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  • 1. Artioli, Yuri
    et al.
    Friedeich, Jana
    Gilbert, Alison J.
    McQuatters-Gollop, Abigail
    Mee, Laurence D.
    Vermaat, Jan E.
    Wulff, Fredrik
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Humborg, Christoph
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Palmeri, Luca
    Pollehne, Falk
    Nutrient budgets for European seas: A measure of the effectiveness of nutrient reduction policies.2008In: Marine Pollution Bulletin, ISSN 0025-326X, E-ISSN 1879-3363, Vol. 56, no 9, p. 1609-1617Article in journal (Refereed)
    Abstract [en]

    Socio-economic development in Europe has exerted increasing pressure on the marine environment. Eutrophication, caused by nutrient enrichment, is evident in regions of all European seas. Its severity varies but has, in places, adversely impacted socio-economic activities. This paper aims to evaluate the effectiveness of recently adopted policies to reduce anthropogenic nutrient inputs to European seas. Nitrogen and phosphorus budgets were constructed for three different periods (prior to severe eutrophication, during severe eutrophication and contemporary) to capture changes in the relative importance of different nutrient sources in four European seas suffering from eutrophication (Baltic Proper, coastal North Sea, Northern Adriatic and North-Western Black Sea Shelf). Policy success is evident for point sources, notably for P in the Baltic and North Seas, but reduction of diffuse sources has been more problematic.

  • 2.
    Eriksson Hägg, Hanna
    et al.
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Humborg, Christoph
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM). Stockholm University, Stockholm Resilience Centre, Baltic Nest Institute.
    Mörth, Carl-Magnus
    Stockholm University, Stockholm Resilience Centre, Baltic Nest Institute.
    Medina, Miguel Rodriguez
    Stockholm University, Stockholm Resilience Centre, Baltic Nest Institute.
    Wulff, Fredrik
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Scenario Analysis on Protein Consumption and Climate Change Effects on Riverine N Export to the Baltic Sea2010In: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 44, no 7, p. 2379-2385Article in journal (Refereed)
    Abstract [en]

    This paper evaluates possible future nitrogen loadings from 105 catchments surrounding the Baltic Sea. Multiple regressions are used to model total nitrogen (TN) flux as a function of specific runoff (0), atmospheric nitrogen deposition, and primary emissions (PE) from humans and livestock. On average cattle contributed with 63%, humans with 20%, and pigs with 17% of the total nitrogen PE to land. Compared to the reference period (1992-1996) we then evaluated two types of scenarios for year 2070. i) An increased protein consumption scenario that led to 16% to 39% increased mean TN flux (kg per km(-2)). ii) Four climate scenarios addressing effects of changes in river discharge. These scenarios showed increased mean TN flux from the northern catchments draining into the Gulf of Bothnia (34%) and the Gulfs of Finland and Riga (14%), while the mean TN flux decreased (-27%) for catchments draining to the Baltic Proper. However, the net effect of the scenarios showed a possible increase in TN flux ranging from 3-72%. Overall an increased demand for animal protein will be instrumental for the Baltic Sea ecosystem and may be a major holdback to fulfill the environmental goals of the Baltic Sea Action Plan.

