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Eutrophication is a major problem in the Baltic Sea caused by the inflow of large loads of nutrients. This is largely due to diffuse and point sources of pollution such as wastewater treatment plants (WWTPs), which discharge poorly treated wastewater via rivers to the sea. The paper quantifies the problem of point source pollution in the Pilica River catchment (central Poland), one of the largest, second order subcatchments of the Vistula River. The main objectives of the research were: (i) quantification of nutrients transfer along the Pilica River continuum from the source to the estuary into the Vistula River, and (ii) evaluation of the influence of WWTPs on eutrophication of the Pilica River and the Baltic Sea. The study showed that the average total phosphorus (TP) and total nitrogen (TN) load discharged from the Pilica catchment amounted to 0.057 t TP km-2 and 1.655 t TN km-2, respectively, and was two and three times higher, respectively, compared to the annual average loads in the Polish territory and the Baltic States. Moreover, the paper presents possible solutions of sustainable planning and management in river catchments based on the ecohydrological concept and ecological engineering. [ABSTRACT FROM AUTHOR]

Finding suitable state indicators is challenging and cumbersome in stochastic and complex ecological systems. Typically, a great focus is given to criteria such as data availability, scientific basis, or measurability. Features associated with the indicator's performance such as sensitivity or robustness are often neglected due to the lack of quantitative validation tools. In this paper, we present a simple but flexible framework for selecting and validating the performance of food web indicators. In specific, we suggest a 7-step process in which indicator performances at a regional scale are quantified and visualized allowing for the selection of complementary indicator suites. We demonstrate its application by comparing the performance of pelagic food web indicators for three basins of the Baltic Sea and by assessing the food web status based on selected indicator suites. Our analysis sheds light on spatial differences in indicator performances with respect to direct and indirect pressures, the role of non-linearity and non-additivity in pressure responses, as well as relationships between indicators caused by species interactions. Moreover, our results suggest that the present food web states in the Bornholm and Gotland basins of the Baltic Sea deviate distinctly from an earlier reference period. We advocate the use of our quantitative framework as decision-support tool for selecting suites of complementary indicators under given management schemes such as the EU Marine Strategy Framework Directive. [ABSTRACT FROM AUTHOR]

Abstract: This paper presents a coupled economic–ecological model that integrates a catchment model with a marine model and incorporates economic data to analyse the long-term economic and ecological consequences of nutrient abatement in the Baltic Sea. The spatially explicit model describes dynamics of soil phosphorus in arable land, developments of nutrient concentrations and phytoplankton biomass in the sea basins, and inter-annual variation in nutrient loads and biophysical processes. The performance of the model is demonstrated by computing the least-cost solution to reach the good environmental state of the sea – as implied by the Baltic Sea Action Plan – within a time span of 40 years. The total cost of achieving this target is 1487 M€ annually. Spatially optimal allocation of load reductions differs from the load reduction targets of the Baltic Sea Action Plan, and focuses more on the control of phosphorus loads. [Copyright &y& Elsevier]