HR: 15:10h
AN: OS33D-07    [Abstracts]
TI: Space variability and time evolution of water quality parameters in coastal area. Results from the lagoon of Venice case study
AU: * solidoro, c
EM: csolidoro@ogs.trieste.it
AF: Istituto Nazionale di Oceanografia e di Geofisica Sperimentale OGS, borgo grotta gigante 42/c, sgonico, ts 34010 Italy
AU: cossarini, g
EM: gcossarini@ogs.trieste.it
AF: Istituto Nazionale di Oceanografia e di Geofisica Sperimentale OGS, borgo grotta gigante 42/c, sgonico, ts 34010 Italy
AU: melaku canu, d
EM: dcanu@ogs.trieste.it
AF: Istituto Nazionale di Oceanografia e di Geofisica Sperimentale OGS, borgo grotta gigante 42/c, sgonico, ts 34010 Italy
AU: pastres, r
EM: pastres@unive.it
AF: universit… di Venezia, dorsoduro 2137, venice, 32100 Italy
AB: The paper presents the result of a number of numerical analysis on nutrients dynamic and plankton evolution in the lagoon of Venice. First we present the results of a statistical analysis on water quality parameters measured in the last 3 years in the Lagoon of Venice, with the aim to draw a basin-scale picture of the spatial distribution and seasonal evolution of macronutrients and chlorophyll a, which is here considered as a proxy of the abundance of the phytoplankton. Multivariate technique and gridding methods were used for investigating the spatial and seasonal variability of the data and for characterizing the trophic evolution of the basin in 2001. The results of the multivariate analysis indicate that the thirty stations can be classified into seven groups, based on the similarity of the temporal evolution of nutrient and clorophill a. Furthermore, these groups reflect the geographic distribution of the station, since the stations closer to the tributary discharges and the ones which are located in southern part of the lagoon were classified into clearly distinct cluster. The analysis of the temporal evolutions of the spatial distributions of the most important water quality parameters, confirms such an interpretation and evidences the role of the tributaries and of the exchanges with the sea in determining the water quality and the dynamics of the ecosystem. The comparison among the three years offers additional support to this interpretation. Secondly we propose a partition of the lagoon in different sub-basins, on the basis of spatial distribution of physical properties, such as relative composition of water entering the lagoon from each of the three inlets, residence time, ventilation time, average salinity, bathymetry. Such a physical based partition is then compared to the classification which emerges from analysis of water quality parameters, and a discussion on the role of the physical and environmental factors which affect such variability is offered. Thirdly, the key role of physical factors is clearly demonstrated and established in quantitative terms by the results of the regression analysis between a trophic indicator, identified in the multivariate analysis, and the yearly averaged values of salinity and residence time, that is of physical parameters which give a measure of the influence of the rivers and of the tidal mixing. A comparison among different yeasr Finally, deterministic models are used to complement the above mentioned findings, by providing estimates of fluxes among macro-ecological compartments, and assessment of the response of the lagoon to different scenario of antrophic forcing and meteo-climatic conditions.
DE: 4842 Modeling
DE: 4845 Nutrients and nutrient cycling
DE: 4227 Diurnal, seasonal, and annual cycles
DE: 4235 Estuarine processes
SC: Ocean Sciences [OS]
MN: 2004 AGU Fall Meeting