  • 3.
    Humborg, Christoph
    et al.
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Mörth, Carl-Magnus
    Department of Geology and Geochemistry.
    Sundbom, M.
    Wulff, Fredrik
    Department of Systems Ecology.
    Riverine transport of biogenic elements to the Baltic Sea: Past and possible future perspectives2007In: Hydrology and Earth System Science, Vol. 11, p. 1593-1607Article in journal (Refereed)
  • 4.
    Humborg, Christoph
    et al.
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Mörth, C-M
    Sundbom, M
    Wulff, Fredrik
    Department of Systems Ecology.
    Riverine transport of biogenic elements to the Baltic Sea – past and possible future perspectives2007In: Hydrology and Earth System Sciences, Vol. 11, p. 1-15Article in journal (Refereed)
  • 5. Johansson, Siw
    et al.
    Wulff, Fredrik
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Bonsdorff, Erik
    The MARE Research Program 1999-2006 - Reflections on program management2007In: Ambio, Vol. 36, no 2, p. 119-122Article in journal (Other academic)
  • 6. Pitkänen, H
    et al.
    Kiirkki, M
    Savchuk, Oleg
    Stockholm University, Faculty of Science, Department of Systems Ecology. marin ekologi.
    Räike, A
    Korpinen, P
    Wulff, Fredrik
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Searching efficient protection strategies for the eutrophied Gulf of Finland: the combined use of 1D and 3D modeling in assessing long-term state scenarios with high spatial resolution2007In: Ambio, Vol. 36, no 2-3, p. 272-279Article in journal (Refereed)
  • 7.
    Savchuk, Oleg P.
    et al.
    Stockholm University, Stockholm Resilience Centre, Baltic Nest Institute.
    Gustafsson, Bo G.
    Stockholm University, Stockholm Resilience Centre, Baltic Nest Institute.
    Rodríguez Medina, Miguel
    Stockholm University, Stockholm Resilience Centre, Baltic Nest Institute.
    Sokolov, Alexander V.
    Stockholm University, Stockholm Resilience Centre, Baltic Nest Institute.
    Wulff, Fredrik V.
    Stockholm University, Stockholm Resilience Centre, Baltic Nest Institute.
    External nutrient loads to the Baltic Sea, 1970-20062012Report (Other academic)
    Abstract [en]

    Any research related to nutrient biogeochemistry of the Baltic Sea, especially studies of eutrophication requires knowledge of the long-term dynamics of external nutrient inputs. Information accumulated in the HELCOM’s pollution load compilations is too aggregated and, until recently, covered only specific years. On the other hand, national datasets with higher resolutions are often difficult to access. Therefore, over the years considerable efforts have been put into a compilation of consistent estimates of nutrient input to the entire Baltic Sea.Excluding exchange with the Skagerrak from this report, the external nutrient input is considered here as consisting of three component parts: waterborne land loads, direct point sources at the coasts, and atmospheric depositions.

    The present reconstruction of time series of these three components is based on three major sources. The compilation of the land loads database has started within the project “Large-scale Environmental Effects and Ecological Processes in the Baltic Sea, 1990-1995” (Wulff et al., 2001c), continued during the MARE (“Marine Research on Eutrophication, 1999-2006”) project (Wulff et al., 2001a, Eriksson Hägg et al., 2010), and was most recently updated and expanded in connection with the latest HELCOM’s activities on the pollution load compilation (HELCOM, 2011) and the revision of the Baltic Sea Action Plan (BSAP, Wulff et al., 2009). However, there is an important difference between information contained in the HELCOM publications and the data presented here.

    By its very international nature HELCOM has to deal with whatever data are officially provided by the contracting parties, ending up with certain gaps and inconsistencies in the data sets (e.g. see discussion in HELCOM, 2011). On the other hand, considering eutrophication as an imbalance in the large-scale nutrient cycles, whereby more nutrients come into the system than leave it (e.g. Savchuk and Wulff, 2009 and references therein), we need to know the total amounts of external input as close to the reality as possible. Therefore, in our reconstructions we have been trying to both fill such gaps in and correct possible sources of inconsistencies. The reconstructed data sets have extensively been used by ourselves for various nutrient budget estimates (e.g. Wulff et al., 2001b, Savchuk, 2005) and as the boundary conditions for biogeochemical models (e.g. Savchuk and Wulff, 2007, 2009) including development of the eutrophication segment of BSAP (Wulff, 2007), as well as by many researchers around the Baltic Sea, for instance, within several projects of the BONUS+ research programme (e.g.Eilola et al., 2011; Eriksson Hägg et al., 2011; Meier et al., 2011).

