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  • 1.
    Alling, Vanja
    et al.
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Porcelli, D.
    Mörth, Carl-Magnus
    Stockholm University, Faculty of Science, Department of Geological Sciences. Stockholm University, Stockholm Resilience Centre, Baltic Nest Institute.
    Anderson, L. G.
    Sanchez-Garcia, L.
    Stockholm University, Faculty of Science, Department of Geological Sciences.
    Gustafsson, Örjan
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Andersson, P. S.
    Humborg, Christoph
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM). Stockholm University, Stockholm Resilience Centre, Baltic Nest Institute.
    Degradation of terrestrial organic carbon, primary production and out-gassing of CO2 in the Laptev and East Siberian Seas as inferred from delta C-13 values of DIC2012In: Geochimica et Cosmochimica Acta, ISSN 0016-7037, E-ISSN 1872-9533, Vol. 95, p. 143-159Article in journal (Refereed)
    Abstract [en]

    The cycling of carbon on the Arctic shelves, including outgassing of CO2 to the atmosphere, is not clearly understood. Degradation of terrestrial organic carbon (OCter) has recently been shown to be pronounced over the East Siberian Arctic Shelf (ESAS), i.e. the Laptev and East Siberian Seas, producing dissolved inorganic carbon (DIC). To further explore the processes affecting DIC, an extensive suite of shelf water samples were collected during the summer of 2008, and assessed for the stable carbon isotopic composition of DIC (delta C-13(DIC)). The delta C-13(DIC) values varied between -7.2 parts per thousand to +1.6 parts per thousand and strongly deviated from the compositions expected from only mixing between river water and seawater. Model calculations suggest that the major processes causing these deviations from conservative mixing were addition of (DIC) by degradation of OCter, removal of DIC during primary production, and outgassing of CO2. All waters below the halocline in the ESAS had delta C-13(DIC) values that appear to reflect mixing of river water and seawater combined with additions of on average 70 +/- 20 mu M of DIC, originating from degradation of OCter in the coastal water column. This is of the same magnitude as the recently reported deficits of DOCter and POCter for the same waters. The surface waters in the East Siberian Sea had higher delta C-13(DIC) values and lower DIC concentrations than expected from conservative mixing, consistent with additions of DIC from degradation of OCter and outgassing of CO2. The outgassing of CO2 was equal to loss of 123 +/- 50 mu M DIC. Depleted delta C-13(POC) values of -29 parts per thousand to -32 parts per thousand in the mid to outer shelf regions are consistent with POC from phytoplankton production. The low delta C-13(POC) values are likely due to low delta C-13(DIC) of precursor DIC, which is due to degradation of OCter, rather than reflecting terrestrial input compositions. Overall, the delta C-13(DIC) values confirm recent suggestions of substantial degradation of OCter over the ESAS, and further show that a large part of the CO2 produced from degradation has been outgassed to the atmosphere.

  • 2.
    Andrejev, Oleg
    et al.
    Finnish Environment Institute.
    Sokolov, Alexander
    Stockholm University, Stockholm Resilience Centre, Baltic Nest Institute.
    Soomere, Tarmo
    Institute of Cybernetics.
    Värv, Rolf
    Institute of Cybernetics.
    Viikmäe, Bert
    Institute of Cybernetics.
    The use of high-resolution bathymetry for circulation modelling in the Gulf of Finland2010In: Estonian Journal of Engineering, Vol. 16, no 3, p. 187-210Article in journal (Refereed)
    Abstract [en]

    We present preliminary results of the extension of the OAAS circulation model to a high-resolution bathymetry with a finest resolution of 0.25 nautical miles in the Gulf of Finland, the Baltic Sea. The models with a resolution of 1 mile or finer are capable of resolving typical mesoscale eddies in this basin where the internal Rossby radius is usually 2–4 km. An increase in the model resolution from 1 to 0.5 NM leads to a clear improvement of the representation of the key hydrophysical fields. A further increase in the resolution to 0.25 NM has a lesser impact on hydro­physical fields, but may lead to some changes in the instantaneous patterns of currents. The para­meterization of the spreading effect of sub-grid-scale turbulence on the trajectories of initially closely located drifters is realized by means of accounting for the largely rotational character of the dynamics in this basin. The modelled average spreading rate for initially closely located particles for 1991 was 2 mm/s.

  • 3. Andrejev, Oleg
    et al.
    Soomere, Tarmo
    Sokolov, Alexander
    Stockholm University, Stockholm Resilience Centre, Baltic Nest Institute.
    Myrberg, Kai
    Stockholm University, Stockholm Resilience Centre, Baltic Nest Institute.
    The role of the spatial resolution of a three-dimensional hydrodynamic model for marine transport risk assessment2011In: Oceanologia, ISSN 0078-3234, Vol. 53, no 1, p. 309-334Article in journal (Refereed)
    Abstract [en]

    The paper addresses the sensitivity of a novel method for quantifying the environmental risks associated with the current-driven transport of adverse impacts released from offshore sources (e.g. ship traffic) with respect to the spatial resolution of the underlying hydrodynamic model. The risk is evaluated as the probability of particles released in different sea areas hitting the coast and in terms of the time after which the hit occurs (particle age) on the basis of a statistical analysis of large sets of 10-day long Lagrangian trajectories calculated for 1987-1991 for the Gulf of Finland, the Baltic Sea. The relevant 21) maps are calculated using the OAAS model with spatial resolutions of 2, 1 and 0.5 nautical miles (nm) and with identical initial, boundary and forcing conditions from the Rossby Centre 3D hydrodynamic model (RCO, Swedish Meteorological and Hydrological Institute). The spatially averaged values of the probability and particle age display hardly any dependence on the resolution. They both reach almost identical stationary levels (0.67-0.69 and ca 5.3 days respectively) after a few years of simulations. Also, the spatial distributions of the relevant fields are qualitatively similar for all resolutions. In contrast, the optimum locations for fairways depend substantially on the resolution, whereas the results for the 2 nm model differ considerably from those obtained using finer-resolution models. It is concluded that eddy-permitting models with a grid step exceeding half the local baroclinic Rossby radius are suitable for a quick check of whether or not any potential gain from this method is feasible, whereas higher-resolution simulations with eddy-resolving models are necessary for detailed planning. The asymptotic values of the average probability and particle age are suggested as an indicator of the potential gain from the method in question and also as a new measure of the vulnerability of the nearshore of water bodies to offshore traffic accidents.

  • 4.
    Barthel, Stephan
    et al.
    Stockholm University, Stockholm Resilience Centre.
    Colding, Johan
    Stockholm University, Stockholm Resilience Centre.
    Ernstson, Henrik
    Stockholm University, Stockholm Resilience Centre.
    Eriksson, Hanna
    Stockholm University, Stockholm Resilience Centre, Baltic Nest Institute.
    Chans att sätta Stockholm på kartan2011In: Svenska DagbladetArticle in journal (Other (popular science, discussion, etc.))
    Abstract [sv]

    Så beskriver ett antal forskare från Stockholm Resilience Centre och KTH läget nu när Albano ska utvecklas till ett nytt universitetsområde. Albano kan bli en internationell förebild när det gäller hållbart byggande om politikerna tar sitt ansvar, skriver forskarna i en debattartikel i Svenska Dagbladet idag. På Stockholm Resilience Centres webbplats finns texten även på engelska.

  • 5.
    Boonstra, Wiebren J.
    et al.
    Stockholm University, Faculty of Science, Stockholm Resilience Centre, Baltic Nest Institute. University of Oslo, Norway.
    de Boer, Florianne W.
    The Historical Dynamics of Social-Ecological Traps2014In: Ambio, ISSN 0044-7447, E-ISSN 1654-7209, Vol. 43, no 3, p. 260-274Article, review/survey (Refereed)
    Abstract [en]

    Environmental degradation is a typical unintended outcome of collective human behavior. Hardin's metaphor of the tragedy of the commons has become a conceived wisdom that captures the social dynamics leading to environmental degradation. Recently, traps has gained currency as an alternative concept to explain the rigidity of social and ecological processes that produce environmental degradation and livelihood impoverishment. The trap metaphor is, however, a great deal more complex compared to Hardin's insight. This paper takes stock of studies using the trap metaphor. It argues that the concept includes time and history in the analysis, but only as background conditions and not as a factor of causality. From a historical-sociological perspective this is remarkable since social-ecological traps are clearly path-dependent processes, which are causally produced through a conjunction of events. To prove this point the paper conceptualizes social-ecological traps as a process instead of a condition, and systematically compares history and timing in one classic and three recent studies of social-ecological traps. Based on this comparison it concludes that conjunction of social and environmental events contributes profoundly to the production of trap processes. The paper further discusses the implications of this conclusion for policy intervention and outlines how future research might generalize insights from historical-sociological studies of traps.

  • 6.
    Boonstra, Wiebren J.
    et al.
    Stockholm University, Faculty of Science, Stockholm Resilience Centre, Baltic Nest Institute.
    Joosse, Sofie
    The Social Dynamics of Degrowth2013In: Environmental Values, ISSN 0963-2719, E-ISSN 1752-7015, Vol. 22, no 2, p. 171-189Article in journal (Refereed)
    Abstract [en]

    Degrowth cannot be realised from within a capitalist society, since growth is the sine qua non for capitalism. But, societies are no blank slates; they are not built from scratch. Putting these two thoughts together seems to make degrowth logically impossible. In this paper we argue that this paradox can be solved with the use of classical and contemporary concepts from the social sciences. We illustrate the use of these concepts with reference to studies on current practices and patterns of food production and consumption. The concept of social mechanism is used to illustrate how social practices can simultaneously reinforce and challenge the dominant (food) regime. We argue that current discussions on degrowth fail to envision how such contrasting developments are linked, and that the degrowth paradox originates in the idea of capitalism and the steady-state economy as alternative systems. The paradox dissolves with studies of mechanisms and social practices that show how the two systems are not autonomous, but 'hybridised' and come into existence and gain shape as reactions to each other.

