Suchergebnisse

A longstanding recognition of eutrophication as the most common threat to the entire Baltic Sea has led to the international agreement on nutrient load reductions within the Baltic Sea Action Plan. The nutrient load reductions were based on quantitative estimates of the "maximum allowed nutrient inputs" evaluated with a help of the decision support system (DSS) Baltic Nest developed within the MARE (Marine Research on Eutrophication) program. As demonstrated by a comparison to available data derived from observations, the marine biogeochemical model SANBALTS (Simple As Necessary Baltic Long-Term large-Scale) used in this evaluationis capable to realistically simulate both contemporary and pre-industrial trophic states of the Baltic Sea. A key to successful performance of SANBALTS lays in accounting for major sources and sinks that determine the size of internal nutrient pools and, thus, govern the large scale Baltic Sea eutrophication. Particularly, the most important phenomena that have to be reproduced by eutrophication models are a) spatial gradients of environmental conditions and limiting nutrients, b) interconnectivity of the major Baltic Sea basins, c) sporadic ventilation of the hypoxia prone deep-water layers with saltwater inflows, d) redox alterations of the coupled nitrogen and phosphorusbiogeochemical cycles, and d) nitrogen fixationby cyanobacteria.At the same time, both a ratherhigh aggregation of ecosystem variables (organic and inorganic forms of nutrients without explicit description of biota) and their correspondent spatial-temporal averaging (annual within homogeneous basins) implemented in SANBALTS make this model not appropriate enough for further revision and elaboration of the BSAP. Because such revision has also to take into consideration indicators required by the Marine Strategy Framework Directive (MSFD) of the European Union and characterized by higher spatial and temporal resolution, e.g.basin-wise winter surface nutrient concentrations and summer phytoplankton biomasses, and because of a necessity to factor in the possible effects of climate fluctuations, the appropriate model must simulate changes in ecosystem seasonal dynamics occurring over tens of years in response to both nutrient load reductions and climate changes. In principle, the continuing development of computing resources has made it feasible to implement for such purposes three-dimensional coupled physical-biogeochemical models with a relatively high resolution. However, with such models a simulation of the entire Baltic Sea over several decades still requires many days of computation even at super computer centers, which greatly hinders numerical experimentation needed for both model calibration and sensitivity analysis, including scenario responses. Therefore, there is a need for the model that is both reliable and convenient enough to be used for the revision of BSAP and implementation of MSFD,as well as for similar managerial tasks within an ecosystem approach. To serve this need, the model should be computationally fast for allowing multiple numerical runs necessary for finding and testing suitable distributions of the water-protection measures. Furthermore, for a building of credibility necessary in the national deliberations and international negotiations it should also be publicly accessible through the decision support system Nest allowing to any interested party running hindcast and scenario experiments as well as visualize its results. For these purposes, we present here the latest developments of the BAltic sea Long-Term large Scale Eutrophication Model (BALTSEM), which captures the main features of the Baltic Sea eutrophication, and now servesas a next generation marine model in the Baltic Nest system. These results as well as hindcast for 1850-2006 and future scenarios can be reproduced and analyzed on-line. Since BALTSEM performance at long-term scales has already been presented by Eilola et al. (2011a) and Gustafsson et al. (2012), this paper is especially focused on a seasonal scale.

In the project ECOSUPPORT, three coupled physical-biogeochemical models (ER-GOM, RCO-SCOBI and BALTSEM) are used to produce an ensemble of combine climate change - nutrient load scenarios. The atmospheric driving forces for the models are produced by two global climate models, ECHAM5 and HadCM3; and these results are dynamically downscaled using the RCAO model at the SMHI, see Meier et al. (2011) and references therein. Since, results from dynamic hydrological models were not available, river runoff were constructed from the net P-E balance of the RCAO model results. Nutrient load scenarios wasto be explicitly given, but effects from climate change induced river runoff variations were estimated. In total, four different climate change scenarios produced and four different assumptions on direct anthropogenic changes in nutrient loads, thus in total 16 combinations. The nutrient load scenarios comprised of; one reference with approximately unchanged loads, one pessimistic business as usual and two more optimistic, current legislation and Baltic Sea Action Plan. All the latter based on previous work. This report describes the construction of these nutrient load scenarios.

