Influence of hydrologic, meteorological and dynamic conditions on the water color

Pigment spatial and temporal variability was studied from the monthly mean CZCS data set for the Adriatic Sea. The differences between seasonal course of in-situ chlorophyll and remotely sensed pigment concentrations (from CZCS satellite data) from the Adriatic are especially large in winter. However, in-situ chlorophyll changes are in accordance with the course of transparency for the Northern and Middle Adriatic. Increased pigment concentrations may not be only indicators of high biological activity but show the presence of suspended and/or dissolved matter whose signals may interfere. The Northern Italian rivers (especially the Po River) intensely supply Northern Adriatic with nutrients, together with mixing of shallow bottom sediments, which are induced by the strong wind episodes. In the warm season, the influence of the river water from the Northern Adriatic is observed down to the middle Adriatic sill, while the Southern Adriatic may be under the influence of Albanian rivers. Therefore, thermohaline properties, hydrological data and pressure gradients were related to the satellite pigment concentrations from different Adriatic sites, in order to have better insight about the possible connections. The pigment variability in the three sites, Northern, Middle, and Southern Adriatic is, in a different way, forced by meteorological, hydrological and oceanographic conditions, caused by dissimilar underlying physical mechanism of these areas due to different depth, location and exposure to various influences. The phytoplankton dynamics in the Northern Adriatic, as reflected in chlorophyll a, is especially influenced by the river runoff.