  • 7. Casini, Michele
    et al.
    Blenckner, Thorsten
    Stockholm University, Stockholm Resilience Centre, Baltic Nest Institute.
    Moellmann, Christian
    Gardmark, Anna
    Lindegren, Martin
    Llope, Marcos
    Kornilovs, Georgs
    Plikshs, Maris
    Stenseth, Nils Christian
    Predator transitory spillover induces trophic cascades in ecological sinks2012In: Proceedings of the National Academy of Sciences of the United States of America, ISSN 0027-8424, E-ISSN 1091-6490, Vol. 109, no 21, p. 8185-8189Article in journal (Refereed)
    Abstract [en]

    Understanding the effects of cross-system fluxes is fundamental in ecosystem ecology and biological conservation. Source-sink dynamics and spillover processes may link adjacent ecosystems by movement of organisms across system boundaries. However, effects of temporal variability in these cross-system fluxes on a whole marine ecosystem structure have not yet been presented. Here we show, using 35 y of multitrophic data series from the Baltic Sea, that transitory spillover of the top-predator cod from its main distribution area produces cascading effects in the whole food web of an adjacent and semi-isolated ecosystem. At varying population size, cod expand/contract their distribution range and invade/retreat from the neighboring Gulf of Riga, thereby affecting the local prey population of herring and, indirectly, zooplankton and phytoplankton via top-down control. The Gulf of Riga can be considered for cod a true sink habitat, where in the absence of immigration from the source areas of the central Baltic Sea the cod population goes extinct due to the absence of suitable spawning grounds. Our results add a metaecosystem perspective to the ongoing intense scientific debate on the key role of top predators in structuring natural systems. The integration of regional and local processes is central to predict species and ecosystem responses to future climate changes and ongoing anthropogenic disturbances.

  • 8. Conley, Daniel J.
    et al.
    Björck, Svante
    Bonsdorff, Erik
    Carstensen, Jacob
    Destouni, Georgia
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Gustafsson, Bo G.
    Stockholm University, Stockholm Resilience Centre, Baltic Nest Institute.
    Hietanen, Susanna
    Kortekaas, Marloes
    Kuosa, Harri
    Meier, H. E. Markus
    Muller-Karulis, Baerbel
    Nordberg, Kjell
    Norkko, Alf
    Nurnberg, Gertrud
    Pitkänen, Heikki
    Rabalais, Nancy N.
    Rosenberg, Rutger
    Savchuk, Oleg P.
    Stockholm University, Stockholm Resilience Centre, Baltic Nest Institute.
    Slomp, Caroline P.
    Voss, Maren
    Wulff, Fredrik
    Stockholm University, Faculty of Science, Department of Systems Ecology. Stockholm University, Stockholm Resilience Centre, Baltic Nest Institute.
    Zillén, Lovisa
    Hypoxia-Related Processes in the Baltic Sea2009In: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 43, no 10, p. 3412-3420Article in journal (Refereed)
    Abstract [en]

    Hypoxia, a growing worldwide problem, has been intermittently present in the modern Baltic Sea since its formation ca. 8000 cal. yr BP. However, both the spatial extent and intensity of hypoxia have increased with anthropogenic eutrophication due to nutrient inputs. Physical processes, which control stratification and the renewal of oxygen in bottom waters, are important constraints on the formation and maintenance of hypoxia. Climate controlled inflows of saline water from the North Sea through the Danish Straits is a critical controlling factor governing the spatial extent and duration of hypoxia. Hypoxia regulates the biogeochemical cycles of both phosphorus (P) and nitrogen (N) in the water column and sediments. Significant amounts of P are currently released from sediments, an order of magnitude larger than anthropogenic inputs. The Baltic Sea is unique for coastal marine ecosystems experiencing N losses in hypoxic waters below the halocline. Although benthic communities in the Baltic Sea are naturally constrained by salinity gradients, hypoxia has resulted in habitat loss over vast areas and the elimination of benthic fauna, and has severely disrupted benthic food webs. Nutrient load reductions are needed to reduce the extent, severity, and effects of hypoxia.

  • 9. Conley, Daniel J.
    et al.
    Bonsdorff, Erik
    Carstensen, Jacob
    Destouni, Georgia
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Gustafsson, Bo G.
    Stockholm University, Stockholm Resilience Centre, Baltic Nest Institute.
    Hansson, Lars-Anders
    Rabalais, Nancy N.
    Voss, Maren
    Zillén, Lovisa
    Tackling hypoxia in the Baltic Sea: Is engineering a solution?2009In: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 43, no 10, p. 3407-3411Article in journal (Refereed)
  • 10. Conley, Daniel J.
    et al.
    Carstensen, Jacob
    Aigars, Juris
    Axe, Philip
    Bonsdorff, Erik
    Eremina, Tatjana
    Haahti, Britt-Marie
    Humborg, Christoph
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM). Stockholm University, Stockholm Resilience Centre, Baltic Nest Institute.
    Jonsson, Per
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Kotta, Jonne
    Lannegren, Christer
    Larsson, Ulf
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Maximov, Alexey
    Medina, Miguel Rodriguez
    Stockholm University, Stockholm Resilience Centre, Baltic Nest Institute.
    Lysiak-Pastuszak, Elzbieta
    Remeikaite-Nikiene, Nijole
    Walve, Jakob
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Wilhelms, Sunhild
    Zillen, Lovisa
    Hypoxia is increasing in the coastal zone of the Baltic Sea2011In: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 45, no 16, p. 6777-6783Article in journal (Refereed)
    Abstract [en]

    Hypoxia is a well-described phenomenon in the offshore waters of the Baltic Sea with both the spatial extent and intensity of hypoxia known to have increased due to anthropogenic eutrophication, however, an unknown amount of hypoxia is present in the coastal zone. Here we report on the widespread unprecedented occurrence of hypoxia across the coastal zone of the Baltic Sea. We have identified 115 sites that have experienced hypoxia during the period 1955-2009 increasing the global total to ca. 500 sites, with the Baltic Sea coastal zone containing over 20% of all known sites worldwide. Most sites experienced episodic hypoxia, which is a precursor to development of seasonal hypoxia. The Baltic Sea coastal zone displays an alarming trend with hypoxia steadily increasing with time since the 1950s effecting nutrient biogeochemical processes, ecosystem services, and coastal habitat.

  • 11.
    Deutsch, Barbara
    et al.
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Alling, Vanja
    Norwegian Geotechnical Institute.
    Humborg, Christoph
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Korth, Frederike
    Leibniz Institute for Baltic Sea Research.
    Moerth, Magnus
    Stockholm University, Stockholm Resilience Centre, Baltic Nest Institute.
    Tracing inputs of terrestrial high molecular weight dissolved organic matter within the Baltic Sea ecosystem2012In: Biogeosciences, ISSN 1726-4170, E-ISSN 1726-4189, Vol. 9, p. 4465-4475Article in journal (Refereed)
    Abstract [en]

    To test the hypothesis whether high molecular weight dissolved organic matter (HMW-DOM) in a high latitude marginal sea is dominated by terrestrial derived matter, 10 stations were sampled along the salinity gradient of the central and northern Baltic Sea and were analyzed for concentrations of dissolved organic carbon as well as δ13C values of HMW-DOM. Different end-member-mixing models were applied to quantify the influence of terrestrial DOM and to test for conservative versus non-conservative behavior of the terrestrial DOM in the different Baltic Sea basins. The share of terrestrial DOM to the total HMW-DOM was calculated for each station, ranging from 43 to 83%. This shows the high influence of terrestrial DOM inputs for the Baltic Sea ecosystem. The data also suggest that terrestrial DOM reaching the open Baltic Sea is not subject to substantial removal anymore. However compared to riverine DOM concentrations, our results indicate that substantial amounts of HMW-DOM (> 50%) seem to be removed near the coastline during estuarine mixing. A budget approach yielded residence times for terrestrial DOM of 2.8, 3.0, and 4.5 yr for the Bothnian Bay, the Bothnian Sea and the Baltic Proper.

  • 12. Eilola, K.
    et al.
    Gustafsson, Bo G.
    Stockholm University, Stockholm Resilience Centre, Baltic Nest Institute.
    Kuznetsov, I.
    Meier, H. E. M.
    Neumann, T.
    Savchuk, O. P.
    Stockholm University, Stockholm Resilience Centre, Baltic Nest Institute.
    Evaluation of biogeochemical cycles in an ensemble of three state-of-the-art numerical models of the Baltic Sea2011In: Journal of Marine Systems, ISSN 0924-7963, E-ISSN 1879-1573, Vol. 88, no 2, p. 267-284Article in journal (Refereed)
    Abstract [en]

    Three state-of-the-art coupled physical-biogeochemical models, the BAltic sea Long-Term large-Scale Eutrophication Model (BALTSEM), the Ecological Regional Ocean Model (ERGOM), and the Swedish Coastal arid Ocean Biogeochemical model coupled to the Rossby Centre Ocean circulation model (RCO-SCOBI), are used to calculate changing nutrient and oxygen dynamics in the Baltic Sea. The models are different in that ERGOM and RCO-SCOBI are three-dimensional (3D) circulation models while BALTSEM resolves the Baltic Sea into 13 dynamically interconnected and horizontally integrated sub-basins. The aim is to assess the simulated long-term dynamics and to discuss the response of the coupled physical-biogeochemical models to changing physical conditions and nutrient loadings during the period 1970-2005. We compared the long-term seasonal and annual statistics of inorganic nitrogen, phosphorus, and oxygen from hindcast simulations with those estimated from observations. We also studied the extension of hypoxic bottom areas covered by waters with O(2)<2 ml O(2) l(-1) and cod reproductive volumes comprising waters with salinity >11 and O(2)>2 ml O(2) l(-1). The models reproduce much of the nutrient biogeochemical cycling in the Baltic proper. However, biases are larger in the Bothnian Sea and Bothnian Bay. No model shows outstanding performance in all aspects but instead the ensemble mean results are better than or as good as the results of any of the individual models. Uncertainties are primarily related to differences in the bioavailable fractions of nutrient loadings from land and parameterizations of key processes like sediment fluxes that are presently not well known. Also the uncertainty related to the initialization of the models in the early 1960s influence the modeled biogeochemical cycles during the investigated period.

