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  • 1.
    Svanbäck, Annika
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Stockholms universitets Östersjöcentrum.
    McCrackin, Michelle L.
    Stockholms universitet, Naturvetenskapliga fakulteten, Stockholms universitets Östersjöcentrum.
    Swaney, Dennis P.
    Linefur, Helena
    Gustafsson, Bo G.
    Stockholms universitet, Naturvetenskapliga fakulteten, Stockholms universitets Östersjöcentrum. University of Helsinki, Finland.
    Howarth, Robert W.
    Humborg, Christoph
    Stockholms universitet, Naturvetenskapliga fakulteten, Stockholms universitets Östersjöcentrum. University of Helsinki, Finland.
    Reducing agricultural nutrient surpluses in a large catchment - Links to livestock density2019Ingår i: Science of the Total Environment, ISSN 0048-9697, E-ISSN 1879-1026, Vol. 648, s. 1549-1559Artikel i tidskrift (Refereegranskat)
    Abstract [en]

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

  • 2.
    McCrackin, Michelle L.
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Stockholms universitets Östersjöcentrum.
    Muller-Karulis, Bärbel
    Stockholms universitet, Naturvetenskapliga fakulteten, Stockholms universitets Östersjöcentrum.
    Gustafsson, Bo G.
    Stockholms universitet, Naturvetenskapliga fakulteten, Stockholms universitets Östersjöcentrum. University of Helsinki, Finland.
    Howarth, Robert W.
    Humborg, Christoph
    Stockholms universitet, Naturvetenskapliga fakulteten, Stockholms universitets Östersjöcentrum. University of Helsinki, Finland.
    Svanbäck, Annika
    Stockholms universitet, Naturvetenskapliga fakulteten, Stockholms universitets Östersjöcentrum.
    Swaney, Dennis P.
    A Century of Legacy Phosphorus Dynamics in a Large Drainage Basin2018Ingår i: Global Biogeochemical Cycles, ISSN 0886-6236, E-ISSN 1944-9224, Vol. 32, nr 7, s. 1107-1122Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    There is growing evidence that the release of phosphorus (P) from legacy stores can frustrate efforts to reduce P loading to surface water from sources such as agriculture and human sewage. Less is known, however, about the magnitude and residence times of these legacy pools. Here we constructed a budget of net anthropogenic P inputs to the Baltic Sea drainage basin and developed a three-parameter, two-box model to describe the movement of anthropogenic P though temporary (mobile) and long-term (stable) storage pools. Phosphorus entered the sea as direct coastal effluent discharge and via rapid transport and slow, legacy pathways. The model reproduced past waterborne P loads and suggested an similar to 30-year residence time in the mobile pool. Between 1900 and 2013, 17 and 27 Mt P has accumulated in the mobile and stable pools, respectively. Phosphorus inputs to the sea have halved since the 1980s due to improvements in coastal sewage treatment and reductions associated with the rapid transport pathway. After decades of accumulation, the system appears to have shifted to a depletion phase; absent further reductions in net anthropogenic P input, future waterborne loads could decrease. Presently, losses from the mobile pool contribute nearly half of P loads, suggesting that it will be difficult to achieve substantial near-term reductions. However, there is still potential to make progress toward eutrophication management goals by addressing rapid transport pathways, such as overland flow, as well as mobile stores, such as cropland with large soil-P reserves.

  • 3.
    Hedberg, Nils
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Stockholms universitets Östersjöcentrum. Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och botanik.
    Stenson, Isabell
    Stockholms universitet, Naturvetenskapliga fakulteten, Stockholms universitets Östersjöcentrum.
    Nitz Pettersson, Mika
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och botanik.
    Warshan, Denis
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och botanik.
    Nguyen-Kim, H.
    Tedengren, Michael
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och botanik.
    Kautsky, Nils
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och botanik.
    Antibiotic use in Vietnamese fish and lobster sea cage farms; implications for coral reefs and human health2018Ingår i: Aquaculture, ISSN 0044-8486, E-ISSN 1873-5622, Vol. 495, s. 366-375Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Several papers have reported on the development of antibiotic resistance and implications for human medicine but fewer deal with environmental impacts of antibiotic use. Marine sea cage aquaculture in SE Asia is often established close to coral reef ecosystems. Large amounts of antibiotics are used in the cultivation of fish and lobster and hence released directly into the environment. This study investigates the antibiotic practices in sea cage farms producing fish and spiny lobster in Vietnam, mainly for the domestic market. There are approximately 3500 sea cage farms in Vietnam and we performed semi-structured interviews with 109 sea cage farmers asking them if they use antibiotics and if so; what sort/when/how often/how much. We found that the Vietnamese cage farmers are using antibiotics in an unstructured way, which seems to have little or no effect on the survival of the stock, or profit of the farm. The fact that the farmers live at their farm and use the sea next to the cages both for fishing and collecting filter-feeding bivalves for direct consumption, as well as a toilet, poses an additional risk for the spreading of human antibiotic resistant pathogens. Thirteen different antibiotics were found in the study. Eighty-two percentage of the lobster farmers and 28% of the fishfarmers used antibiotics. The average amounts used were over 5 kg per produced ton of lobster and about 0.6 kg per ton of fish, which is much higher than in other studies. Several antibiotic substances listed as critical and highly important for human medicine by WHO were used prophylactically and routinely with little control and enforcement of regulations. We tested and detected antibiotic resistance to Tetracycline, Vancomycin and Rifampicin in the coral associated bacteria Bacillus niabensis as far as 660m from fish farms with resistance decreasing with distance from the cage farms. The antibiotics are likely to have negative effects on the coral-symbiont relationship adding further risks to an already stressed environment.

