Explore the vast range of titles available.

In order to assess the progress toward eutrophication management goals, it is important to understand trends in land-based nutrient use. Here we present net anthropogenic nitrogen and phosphorus inputs (NANI and NAPI, respectively) for 2000 and 2010 for the Baltic Sea watershed. Overall, across the entire Baltic, between the 5-year periods centered on 2000 and 2010, NANI and NAPI decreased modestly by –6 and –4%, respectively, but with substantial regional variation, including major increases in the Gulf of Riga drainage basin (+19 and +58%, respectively) and decreases in the Danish Straits drainage basin (–25 and –40% respectively). The changes were due primarily to changes in mineral fertilizer use. Mineral fertilizers dominated inputs, at 57% of both NANI and NAPI in 2000, increasing to 68 and 70%, respectively, by 2010. Net food and feed imports declined over that period, corresponding to increased crop production; either fewer imports of food and feedstocks were required to feed humans and livestock, or more of these commodities were exported. A strong linear relationship exists between regional net nutrient inputs and riverine nutrient fluxes for both periods. About 17% of NANI and 4.7% of NAPI were exported to the sea in 2000; these relationships did not significantly differ from those for 2010. Changes in NANI from 2000 to 2010 across basins were directly proportional rather than linearly related to changes in total N (TN) fluxes to the sea (i.e., no change in NANI suggests no change in TN flux). Similarly, for all basins except those draining to the Baltic Proper, changes in NAPI were proportional to changes in total P (TP) fluxes. The Danish Straits decreased most between 2000 and 2010, where NANI and NAPI declined by 25 and 40%, respectively, and corresponding fluxes of TN and TP declined 31 and 18%, respectively. For the Baltic Proper, NAPI was relatively unchanged between 2000 and 2010, while riverine TP fluxes decreased 25%, due possibly to lagged effects of fertilizer reduction resulting from socio-political changes in the early 1990s or improvements in sewage treatment capabilities. For most regions, further reductions in NANI and NAPI could be achieved by more efficient production and greater substitution of manure for imported mineral fertilizers.

The July 2021 flood in central Europe was one of the five costliest disasters in Europe in the last half century, with an estimated total damage of EUR 32 billion. The aim of this study is to analyze and assess the flood within an interdisciplinary approach along its entire process chain: the synoptic setting of the atmospheric pressure fields, the processes causing the high rainfall totals, the extraordinary streamflows and water levels in the affected catchments, the hydro-morphological effects, and the impacts on infrastructure and society. In addition, we address the question of what measures are possible to generate added value to early response management in the immediate aftermath of a disaster. The superposition of several factors resulted in widespread extreme precipitation totals and water levels well beyond a 100-year event: slow propagation of the low pressure system Bernd, convection embedded in a mesoscale precipitation field, unusually moist air masses associated with a significant positive anomaly in sea surface temperature over the Baltic Sea, wet soils, and steep terrain in the affected catchments. Various hydro-morphodynamic processes as well as changes in valley morphology observed during the event exacerbated the impact of the flood. Relevant effects included, among many others, the occurrence of extreme landscape erosion, rapidly evolving erosion and scour processes in the channel network and urban space, recruitment of debris from the natural and urban landscape, and deposition and clogging of bottlenecks in the channel network with eventual collapse. The estimation of inundation areas as well as the derived damage assessments were carried out during or directly after the flood and show the potential of near-real-time forensic disaster analyses for crisis management, emergency personnel on-site, and the provision of relief supplies. This study is part one of a two-paper series. The second part (Ludwig et al., 2022) puts the July 2021 flood into a historical context and into the context of climate change.

The Baltic Sea Action Plan and the EU Water Framework Directive both require substantial additional reductions of nutrient loads (N and P) to the marine environment. Focusing on nitrogen, we present a widely applicable concept for spatially differentiated regulation, exploiting the large spatial variations in the natural removal of nitrate in groundwater and surface water. By targeting mitigation measures towards areas where nature’s own capacity for removal is low, spatially differentiated regulation can be more cost-effective than the traditional uniform regulation. We present a methodology for upscaling local modelling results on targeted measures at field scale to Baltic Sea drainage basin scale. The paper assesses the potential gain and discusses key challenges related to implementation of spatially differentiated regulation, including the need for more scientific knowledge, handling of uncertainties, practical constraints related to agricultural practice and introduction of cogovernance regimes.