  • 13.
    Eilola, K.
    et al.
    Swedish Meteorological and Hydrological Institute.
    Gustafsson, Bo
    Stockholm University, Stockholm Resilience Centre, Baltic Nest Institute.
    Savchuck, Oleg
    Stockholm University, Stockholm Resilience Centre.
    Quality assessment of state-of-the-art coupled physical-biogeochemical models in hindcast simulations 1970-20052010Report (Other academic)
    Abstract [en]

    The objectives of the project ECOSUPPORT (Advanced modeling tool for scenarios of the Baltic Sea ECOsystem to SUPPORT decision making) are to calculate the combined effects of changing climate and changing human activity (e.g. changing nutrient loads) on the Baltic Sea ecosystem. Three state-of-the-art coupled physical-biogeochemical models (BALTSEM, ERGOM, and RCO-SCOBI) are used to calculate changing concentrations of nitrate, ammonium, phosphate, diatoms, flagellates, cyanobacteria, zooplankton, detritus, and oxygen in the Baltic Sea. The models are structurally different in that ERGOM and RCO-SCOBI are 3D circulation models with uniform high horizontal resolution while BALTSEM resolves the Baltic Sea spatially in 13 sub-basins. This report summarises first results of the quality assessment and model intercomparison within ECOSUPPORT. Results from hindcast simulations are compared with observations for the period 1970-2005. We found that all three investigated models are able to reproduce the observed variability of biogeochemical cycles well. Uncertainties are primarily related to differences in the bioavailable fractions of nutrient loadings from land and parameterizations of key processes like sediment fluxes that are presently not well known. Avsikten med projektet ECOSUPPORT (Advanced modeling tool for scenarios of the Baltic Sea ECOsystem to SUPPORT decision making) är att undersöka hur klimatförändringar tillsammans med mänsklig aktivitet (förändrad närsaltstillförsel) påverkar Östersjöns ekosystem. Tre kopplade fysiska-biogeokemiska modeller (BALTSEM, ERGOM, and RCO-SCOBI) används för att beräkna hur koncentrationer av nitrat, ammonium, fosfat, diatoméer, flagellater, cyanobakterier, djurplankton, detritus och löst syrgas i Östersjön förändras. Modellerna skiljer sig strukturellt åt genom att ERGOM och RCO-SCOBI är tredimensionella modeller med hög horisontell upplösning medan BALTSEM delar upp östersjön rumsligt i 13 delbassänger. Denna rapport sammanfattar resultaten från en första modelljämförelse och kvalitetsbedömning där modellresultat för tidsperioden 1970-2005 jämförs med observationer från samma period. Alla tre modellerna visar att de kan återskapa den observerade biogeokemiska variabiliteten väl. Osäkerheter är huvudsakligen relaterade till skillnader i andelen av näringstillförseln från land som antas vara biologiskt tillgänglig och till beskrivningarna av viktiga processer, som t.ex. flöden från sedimenten, där kunskapen för närvarande är bristfällig.

  • 14.
    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).
    Mörth, Carl- Magnus
    Stockholm University, Faculty of Science, Department of Geology and Geochemistry.
    Rodriguez Medina, Miguel
    Stockholm University, Stockholm Resilience Centre, Baltic Nest Institute.
    Scenario Analysis on Human Protein consumption and Climate change effects on riverine N export to the Balitc SeaManuscript (preprint) (Other academic)
  • 15.
    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.

  • 16.
    Eriksson Hägg, Hanna
    et al.
    Stockholm University, Stockholm Resilience Centre, Baltic Nest Institute. Stockholm University, Faculty of Science, Department of Geology and Geochemistry.
    Humborg, Christoph
    Stockholm University, Stockholm Resilience Centre, Baltic Nest Institute. Stockholm University, Faculty of Science, Department of Geology and Geochemistry.
    Swaney, D. P.
    Mörth, Carl-Magnus
    Stockholm University, Stockholm Resilience Centre, Baltic Nest Institute. Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Riverine nitrogen export in Swedish catchments dominated by atmospheric inputs2012In: Biogeochemistry, ISSN 0168-2563, E-ISSN 1573-515X, Vol. 111, no 1-3, p. 203-217Article in journal (Refereed)
    Abstract [en]

    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 (NOy) as atmospheric input (r(2) = 0.70) rather than total deposition (i.e., both oxidized and reduced nitrogen, NOy + NHx deposition, r(2) = 0.62). The y-intercept (NANI = 0) for the NANI calculated with NOy is significantly different from zero (p = 0.0042*) and indicates a background flux from the catchment of some 100 kg N km(-2) year(-1) 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 (NOy and NOy + NHx), 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(-1). Besides hydraulic load the percent total forest cover also affects the nitrogen export primarily in the northern and western catchments.

  • 17. Ferreira, Joao G.
    et al.
    Andersen, Jesper H.
    Borja, Angel
    Bricker, Suzanne B.
    Camp, Jordi
    da Silva, Margarida Cardoso
    Garces, Esther
    Heiskanen, Anna-Stiina
    Humborg, Christoph
    Stockholm University, Stockholm Resilience Centre, Baltic Nest Institute.
    Ignatiades, Lydia
    Lancelot, Christiane
    Menesguen, Alain
    Tett, Paul
    Hoepffner, Nicolas
    Claussen, Ulrich
    Overview of eutrophication indicators to assess environmental status within the European Marine Strategy Framework Directive2011In: Estuarine, Coastal and Shelf Science, ISSN 0272-7714, E-ISSN 1096-0015, Vol. 93, no 2, p. 117-131Article in journal (Refereed)
    Abstract [en]

    In 2009, following approval of the European Marine Strategy Framework Directive (MSFD, 2008/56/EC), the European Commission (EC) created task groups to develop guidance for eleven quality descriptors that form the basis for evaluating ecosystem function. The objective was to provide European countries with practical guidelines for implementing the MSFD, and to produce a Commission Decision that encapsulated key points of the work in a legal framework. This paper presents a review of work carried out by the eutrophication task group, and reports our main findings to the scientific community. On the basis of an operational, management-oriented definition, we discuss the main methodologies that could be used for coastal and marine eutrophication assessment. Emphasis is placed on integrated approaches that account for physico-chemical and biological components, and combine both pelagic and benthic symptoms of eutrophication, in keeping with the holistic nature of the MSFD. We highlight general features that any marine eutrophication model should possess, rather than making specific recommendations. European seas range from highly eutrophic systems such as the Baltic to nutrient-poor environments such as the Aegean Sea. From a physical perspective, marine waters range from high energy environments of the north east Atlantic to the permanent vertical stratification of the Black Sea. This review aimed to encapsulate that variability, recognizing that meaningful guidance should be flexible enough to accommodate the widely differing characteristics of European seas, and that this information is potentially relevant in marine ecosystems worldwide. Given the spatial extent of the MSFD, innovative approaches are required to allow meaningful monitoring and assessment. Consequently, substantial logistic and financial challenges will drive research in areas such as remote sensing of harmful algal blooms, in situ sensor development, and mathematical models. Our review takes into account related legislation, and in particular the EU Water Framework Directive (WFD - 2000/60/EC), which deals with river basins, including estuaries and a narrow coastal strip, in order to examine these issues within the framework of integrated coastal zone management.

  • 18.
    Folke, Carl
    et al.
    Stockholm University, Stockholm Resilience Centre. The Beijer Institute, Royal Swedish Academy of Sciences, Sweden.
    Jansson, Åsa
    Stockholm University, Stockholm Resilience Centre. The Beijer Institute, Royal Swedish Academy of Sciences, Sweden.
    Rockström, Johan
    Stockholm University, Stockholm Resilience Centre, Stockholm Environment Institute.
    Olsson, Per
    Stockholm University, Stockholm Resilience Centre.
    Crépin, Anne-Sophie
    Stockholm University, Stockholm Resilience Centre. The Beijer Institute, Royal Swedish Academy of Sciences, Sweden.
    Ebbesson, Jonas
    Stockholm University, Stockholm Resilience Centre. Stockholm University, Faculty of Law, Department of Law, Stockholm Environmental Law and Policy Centre.
    Elmqvist, Thomas
    Stockholm University, Stockholm Resilience Centre. Stockholm University, Faculty of Science, Department of Systems Ecology.
    Galaz, Victor
    Stockholm University, Stockholm Resilience Centre.
    Moberg, Fredrik
    Stockholm University, Stockholm Resilience Centre. Albaeco, Stockholm, Sweden .
    Nilsson, Måns
    Stockholm University, Stockholm Resilience Centre, Stockholm Environment Institute.
    Österblom, Henrik
    Stockholm University, Stockholm Resilience Centre, Baltic Nest Institute.
    Persson, Åsa
    Stockholm University, Stockholm Resilience Centre, Stockholm Environment Institute.
    Peterson, Garry
    Stockholm University, Stockholm Resilience Centre.
    Steffen, Will
    Stockholm University, Stockholm Resilience Centre.
    Walker, Brian
    Stockholm University, Stockholm Resilience Centre. The Beijer Institute, Royal Swedish Academy of Sciences, Sweden; CSIRO Sustainable Ecosystems, Canberra, ACT, Australia .
    Reconnecting to the biosphere2011In: Ambio, ISSN 0044-7447, E-ISSN 1654-7209, Vol. 40, no 7, p. 719-738Article in journal (Refereed)
    Abstract [en]

    Humanity has emerged as a major force in the operation of the biosphere, with a significant imprint on the Earth System, challenging social-ecological resilience. This new situation calls for a fundamental shift in perspectives, world views, and institutions. Human development and progress must be reconnected to the capacity of the biosphere and essential ecosystem services to be sustained. Governance challenges include a highly interconnected and faster world, cascading social-ecological interactions and planetary boundaries that create vulnerabilities but also opportunities for social-ecological change and transformation. Tipping points and thresholds highlight the importance of understanding and managing resilience. New modes of flexible governance are emerging. A central challenge is to reconnect these efforts to the changing preconditions for societal development as active stewards of the Earth System. We suggest that the Millennium Development Goals need to be reframed in such a planetary stewardship context combined with a call for a new social contract on global sustainability. The ongoing mind shift in human relations with Earth and its boundaries provides exciting opportunities for societal development in collaboration with the biosphere-a global sustainability agenda for humanity.