  • 4. Angove, Charlotte
    et al.
    Norkko, Alf
    Stockholms universitet, Naturvetenskapliga fakulteten, Stockholms universitets Östersjöcentrum. University of Helsinki, Finland.
    Gustafsson, Camilla
    Assessing the efficiencies and challenges for nutrient uptake by aquatic plants2018Ingår i: Journal of Experimental Marine Biology and Ecology, ISSN 0022-0981, E-ISSN 1879-1697, Vol. 507, s. 23-30Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Aquatic plant meadows are valuable components to the 'coastal filter' and it is important to understand the processes that drive their ability to cycle nutrients. However, at present, the field-based evidence for understanding the drivers of nutrient uptake by plants is lacking. This study aimed to investigate how well individual shoots of aquatic plants could meet their nitrogen demands using the sediment nutrient pool (porewater ammonium) and to explore which traits helped to facilitate such uptake. Several species were investigated in shallow, submerged (2-4 m) mixed-species communities in the northern Baltic Sea using incubation experiments with enriched ammonium. After a 3.5 h incubation time, individuals were collected and analysed for nitrogen (% DW) and N-15 (at-%) concentrations. Uptake by plants was calculated per unit nitrogen in response to the N-15 labelled source and to overall nitrogen availability. Background porewater ammonium availability was highly variable between individual plants. Species identity did not significantly affect uptake metrics and the effect of ambient porewater availability was weak. As biomass increased there were significant logarithmic declines in the 95th quantiles of nutrient uptake rates, ambient porewater nutrient availability and aboveground nitrogen tissue concentrations (% DW). Such findings suggested that uptake rates of plants were significantly demand driven and the nutrient conditions of the porewater were significantly driven by the demands of the plant. Findings parameterised the unfulfilled potential for some aquatic plants to cycle nutrients more efficiently and highlighted the potential importance of access to new nutrient sources as a way of enhancing nutrient cycling by aquatic plants. Plant traits and community properties such as the activity of infauna could facilitate such an access and are likely important for nutrient uptake.

  • 5. Cvitanovic, Chris
    et al.
    Löf, Marie F.
    Stockholms universitet, Naturvetenskapliga fakulteten, Stockholms universitets Östersjöcentrum.
    Norström, Albert V.
    Stockholms universitet, Naturvetenskapliga fakulteten, Stockholm Resilience Centre.
    Reed, Mark S.
    Building university-based boundary organisations that facilitate impacts on environmental policy and practice2018Ingår i: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 13, nr 9, artikel-id e0203752Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Responding to modern day environmental challenges for societal well-being and prosperity necessitates the integration of science into policy and practice. This has spurred the devel- opment of novel institutional structures among research organisations aimed at enhancing the impact of environmental science on policy and practice. However, such initiatives are seldom evaluated and even in cases where evaluations are undertaken, the results are rarely made publicly available. As such there is very little empirically grounded guidance available to inform other organisations in this regard. To help address this, the aim of this study is to evaluate the Baltic Eye Project at Stockholm University – a unique team consisting of researchers from different fields, science communicators, journalists and policy analysts – working collectively to support evidence-informed decision-making relating to the sustainable management of the Baltic Sea environment. Specifically, through qualitative interviews, we (1) identify the impacts achieved by the Baltic Eye Project; (2) understand the challenges and barriers experienced throughout the Baltic Eye Project; and (3) highlight the key features that are needed within research organisations to enhance the impact of science on policy and practice. Results show that despite only operating for three years, the Baltic Eye Project has achieved demonstrable impacts on a range of levels: impacts on policy and practice, impacts to individuals working within the organisation and impacts to the broader University. We also identify a range of barriers that have limited impacts to date, such as a lack of clear goals at the establishment of the Baltic Eye Project and existing metrics of aca- demic impact (e.g. number of publications). Finally, based on the experiences of employees at the Baltic Eye Project, we identify the key organisational, individual, financial, material, practical, political, and social features of university-based boundary organisations that have impact on policy and practice. In doing so this paper provides empirically-derived guidance to help other research organisations increase their capacity to achieve tangible impacts on environmental policy and practice.

