1. … with a trend of improving trophic status. Inflow (757 r. km) mg chl a m -3 Outflow (163 r. km) mg chl a m -3 An order of magnitude increase in 1-2 weeks. An order of magnitude increase in 1-2 weeks.

2. Factors potentially contributing to the increase in algal biomass Factors potentially contributing to the increase in algal biomass - Altered flow pattern (flood protection, storage) - Nutrient loads (sewage & diffuse agricultural) - Polluted tributaries - Hypertrophic oxbow lakes - Inshore retention zones

3. Aims of the study - To assess the relative importance of various factors in phytoplankton dynamics by using high resolution longitudinal data and hydrodynamical modeling. - To test the applicability of automatic measuring devices (DF spectroscope, light scattering sensors) used with success in Lake Balaton for monitoring running waters.

4. Presentation structure - Data collection. - Hydrodynamical modeling (Kozma & Koncsos). - Comparison of manual and automatic measurements. - Primary data analysis. - Phytoplankton dynamics (Honti et al.). ( - Nutrient retention (Kovács et al.). )

5. Measurements: 17 to 21 July 2006 downstream 22 to 26 July 2006 upstream Measurements: 17 to 21 July 2006 downstream 22 to 26 July 2006 upstream No measurements during the nights. No measurements during the nights. m 3 s -1