  • 19. Gren, Ing-Marie
    et al.
    Savchuck, Oleg P.
    Stockholm University, Stockholm Resilience Centre, Baltic Nest Institute.
    Jansson, Torbjörn
    Cost-Effective Spatial and Dynamic Management of a Eutrophied Baltic Sea2013In: Marine Resource Economics, ISSN 0738-1360, Vol. 28, no 3, p. 263-284Article in journal (Refereed)
    Abstract [en]

    The purpose of this article is to calculate cost-effective spatial and dynamic allocations of nutrient abatement for reaching targets in a large sea with different and interlinked marine basins. A discrete dynamic model was constructed to account for measures affecting both nitrogen and phosphorus and heterogeneous and coupled marine basins within the sea. Theoretical results revealed that positive decay rates of nutrient pools in the marine basins reduce abatement costs by delaying abatement over time. The results also showed that simultaneous management of both nutrients reduces overall abatement costs as compared with separate management. An empirical application to the intergovernmental agreement on nutrient pool targets in the Baltic Sea was made by combining results from an oceanographic model with an economic model of abatement costs. The results indicate that modest changes in decay rates make a significant impact on abatement costs and that simultaneous implementation of targets for both nutrients can reduce total cost by approximately 15% compared with separate treatment. A robust result is the finding that one country, Poland, faces much higher abatement costs than the other eight riparian countries because of its relatively large discharges into a marine basin with a stringent phosphorus target and slow response to load changes.

  • 20.
    Gustafsson, Bo G.
    et al.
    Stockholm University, Stockholm Resilience Centre, Baltic Nest Institute.
    Rodriguez Medina, Miguel
    Stockholm University, Stockholm Resilience Centre, Baltic Nest Institute.
    Validation data set compiled from Baltic Environmental Database - Version 22011Report (Other (popular science, discussion, etc.))
  • 21.
    Gustafsson, Bo G.
    et al.
    Stockholm University, Stockholm Resilience Centre, Baltic Nest Institute.
    Schenk, Frederik
    Blenckner, Thorsten
    Stockholm University, Stockholm Resilience Centre, Baltic Nest Institute.
    Eilola, Kari
    Meier, H. E. Markus
    Muller-Karulis, Barbel
    Stockholm University, Stockholm Resilience Centre, Baltic Nest Institute.
    Neumann, Thomas
    Ruoho-Airola, Tuija
    Savchuk, Oleg P.
    Stockholm University, Stockholm Resilience Centre, Baltic Nest Institute.
    Zorita, Eduardo
    Reconstructing the Development of Baltic Sea Eutrophication 1850-20062012In: Ambio, ISSN 0044-7447, E-ISSN 1654-7209, Vol. 41, no 6, p. 534-548Article in journal (Refereed)
    Abstract [en]

    A comprehensive reconstruction of the Baltic Sea state from 1850 to 2006 is presented: driving forces are reconstructed and the evolution of the hydrography and biogeochemical cycles is simulated using the model BALTSEM. Driven by high resolution atmospheric forcing fields (HiResAFF), BALTSEM reproduces dynamics of salinity, temperature, and maximum ice extent. Nutrient loads have been increasing with a noteworthy acceleration from the 1950s until peak values around 1980 followed by a decrease continuing up to present. BALTSEM shows a delayed response to the massive load increase with most eutrophic conditions occurring only at the end of the simulation. This is accompanied by an intensification of the pelagic cycling driven by a shift from spring to summer primary production. The simulation indicates that no improvement in water quality of the Baltic Sea compared to its present state can be expected from the decrease in nutrient loads in recent decades.

  • 22. Gårdmark, Anna
    et al.
    Lindegren, Martin
    Neuenfeldt, Stefan
    Blenckner, Thorsten
    Stockholm University, Faculty of Science, Stockholm Resilience Centre, Baltic Nest Institute.
    Heikinheimo, Outi
    Müller-Karulis, Barbel
    Stockholm University, Faculty of Science, Stockholm Resilience Centre, Baltic Nest Institute. Institute of Food Safety, Animal Health and Environment BIOR, Latvia.
    Niiranen, Susa
    Stockholm University, Faculty of Science, Stockholm Resilience Centre, Baltic Nest Institute.
    Tomczak, Maciej T.
    Stockholm University, Faculty of Science, Stockholm Resilience Centre, Baltic Nest Institute.
    Aro, Eero
    Wikström, Anders
    Moellmann, Christian
    Biological ensemble modeling to evaluate potential futures of living marine resources2013In: Ecological Applications, ISSN 1051-0761, E-ISSN 1939-5582, Vol. 23, no 4, p. 742-754Article in journal (Refereed)
    Abstract [en]

    Natural resource management requires approaches to understand and handle sources of uncertainty in future responses of complex systems to human activities. Here we present one such approach, the biological ensemble modeling approach,'' using the Eastern Baltic cod (Gadus morhua callarias) as an example. The core of the approach is to expose an ensemble of models with different ecological assumptions to climate forcing, using multiple realizations of each climate scenario. We simulated the long-term response of cod to future fishing and climate change in seven ecological models ranging from single-species to food web models. These models were analyzed using the biological ensemble modeling approach'' by which we (1) identified a key ecological mechanism explaining the differences in simulated cod responses between models, (2) disentangled the uncertainty caused by differences in ecological model assumptions from the statistical uncertainty of future climate, and (3) identified results common for the whole model ensemble. Species interactions greatly influenced the simulated response of cod to fishing and climate, as well as the degree to which the statistical uncertainty of climate trajectories carried through to uncertainty of cod responses. Models ignoring the feedback from prey on cod showed large interannual fluctuations in cod dynamics and were more sensitive to the underlying uncertainty of climate forcing than models accounting for such stabilizing predator-prey feedbacks. Yet in all models, intense fishing prevented recovery, and climate change further decreased the cod population. Our study demonstrates how the biological ensemble modeling approach makes it possible to evaluate the relative importance of different sources of uncertainty in future species responses, as well as to seek scientific conclusions and sustainable management solutions robust to uncertainty of food web processes in the face of climate change.

  • 23. Hong, Bongghi
    et al.
    Swaney, Dennis P.
    Mörth, Carl-Magnus
    Stockholm University, Stockholm Resilience Centre, Baltic Nest Institute.
    Smedberg, Erik
    Stockholm University, Stockholm Resilience Centre, Baltic Nest Institute.
    Hägg, Hanna Eriksson
    Stockholm University, Stockholm Resilience Centre, Baltic Nest Institute.
    Humborg, Christoph
    Stockholm University, Stockholm Resilience Centre, Baltic Nest Institute.
    Howarth, Robert W.
    Bouraoui, Faycal
    Evaluating regional variation of net anthropogenic nitrogen and phosphorus inputs (NANI/NAPI), major drivers, nutrient retention pattern and management implications in the multinational areas of Baltic Sea basin2012In: Ecological Modelling, ISSN 0304-3800, E-ISSN 1872-7026, Vol. 227, p. 117-135Article in journal (Refereed)
    Abstract [en]

    The NANI/NAPI (net anthropogenic nitrogen/phosphorus input) Calculator Toolbox described in this paper is designed to address the consequences to Baltic Sea nutrient loads of the significant variation in agronomic practices and dietary preferences among European countries whose watersheds comprise the Baltic Sea basin. A primary objective of this work is to develop regional parameters and datasets for this budgeting tool. A previous version of the toolbox was applied to the entire contiguous United States to calculate NANI and its components (atmospheric N deposition, fertilizer N application, agricultural N fixation and N in net food and feed imports). Here, it is modified for application to the Baltic Sea catchments, where coastal watersheds from several countries are draining to international waters. A similar accounting approach is taken for calculating NAPI, which includes fertilizer P application, P in net food and feed imports and non-food use of P by human. Regional variation of NANI/NAPI parameters (agricultural fixation rates, human intake rates and livestock intake and excretion rates) are estimated, and their impact on the regional nutrient budget and the riverine nutrient flux is evaluated. There is a distinct north-to-south gradient in NANI and NAPI across the Baltic Sea catchments, and regional nutrient inputs are strongly related to riverine nutrient fluxes. Analysis of regional nutrient retention pattern indicates that, for some countries, compliance to the Baltic Sea Action Plan would imply enormous changes in the agricultural sector.