  • 6.
    Brüchert, Volker
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för geologiska vetenskaper.
    Bröder, Lisa
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Sawicka, Joanna E.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för geologiska vetenskaper.
    Tesi, Tommaso
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi. nstitute of Marine Sciences, National Research Council, Italy.
    Joye, Samantha P.
    Sun, Xiaole
    Stockholms universitet, Naturvetenskapliga fakulteten, Stockholms universitets Östersjöcentrum.
    Semiletov, Igor P.
    Samarkin, Vladimir A.
    Carbon mineralization in Laptev and East Siberian sea shelf and slope sediment2018Ingår i: Biogeosciences, ISSN 1726-4170, E-ISSN 1726-4189, Vol. 15, nr 2, s. 471-490Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The Siberian Arctic Sea shelf and slope is a key region for the degradation of terrestrial organic material transported from the organic carbon-rich permafrost regions of Siberia. We report on sediment carbon mineralization rates based on O2 microelectrode profiling, intact sediment core incubations, 35 S-sulfate tracer experiments, porewater dissolved inorganic carbon (DIC), δ13 CDIC, and iron, manganese, and ammonium concentrations from 20 shelf and slope stations. This data set provides a spatial overview of sediment carbon mineralization rates and pathways over large parts of the outer Laptev and East Siberian Arctic shelf and slope, and allowed us to assess degradation rates and efficiency of carbon burial in these sediments. Rates of oxygen uptake and iron and manganese reduction were comparable to temperate shelf and slope environments, but bacterial sulfate reduction rates were comparatively low. In the topmost 20 to 50 cm of sediment, aerobic carbon mineralization dominated degradation and comprised on average 82% of the depthintegrated carbon mineralization. Oxygen uptake rates and 35 S-sulfate reduction rates were higher in the eastern East Siberian Sea shelf compared to the Laptev Sea shelf. DIC/NH4 + ratios in porewaters and the stable carbon isotope composition of remineralized DIC indicated that the degraded organic matter on the Siberian shelf and slope was a mixture of marine and terrestrial organic matter. Based on dual end member calculations, the terrestrial organic carbon contribution varied between 32% and 36%, with a higher contribution in the Laptev Sea than in the East Siberian Sea. Extrapolation of the measured degradation rates using  isotope end member apportionment over the outer shelf of the Laptev and East Siberian Sea suggests that about 16 Tg C per year are respired in the outer shelf sea floor sediment. Of the organic matter buried below the oxygen penetration depth, between 0.6 and 1.3 Tg C per year are degraded by anaerobic processes, with a terrestrial organic carbon contribution ranging between 0.3 and 0.5 Tg per year.

  • 7. Zhong, Jun
    et al.
    Li, Si-Liang
    Liu, Jing
    Ding, Hu
    Sun, Xiaole
    Stockholms universitet, Naturvetenskapliga fakulteten, Stockholms universitets Östersjöcentrum.
    Xu, Sheng
    Wang, Tiejun
    Ellam, Rob M.
    Liu, Cong-Qiang
    Climate Variability Controls on CO2 Consumption Fluxes and Carbon Dynamics for Monsoonal Rivers: Evidence From Xijiang River, Southwest China2018Ingår i: Journal of Geophysical Research - Biogeosciences, ISSN 2169-8953, E-ISSN 2169-8961, Vol. 123, nr 8, s. 2553-2567Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The feedbacks of climate variability on CO2 consumption fluxes and carbon dynamics are thought to play an important role in moderating the global carbon cycle. High-frequency sampling campaigns and analyses were conducted in this study to investigate temporal variations of river water chemistry and the impacts of climate variability on CO2 consumption fluxes and carbon dynamics for the Xijiang River, Southwest China. Physical processes modify biogeochemical processes, so major ions display different responses to changing discharge. The annual CO2 consumption rate is (6.8 +/- 0.2) x 10(6) ton/year by carbonate weathering and (2.4 +/- 0.3) x 10(6) ton/year by silicate weathering. The annual CO2 consumption flux is much higher than most world rivers, and strong CO2 consumption capacities are observed in catchments in Southwest China. Lower negative delta C-13(DIC) values are found in the high-flow season which corresponds with high temperatures compared to those in the low-flow season. High discharge will accelerate material transport, and high temperatures will increase primary production in the catchment, both of which can be responsible for the shift of delta C-13(DIC) values in the high-flow season. Increased mineral weathering and biological carbon influx in the catchment are the main factors controlling carbon dynamics. Overall, these findings highlight the sensitivity of CO2 consumption fluxes and carbon dynamics in response to climate variability in the riverine systems. Plain Language Summary There are feedbacks between climate variability and CO2 consumption fluxes by chemical weathering and carbon dynamics. Significant temporal variations of major ions and delta C-13(DIC) are observed in the Xijiang River. Multiple biogeochemical processes occur under various hydrological conditions, shifting major ions concentrations, and delta C-13(DIC). The annual CO2 consumption rate is (6.8 +/- 0.2) x 10(6) ton/year by carbonate weathering and (2.4 +/- 0.3) x 10(6) ton/year by silicate weathering. The annual CO2 consumption rates in the Xijiang River only account for a small fraction in the global CO2 consumption rates; the CO2 consumption capacity is much higher than the global average, while much lower than its source tributaries (Beipan and Nanpan Rivers). Slow subsurface flow paths with longer transit times switch to rapid near-surface flow paths with shorter transit times, as discharge increases. High temperatures increase reaction rates, and high discharge rates remove transport limitation, both of which would accelerate the chemical weathering rates. In the high-flow season, high discharge accompanying with high temperatures, large amounts of delta C-13-depleted biological carbon, flushes into the river, affecting the carbon dynamics.