In this study, quantitative models of the agricultural sector and nutrient transport and cycling are used to analyse the impacts in the Baltic Sea of replacing the current Greening measures of the EU's Common Agricultural Policy with a package of investments in manure handling. The investments aim at improving nutrient utilization and reducing nitrogen leaching, based on the assumption that lagging farms and regions can catch up with observed good practice. Our results indicate that such investments could reduce nitrogen surpluses in agriculture by 18% and nitrogen concentrations in the Baltic Sea by 1 to 9% depending on the basin. The Greening measures, in contrast, are found to actually increase nitrogen leaching. ; Peer reviewed

In this study, quantitative models of the agricultural sector and nutrient transport and cycling are used to analyse the impacts in the Baltic Sea of replacing the current Greening measures of the EU's Common Agricultural Policy with a package of investments in manure handling. The investments aim at improving nutrient utilization and reducing nitrogen leaching, based on the assumption that lagging farms and regions can catch up with observed good practice. Our results indicate that such investments could reduce nitrogen surpluses in agriculture by 18% and nitrogen concentrations in the Baltic Sea by 1 to 9% depending on the basin. The Greening measures, in contrast, are found to actually increase nitrogen leaching.

Agriculture is an important source of nitrogen and phosphorous loads to the Baltic Sea. We study how the European Union's (EU) Common Agricultural Policy (CAP), and in particular how its first pillar, containing most of the budget and the decoupled farm payments, affects eutrophication. To aid our study, we use three simulation models, covering the agricultural sector in the EU, a hydrological nutrient flow model and a model of eutrophication in the Baltic Sea. We compute changes in key eutrophication indicators in a business-as-usual baseline and in a hypothetical situation where the first pillar of the CAP, containing the direct payments, greening and accompanying measures, is not present. Comparing the outcomes, we find that in the scenario without the first pillar, production and agricultural land use is lower, while yields and fertiliser use per hectare are higher, causing less nitrogen and phosphorous loads (0.5 to 4% depending on the basin) and less eutrophication in the Baltic Sea as net effect. We therefore conclude that the policies of the first pillar of the CAP contribute to increased eutrophication in the Baltic Sea. ; Peer reviewed

Agriculture is an important source of nitrogen and phosphorous loads to the Baltic Sea. We study how the European Union's (EU) Common Agricultural Policy (CAP), and in particular how its first pillar, containing most of the budget and the decoupled farm payments, affects eutrophication. To aid our study, we use three simulation models, covering the agricultural sector in the EU, a hydrological nutrient flow model and a model of eutrophication in the Baltic Sea. We compute changes in key eutrophication indicators in a business-as-usual baseline and in a hypothetical situation where the first pillar of the CAP, containing the direct payments, greening and accompanying measures, is not present. Comparing the outcomes, we find that in the scenario without the first pillar, production and agricultural land use is lower, while yields and fertiliser use per hectare are higher, causing less nitrogen and phosphorous loads (0.5 to 4% depending on the basin) and less eutrophication in the Baltic Sea as net effect. We therefore conclude that the policies of the first pillar of the CAP contribute to increased eutrophication in the Baltic Sea.

A common intention in ecosystem approach to management of marine resources worldwide has become a 'restoration of ecosystems' to some better shape. Although appealing, this political, rather vague aim has to be made more precise in order to be useful as a management objective. Therefore, a crucial role in defining EO, EQS, ES, ET, and similar characteristics set forward by, e.g. BSAP, MSFD, ND, UWWTD, and WFD as well as by many other acronyms to come, belongs to some conventional numbers that are considered as representing so-called background or reference conditions, which existed before significant man-made disturbances. At the Baltic Sea, experiencing human influence for centuries, quantification of the reference conditions and designing of desired state of restored marine ecosystems is complicated by both the uncertainty of which past times might be considered as reference times and the lack of essential observations from those times. One of the major, if not the only reliable method for reconstruction of the reference trophic state is it's simulation with biogeochemical models forced by the appropriate boundary conditions, including external nutrient inputs corresponding to the reference time interval. Once reconstructed, estimates of such "pristine" or, better to say, "pre-industrial" loads and their historical development can also be used both to test models' capabilities in reproducing pre-eutrophied state of the Baltic Sea and to study the very development of its eutrophication. Plausible solution of these problems gives more credibility to simulated responses of the marine ecosystems to scenarios of load reductions. For the Baltic Sea, such approach was initiated by Schernewski and Neumann (2005) and Savchuk et al. (2008) and further developed in the ECOSUPPORT Project (Gustafsson et al., 2012), where also a reconstruction of nutrient inputs since 1850 was briefly described. In order to facilitate distribution of reconstructed inputs and their usage, here we describe the process of reconstruction in more detail and make available the full data sets in digital form. The reconstructed external nutrient inputs comprise two periods. Land loads and atmospheric deposition in 1970-2006 are based on the best available data with sufficiently high coverage and resolution (Savchuk et al., 2012), while temporal dynamics over 1850-1970 were interpolated between estimates prescribed for a few fixed years. Similarly to the dataset for 1970-2006, the reconstructed inputs are aggregated according to the spatial segmentation of the Baltic Sea (Fig. 1) currently implemented in the biogeochemical model BALTSEM (BAltic sea Long-Term large Scale Eutrophication Model).