  • 24.
    Humborg, Christoph
    et al.
    Stockholm University, Stockholm Resilience Centre. Stockholm University, Stockholm Resilience Centre, Baltic Nest Institute.
    Österblom, Henrik
    Stockholm University, Stockholm Resilience Centre, Baltic Nest Institute.
    Modeller för Östersjöns hälsa2009In: Miljöforskning, no 3/4Article in journal (Other (popular science, discussion, etc.))
  • 25.
    Humborg, Cristoph
    et al.
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Mörth, Carl Magnus
    Stockholm University, Faculty of Science, Department of Geology and Geochemistry.
    Sundbom, Marcus
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Borg, Hans
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Blenckner, Thorsten
    Stockholm University, Stockholm Resilience Centre, Baltic Nest Institute.
    Giesler, R.
    Ittekkot, V.
    CO2 supersaturation along the aquatic conduit in Swedish watersheds as constrained by terrestrial respiration, aquatic respiration and weathering2010In: Global Change Biology, ISSN 1354-1013, E-ISSN 1365-2486, Vol. 6, no 7, p. 1966-1978Article in journal (Refereed)
    Abstract [en]

    We tested the hypothesis that CO2 supersaturation along the aquatic conduit over Sweden can be explained by processes other than aquatic respiration. A first generalized-additive model (GAM) analysis evaluating the relationships between single water chemistry variables and pCO(2) in lakes and streams revealed that water chemistry variables typical for groundwater input, e.g., dissolved silicate (DSi) and Mg2+ had explanatory power similar to total organic carbon (TOC). Further GAM analyses on various lake size classes and stream orders corroborated the slightly higher explanatory power for DSi in lakes and Mg2+ for streams compared with TOC. Both DSi and TOC explained 22-46% of the pCO(2) variability in various lake classes (0.01-> 100 km2) and Mg2+ and TOC explained 11-41% of the pCO(2) variability in the various stream orders. This suggests that aquatic pCO(2) has a strong groundwater signature. Terrestrial respiration is a significant source of the observed supersaturation and we may assume that both terrestrial respiration and aquatic respiration contributed equally to pCO(2) efflux. pCO(2) and TOC concentrations decreased with lake size suggesting that the longer water residence time allow greater equilibration of CO2 with the atmosphere and in-lake mineralization of TOC. For streams, we observed a decreasing trend in pCO(2) with stream orders between 3 and 6. We calculated the total CO2 efflux from all Swedish lakes and streams to be 2.58 Tg C yr-1. Our analyses also demonstrated that 0.70 Tg C yr-1 are exported to the ocean by Swedish watersheds as HCO3- and CO(3)2- of which about 0.56 Tg C yr-1 is also a residual from terrestrial respiration and constitute a long-term sink for atmospheric CO2. Taking all dissolved inorganic carbon (DIC) fluxes along the aquatic conduit into account will lower the estimated net ecosystem C exchange (NEE) by 2.02 Tg C yr-1, which corresponds to 10% of the NEE in Sweden.

  • 26.
    Jilbert, T.
    et al.
    Department of Earth Sciences (Geochemistry), Faculty of Geosciences, Utrecht University.
    Slomp, C. P.
    Department of Earth Sciences (Geochemistry), Faculty of Geosciences, Utrecht University.
    Gustafsson, Bo G.
    Stockholm University, Stockholm Resilience Centre, Baltic Nest Institute.
    Boer, W.
    Royal Netherlands Institute for Sea Research.
    Beyond the Fe-P-redox connection: preferential regeneration of phosphorus from organic matter as a key control on Baltic Sea nutrient cycles2011In: Biogeosciences, ISSN 1726-4170, E-ISSN 1726-4189, Vol. 8, p. 1699-1720Article in journal (Refereed)
    Abstract [en]

    Patterns of regeneration and burial of phosphorus (P) in the Baltic Sea are strongly dependent on redox conditions. Redox varies spatially along water depth gradients and temporally in response to the seasonal cycle and multidecadal hydrographic variability. Alongside the well-documented link between iron oxyhydroxide dissolution and release of P from Baltic Sea sediments, we show that preferential remineralization of P with respect to carbon (C) and nitrogen (N) during degradation of organic matter plays a key role in determining the surplus of bioavailable P in the water column. Preferential remineralization of P takes place both in the water column and upper sediments and its rate is shown to be redox-dependent, increasing as reducing conditions become more severe at greater water-depth in the deep basins. Existing Redfield-based biogeochemical models of the Baltic may therefore underestimate the imbalance between N and P availability for primary production, and hence the vulnerability of the Baltic to sustained eutrophication via the fixation of atmospheric N. However, burial of organic P is also shown to increase during multidecadal intervals of expanded hypoxia, due to higher net burial rates of organic matter around the margins of the deep basins. Such intervals may be characterized by basin-scale acceleration of all fluxes within the P cycle, including productivity, regeneration and burial, sustained by the relative accessibility of the water column P pool beneath a shallow halocline.

  • 27.
    Kadin, Martina
    et al.
    Stockholm University, Stockholm Resilience Centre.
    Österblom, Henrik
    Stockholm University, Stockholm Resilience Centre, Baltic Nest Institute.
    Bignert, Anders
    Swedish Museum of Natural History.
    Hentati-Sundberg, Jonas
    Stockholm University, Stockholm Resilience Centre.
    Olsson, Olof
    Stockholm University, Stockholm Resilience Centre.
    Trends, changes and uncertainties in bycatch of common murres in the Baltic SeaManuscript (preprint) (Other academic)
  • 28.
    Kadin, Martina
    et al.
    Stockholm University, Stockholm Resilience Centre.
    Österblom, Henrik
    Stockholm University, Stockholm Resilience Centre, Baltic Nest Institute.
    Hentati-Sundberg, Jonas
    Stockholm University, Stockholm Resilience Centre.
    Olsson, Olof
    Stockholm University, Stockholm Resilience Centre.
    Contrasting effects of food quality and quantity on a marine top predator2012In: Marine Ecology Progress Series, ISSN 0171-8630, E-ISSN 1616-1599, Vol. 444, p. 239-249Article in journal (Refereed)
    Abstract [en]

    Overfishing of predatory fish has contributed to an increase in forage-fish stocks. At the same time, a rising demand for forage fish to supply fishmeal markets, in combination with ­climate change, has put strong pressure on these stocks, and this, in turn, has had an impact on marine top predators. We examined how inter-annual variation in food quality (sprat Sprattus sprattus weight-at-age) and quantity (sprat abundance) influenced Baltic Sea common murres Uria aalge during chick-rearing. Fledging success, i.e. survival from hatching to fledging, showed a positive relationship with food quality, but we found no effect of food quantity. We found no relationship between food quality and parental behaviour or chick feeding parameters, but a negative relationship between food quantity and trip duration. Our data indicate that there was room for parental birds to increase their effort to compensate for reduced food quality, but we found no signs of such compensation. We analysed different types of fish and seabird life-history data to separate effects of food quantity and quality on a top predator. Understanding such effects can contribute to clarifying causes and consequences for observed changes in life-history parameters and population dynamics of top predators.

  • 29. Leavitt, Peter R.
    et al.
    Fritz, S.C.
    Anderson, N.J.
    Baker, P.A.
    Blenckner, T.
    Stockholm University, Stockholm Resilience Centre, Baltic Nest Institute.
    Bunting, L.
    Catalan, J
    Conley, D.J.
    Hobbs, W.
    Jeppesen, E.
    Korhola, A.
    McGowan, S.
    Rühland, K
    Rusak, J.A.
    Simpson, G.L.
    Solovieva, N.
    Werne, J.
    Paleolimnological evidence of the effects on lakes of energy and mass transfer from climate and humans.2009In: Limnology and Oceanography, ISSN 0024-3590, E-ISSN 1939-5590, Vol. 54, p. 2330-2348Article in journal (Refereed)
  • 30. Lindegren, Martin
    et al.
    Blenckner, Thorsten
    Stockholm University, Stockholm Resilience Centre, Baltic Nest Institute.
    Stenseth, Nils C.
    Nutrient reduction and climate change cause a potential shift from pelagic to benthic pathways in a eutrophic marine ecosystem2012In: Global Change Biology, ISSN 1354-1013, E-ISSN 1365-2486, Vol. 18, no 12, p. 3491-3503Article in journal (Refereed)
    Abstract [en]

    The degree to which marine ecosystems may support the pelagic or benthic food chain has been shown to vary across natural and anthropogenic gradients for e.g., in temperature and nutrient availability. Moreover, such external forcing may not only affect the flux of organic matter but could trigger large and abrupt changes, i.e., trophic cascades and ecological regime shifts, which once having occurred may prove potentially irreversible. In this study, we investigate the state and regulatory pathways of the Kattegat; a eutrophied and heavily exploited marine ecosystem, specifically testing for the occurrence of regime shifts and the relative importance of multiple drivers, e.g., climate change, eutrophication and commercial fishing on ecosystem dynamics and trophic pathways. Using multivariate statistics and nonlinear regression on a comprehensive data set, covering abiotic factors and biotic variables across all trophic levels, we here propose a potential regime shift from pelagic to benthic regulatory pathways; a possible first sign of recovery from eutrophication likely triggered by drastic nutrient reductions (involving both nitrogen and phosphorus), in combination with climate-driven changes in local environmental conditions (e.g., temperature and oxygen concentrations).

  • 31.
    Lyon, Steve W.
    et al.
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Destouni, Georgia
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Mörth, M.
    Stockholm University, Faculty of Science, Department of Geology and Geochemistry.
    Humborg, C.
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM). Stockholm University, Stockholm Resilience Centre, Baltic Nest Institute.
    Giesler, R.
    Evaluating the influence of changes to hydrologic flow pathways on carbon cycling in a sub-arctic catchment2009In: Eos Trans. AGU, 90(52), Fall Meet. Suppl., Abstract H34E-06, San Francisco, USA, 14-18 December, 2009, 2009Conference paper (Refereed)
  • 32. MacKenzie, Brian R.
    et al.
    Meier, H. E. Markus
    Lindegren, Martin
    Neuenfeldt, Stefan
    Eero, Margit
    Blenckner, Thorsten
    Stockholm University, Stockholm Resilience Centre, Baltic Nest Institute.
    Tomczak, Maciej T.
    Stockholm University, Stockholm Resilience Centre, Baltic Nest Institute.
    Niiranen, Susa
    Stockholm University, Stockholm Resilience Centre, Baltic Nest Institute.
    Impact of Climate Change on Fish Population Dynamics in the Baltic Sea: A Dynamical Downscaling Investigation2012In: Ambio, ISSN 0044-7447, E-ISSN 1654-7209, Vol. 41, no 6, p. 626-636Article in journal (Refereed)
    Abstract [en]

    Understanding how climate change, exploitation and eutrophication will affect populations and ecosystems of the Baltic Sea can be facilitated with models which realistically combine these forcings into common frameworks. Here, we evaluate sensitivity of fish recruitment and population dynamics to past and future environmental forcings provided by three ocean-biogeochemical models of the Baltic Sea. Modeled temperature explained nearly as much variability in reproductive success of sprat (Sprattus sprattus; Clupeidae) as measured temperatures during 1973-2005, and both the spawner biomass and the temperature have influenced recruitment for at least 50 years. The three Baltic Sea models estimate relatively similar developments (increases) in biomass and fishery yield during twenty-first century climate change (ca. 28 % range among models). However, this uncertainty is exceeded by the one associated with the fish population model, and by the source of global climate data used by regional models. Knowledge of processes and biases could reduce these uncertainties.

