Geographia Polonica (2025) vol. 98, iss. 2
Phytoplankton blooms localized by Sentinel-2 images and hydrodynamic modelling – Sulejów Reservoir on the Pilica River, Poland
Geographia Polonica (2025) vol. 98, iss. 2, pp. 211-229 | 
Full text
doi: https://doi.org/10.7163/GPol.0300
Abstract
Reservoirs created by damming rivers significantly modify abiotic and biotic environmental components. A major consequence is the accumulation of sediments and nutrients, degrading water quality through eutrophication.This study focused on the Sulejów Reservoir in Central Poland, examining nutrient balance,phytoplankton blooms using Sentinel-2 satellite data, and wind-driven surface currents with the CCHE2D hydrodynamic model. Eight Sentinel-2 images from the 2020 vegetation season and the Normalized Difference Chlorophyll Index (NDCI) were used to assess phytoplankton distribution. Results indicate the reservoirmainly acts as a nutrient sink, but under low-flow and intense bloom conditions, it can become a nutrient source. Coupling remote sensing with hydrodynamic modeling effectively interpreted flow patterns and nutrient dynamics. For the first time, the influence of eddy structures and wind on phytoplankton distribution in the lacustrine zone was demonstrated.
Keywords: eutrophication, phytoplankton blooms, Sentinel-2, hydrodynamic modelling, Pilica River, Sulejów Reservoir, NDCl, CCHE2D
[peshang.hamakarim@student.uw.edu.p], Doctoral School of Exact and Natural Sciences Discipline of Earth and Related Environmental Sciences, University of Warsaw Stefana Banacha 2c, 02-097 Warsaw: Poland
[mkalinow@igf.edu.pl], Institute of Geophysics Polish Academy of Sciences Księcia Janusza 64, 01-452 Warsaw: Poland
[aleksandra.zieminska-stolarska@p.lodz.pl], Faculty of Process and Environmental Engineering Technical University of Lodz Wólczańska 213, 93-005 Łódź: Poland
[asmagnus@uw.edu.pl], Faculty of Geography and Regional Studies University of Warsaw Krakowskie Przedmieście 30, 00-927 Warsaw: Poland
