90th percentile of the long-term collected chlorophyll data set. Due to the high seasonal variability of phytoplankton biomass, the annual values were not considered adequate and the classification tool was developed on seasonal basis. The High/Good (H/G) and Good/Moderate (GM) boundaries were defined as seasonal from the long term data sets for Surmene and Sinop sites. All the boundaries were higher at the Sinop site. Ecological quality ratios distributed between 0-1. It would be necessary to underline the fact that these class boundaries might be higher for waters where depths are below 30 m and salinity values are less than 17.5. However, there is not enough data to support this assumption for the near coast waters of the SE Black Sea. Eventhough Chl-a scaling can not be used as a single tool for the ecological quality classification it is a reliable approach to use the obtained boundaries at temporal and spatial scales for the quality classification of SE Black Sea waters above 30 m depth

Socioeconomic Response to Water Quality: a First Experience in Science and Policy Integration for the Izmit Bay Coastal System

Deterioration of the Izmit Bay ecosystem, mainly caused by heavy industrialization and urbanization, has significantly impaired its beneficial use and resulted in the surrounding coastal zone losing its attractiveness for the inhabitants. An integrated coastal zone management approach has become an important requirement of future development plans to protect this fragile bay ecosystem. One of the main indicators of deterioration of the Izmit Bay coastal system is the decreasing water quality resulting from increased nutrient loads from the surrounding land.The consensus during the initial stakeholder meeting confirmed the widespread awareness of this phenomenon and "improvement of water quality in Izmit Bay" was determined as the main policy issue at stake. Public perception of and satisfaction with water quality were measured by a willingness to pay (WTP) survey. The WTP for improved water quality was analyzed using the contingent valuation method. According to the questionnaire survey, 55% of the participants are willing to pay to increase the water quality. Impact of water quality on real-estate values was evaluated by hedonic pricing method, which is suitable for estimating direct and indirect use values of water resources. These results were used in a simulation model to assess coupled ecosystem, social, and economic system functioning of the Izmit Bay in response to various scenarios, and thus, to permit the necessary actions to be taken proactively. Two scenario simulations, for which domestic and runoff nitrogen loads are reduced independently, showed that hypothetical domestic wastewater treatment resulted in an improvement in simulated water transparency. The results suggest that domestic wastewater treatment should be a first priority for local administrations