  • 33. Meier, H. E. M.
    et al.
    Gustafsson, B. G.
    Stockholm University, Stockholm Resilience Centre. Stockholm University, Stockholm Resilience Centre, Baltic Nest Institute.
    Vad styr saltvattensinbrotten till Östersjön?2009Report (Other academic)
  • 34. Meier, H. E. M.
    et al.
    Hordoir, R.
    Andersson, H. C.
    Dieterich, C.
    Eilola, K.
    Gustafsson, Bo G.
    Stockholm University, Stockholm Resilience Centre, Baltic Nest Institute.
    Hoglund, A.
    Schimanke, S.
    modeling the combined impact of changing climate and changing nutrient loads on the baltic sea environment in an ensemble of transient simulations for 1961 20992012In: Climate Dynamics, ISSN 0930-7575, E-ISSN 1432-0894, Vol. 39, no 9-10, p. 2421-2441Article in journal (Refereed)
    Abstract [en]

    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.

  • 35. Meier, H. E. Markus
    et al.
    Muller-Karulis, Barbel
    Stockholm University, Stockholm Resilience Centre, Baltic Nest Institute.
    Andersson, Helen C.
    Dieterich, Christian
    Eilola, Kari
    Gustafsson, Bo G.
    Stockholm University, Stockholm Resilience Centre, Baltic Nest Institute.
    Hoglund, Anders
    Hordoir, Robinson
    Kuznetsov, Ivan
    Neumann, Thomas
    Ranjbar, Zohreh
    Savchuk, Oleg P.
    Stockholm University, Stockholm Resilience Centre, Baltic Nest Institute.
    Schimanke, Semjon
    Impact of Climate Change on Ecological Quality Indicators and Biogeochemical Fluxes in the Baltic Sea: A Multi-Model Ensemble Study2012In: Ambio, ISSN 0044-7447, E-ISSN 1654-7209, Vol. 41, no 6, p. 558-573Article in journal (Refereed)
    Abstract [en]

    Multi-model ensemble simulations using three coupled physical-biogeochemical models were performed to calculate the combined impact of projected future climate change and plausible nutrient load changes on biogeochemical cycles in the Baltic Sea. Climate projections for 1961-2099 were combined with four nutrient load scenarios ranging from a pessimistic business-as-usual to a more optimistic case following the Helsinki Commission's (HELCOM) Baltic Sea Action Plan (BSAP). The model results suggest that in a future climate, water quality, characterized by ecological quality indicators like winter nutrient, summer bottom oxygen, and annual mean phytoplankton concentrations as well as annual mean Secchi depth (water transparency), will be deteriorated compared to present conditions. In case of nutrient load reductions required by the BSAP, water quality is only slightly improved. Based on the analysis of biogeochemical fluxes, we find that in warmer and more anoxic waters, internal feedbacks could be reinforced. Increased phosphorus fluxes out of the sediments, reduced denitrification efficiency and increased nitrogen fixation may partly counteract nutrient load abatement strategies.

  • 36.
    Meier, H.E.M.
    et al.
    Stockholm University, Faculty of Science, Department of Meteorology . Swedish Meteorological and Hydrological Institute, Department of Research and Development, Norrköping.
    Andersson, H.
    Swedish Meteorological and Hydrological Institute, Department of Research and Development, Norrköping.
    Dieterich, H.
    Swedish Meteorological and Hydrological Institute, Department of Research and Development, Norrköping.
    Eilola, K.
    Gustavsson, Bo
    Stockholm University, Stockholm Resilience Centre, Baltic Nest Institute.
    Höglund, A.
    Hordoir, R.
    Schimanke, S.
    Transient scenario simulations for the Baltic Sea Region during the 21st century2011Report (Refereed)
    Abstract [en]

    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 have been 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). In this study we focussed on annual and seasonal mean changes of ecological quality indicators describing the environmental status of the Baltic Sea. In correspondence with earlier studies we found that the impact of changing climate on the Baltic biogeo-chemistry might be signi cant. Assuming reference loadings the water quality in all climate scenarios is reduced at the end of the century. The impact of nutrient load reductions according to the BSAP will be less e ective in future climate compared to present climate.However, the results of the pessimistic business-as-usual scenario suggest that policy makers should act to avoid much worse environ-mental conditions than today.

  • 37.
    Meier, Markus
    et al.
    Stockholm University, Faculty of Science, Department of Meteorology .
    Andersson, Helen C.
    Arheimer, Berit
    Blenckner, Thorsten
    Stockholm University, Stockholm Resilience Centre, Baltic Nest Institute.
    Chubarenko, Boris
    Donnelly, Chantal
    Eilola, Kari
    Gustafsson, Bo G.
    Stockholm University, Stockholm Resilience Centre, Baltic Nest Institute.
    Hansson, Anders
    Havenhand, Jonathan
    Hoglund, Anders
    Kuznetsov, Ivan
    MacKenzie, Brian R.
    Müller-Karulis, Barbel
    Stockholm University, Stockholm Resilience Centre, Baltic Nest Institute.
    Neumann, Thomas
    Niiranen, Susa
    Stockholm University, Stockholm Resilience Centre, Baltic Nest Institute.
    Piwowarczyk, Joanna
    Raudsepp, Urmas
    Reckermann, Marcus
    Ruoho-Airola, Tuija
    Savchuk, Oleg P.
    Stockholm University, Stockholm Resilience Centre, Baltic Nest Institute.
    Schenk, Frederik
    Schimanke, Semjon
    Vali, Germo
    Weslawski, Jan-Marcin
    Zorita, Eduardo
    Comparing reconstructed past variations and future projections of the Baltic sea ecosystem first results from multi model ensemble simulations2012In: Environmental Research Letters, ISSN 1748-9326, E-ISSN 1748-9326, Vol. 7, no 3, p. 034005-Article in journal (Refereed)
    Abstract [en]

    Multi-model ensemble simulations for the marine biogeochemistry and food web of the Baltic Sea were performed for the period 1850-2098, and projected changes in the future climate were compared with the past climate environment. For the past period 1850-2006, atmospheric, hydrological and nutrient forcings were reconstructed, based on historical measurements. For the future period 1961-2098, scenario simulations were driven by regionalized global general circulation model (GCM) data and forced by various future greenhouse gas emission and air-and riverborne nutrient load scenarios (ranging from a pessimistic 'business-as-usual' to the most optimistic case). To estimate uncertainties, different models for the various parts of the Earth system were applied. Assuming the IPCC greenhouse gas emission scenarios A1B or A2, we found that water temperatures at the end of this century may be higher and salinities and oxygen concentrations may be lower than ever measured since 1850. There is also a tendency of increased eutrophication in the future, depending on the nutrient load scenario. Although cod biomass is mainly controlled by fishing mortality, climate change together with eutrophication may result in a biomass decline during the latter part of this century, even when combined with lower fishing pressure. Despite considerable shortcomings of state-of-the-art models, this study suggests that the future Baltic Sea ecosystem may unprecedentedly change compared to the past 150 yr. As stakeholders today pay only little attention to adaptation and mitigation strategies, more information is needed to raise public awareness of the possible impacts of climate change on marine ecosystems.

  • 38. Meier, Markus
    et al.
    Andersson, Helen C.
    Eilola, Kari
    Gustafsson, Bo G.
    Stockholm University, Stockholm Resilience Centre, Baltic Nest Institute.
    Kuznetsov, I.
    Muller-Karulis, Bärbel
    Stockholm University, Stockholm Resilience Centre, Baltic Nest Institute.
    Neumann, T.
    Savchuk, Oleg P.
    Stockholm University, Stockholm Resilience Centre, Baltic Nest Institute.
    Hypoxia in future climates: a model ensemble study for the Baltic Sea2011In: Geophysical Research Letters, ISSN 0094-8276, E-ISSN 1944-8007, Vol. 38, p. L24608-Article in journal (Refereed)
    Abstract [en]

    Using an ensemble of coupled physical-biogeochemical models driven with regionalized data from global climate simulations we are able to quantify the influence of changing climate upon oxygen conditions in one of the numerous coastal seas (the Baltic Sea) that suffers worldwide from eutrophication and from expanding hypoxic zones. Applying various nutrient load scenarios we show that under the impact of warming climate hypoxic and anoxic areas will very likely increase or at best only slightly decrease (in case of optimistic nutrient load reductions) compared to present conditions, regardless of the used global model and climate scenario. The projected decreased oxygen concentrations are caused by (1) enlarged nutrient loads due to increased runoff, (2) reduced oxygen flux from the atmosphere to the ocean due to increased temperature, and (3) intensified internal nutrient cycling. In future climate a similar expansion of hypoxia as projected for the Baltic Sea can be expected also for other coastal oceans worldwide.

