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Currently, there is a major concern about the future of nutrient loads discharged into the Baltic Sea from Polish rivers because they are main contributors to its eutrophication. To date, no watershed-scale studies have properly addressed this issue. This paper fills this gap by using a scenario-modeling framework applied in the Reda watershed, a small (482 km) agricultural coastal area in northern Poland. We used the SWAT model to quantify the effects of future climate, land cover, and management changes under multiple scenarios up to the 2050s. The combined effect of climate and land use change on N-NO and P-PO loads is an increase by 20-60 and 24-31 %, respectively, depending on the intensity of future agricultural usage. Using a scenario that assumes a major shift toward a more intensive agriculture following the Danish model would bring significantly higher crop yields but cause a great deterioration of water quality. Using vegetative cover in winter and spring (VC) would be a very efficient way to reduce future P-PO loads so that they are lower than levels observed at present. However, even the best combination of measures (VC, buffer zones, reduced fertilization, and constructed wetlands) would not help to remediate heavily increased N-NO loads due to climate change and agricultural intensification. [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]

The paper studies the vulnerability and protection of marine environments of two semi-closed seas, the Baltic and the Adriatic, in terms of physical and socio-economic factors. Institutional and technical instruments and policies of protection, at global, pan-European, EU and regional levels, are reviewed. The pioneering role (for Baltic) of the Helsinki Convention, signed in 1974 by the Baltic coastal states, is highlighted, whereby all sources of pollution were made subject to one single instrument. There is no similar comprehensive agreement yet on the semi-closed Adriatic Sea, but protection of the Adriatic Sea is included in the Barcelona Convention signed in 1976 by 16 states and the European Union (presently there are 22 parties to the convention) which was a follow up of the pioneering (for Adriatic) Mediterranean Action Plan signed by contracting parties in 1975. The Baltic region, with 90 million people in its catchment area, is economically well developed; out of nine of its coastal states, eight are EU members. The catchment area of the Adriatic, home to about 15 million people, is characterised by even larger socio-economic contrasts, with Italy as the dominating player as for population size and the economy. The marine and coastal environmental burdens of both the Baltic and the Adriatic are mainly due to agriculture, industry, shipping, fisheries, and tourism, not to forget the legacies of unsustainable past. The Adriatic, a busy transportation route for oil vessels, is one of the most vulnerable areas in the Mediterranean. [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]

The Ponto-Caspian amphipod Chelicorophium curvispinum (G.O. Sars, 1895) was first recorded in the Baltic Sea catchment area in the early 20th century. Since then the species has considerably extended its distribution. Here, we present the first record of the invasive amphipod in Sweden (Drottingholm, Lake Mälaren, SE Sweden). It is plausible that C. curvispinum was initially introduced via shipping to the brackish waters of the Stockholm Archipelago. National ferry traffic may have provided a subsequent means of transport for this species from Stockholm centrum to Lake Mälaren. [ABSTRACT FROM AUTHOR]

We present the first estimates of net anthropogenic nitrogen input (NANI) in European boreal catchments. In Swedish catchments, nitrogen (N) deposition is a major N input (31-94%). Hence, we used two different N deposition inputs to calculate NANI for 36 major Swedish catchments. The relationship between riverine N export and NANI was strongest when using only oxidized deposition (NO) as atmospheric input (r = 0.70) rather than total deposition (i.e., both oxidized and reduced nitrogen, NO + NH deposition, r = 0.62). The y-intercept (NANI = 0) for the NANI calculated with NO is significantly different from zero ( p = 0.0042*) and indicates a background flux from the catchment of some 100 kg N km year in addition to anthropogenic inputs. This agrees with similar results from North American boreal catchments. The slope of the linear regressions was 0.25 for both N deposition inputs (NO and NO + NH), suggesting that on average, 25% of the anthropogenic N inputs is exported by rivers to the Baltic Sea. Agricultural catchments in central and southern Sweden have increased their riverine N export up to tenfold compared to the inferred background flux. Although the relatively unperturbed northernmost catchments receive significant N loads from atmospheric deposition, these catchments do not show significantly elevated riverine N export. The fact that nitrogen export in Swedish catchments appears to be higher in proportion to NANI at higher loads suggests that N retention may be saturating as loading rates increase. In northern and western Sweden the export of nitrogen is largely controlled by the hydraulic load, i.e., the riverine discharge normalized by water surface area, which has units of distance time. Besides hydraulic load the percent total forest cover also affects the nitrogen export primarily in the northern and western catchments. [ABSTRACT FROM AUTHOR]