  • 8.
    Donadi, Serena
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och botanik. Swedish University of Agricultural Sciences, Sweden; University of Groningen, The Netherlands.
    Nilsson Austin, Åsa
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och botanik.
    Svartgren, Evira
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och botanik.
    Eriksson, Britas Klemens
    Stockholms universitet, Naturvetenskapliga fakulteten, Stockholms universitets Östersjöcentrum.
    Hansen, J. P.
    Eklöf, Johan S.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och botanik.
    Density-dependent positive feedbacks buffer aquatic plants from interactive effects of eutrophication and predator loss2018Ingår i: Ecology, ISSN 0012-9658, E-ISSN 1939-9170, Vol. 99, nr 11, s. 2515-2524Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Self-facilitation allows populations to persist under disturbance by ameliorating experienced stress. In coastal ecosystems, eutrophication and declines of large predatory fish are two common disturbances that can synergistically impact habitat-forming plants by benefitting ephemeral algae. In theory, density-dependent intraspecific plant facilitation could weaken such effects by ameliorating the amount of experienced stress. Here, we tested whether and how shoot density of a common aquatic plant (Myriophyllum spicatum) alters the response of individual plants to eutrophication and exclusion of large predatory fish, using a 12-week cage experiment in the field. Results showed that high plant density benefitted individual plant performance, but only when the two stressors were combined. Epiphytic algal biomass per plant more than doubled in cages that excluded large predatory fish, indicative of a trophic cascade. Moreover, in this treatment, individual shoot biomass, as well as number of branches, increased with density when nutrients were added, but decreased with density at ambient nutrient levels. In contrast, in open cages that large predatory fish could access, epiphytic algal biomass was low and individual plant biomass and number of branches were unaffected by plant density and eutrophication. Plant performance generally decreased under fertilization, suggesting stressful conditions. Together, these results suggest that intraspecific plant facilitation occurred only when large fish exclusion (causing high epiphyte load) was accompanied by fertilization, and that intraspecific competition instead prevailed when no nutrients were added. As coastal ecosystems are increasingly exposed to multiple and often interacting stressors such as eutrophication and declines of large predatory fish, maintaining high plant density is important for ecosystem-based management.

  • 9.
    Bolinius, Dämien J.
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Stockholms universitets Östersjöcentrum.
    Sobek, Anna
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Löf, Marie F.
    Stockholms universitet, Naturvetenskapliga fakulteten, Stockholms universitets Östersjöcentrum.
    Undeman, Emma
    Stockholms universitet, Naturvetenskapliga fakulteten, Stockholms universitets Östersjöcentrum.
    Evaluating the consumption of chemical products and articles as proxies for diffuse emissions to the environment2018Ingår i: Environmental Science: Processes & Impacts, ISSN 2050-7887, E-ISSN 2050-7895, Vol. 20, nr 10, s. 1427-1440Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this study we have evaluated the use of consumption of manufactured products (chemical products and articles) in the EU as proxies for diffuse emissions of chemicals to the environment. The content of chemical products is relatively well known. However, the content of articles (products defined by their shape rather than their composition) is less known and currently has to be estimated from chemicals that are known to occur in a small set of materials, such as plastics, that are part of the articles. Using trade and production data from Eurostat in combination with product composition data from a database on chemical content in materials (the Commodity Guide), we were able to calculate trends in the apparent consumption and in-use stocks for 768 chemicals in the EU for the period 2003-2016. The results showed that changes in the apparent consumption of these chemicals over time are smaller than in the consumption of corresponding products in which the chemicals are present. In general, our results suggest that little change in chemical consumption has occurred over the timespan studied, partly due to the financial crisis in 2008 which led to a sudden drop in the consumption, and partly due to the fact that each of the chemicals studied is present in a wide variety of products. Estimated in-use stocks of chemicals show an increasing trend over time, indicating that the mass of chemicals in articles in the EU, that could potentially be released to the environment, is increasing. The quantitative results from this study are associated with large uncertainties due to limitations of the available data. These limitations are highlighted in this study and further underline the current lack of transparency on chemicals in articles. Recommendations on how to address these limitations are also discussed.