  • 39. Mort, Haydon P.
    et al.
    Slomp, Caroline P.
    Gustafsson, Bo G.
    Stockholm University, Stockholm Resilience Centre, Baltic Nest Institute.
    Andersen, Thorbjorn J.
    Phosphorus recycling and burial in Baltic Sea sediments with contrasting redox conditions2010In: Geochimica et Cosmochimica Acta, ISSN 0016-7037, E-ISSN 1872-9533, Vol. 74, no 4, p. 1350-1362Article in journal (Refereed)
    Abstract [en]

    In this study, redox-dependent phosphorus (P) recycling and burial at 6 sites in the Baltic Sea is investigated using a combination of porewater and sediment analyses and sediment age dating (Pb-210 and Cs-117). We focus on sites in the Kattegat, Danish Straits and Baltic Proper where present-day bottom water redox conditions range from fully oxygenated and seasonally hypoxic to almost permanently anoxic and sulfidic. Strong surface enrichments of Fe-oxide bound P are observed at oxic and seasonally hypoxic sites but not in the anoxic basins. Reductive dissolution of Fe-oxides and release of the associated P supports higher sediment-water exchange of PO4 at hypoxic sites (up to similar to 800 mu mol P m(-2) d(-1)) than in the anoxic basins. This confirms that Fe-bound P in surface sediments in the Baltic acts as a major internal source of P during seasonal hypoxia, as suggested previously from water column studies. Most burial of P takes place as organic P. We find no evidence for significant authigenic Ca-P formation or biogenic Ca-P burial. The lack of major inorganic P burial sinks makes the Baltic Sea very sensitive to the feedback loop between increased hypoxia, enhanced regeneration of P and increased primary productivity. Historical records of bottom water oxygen at two sites (Bornholm, Northern Gotland) show a decline over the past century and are accompanied by a rise in values for typical sediment proxies for anoxia (total sulfur, molybdenum and organic C/P ratios). While sediment reactive P concentrations in anoxic basins are equal to or higher than at oxic sites, burial rates of P at hypoxic and anoxic sites are up to 20 times lower because of lower sedimentation rates. Nevertheless, burial of reactive P in both hypoxic and anoxic areas is significant because of their large surface area and should be accounted for in budgets and models for the Baltic Sea.

  • 40. Myrberg, Kai
    et al.
    Ryabchenko, Vladimir
    Isaev, Alexei
    Vankevich, Roman
    Andrejev, Oleg
    Bendtsen, Jorgen
    Erichsen, Anders
    Funkquist, Lennart
    Inkala, Arto
    Neelov, Ivan
    Rasmus, Kai
    Medina, Miguel Rodriguez
    Stockholm University, Stockholm Resilience Centre, Baltic Nest Institute.
    Raudsepp, Urmas
    Passenko, Jelena
    Söderkvist, Johan
    Sokolov, Alexander
    Stockholm University, Stockholm Resilience Centre, Baltic Nest Institute.
    Kuosa, Harri
    Anderson, Thomas R.
    Lehmann, Andreas
    Skogen, Morten D.
    Validation of three-dimensional hydrodynamic models of the Gulf of Finland2010In: Boreal environment research, ISSN 1239-6095, E-ISSN 1797-2469, Vol. 15, no 5, p. 453-479Article in journal (Refereed)
    Abstract [en]

    A model-intercomparison study was conducted, the first of its kind for the Baltic Sea, whose aim was to systematically simulate the basic three-dimensional hydrographic properties of a realistic, complex basin. Simulations of the hydrographic features of the Gulf of Finland for the summer autumn of 1996 by six three-dimensional hydrodynamic models were compared. Validation was undertaken using more than 300 vertical hydrographic profiles of salinity and temperature. The analysis of model performance, including averaging of the ensemble results, was undertaken with a view to assessing the potential suitability of the models in reproducing the physics of the Baltic Sea accurately enough to serve as a basis for accurate simulations of biogeochemistry once ecosystem models are incorporated. The performance of the models was generally satisfactory. Nevertheless, all the models had some difficulties in correctly simulating vertical profiles of temperature and salinity, and hence mixed layer dynamics, particularly in the eastern Gulf of Finland. Results emphasized the need for high resolution in both vertical and horizontal directions in order to resolve the complex dynamics and bathymetry of the Baltic Sea. Future work needs to consider the choice of mixing and advection schemes, moving to higher resolution, high-frequency forcing, and the accurate representation of river discharges and boundary conditions.

  • 41. Möllmann, Christian
    et al.
    Blenckner, Thorsten
    Stockholm University, Stockholm Resilience Centre, Baltic Nest Institute.
    Casini, Michele
    Gårdmark, Anna
    Lindegren, Martin
    Beauty is in the eye of the beholder: management of Baltic cod stock requires an ecosystem approach2011In: Marine Ecology Progress Series, ISSN 0171-8630, E-ISSN 1616-1599, Vol. 431, p. 293-297Article in journal (Refereed)
    Abstract [en]

    In a recent ‘As We See It’ article, Cardinale & Svedäng (2011; Mar Ecol Prog Ser 425:297–301) used the example of the Eastern Baltic (EB) cod stock to argue that the concept of ecosystem regime shifts, especially the potential existence of alternative stable states (or dynamic regimes), blurs the fact that human exploitation (i.e. fishing) is the strongest impact on marine ecosystems. They further concluded that single-species approaches to resource management are functioning and that ecosystem-based approaches are not necessary. We (1) argue that the recent increase in the EB cod stock is inherently uncertain, (2) discuss the critique of the regime shift concept, and (3)  describe why the EB cod stock dynamics demonstrates the need for an ecosystem approach to fisheries management.

  • 42.
    Müller-Karulis, Bärbel
    et al.
    Stockholm University, Stockholm Resilience Centre, Baltic Nest Institute.
    Aigars, Juris
    Latvian Institute of Aquatic Ecology, 8 Daugavgrivas, LV-1048 Riga, Latvia.
    Modeling the long-term dynamics of nutrients and phytoplankton in the Gulf of Riga2011In: Journal of Marine Systems, ISSN 0924-7963, E-ISSN 1879-1573, Vol. 87, no 3-4, p. 161-176Article in journal (Refereed)
    Abstract [en]

    The long term dynamics of nitrogen, phosphorus, and phytoplankton in the Gulf of Riga were simulated with a biogeochemical box model that resolved seasonal cycles. The model was calibrated using a numerical optimization procedure that adjusted 37 parameters to maximize the model data fit for field observations from 1973 to 2000 and validated with an independent dataset covering 2001-2007. Both the long-term increase and subsequent decline in winter nitrogen concentrations, as well as the continuous increase in winter phosphate levels were well reproduced by the model, which also gave reasonable representations of the seasonal dynamics of nutrients and phytoplankton. Starting from the mid-1990s, the model simulated an increase in cyanobacteria growth sustained by internal phosphorus loading. While nitrogen was efficiently removed by denitrification from the Gulf of Riga, comparatively slow export to the Baltic Proper was the main removal pathway of phosphorus. Modeled residence times were 5.4 years for nitrogen and 38 years for phosphorus. Scenario simulations indicated that the Gulf of Riga responds to phosphorus load reductions with a gradual decrease in primary production and cyanobacteria growth, while the effect of nitrogen load reductions is largely offset by nitrogen fixation.

  • 43. Naddafi, Rahmat
    et al.
    Blenckner, Thorsten
    Stockholm University, Stockholm Resilience Centre, Baltic Nest Institute.
    Eklöv, Peter
    Pettersson, Kurt
    Physical and chemical properties determine zebra mussel invasion success in lakes2011In: Hydrobiologia, ISSN 0018-8158, E-ISSN 1573-5117, Vol. 669, no 1, p. 227-236Article in journal (Refereed)
    Abstract [en]

    To address the question whether the abundance of an invasive species can be explained by physical and chemical properties of the invaded ecosystems, we gathered density data of invasive zebra mussels and the physical and chemical data of ecosystems they invaded. We assembled published data from 55 European and 13 North American lakes and developed a model for zebra mussel density using a generalized additive model (GAM) approach. Our model revealed that the joint effect of surface area, total phosphorus and calcium concentrations explained 62% of the variation in Dreissena density. Our study indicates that large and less productive North American lakes can support larger local populations of zebra mussels. Our results suggest that the proliferation of an exotic species in an area can partially be explained by physical and chemical properties of the recipient environment.

  • 44. Neumann, Thomas
    et al.
    Eilola, Kari
    Gustafsson, Bo
    Stockholm University, Stockholm Resilience Centre, Baltic Nest Institute.
    Muller-Karulis, Bärbel
    Stockholm University, Stockholm Resilience Centre, Baltic Nest Institute.
    Kuznetsov, Ivan
    Meier, H. E. Markus
    Savchuk, Oleg P.
    Stockholm University, Stockholm Resilience Centre, Baltic Nest Institute.
    Extremes of Temperature, Oxygen and Blooms in the Baltic Sea in a Changing Climate2012In: Ambio, ISSN 0044-7447, E-ISSN 1654-7209, Vol. 41, no 6, p. 574-585Article in journal (Refereed)
    Abstract [en]

    In the future, the Baltic Sea ecosystem will be impacted both by climate change and by riverine and atmospheric nutrient inputs. Multi-model ensemble simulations comprising one IPCC scenario (A1B), two global climate models, two regional climate models, and three Baltic Sea ecosystem models were performed to elucidate the combined effect of climate change and changes in nutrient inputs. This study focuses on the occurrence of extreme events in the projected future climate. Results suggest that the number of days favoring cyanobacteria blooms could increase, anoxic events may become more frequent and last longer, and salinity may tend to decrease. Nutrient load reductions following the Baltic Sea Action Plan can reduce the deterioration of oxygen conditions.