Riverine nutrient loads are among the major causes of eutrophication of the Baltic Sea. This study applied the Soil & Water Assessment Tool (SWAT) in three catchments flowing to the Baltic Sea, namely Vantaanjoki (Finland), Fyrisån (Sweden), and Słupia (Poland), to simulate the effectiveness of nutrient control measures included in the EU’s Water Framework Directive River Basin Management Plans (RBMPs). Moreover, we identified similar, coastal, middle-sized catchments to which conclusions from this study could be applicable. The first modelling scenario based on extrapolation of the existing trends affected the modelled nutrient loads by less than 5%. In the second scenario, measures included in RBMPs showed variable effectiveness, ranging from negligible for Słupia to 28% total P load reduction in Vantaanjoki. Adding spatially targeted measures to RBMPs (third scenario) would considerably improve their effectiveness in all three catchments for both total N and P, suggesting a need to adopt targeting more widely in the Baltic Sea countries.

The combined future impacts of climate change and industrial and agricultural practices in the Baltic Sea catchment on the Baltic Sea ecosystem were assessed. For this purpose 16 transient simulations for 1961–2099 using a coupled physical-biogeochemical model of the Baltic Sea were performed. Four climate scenarios were combined with four nutrient load scenarios ranging from a pessimistic business-as-usual to a more optimistic case following the Baltic Sea Action Plan (BSAP). Annual and seasonal mean changes of climate parameters and ecological quality indicators describing the environmental status of the Baltic Sea like bottom oxygen, nutrient and phytoplankton concentrations and Secchi depths were studied. Assuming present-day nutrient concentrations in the rivers, nutrient loads from land increase during the twenty first century in all investigated scenario simulations due to increased volume flows caused by increased net precipitation in the Baltic catchment area. In addition, remineralization rates increase due to increased water temperatures causing enhanced nutrient flows from the sediments. Cause-and-effect studies suggest that both processes may play an important role for the biogeochemistry of eutrophicated seas in future climate partly counteracting nutrient load reduction efforts like the BSAP.

Pollution with excess nutrients deteriorate the water quality of the Baltic Sea. The effect of combined land use and climate scenarios on nitrate leaching and nitrogen (N) loads to surface waters from two Baltic Sea catchments (Norsminde in Denmark and Kocinka in Poland) was explored using different models; the NLES and Daisy models for nitrate leaching, and MIKE SHE or MODFLOW/MT3DMS for N transport. Three Shared Socioeconomic Pathways (SSP1, SSP2 and SSP5) defined change in land use and agricultural activities. The climate change scenarios covered 2041–2060 compared with 1991–2010 under RCP8.5, applying four different climate models. Increases in predicted N-load from climate change vary from 20 to 60% depending on climate model. SSPs moderate these N-load changes with small changes for SSP1 to large increases for SSP5, with greater increases for Norsminde than Kocinka due to land use differences. This stresses needs for new measures and governing schemes to meet sustainability targets.

The Baltic Sea Action Plan (BSAP) requires tools to simulate effects and costs of various nutrient abatement strategies. Hierarchically connected databases and models of the entire catchment have been created to allow decision makers to view scenarios via the decision support system NEST. Increased intensity in agriculture in transient countries would result in increased nutrient loads to the Baltic Sea, particularly from Poland, the Baltic States, and Russia. Nutrient retentions are high, which means that the nutrient reduction goals of 135 000 tons N and 15 000 tons P, as formulated in the BSAP from 2007, correspond to a reduction in nutrient loadings to watersheds by 675 000 tons N and 158 000 tons P. A cost-minimization model was used to allocate nutrient reductions to measures and countries where the costs for reducing loads are low. The minimum annual cost to meet BSAP basin targets is estimated to 4.7 billion .

