Trace metals and polycyclic aromatic hydrocarbons in the Eastern Mediterranean sediments: Concentration ranges as a tool for quality control of large data collections.

Assessing the status of marine pollution at regional and sub-regional scales requires the use of comparable and harmonized data provided by multiple institutions, located in several countries. Standardized data management and quality control are crucial for supporting a coherent evaluation of marine pollution. Taking the Eastern Mediterranean Sea as a case study, we propose an approach to improve the quality control procedures used for sediment pollution data, thus supporting a harmonized environmental assessment. The regional ranges of contaminant concentrations in sediments were identified based on an in-depth literature review, and the lowest measured concentrations were evaluated to determine the "background concentrations" of chemical substances not yet targeted in the Mediterranean Sea. In addition, to verify the suitability of the approach for validating large data collections provided by multiple sources, the determined ranges were used to validate a regional dataset available through EMODnet data infrastructure.

Seasonal fluctuations of DIN/DIP and DON/DOP ratio in the northern Adriatic Sea.

Within the frame of PRISMA 1 "Biogeochemical cycles" research project (April 1995-January 1996) the quantities and the compartments of dissolved nitrogen and phosphorus have been studied in the northern Adriatic basin, considering also the organic pools. The research aimed to provide a better understanding of nutrient availability and to investigate the possible factors which promote the phenomenon of mucilage formation. For this purpose, the availability and the ratios between dissolved nitrogen and phosphorus considering both inorganic and organic fractions have been studied in relation to variations of river outflow and of biological activities. The results obtained reveal the large importance of organic nitrogen (annual average 16 microM) and phosphorus (annual average 0.13 microM) in contributing to the total nutrient availability (annual average total dissolved nitrogen: 29 microM and phosphorus: 0.18 microM) and the pronounced seasonal variability mainly ascribable to biological processes of uptake and remineralization. Furthermore, beside the well documented unbalanced ratio between inorganic nitrogen and phosphorus, the results obtained point out, for the first time, the unbalance also in the organic compartment (ratio between organic nitrogen and phosphorus ranges between 50 and 530), whose consequences might be important in relation to the phenomenon of mucilage formation.