  • 45.
    Niiranen, Susa
    et al.
    Stockholm University, Stockholm Resilience Centre, Baltic Nest Institute.
    Blenckner, Thorsten
    Stockholm University, Stockholm Resilience Centre, Baltic Nest Institute.
    Hjerne, Olle
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Tomczak, Maciej T.
    Stockholm University, Stockholm Resilience Centre, Baltic Nest Institute.
    Uncertainties in a Baltic Sea Food-Web Model Reveal Challenges for Future Projections2012In: Ambio, ISSN 0044-7447, E-ISSN 1654-7209, Vol. 41, no 6, p. 613-625Article in journal (Refereed)
    Abstract [en]

    Models that can project ecosystem dynamics under changing environmental conditions are in high demand. The application of such models, however, requires model validation together with analyses of model uncertainties, which are both often overlooked. We carried out a simplified model uncertainty and sensitivity analysis on an Ecopath with Ecosim food-web model of the Baltic Proper (BaltProWeb) and found the model sensitive to both variations in the input data of pre-identified key groups and environmental forcing. Model uncertainties grew particularly high in future climate change scenarios. For example, cod fishery recommendations that resulted in viable stocks in the original model failed after data uncertainties were introduced. In addition, addressing the trophic control dynamics produced by the food-web model proved as a useful tool for both model validation, and for studying the food-web function. These results indicate that presenting model uncertainties is necessary to alleviate ecological surprises in marine ecosystem management.

  • 46.
    Niiranen, Susa
    et al.
    Stockholm University, Stockholm Resilience Centre.
    Blenckner, Thorsten
    Stockholm University, Stockholm Resilience Centre.
    Yletyinen, Johanna
    Stockholm University, Stockholm Resilience Centre.
    Otto, Saskia
    Stockholm University, Stockholm Resilience Centre.
    Meier, H. E. Markus
    Stockholm University, Faculty of Science, Department of Meteorology .
    Hjerne, Olle
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Tomczak, Maciej T
    Stockholm University, Stockholm Resilience Centre, Baltic Nest Institute.
    The potential risk of regime shifts and changes in ecosystem dynamics in the future Baltic SeaArticle in journal (Refereed)
  • 47.
    Norkko, Joanna
    et al.
    Environmental and Marine Biology, Department of Biosciences, Åbo Akademi University.
    Reed, Daniel
    Stockholm University, Stockholm Resilience Centre, Baltic Nest Institute.
    Timmermann, Karen
    Institute of Bioscience, Aarhus University, 4000 Roskilde, Denmark.
    Gustafsson, Bo
    Stockholm University, Stockholm Resilience Centre, Baltic Nest Institute.
    Bonsdorff, Erik
    Abo Akad Univ, Dept Biosci,Turku, Finland .
    Slomp, Caroline
    Univ Utrecht, Dept Earth Sci Geochem, Fac Geosci, Utrecht, Netherlands .
    Carstensen, Jacob
    Aarhus Univ, Inst Biosci, DK-4000 Roskilde, Denmark .
    Conley, Daniel
    Lund Univ, GeoBiosphere Sci Ctr, Dept Earth & Environm Sci, Lund, Sweden .
    Norkko, Alf
    Univ Gothenburg, Dept Marine Ecol Kristineberg, Sweden .
    A welcome can of worms?: hypoxia mitigation by an invasive species2011In: Global Change Biology, ISSN 1354-1013, E-ISSN 1365-2486Article in journal (Refereed)
    Abstract [en]

    Invasive species and bottom-water hypoxia both constitute major global threats to the diversity and integrity of marine ecosystems. These stressors may interact with unexpected consequences, as invasive species that require an initial environmental disturbance to become established can subsequently become important drivers of ecological change. There is recent evidence that improved bottom-water oxygen conditions in coastal areas of the northern Baltic Sea coincide with increased abundances of the invasive polychaetes Marenzelleria spp. Using a reactive-transport model, we demonstrate that the long-term bioirrigation activities of dense Marenzelleria populations have a major impact on sedimentary phosphorus dynamics. This may facilitate the switch from a seasonally hypoxic system back to a normoxic system by reducing the potential for sediment-induced eutrophication in the upper water column. In contrast to short-term laboratory experiments, our simulations, which cover a 10-year period, show that Marenzelleria has the potential to enhance long-term phosphorus retention in muddy sediments. Over time bioirrigation leads to a substantial increase in the iron-bound phosphorus content of sediments while reducing the concentration of labile organic carbon. As surface sediments are maintained oxic, iron oxyhydroxides are able to persist and age into more refractory forms. The model illustrates mechanisms through which Marenzelleria can act as a driver of ecological change, although hypoxic disturbance or natural population declines in native species may be needed for them to initially become established. Invasive species are generally considered to have a negative impact; however, we show here that one of the main recent invaders in the Baltic Sea may provide important ecosystem services. This may be of particular importance in low-diversity systems, where disturbances may dramatically alter ecosystem services due to low functional redundancy. Thus, an environmental problem in one region may be either exacerbated or alleviated by a single species from another region, with potentially ecosystem-wide consequences.

  • 48.
    Nyström, Magnus
    et al.
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Norström, Albert
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Bleckner, Thorsten
    Stockholm University, Stockholm Resilience Centre, Baltic Nest Institute.
    de la Torre Castro, Maricela
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Eklöf, Johan
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Folke, Carl
    Stockholm University, Stockholm Resilience Centre.
    Österblom, Henrik
    Stockholm University, Stockholm Resilience Centre, Baltic Nest Institute.
    Steneck, Robert
    School of Marine Sciences, University of Maine.
    Thyresson, Matilda
    Troell, Max
    The Beijer Institute, the Royal Swedish Academy of Sciences.
    Steering feedbacks toward healthier marine ecosystemsManuscript (preprint) (Other academic)
    Abstract [en]

    Marine ecosystem decline is accelerating. At some point degradation may pass a tipping point beyond which ecosystems become trapped in alternative degraded states, as a result of changes in critical feedbacks. Self-reinforcing feedbacks pose a major challenge for managers and policy-makers seeking remedial actions to curb the marine crisis. Here we synthesize the dynamics of critical feedbacks of the degraded states in five socio-economically important marine ecosystems; coral reefs, kelp forests, seagrass beds, shallow unvegetated soft-bottom habitats, and coastal pelagic food webs. A better understanding of the way human actions influence the strength and direction of feedbacks, how different feedbacks interact and at what scales they operate, is crucial for successful implementation of marine ecosystem management. We advocate a critical-feedback management approach that ventures beyond traditionally discipline boundaries, as an essential element of marine ecosystem management.

  • 49.
    Nyström, Magnus
    et al.
    Stockholm University, Stockholm Resilience Centre, Baltic Nest Institute.
    Norström, Albert V.
    Blenckner, Thorsten
    Stockholm University, Stockholm Resilience Centre, Baltic Nest Institute.
    de la Torre-Castro, Maricela
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Eklöf, Johan S.
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Folke, Carl
    Österblom, Henrik
    Stockholm University, Stockholm Resilience Centre, Baltic Nest Institute.
    Steneck, Robert S.
    Thyresson, Matilda
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Troell, Max
    Confronting Feedbacks of Degraded Marine Ecosystems2012In: Ecosystems (New York. Print), ISSN 1432-9840, E-ISSN 1435-0629, Vol. 15, no 5, p. 695-710Article in journal (Refereed)
    Abstract [en]

    In many coastal areas, marine ecosystems have shifted into contrasting states having reduced ecosystem services (hereafter called degraded). Such degraded ecosystems may be slow to revert to their original state due to new ecological feedbacks that reinforce the degraded state. A better understanding of the way human actions influence the strength and direction of feedbacks, how different feedbacks could interact, and at what scales they operate, may be necessary in some cases for successful management of marine ecosystems. Here we synthesize interactions of critical feedbacks of the degraded states from six globally distinct biomes: coral reefs, kelp forests, seagrass beds, shallow soft sediments, oyster reefs, and coastal pelagic food webs. We explore to what extent current management captures these feedbacks and propose strategies for how and when (that is, windows of opportunity) to influence feedbacks in ways to break the resilience of the degraded ecosystem states. We conclude by proposing some challenges for future research that could improve our understanding of these issues and emphasize that management of degraded marine states will require a broad social-ecological approach to succeed.

  • 50. Omstedt, Anders
    et al.
    Edman, Moa
    Claremar, Bjorn
    Frodin, Peter
    Gustafsson, Erik
    Stockholm University, Stockholm Resilience Centre, Baltic Nest Institute.
    Humborg, Christoph
    Stockholm University, Stockholm Resilience Centre, Baltic Nest Institute.
    Hägg, Hanna
    Stockholm University, Stockholm Resilience Centre, Baltic Nest Institute.
    Mörth, Magnus
    Stockholm University, Stockholm Resilience Centre, Baltic Nest Institute.
    Rutgersson, Anna
    Schurgers, Guy
    Smith, Benjamin
    Wällstedt, Teresia
    Stockholm University, Stockholm Resilience Centre, Baltic Nest Institute.
    Yurova, Alla
    Future changes in the Baltic Sea acid-base (pH) and oxygen balances2012In: Tellus. Series B, Chemical and physical meteorology, ISSN 0280-6509, E-ISSN 1600-0889, Vol. 64, p. 19586-Article in journal (Refereed)
    Abstract [en]

    Possible future changes in Baltic Sea acid-base (pH) and oxygen balances were studied using a catchment-sea coupled model system and numerical experiments based on meteorological and hydrological forcing datasets and scenarios. By using objective statistical methods, climate runs for present climate conditions were examined and evaluated using Baltic Sea modelling. The results indicate that increased nutrient loads will not inhibit future Baltic Sea acidification; instead, the seasonal pH cycle will be amplified by increased biological production and mineralization. All examined scenarios indicate future acidification of the whole Baltic Sea that is insensitive to the chosen global climate model. The main factor controlling the direction and magnitude of future pH changes is atmospheric CO2 concentration (i.e. emissions). Climate change and land-derived changes (e. g. nutrient loads) affect acidification mainly by altering the seasonal cycle and deep-water conditions. Apart from decreasing pH, we also project a decreased saturation state of calcium carbonate, decreased respiration index and increasing hypoxic area - all factors that will threaten the marine ecosystem. We demonstrate that substantial reductions in fossil-fuel burning are needed to minimise the coming pH decrease and that substantial reductions in nutrient loads are needed to reduce the coming increase in hypoxic and anoxic waters.

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