  • 10.
    Dahlgren Strååt, Kim
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Mörth, Carl-Magnus
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för geologiska vetenskaper. Stockholms universitet, Naturvetenskapliga fakulteten, Stockholms universitets Östersjöcentrum.
    Undeman, Emma
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi. Stockholms universitet, Naturvetenskapliga fakulteten, Stockholms universitets Östersjöcentrum.
    Future export of particulate and dissolved organic carbon from land to coastal zones of the Baltic Sea2018Ingår i: Journal of Marine Systems, ISSN 0924-7963, E-ISSN 1879-1573, Vol. 177, s. 8-20Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The Baltic Sea is a semi-enclosed brackish sea in Northern Europe with a drainage basin four times larger than the sea itself. Riverine organic carbon (Particulate Organic Carbon, POC and Dissolved Organic Carbon, DOC) dominates carbon input to the Baltic Sea and influences both land-to-sea transport of nutrients and contaminants, and hence the functioning of the coastal ecosystem. The potential impact of future climate change on loads of POC and DOC in the Baltic Sea drainage basin (BSDB) was assessed using a hydrological-biogeochemical model (CSIM). The changes in annual and seasonal concentrations and loads of both POC and DOC by the end of this century were predicted using three climate change scenarios and compared to the current state. In all scenarios, overall increasing DOC loads, but unchanged POC loads, were projected in the north. In the southern part of the BSDB, predicted DOC loads were not significantly changing over time, although POC loads decreased in all scenarios. The magnitude and significance of the trends varied with scenario but the sign (+ or -) of the projected trends for the entire simulation period never conflicted. Results were discussed in detail for the middle CO2 emission scenario (business as usual, a1b). On an annual and entire drainage basin scale, the total POC load was projected to decrease by ca 7% under this scenario, mainly due to reduced riverine primary production in the southern parts of the BSDB. The average total DOC load was not predicted to change significantly between years 2010 and 2100 due to counteracting decreasing and increasing trends of DOC loads to the six major sub-basins in the Baltic Sea. However, predicted seasonal total loads of POC and DOC increased significantly by ca 46% and 30% in winter and decreased by 8% and 21% in summer over time, respectively. For POC the change in winter loads was a consequence of increasing soil erosion and a shift in duration of snowfall and onset of the spring flood impacting the input of terrestrial litter, while reduced primary production mainly explained the differences predicted in summer. The simulations also showed that future changes in POC and DOC export can vary significantly across the different sub-basins of the Baltic Sea. These changes in organic carbon input may impact future coastal food web structures e.g. by influencing bacterial and phytoplankton production in coastal zones, which in turn may have consequences at higher trophic levels.

  • 11. Snelgrove, Paul V. R.
    et al.
    Soetaert, Karline
    Solan, Martin
    Thrush, Simon
    Wei, Chih-Lin
    Danovaro, Roberto
    Fulweiler, Robinson W.
    Kitazato, Hiroshi
    Ingole, Baban
    Norkko, Alf
    Stockholms universitet, Naturvetenskapliga fakulteten, Stockholms universitets Östersjöcentrum. University of Helsinki, Finland.
    Parkes, R. John
    Volkenborn, Nils
    Global Carbon Cycling on a Heterogeneous Seafloor2018Ingår i: Trends in Ecology & Evolution, ISSN 0169-5347, E-ISSN 1872-8383, Vol. 33, nr 2, s. 96-105Artikel, forskningsöversikt (Refereegranskat)
    Abstract [en]

    Diverse biological communities mediate the transformation, transport, and storage of elements fundamental to life on Earth, including carbon, nitrogen, and oxygen. However, global biogeochemical model outcomes can vary by orders of magnitude, compromising capacity to project realistic ecosystem responses to planetary changes, including ocean productivity and climate. Here, we compare global carbon turnover rates estimated using models grounded in biological versus geochemical theory and argue that the turnover estimates based on each perspective yield divergent outcomes. Importantly, empirical studies that include sedimentary biological activity vary less than those that ignore it. Improving the relevance of model projections and reducing uncertainty associated with the anticipated consequences of global change requires reconciliation of these perspectives, enabling better societal decisions on mitigation and adaptation.

  • 12. Uusitalo, Laura
    et al.
    Tomczak, Maciej T.
    Stockholms universitet, Naturvetenskapliga fakulteten, Stockholms universitets Östersjöcentrum.
    Muller-Karulis, Bärbel
    Stockholms universitet, Naturvetenskapliga fakulteten, Stockholms universitets Östersjöcentrum.
    Putnis, Ivars
    Trifonova, Neda
    Tucker, Allan
    Hidden variables in a Dynamic Bayesian Network identify ecosystem level change2018Ingår i: Ecological Informatics, ISSN 1574-9541, E-ISSN 1878-0512, Vol. 45, s. 9-15Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Ecosystems are known to change in terms of their structure and functioning over time. Modelling this change is a challenge, however, as data are scarce, and models often assume that the relationships between ecosystem components are invariable over time. Dynamic Bayesian Networks (DBN) with hidden variables have been proposed as a method to overcome this challenge, as the hidden variables can capture the unobserved processes. In this paper, we fit a series of DBNs with different hidden variable structures to a system known to have undergone a major structural change, i.e. the Baltic Sea food web. The exact setup of the hidden variables did not considerably affect the result, and the hidden variables picked up a pattern that agrees with previous research on the system dynamics.