    The implemented nutrient inputs have naturally been described in these publications, but briefly. In order to facilitate afurther 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 data used for the reconstruction have kindly been provided by several institutions and agencies around the Baltic Sea (see below) as well as directly by HELCOM during preparation of PLC-4 and PLC-5 (see HELCOM, 2004, 2011). Since not all data providershad given the permission to distribute the original raw measurements, we have here 

    3 aggregated all the inputs 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). Note also that some part of riverine inputs is available in a decision support system Baltic Nest with a much higher spatial resolution, as is further explained below.

    Download full text (pdf)
    Technical Report No. 5. External nutrient loads to the Baltic Sea, 1970-2006.
  • 8. Savchuk, Oleg P.
    et al.
    Wulff, Fredrik
    Hille, Sven
    Humborg, Christoph
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Pollehne, Falk
    The Baltic Sea a century ago – a reconstruction from model simulations, verified by observations.2008In: Journal of Marine Systems, Vol. 74, p. 485-494Article in journal (Refereed)
    Abstract [en]

    “Pre-industrial” trophic conditions in the Baltic Sea were simulated with SANBALTS (Simple As Necessary BAltic Long-Term large Scale) model. External nutrient inputs to the major basins of the Baltic Sea a century ago were reconstructed from various literature and data sources. The reconstructed input of total nitrogen was less than a half and that of total phosphorus was about a third of their contemporary values. The simulated “pre-industrial” conditions are validated by comparison to actual historical data on the water transparency, oxygen concentration, primary production, and net sediment accumulation. The “pre-industrial” trophic state could have been more phosphorus limited than today because simulated basin-wide annual averages of dissolved inorganic phosphorus concentrations of 0.06–0.3 µM P are about 40–80% of their present day values, while dissolved inorganic nitrogen concentrations of 2–4 µM N are almost the same as today or even slightly higher.

  • 9.
    Savchuk, Oleg
    et al.
    Stockholm University, Faculty of Science, Department of Systems Ecology. marin ekologi.
    Wulff, Fredrik
    Stockholm University, Faculty of Science, Department of Systems Ecology. marin ekologi.
    Modeling the Baltic sea eutrophication in a decision support system2007In: Ambio, Vol. 36, no 2-3, p. 141-148Article in journal (Refereed)
  • 10.
    Thomas, Helmuth
    et al.
    Department of Oceanography, Dalhousie University, Halifax, Canada.
    Pempkowiak, Janusz
    Institute of Oceanology, Polish Academy of Sciences.
    Wulff, Fred
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Nagel, Klaus
    Department of Marine Chemistry.
    The Baltic Sea: a global synthesis2010In: Carbon and Nutrient Fluxes in Continental Margins: A global synthesis", GLobal Change / [ed] Liu, K.-K.; Atkinson, L.; Quiñones, R.; Talaue-McManus, L., Springer, 2010, 1, p. 334-345Chapter in book (Other academic)
  • 11. Vahtera, Emil
    et al.
    Gustafsson, BG
    Kuosa, H
    Pitkänen, H
    Savchuk, Oleg
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Tamminen, T
    Viitasalo, M
    Voss, M
    Wasmund, N
    Wulff, Fredrik
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Internal ecosystem feedbacks enhance nitrogen-fixing cyanobacteria blooms and complicate management in the Baltic Sea2007In: Ambio, Vol. 36, no 2-3, p. 186-194Article in journal (Refereed)
  • 12.
    Wulff, Fredrik
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Is there a future for the Baltic?2008In: NEFCO Newsletter December 10Article in journal (Other (popular science, discussion, etc.))
  • 13.
    Wulff, Fredrik
    et al.
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Eyre, Bradley D.
    Johnstone, Ron
    Nitrogen versus phosphorus limitation in a subtropical coastal embayment (Moreton Bay; Australia): Implications for management2011In: Ecological Modelling, ISSN 0304-3800, E-ISSN 1872-7026, Vol. 222, no 1, p. 120-130Article in journal (Refereed)
    Abstract [en]