The unsustainable settlement and high industrialization around the catchment of the Baltic Sea has left records of anthropogenic heavy metal contamination in Baltic Sea sediments. Here, we show that sediments record post-industrial and anthropogenic loads of Cd, Zn, and Pb over a large spatial scale in the Baltic Sea. We also demonstrate that there is a control on the accumulation of these metals in relation to oxic/anoxic conditions of bottom waters. The total concentrations of Cd, Zn, and Pb were obtained with the near-total digestion method in thirteen cores collected from the Bothnian Bay, the Bothnian Sea, and the west and central Baltic Proper. The lowest average concentrations of Cd, Zn, and Pb were observed in Bothnian Bay (0.4, 125, 40.2 mg kg −1 DW, respectively). In contrast, the highest concentrations were observed in the west Baltic Proper (5.5, 435, and 56.6 mg kg −1 DW, respectively). The results indicate an increasing trend for Cd, Zn, and Pb from the early nineteenth century until the 1970s, followed by a decrease until 2000–2008. However, surface sediments still have concentrations above the pre-industrial values suggested by the Swedish EPA (Cd is 0.2, Zn is 85, and Pb is 31 mg kg −1 DW). The results also show that the pre-industrial Cd, Zn, and Pb concentrations obtained from 3 cores with ages < 1500 B.C. were 1.8, 1.7, and 1.2 times higher, respectively, than the pre-industrial values suggested by the Swedish EPA. To conclude, accumulations of metals in the Baltic Sea are governed by anthropogenic load and the redox conditions of the environment. The significance of correct environmental governance (measures) can be illustrated with the reduction in the pollution of Pb, Zn, and Cd within the Baltic Sea since the 1980s .

Currently, research on apicomplexan Sarcocystis parasites is mainly carried out by analyzing animal carcasses. However, environmental studies would not only allow faster detection of possible sources of infection but also avoid the use of animals for investigations. Therefore, in the current study, we aimed to identify tested Sarcocystis species in sediment collected from water bodies located in the southeastern Baltic countries. A total of 99 sediment samples were collected during the summer from different types of water bodies in Estonia, Latvia, Lithuania, and Poland. Species-specific nested PCR targeting cox1 gene was used for the detection of selected Sarcocystis species ( S . cruzi , S . bovifelis , S . hirsuta , S . arieticanis , S . tenella , S . capracanis , S . miescheriana , and S . bertrami ) infecting livestock. The results showed a statistically lower ( p  < 0.05) occurrence of Sarcocystis parasites in Estonia (50%) compared to three countries, where the detection rate of Sarcocystis spp. DNA was remarkably higher, ranging from 88 to 100%. Among Sarcocystis species tested, S . cruzi (83.8%) and S . arieticanis (55.6%) using cattle and sheep as their intermediate hosts were most commonly identified. The detection rates of some of the analyzed Sarcocystis species were significantly different in southeastern Baltic countries. It is discussed that the detection rates of certain Sarcocystis species depend not only on the number of animals per 1 km 2 but also on various ecological factors and farming practices that differ in the amount of contact domestic animals have with predators and the potential for animals to become infected through natural water or food sources.

Mercury (Hg) is deposited temporarily in soil and can be remobilised into rivers and seas. Given that rivers are a significant part of the mercury budget in the southern Baltic region (inland sea located in northern Europe) and meteorological changes (e.g. intense rain, drought) are observed more frequently, it is important to recognize the factors affecting the cycling of bioavailable Hg forms. The aim of this study was to identify the processes influencing the changes of labile and stabile mercury proportion in soil and the potential impact on the outflow of labile Hg into fluvial systems. For this purpose, soil samples, river sediments, and river water were collected from the Reda River (southern Baltic Sea catchment area) during the 2015 hydrologic year. The material was analysed for total and particulate mercury content and Hg forms, by a thermo-desorption method. The analysis showed that due to changes of meteorological and hydrological conditions Hg can enter rivers and then be introduced into the marine environment in various forms. On the one hand due to high precipitation events washing out of labile (i.e. bond with halogenides, MeHg, HgSO 4 ), Hg forms into the river can be enhanced which affects increasing of availability of the most dangerous Hg form in the water systems. On the other hand the same event can cause the limitation of bioavailable mercury forms by a conversion of labile Hg into the most stable one (HgSO 4 ➔ HgS) under anaerobic conditions.