  • 13.
    Li, Zhe
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Undeman, Emma
    Stockholms universitet, Naturvetenskapliga fakulteten, Stockholms universitets Östersjöcentrum.
    Papa, Ester
    McLachlan, Michael S.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    High-throughput evaluation of organic contaminant removal efficiency in a wastewater treatment plant using direct injection UHPLC-Orbitrap-MS/MS2018Ingår i: Environmental Science: Processes & Impacts, ISSN 2050-7887, E-ISSN 2050-7895, Vol. 20, nr 3, s. 561-571Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The removal efficiency (RE) of organic contaminants in wastewater treatment plants (WWTPs) is a major determinant of the environmental impact of these contaminants. However, RE data are available for only a few chemicals due to the time and cost required for conventional target analysis. In the present study, we applied non-target screening analysis to evaluate the RE of polar contaminants, by analyzing influent and effluent samples from a Swedish WWTP with direct injection UHPLC-Orbitrap-MS/MS. Matrix effects were evaluated by spiking the samples with isotope-labeled standards of 40 polar contaminants. For 85% of the compounds, the matrix effects in the influent and effluent were not significantly different. Approximately 10000 compounds were detected in the wastewater, of which 319 were identified by using the online database mzCloud. Level 1 identification confidence was achieved for 31 compounds for which we had reference standards, and level 2 was achieved for the remainder. RE was calculated from the ratio of the peak areas in the influent and the effluent from the non-target analysis. Good agreement was found with RE determined from the target analysis of the target compounds. The method generated reliable estimates of RE for large numbers of contaminants with comparatively low effort and is foreseen to be particularly useful in applications where information on a large number of chemicals is needed.

  • 14. Kauppi, L.
    et al.
    Bernard, G.
    Bastrop, R.
    Norkko, Alf
    Stockholms universitet, Naturvetenskapliga fakulteten, Stockholms universitets Östersjöcentrum. University of Helsinki, Finland.
    Norkko, J.
    Increasing densities of an invasive polychaete enhance bioturbation with variable effects on solute fluxes2018Ingår i: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 8, artikel-id 7619Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Bioturbation is a key process affecting nutrient cycling in soft sediments. The invasive polychaete genus Marenzelleria spp. has established successfully throughout the Baltic Sea increasing species and functional diversity with possible density-dependent effects on bioturbation and associated solute fluxes. We tested the effects of increasing density of M. arctia, M. viridis and M. neglecta on bioturbation and solute fluxes in a laboratory experiment. Benthic communities in intact sediment cores were manipulated by adding increasing numbers of Marenzelleria spp. The results showed that Marenzelleria spp. in general enhanced all bioturbation metrics, but the effects on solute fluxes varied depending on the solute, on the density and species identity of Marenzelleria, and on the species and functional composition of the surrounding community. M. viridis and M. neglecta were more important in predicting variation in phosphate and silicate fluxes, whereas M. arctia had a larger effect on nitrogen cycling. The complex direct and indirect pathways indicate the importance of considering the whole community and not just species in isolation in the experimental studies. Including these interactions provides a way forward regarding our understanding of the complex ecosystem effects of invasive species.

  • 15. Fripiat, F.
    et al.
    Declercq, M.
    Sapart, C. J.
    Anderson, L. G.
    Brüchert, Volker
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för geologiska vetenskaper.
    Deman, F.
    Fonseca-Batista, D.
    Humborg, Christoph
    Stockholms universitet, Naturvetenskapliga fakulteten, Stockholms universitets Östersjöcentrum, Baltic Nest Institute.
    Roukaerts, A.
    Semiletov, I. P.
    Dehairs, F.
    Influence of the bordering shelves on nutrient distribution in the Arctic halocline inferred from water column nitrate isotopes2018Ingår i: Limnology and Oceanography, ISSN 0024-3590, E-ISSN 1939-5590, Vol. 63, nr 5, s. 2154-2170Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The East Siberian Sea and contiguous western Arctic Ocean basin are characterized by a subsurface nutrient maximum in the halocline, generally attributed to both Pacific inflow and intensive remineralization in shelf bottom waters that are advected into the central basin. We report nitrogen and oxygen isotopic measurement of nitrate from the East Siberian Sea and western Eurasian Basin, in order to gain insight into how nitrate is processed by the microbial community and redistributed in the Arctic Ocean. A large decoupling between nitrate delta N-15 and delta O-18 is reported, increasing and decreasing upward from the Atlantic temperature maximum layer toward the surface, respectively. A correlation between water and nitrate delta O-18 indicates that most of the nitrate (> 60%) at the halocline has been regenerated within the Arctic Ocean. The increase in nitrate delta N-15 correlates with the fixed N deficit, indicating a causal link between the loss of fixed N and the delta N-15 enrichment. This suggests that a significant share of benthic denitrification is driven by nitrate supplied by remineralization and partial nitrification, allowing residual delta N-15-enriched ammonium to diffuse out of the sediments. By increasing nutrient concentrations and fixed N deficit in shelf bottom waters, this imprint is attenuated offshore following advection into the halocline by nitrate regeneration and mixing. Estimation of the sedimentary isotope effect related to benthic denitrification yields values in the range of 2.4-3.8 parts per thousand, with its magnitude driven by both the degree of coupling between remineralization and nitrification, and fixed N concentrations in shelf bottom waters.

