A combinated approach to investigate the biochemistry and hydrography of a shallow bay in the South Adriatic Sea: The Gulf of Manfredonia (Italy)

The main goal of this study is to understand the hydrological and biochemical set up and processes of a marine coastal area located in the western side of the south Adriatic sea (the gulf of Manfredonia) by the use of both satellite images and in situ investigations A water sampling in the gulf of Manfredonia was performed at 18 fixed stations in June 2003; physico-chemical and biological parameters (temperature, salinity, dissolved oxygen and fluorescence) were measured along the water column and water samples were collected to analyse dissolved nutrients (ammonia, nitrite, nitrate, phosphate and silicate), total nutrients (nitrogen and phosphorus), chlorophyll a and total suspended solids. Surface spatial distributions of field collected data were examined to characterize biochemical and hydrographic conditions of the Gulf of Manfredonia and these results were related with the remote sensing analysis data. Remote sensed data (obtained by Landsat 7 TM and Modis Terra) were processed to obtain maps of chlorophyll a, temperature and optical characteristics of the gulf; these maps were compared to in situ data. From physico-chemical measurements no stratification was observed in the water column except for the south-eastern area. High concentrations of silicate and ammonia were observed in the northern zone of the gulf, while nitrate, phosphate, chlorophyll a and total suspended solids distributions showed higher values in the central coastal zone. These results were confirmed by remote sensing analysis; Modis elaboration showed a distribution with higher concentrations of chlorophyll a near the coast and Landsat images highlighted the extension of the surrounding agricultural areas crossed by the two main rivers which discharge into the gulf. The integration between field data with the remote sensing analysis showed to be a valid support in coastal zone management

Early diagenesis processes in a fish farm affected area (Loch Creran, Scotland): preliminary results (Poster)

In the context of the EU funded COBO project, consequences of fish farm activities on bio-geochemical processes in surface sediments of a Northern fjord (Loch Creran, Scotland) has been studied. Seven cores in May and three cores in August 2006 were collected to study early diagenesis processes and benthic fluxes. Each core was extruded, pore waters were extracted and analyzed for nutrients (NH3, NO3, NO2, PO4, Si(OH)4, TCO2), metals (Fe, Mn) and sulphates; diffusive fluxes at the sediment-water interface were calculated. Preliminary results show that the area, affected by fish farm wastes, is characterized by more intensive early diagenesis benthic processes (from 2 to 4 times more than unaffected area) due to higher reactive organic matter inputs to the sediment. Seasonal variations with increased diagenetic processes in summer were also recorded. In spring and in summer both, sediments from the impacted area and the control site are affected by strong bio-irrigation processes. Calculated benthic fluxes reflect the early diagenesis patterns with more intensive nutrient fluxes to the overlying water in the fish farm affected area and in the summer season

New technologies to study effects of physical disturbances at the sediment-water interface: The development of an Integrated Sediment Disturber (ISD)(Vortrag)

New, innovative technologies were developed and integrated within the EU-project COBO (Coastal Ocean Benthic Observatory) to investigate benthic responses to natural and anthropogenic impacts. The Alfred Wegener Institute for Polar and Marine Research (AWI) leads a work-package developing the so-called Integrated Sediment Disturber (ISD) to study the complex interactions between the biota and environmental perturbations and relaxations. The ISD carries three rotating fork-like disturber units able to rework the upper sediment layers at chosen time intervals. An Autonomous Positioning Drive allows the positioning of oxygen micro-sensors within and between the disturbed zones. A camera system continuously monitors all ISD actions. The ISD was deployed for a 2 months experiment in summer/autumn 2006. Sediment sampling has been carried out at the start, after one month and at the end of the long-term deployment. Scientific aims of the experiment are: to investigate benthic community function, with a focus on carbon and nutrient regeneration to investigate response to physical and chemical perturbation (organic additions, resuspension, anoxia) by benthic communities to examine functional resistance and resilience to single and combined pressure

Biogeochemistry of sediments affected by fish farm snowfall (Loch Creran, Scotland) (Poster)

In the context of the COBO project (funded by EU FP 6), consequences of a fish farm activity on biogeochemistry composition and processes of bottom sediments below the fish farm cages have been evaluated. The fish farm was located in a northern fjord (Loch Creran, Scotland). The study was carried out three months after the removing of the cages. Seven cores in May and three cores in August 2006 were collected to study early diagenesis processes and to calculate benthic fluxes. Each core was extruded; pore waters were extracted and analyzed for nutrients (NH3, NO3, NO2, PO4, Si(OH)4, and TCO2), metals (Fe and Mn) and sulphates; diffusive fluxes at the sediment-water interface were calculated by applying Ficks first law. Preliminary results show sediments lying down to the fish farm were characterized by more intensive early diagenesis processes (from 2 to 4 times more than blank area). This means the fish farm produce high reactive organic matter snow that increases the reactivity of bottom sediments. Seasonal variations with increased diagenetic processes in summer were also recorded. In spring and in summer sediments both from the impacted area and the control sites were affected by strong bio-irrigation processes. Calculated benthic fluxes reflect the early diagenesis patterns with more intensive nutrient fluxes to the overlying water in the fish farm affected area and in the summer season, this suggests sediments affected by fish farm activity contribute more to eutrophication of confined coastal waters