    An approach combining nutrient budgets, dynamic modelling, and field observations of phytoplankton and nitrogen (N(2))-fixing Lyngbya majuscula following changes in wastewater N loads, was used to demonstrate that Moreton Bay is potentially phosphorus (P) limited. Modelling and nutrient budgeting shows that benthic N-fixation loads are high, allowing the system to overcome any potential N-limitation. Phytoplankton biomass has shown little change from 1991 to 2006 in the sections of Moreton Bay most impacted by wastewater effluents, despite a large reduction in wastewater N loads from 2000 to 2002. This is consistent with modelling that also showed no reduction in primary productivity associated with reduced N loads. Most importantly, there have been rapid increases in the occurrence of N-fixing L majuscula in Moreton Bay as wastewater P loads have increased relative to wastewater N loads. This is also consistent with modelling. This work supports the premise that there may be fundamental differences in nutrient limitation of primary production between subtropical and temperate coastal systems due to differences in the importance of internal nitrogen sources and sinks (N-fixation and denitrification). These differences need to be recognised for optimum management of coastal systems.

  • 14.
    Wulff, Fredrik
    et al.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences. Stockholm University, Faculty of Science, Stockholm University Baltic Sea Centre, Baltic Nest Institute.
    Humborg, Christoph
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM). Stockholm University, Faculty of Science, Stockholm University Baltic Sea Centre, Baltic Nest Institute.
    Andersen, Hans Estrup
    Blicher-Mathiesen, Gitte
    Czajkowski, Mikolaj
    Elofsson, Katarina
    Fonnesbech-Wulff, Anders
    Hasler, Berit
    Hong, Bongghi
    Jansons, Viesturs
    Mörth, Carl-Magnus
    Stockholm University, Faculty of Science, Department of Geological Sciences.
    Smart, James C. R.
    Smedberg, Erik
    Stockholm University, Faculty of Science, Stockholm University Baltic Sea Centre, Baltic Nest Institute.
    Stålnacke, Per
    Swaney, Dennis P.
    Thodsen, Hans
    Was, Adam
    Zylicz, Tomasz
    Reduction of Baltic Sea Nutrient Inputs and Allocation of Abatement Costs Within the Baltic Sea Catchment2014In: Ambio, ISSN 0044-7447, E-ISSN 1654-7209, Vol. 43, no 1, p. 11-25Article in journal (Refereed)
    Abstract [en]

    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 a,not sign.

  • 15.
    Wulff, Fredrik
    et al.
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Savchuk, O.
    Sokolov, A.
    Humborg, Christoph
    Department of Applied Environmental Science (ITM).
    Mörth, Carl-Magnus
    Department of Geology and Geochemistry.
    Management options and effects on a marine ecosystem: Assessing the future of the Baltic2007In: Ambio, Vol. 37, p. 237-243Article in journal (Refereed)
  • 16.
    Wulff, Fredrik
    et al.
    Stockholm University, Faculty of Science, Department of Systems Ecology. marin ekologi.
    Savchuk, Oleg
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Sokolov, Alexander
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Humborg, Christoph
    Department of Applied Environmental Science (ITM).
    Mörth, C-M
    Management options and effects on a marine ecosystem: assessing the future of the Baltic Sea2007In: Ambio, Vol. 36, no 2-3, p. 243-249Article in journal (Refereed)
  • 17.
    Wulff, Fredrik
    et al.
    Stockholm University, Faculty of Science, Stockholm University Baltic Sea Centre, Baltic Nest Institute.
    Sokolov, Alexander
    Stockholm University, Faculty of Science, Stockholm University Baltic Sea Centre, Baltic Nest Institute.
    Savchuk, Oleg
    Stockholm University, Faculty of Science, Stockholm University Baltic Sea Centre, Baltic Nest Institute.
    Nest – a decision support systemfor management of the Baltic Sea: A user manual2013Report (Other academic)
    Abstract [en]

    The decision support system Nest was initially developed within the MISTRA-funded MARE research program, which was completed in 2007. Nest was then successfully used for the development of the eutrophication segment of the HELCOM Baltic Sea Action Plan, where nutrient load reductions needed to reach a healthy Baltic Sea were calculated, as were the allocations between countries. Nest is also used in many research programs.

