Distribution of selenium in the plume of the Gediz River, Izmir Bay, Aegean Sea

Selenium (Se) variations in the water column, suspended particulate matter, and sediment through the salinity gradient, together with water-quality parameters, were investigated over four different river conditions: lowest–highest runoff and high–low production period between November 2004 and August 2005 in the plume of the Gediz River, Aegean Sea, Turkey. The drainage basin of the Gediz delta is predominantly agricultural and industrial in character. Dissolved Se exceeded the water-quality standard of 5 μg L–1 during high flow and varied from 9.4 μg L–1 to 0.02 μg L–1 through the salinity gradient during the study period. Particulate Se ranged from 5.2 μg L–1 to 0.02 μg L–1. Sediment in the river mouth was highly affected by Se contamination and reached a level greater than four times (7.6 μg L–1 dry wt) the background level. The results indicated that Se supplied by the river was removed rapidly from the water column before the salinity reached an average value of about 20 and accumulated within the delta

An objective framework to test the quality of candidate indicators of good environmental status

Large efforts are on-going within the EU to prepare the Marine Strategy Framework Directive's (MSFD) assessment of the environmental status of the European seas. This assessment will only be as good as the indicators chosen to monitor the 11 descriptors of good environmental status (GEnS). An objective and transparent framework to determine whether chosen indicators actually support the aims of this policy is, however, not yet in place. Such frameworks are needed to ensure that the limited resources available to this assessment optimize the likelihood of achieving GEnS within collaborating states. Here, we developed a hypothesis-based protocol to evaluate whether candidate indicators meet quality criteria explicit to the MSFD, which the assessment community aspires to. Eight quality criteria are distilled from existing initiatives, and a testing and scoring protocol for each of them is presented. We exemplify its application in three worked examples, covering indicators for three GEnS descriptors (1, 5, and 6), various habitat components (seaweeds, seagrasses, benthic macrofauna, and plankton), and assessment regions (Danish, Lithuanian, and UK waters). We argue that this framework provides a necessary, transparent and standardized structure to support the comparison of candidate indicators, and the decision-making process leading to indicator selection. Its application could help identify potential limitations in currently available candidate metrics and, in such cases, help focus the development of more adequate indicators. Use of such standardized approaches will facilitate the sharing of knowledge gained across the MSFD parties despite context-specificity across assessment regions, and support the evidence-based management of European seas

The occurrence and behaviour of phosphate fractions in Izmir Bay, Aegean Sea

The area around Izmir Bay (Turkey) is heavily urbanized and receives, therefore, high concentrations of phosphate originating from industrial and municipal inputs. During the surveys between April 1993 and July 1994, the total phosphate concentrations were highest in the Inner Bay (6.45 muM and 5.59 muM in the surface and bottom water, respectively) where very dense anthropogenic pollution occurs. The total phosphate value gradually decreased towards the Outer Bay where 0.70 muM and 1.18 muM were found in the surface and bottom water, respectively. The distribution of dissolved inorganic, dissolved organic and particulate phosphate along the bay reflected some peculiar spatial and temporal patterns. A high percentage of dissolved organic phosphate was observed in the Outer Bay while the particulate phosphate peaked in the Middle Bay where an upwelling mechanism was observed. In the bay, the biological production was strongly correlated with the variations in the dissolved inorganic, organic and particulate phosphate. The high phosphate concentration in particles caused the particulate phosphate formed in the Inner Bay to be transported to the outer parts of the bay because of the short water residence time. On the other hand, Principal Component Analysis showed that about 35% of the variation in all variables measured were related to the total phosphate, total dissolved phosphate, dissolved inorganic phosphate and particulate phosphate together with ammonium and reactive-Fe while about 14% of the variation was related to the dissolved organic phosphate and the number of phytoplankton cells, chl-a, pH and O(2)