Future observational and modelling needs identified on the basis of the existing shelf data

NOWESP has compiled a vast quantity of existing data from the North-West European Shelf. Such a focused task is without precedence. It is now highly recommended that one, or a few national and international data centres or agencies should be chosen and properly supported by the EU, where all available observational data, including the NOWESP data, are collected, stored, regularly updated by the providers of the data, and made available to the researchers. International agreement must be reached on the quality control procedures and quality standards for data to be stored in these data bases. Proper arrangements should be made to preserve the economic value of the data for their "owners" without compromising use of the data by researchers or duplicating data collecting efforts. The continental shelf data needed are concentration fields of temperature, salinity, nutrients, suspended matter and chlorophyll, which can be called "climatological" fields. For this purpose at least one monthly survey on the whole European shelf is needed at least during five years, with a proper spatial resolution e.g. 1 degree by 1 degree, and at least in those areas where climatological data are now totally lacking. From the modelling point of view an alternative would be the availability of data from sufficiently representative fixed stations on the shelf, with weekly sampling for several years

Tracing Nutrients and Contaminants in Nearshore Food Web

Sewage derived organic matter from domestic and municipal wastewater, promotes enhanced secondary productivity, eutrophication and trace metal contamination, reduction in oxygen levels, and biodiversity. It poses a potential impact on human health, contamination of seafood and water and ecological disturbances in the natural aquatic ecosystem. Thus, this research examined the impact of improvement in treatment and disposal schemes employed by a municipal sewage treatment facility on a previously sewage contaminated coastal marine system. It took a critical look into the influence of the discharged of inadequately treated sewage effluent and the modern improved mitigating efforts put in place to ensure proper treatment and disposal by the municipal wastewater treatment plant on the coastal marine waters. It also investigated the influence of other potential terrestrial organic nutrients and contaminants on the coastal marine waters, the flow of energy and their fate through the natural coastal marine food web. Stable isotope analyses incorporated with mixing models, other independent chemical tracers such as (i.e. faecal sterol, fatty acid and elemental analyses) were utilised to infer change in the sewage derived organic matter dynamics of the coastal marine waters. The detected change was attributed to the modification in wastewater treatment and disposal techniques adopted by the municipal wastewater treatment plant. The differences in the carbon and nitrogen isotope ratios of Mytilus galloprovincialis (sentinel organism) were assessed in a preliminary survey to determine the tissues of choice as indicative tools for long-term ecological-based study aimed at tracing the sources and fate of sewage organic materials in the coastal marine waters. The preliminary survey aided the experimental design of the study. Isotope mass balance mixing models were fitted to quantify the contributions of land-based organic materials as part of the diet constituents to examine the influence of terrigenous materials on observed diet switching changes from sewage-derived nutrient source to marine nutrient source in Mytilus galloprovincialis, a prevalent resident marine bivalve collected at the nearshore marine waters. Biochemical compositions and elemental concentrations (independent tracers) in Mytilus galloprovincialis were analysed and used as independent indicative tools for testing the assumptions obtained from the stable isotope analysis mixing models. The tracers indicated the source of nourishment to the resident organism and provided additional insight into the organic nutrient supply and contaminant dynamics of the coastal marine waters. The independent tracers revealed that the marine particulate organic matter was main source of nourishment to the marine bivalve. The sea lion colony provided a minor contribution of faecal matter to the nearshore marine waters. The chemical tracers affirmed that the improvement in the treatment and disposal methods had a positive impact on the nearshore marine waters. Trace metal levels and human health risk assessment on the nearshore marine bivalve affirmed the safe human consumption of the nearshore marine fisheries