  • 16. Nielsen, Rasmus J.
    et al.
    Thunberg, Eric
    Holland, Daniel S.
    Schmidt, Jorn O.
    Fulton, Elizabeth A.
    Bastardie, Francois
    Punt, Andre E.
    Allen, Icarus
    Bartelings, Heleen
    Bertignac, Michel
    Bethke, Eckhard
    Bossier, Sieme
    Buckworth, Rick
    Carpenter, Griffin
    Christensen, Asbjorn
    Christensen, Villy
    Da-Rocha, José M.
    Deng, Roy
    Dichmont, Catherine
    Doering, Ralf
    Esteban, Aniol
    Fernandes, Jose A.
    Frost, Hans
    Garcia, Dorleta
    Gasche, Loic
    Gascuel, Didier
    Gourguet, Sophie
    Groeneveld, Rolf A.
    Guillén, Jordi
    Guyader, Olivier
    Hamon, Katell G.
    Hoff, Ayoe
    Horbowy, Jan
    Hutton, Trevor
    Lehuta, Sigrid
    Little, Richard L.
    Lleonart, Jordi
    Macher, Claire
    Mackinson, Steven
    Mahevas, Stephanie
    Marchal, Paul
    Mato-Amboage, Rosa
    Mapstone, Bruce
    Maynou, Francesc
    Merzéréaud, Mathieu
    Palacz, Artur
    Pascoe, Sean
    Paulrud, Anton
    Plaganyi, Eva
    Prellezo, Raul
    van Putten, Elizabeth I.
    Quaas, Martin
    Ravn-Jonsen, Lars
    Sanchez, Sonia
    Simons, Sarah
    Thébaud, Olivier
    Tomczak, Maciej T.
    Stockholms universitet, Naturvetenskapliga fakulteten, Stockholms universitets Östersjöcentrum.
    Ulrich, Clara
    van Dijk, Diana
    Vermard, Youen
    Voss, Rudi
    Waldo, Staffan
    Integrated ecological–economic fisheries models—Evaluation, review and challenges for implementation2018Ingår i: Fish and Fisheries, ISSN 1467-2960, E-ISSN 1467-2979, Vol. 19, nr 1, s. 1-29Artikel, forskningsöversikt (Refereegranskat)
    Abstract [en]

    Marine ecosystems evolve under many interconnected and area-specific pressures. To fulfil society's intensifying and diversifying needs while ensuring ecologically sustainable development, more effective marine spatial planning and broader-scope management of marine resources is necessary. Integrated ecological–economic fisheries models (IEEFMs) of marine systems are needed to evaluate impacts and sustainability of potential management actions and understand, and anticipate ecological, economic and social dynamics at a range of scales from local to national and regional. To make these models most effective, it is important to determine how model characteristics and methods of communicating results influence the model implementation, the nature of the advice that can be provided and the impact on decisions taken by managers. This article presents a global review and comparative evaluation of 35 IEEFMs applied to marine fisheries and marine ecosystem resources to identify the characteristics that determine their usefulness, effectiveness and implementation. The focus is on fully integrated models that allow for feedbacks between ecological and human processes although not all the models reviewed achieve that. Modellers must invest more time to make models user friendly and to participate in management fora where models and model results can be explained and discussed. Such involvement is beneficial to all parties, leading to improvement of models and more effective implementation of advice, but demands substantial resources which must be built into the governance process. It takes time to develop effective processes for using IEEFMs requiring a long-term commitment to integrating multidisciplinary modelling advice into management decision-making.

  • 17.
    Savchuck, Oleg P.
    Stockholms universitet, Naturvetenskapliga fakulteten, Stockholms universitets Östersjöcentrum, Baltic Nest Institute.
    Large-Scale Nutrient Dynamics in the Baltic Sea, 1970–20162018Ingår i: Frontiers in Marine Science, E-ISSN 2296-7745, Vol. 5, artikel-id 95Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The Baltic Sea is one of the world's marine areas well-covered by both long-term observations and oceanographic studies. It is also a large coastal area in which eutrophication had already been recognized half a century ago. While the mechanisms of eutrophication are largely understood, several features are less recognized and sometimes neglected, including: (a) natural and anthropogenic North-South and East-West nutrient gradients within the drainage basin and marine ecosystems; (b) the compensatory potential of the interconnectivity between the Baltic Sea basins; (c) long nutrient residence times and high buffer capacity of the system, resulting in slow responses to nutrient load reductions. Particularly important is the interaction of (d) naturally occurring saltwater inflows sporadically ventilating deep water layers and (e) a partly man-made intensification of biological oxygen consumption. Resulting redox alterations of biogeochemical nitrogen and phosphorus cycles are locked in a “vicious circle” that promotes cyanobacterial nitrogen fixation, thereby hindering nitrogen load reduction and sustaining an elevated trophic state. This tight coupling of natural environmental variation and human impacts complicates both scientific studies and management recommendations. Our primary objective is to describe all these features and mechanisms with the best available data on nutrient loads, and unique estimates of the basin-wide nutrient pools. These data are presented as both long-term time series and empirical nutrient budgets. The analysis is supplemented by results of biogeochemical modeling. A second, more practical objective is to make these time series available to the community.