    The maintenance and further development of Nest has continued within the Baltic Nest Institute. The Nest system links the entire Baltic Sea region, from watershed to offshore ecosystems, through data and models. It is available online, free of charge, and can be run in both expert and standard mode. The main target groups of the Nest system are decision-makers and scientists in the Baltic region interacting with the Helsinki Commission (HELCOM), as well as those working on the implementation of the EU Water Framework Directive and Marine Strategy Framework Directive.

    We also hope that it can be useful for students interested in learning more about the Baltic Sea. The different components describe forcing by nutrient inputs and characteristics of the drainage and sea basins. The marine models describe the physics and biogeochemistry of the Sea, as well as of its food webs (to the levels of man and seals), and are used in scenarios of how fisheries, eutrophication, and climate change affect this unique ecosystem.

    Finally, the strong interdependence of the countries around the Baltic is illustrated when the costs for reducing nutrient load, with or without cooperation, are calculated. This manual is by no means the final version: it will be continuously improved and modified, both as a result of user inputs and when components of Nest are modified. Nest has been designed as a web distributed system and to use it you need access to the Internet; some components are installed on your (client) computer, others are installed on the servers that you communicate with. Experts continuously update the components of Nest. Each time you start the program, your client software is checked and updated if a new version is available. This procedure ensures that you always use the most recent version of Nest. 

    Download full text (pdf)
    fulltext
  • 18.
    Österblom, Henrik
    et al.
    Stockholm University, Faculty of Science, Department of Systems Ecology. Stockholm University, Stockholm Resilience Centre.
    Hansson, Sture
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Larsson, Ulf
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Hjerne, Olle
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Wulff, Fredrik
    Stockholm University, Faculty of Science, Department of Systems Ecology. Stockholm University, Stockholm Resilience Centre.
    Elmgren, Ragnar
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Folke, Carl
    Stockholm University, Faculty of Science, Department of Systems Ecology. Stockholm University, Stockholm Resilience Centre.
    Human-induced trophic cascades and ecological regime shifts in the Baltic Sea2007In: Ecosystems (New York. Print), ISSN 1432-9840, E-ISSN 1435-0629, Vol. 10, no 6, p. 877-889Article in journal (Refereed)
    Abstract [en]

    The ecosystems of coastal and enclosed seas are under increasing anthropogenic pressure worldwide, with Chesapeake Bay, the Gulf of Mexico and the Black and Baltic Seas as well known examples. We use an ecosystem model (Ecopath with Ecosim, EwE) to show that reduced top-down control (seal predation) and increased bottom-up forcing (eutrophication) can largely explain the historical dynamics of the main fish stocks (cod, herring and sprat) in the Baltic Sea between 1900 and 1980. Based on these results and the historical fish stock development we identify two major ecological transitions. A shift from seal to cod domination was caused by a virtual elimination of marine mammals followed by a shift from an oligotrophic to a eutrophic state. A third shift from cod to clupeid domination in the late 1980s has previously been explained by overfishing of cod and climatic changes. We propose that the shift from an oligotrophic to a eutrophic state represents a true regime shift with a stabilizing mechanism for a hysteresis phenomenon. There are also mechanisms that could stabilize the shift from a cod to clupeid dominated ecosystem, but there are no indications that the ecosystem has been pushed that far yet. We argue that the shifts in the Baltic Sea are a consequence of human impacts, although variations in climate may have influenced their timing, magnitude and persistence.

1 - 18 of 18
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