The separation between crop- and livestock production is an important driver of agricultural nutrient surpluses in many parts of the world. Nutrient surpluses can be symptomatic of poor resource use efficiency and contribute to environmental problems. Thus, it is important not only to identify where surpluses can be reduced, but also the potential policy tools that could facilitate reductions. Here, we explored linkages between livestock production and nutrient flows for the Baltic Sea catchment and discuss management practices and policies that influence the magnitude of nutrient surpluses. We found that the majority of nutrients cycled through the livestock sector and that large nitrogen and phosphorus surpluses often occurred in regions with high livestock density. Imports of mineral fertilizers and feed to the catchment increased overall surpluses, which in turn increased the risk of nutrient losses from agriculture to the aquatic environment. Many things can be done to reduce agricultural nutrient surpluses; an important example is using manure nutrients more efficiently in crop production, thereby reducing the need to import mineral fertilizers. Also, existing soil P reserves could be used to a greater extent, which further emphasizes the need to improve nutrient management practices. The countries around the Baltic Sea used different approaches to manage agricultural nutrient surpluses, and because eight of the coastal countries are members in the European Union (EU), common EU policies play an important role in management. We observed reductions in surpluses between 2000 and 2010 in some countries, which suggested the influence of different approaches to management and policy and that there are opportunities for further improvement. However, the separation between crop and livestock production in agriculture appears to be an underlying cause of nutrient surpluses; thus, further research is needed to understand how policy can address these structural issues and increase sustainability in food production. (C) 2018 The Authors. Published by Elsevier B.V. ; Peer reviewed

AbstractDecision-support tools (DSTs) synthesize complex information to assist environmental managers in the decision-making process. Here, we review DSTs applied in the Baltic Sea area, to investigate how well the ecosystem approach is reflected in them, how different environmental problems are covered, and how well the tools meet the needs of the end users. The DSTs were evaluated based on (i) a set of performance criteria, (ii) information on end user preferences, (iii) how end users had been involved in tool development, and (iv) what experiences developers/hosts had on the use of the tools. We found that DSTs frequently addressed management needs related to eutrophication, biodiversity loss, or contaminant pollution. The majority of the DSTs addressed human activities, their pressures, or environmental status changes, but they seldom provided solutions for a complete ecosystem approach. In general, the DSTs were scientifically documented and transparent, but confidence in the outputs was poorly communicated. End user preferences were, apart from the shortcomings in communicating uncertainty, well accounted for in the DSTs. Although end users were commonly consulted during the DST development phase, they were not usually part of the development team. Answers from developers/hosts indicate that DSTs are not applied to their full potential. Deeper involvement of end users in the development phase could potentially increase the value and impact of DSTs. As a way forward, we propose streamlining the outputs of specific DSTs, so that they can be combined to a holistic insight of the consequences of management actions and serve the ecosystem approach in a better manner.

Much of the Baltic Sea is currently classified as 'affected by eutrophication'. The causes for this are twofold. First, current levels of nutrient inputs (nitrogen and phosphorus) from human activities exceed the natural processing capacity with an accumulation of nutrients in the Baltic Sea over the last 50-100 years. Secondly, the Baltic Sea is naturally susceptible to nutrient enrichment due to a combination of long retention times and stratification restricting ventilation of deep waters. Here, based on a unique data set collated from research activities and long-term monitoring programs, we report on the temporal and spatial trends of eutrophication status for the open Baltic Sea over a 112-year period using the HELCOM Eutrophication Assessment Tool (HEAT 3.0). Further, we analyse variation in the confidence of the eutrophication status assessment based on a systematic quantitative approach using coefficients of variation in the observations. The classifications in our assessment indicate that the first signs of eutrophication emerged in the mid-1950s and the central parts of the Baltic Sea changed from being unaffected by eutrophication to being affected. We document improvements in eutrophication status that are direct consequences of long-term efforts to reduce the inputs of nutrients. The reductions in both nitrogen and phosphorus loads have led to large-scale alleviation of eutrophication and to a healthier Baltic Sea. Reduced confidence in our assessment is seen more recently due to reductions in the scope of monitoring programs. Our study sets a baseline for implementation of the ecosystem-based management strategies and policies currently in place including the EU Marine Strategy Framework Directives and the HELCOM Baltic Sea Action Plan. ; Peer reviewed