The Mediterranean is a clear example of a sea at risk, and an increasing number of pressures are menacing its integrity. However, these are poorly known and this project has targeted to set a baseline of quality in terms of input loads, contamination levels and biological status and effects. To do this the consortium has determined the presence of pollutants, nutrients and key elements in all relevant compartments of the open Mediterranean ecosystem, such as water column (down to bottom waters), suspended and settling (sediment traps) particles, sediments and benthic fauna, thus providing, for the first time, a comprehensive database of these substances in this sensitive environment. These results are of interest to individual researchers and research institutions, and national and international bodies concerned with the quality of the marine environment.
Samples were mainly collected during the 6 main ADIOS cruises, using adequate equipment, including Niskin bottles, in-situ pumps and sediment traps for the water column, and maxicorer and benthic traps for the deep environment.
The studied substances included:
- Pollutants: metals (Pb isotopes, Cd, Zn, Hg, other trace metals), organic pollutants (NAHs, PAHs, PCBs, black carbon) and man-made radionuclides (137Cs, 239,240Pu);
- Nutrients: N compounds, P, Si, Fe;
- Key substances: dust, TOC;
- Tracers: Al, Na, Ca, Nd isotopes, 210Pb, 210Po, 226Ra, mineralogy.
These substances were analysed using state-of-the-art techniques and, whenever possible, a single laboratory was in charge of the analysis of specific substances in all relevant compartments.
The main conclusion obtained from this work is that all pollutants are present at detectable levels in the deep Mediterranean environment. These can be traced along all compartments and finally found in benthic biota. The main pollution vector to the deep Mediterranean environment is settling of suspended matter, which carries down the atmospherically deposited substances, including pollutants mainly derived from the industrialized countries. Pollution is recorded in abyssal sediments down to almost 5cm depth, due to sediment mixing. Sedimentation rates in the interest areas were also determined by 14C dating. Radiotracers indicated that not all the activity arrived to the bottom sediments, but a fraction was adverted and/or scavenged in the continental margins.
The open western Mediterranean environment seems to be N limited for what concerns the "classical" food web. On the other hand, the microbial food web seems to be progressively P-limited by the scarcity of the dissolved organic phosphorus pool. These results contribute to better understand the biogeochemical cycles of N and P in the Mediterranean environment.
These results will be mainly exploited through publication in international journals. In the mean while, those interested can contact the scientists owners of the data, with whom specific exploitation agreements must be agreed.