  • 18. Carstensen, Jacob
    et al.
    Chierici, Melissa
    Gustafsson, Bo G.
    Stockholms universitet, Naturvetenskapliga fakulteten, Stockholms universitets Östersjöcentrum, Baltic Nest Institute. University of Helsinki, Finland.
    Gustafsson, Erik
    Stockholms universitet, Naturvetenskapliga fakulteten, Stockholms universitets Östersjöcentrum, Baltic Nest Institute.
    Long-Term and Seasonal Trends in Estuarine and Coastal Carbonate Systems2018Ingår i: Global Biogeochemical Cycles, ISSN 0886-6236, E-ISSN 1944-9224, Vol. 32, nr 3, s. 497-513Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Coastal pH and total alkalinity are regulated by a diverse range of local processes superimposed on global trends of warming and ocean acidification, yet few studies have investigated the relative importance of different processes for coastal acidification. We describe long-term (1972-2016) and seasonal trends in the carbonate system of three Danish coastal systems demonstrating that hydrological modification, changes in nutrient inputs from land, and presence/absence of calcifiers can drastically alter carbonate chemistry. Total alkalinity was mainly governed by conservative mixing of freshwater (0.73-5.17mmolkg(-1)) with outer boundary concentrations (similar to 2-2.4mmolkg(-1)), modulated seasonally and spatially (similar to 0.1-0.2mmolkg(-1)) by calcifiers. Nitrate assimilation by primary production, denitrification, and sulfate reduction increased total alkalinity by almost 0.6mmolkg(-1) in the most eutrophic system during a period without calcifiers. Trends in pH ranged from -0.0088year(-1) to 0.021year(-1), the more extreme of these mainly driven by salinity changes in a sluice-controlled lagoon. Temperature increased 0.05 degrees Cyr(-1) across all three systems, which directly accounted for a pH decrease of 0.0008year(-1). Accounting for mixing, salinity, and temperature effects on dissociation and solubility constants, the resulting pH decline (0.0040year(-1)) was about twice the ocean trend, emphasizing the effect of nutrient management on primary production and coastal acidification. Coastal pCO(2) increased similar to 4 times more rapidly than ocean rates, enhancing CO2 emissions to the atmosphere. Indeed, coastal systems undergo more drastic changes than the ocean and coastal acidification trends are substantially enhanced from nutrient reductions to address coastal eutrophication.

  • 19.
    Savchuck, Oleg P.
    Stockholms universitet, Naturvetenskapliga fakulteten, Stockholms universitets Östersjöcentrum, Baltic Nest Institute.
    Myths of the Baltic Sea eutrophication2018Ingår i: Journal of Aquaculture & Marine Biology, ISSN 2378-3184, Vol. 7, nr 2, s. 92-93Artikel i tidskrift (Övrigt vetenskapligt)
  • 20.
    Fransner, Filippa
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Meteorologiska institutionen (MISU).
    Gustafsson, Erik
    Stockholms universitet, Naturvetenskapliga fakulteten, Stockholms universitets Östersjöcentrum, Baltic Nest Institute.
    Tedesco, Letizia
    Vichi, Marcello
    Hordoir, Robinson
    Roquet, Fabien
    Stockholms universitet, Naturvetenskapliga fakulteten, Meteorologiska institutionen (MISU).
    Spilling, Kristian
    Kuznetsov, Ivan
    Eilola, Kari
    Mörth, Carl-Magnus
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för geologiska vetenskaper.
    Humborg, Christoph
    Stockholms universitet, Naturvetenskapliga fakulteten, Stockholms universitets Östersjöcentrum, Baltic Nest Institute. University of Helsinki, Finland.
    Nycander, Jonas
    Stockholms universitet, Naturvetenskapliga fakulteten, Meteorologiska institutionen (MISU).
    Non-Redfieldian Dynamics Explain Seasonal pCO2 Drawdown in the Gulf of Bothnia2018Ingår i: Journal of Geophysical Research - Oceans, ISSN 2169-9275, E-ISSN 2169-9291, Vol. 123, nr 1, s. 166-188Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    High inputs of nutrients and organic matter make coastal seas places of intense air‐sea CO2 exchange. Due to their complexity, the role of coastal seas in the global air‐sea CO2 exchange is, however, still uncertain. Here, we investigate the role of phytoplankton stoichiometric flexibility and extracellular DOC production for the seasonal nutrient and CO2 partial pressure (pCO2) dynamics in the Gulf of Bothnia, Northern Baltic Sea. A 3‐D ocean biogeochemical‐physical model with variable phytoplankton stoichiometry is for the first time implemented in the area and validated against observations. By simulating non‐Redfieldian internal phytoplankton stoichiometry, and a relatively large production of extracellular dissolved organic carbon (DOC), the model adequately reproduces observed seasonal cycles in macronutrients and pCO2. The uptake of atmospheric CO2 is underestimated by 50% if instead using the Redfield ratio to determine the carbon assimilation, as in other Baltic Sea models currently in use. The model further suggests, based on the observed drawdown of pCO2, that observational estimates of organic carbon production in the Gulf of Bothnia, derived with the method, may be heavily underestimated. We conclude that stoichiometric variability and uncoupling of carbon and nutrient assimilation have to be considered in order to better understand the carbon cycle in coastal seas.

  • 21.
    McCrackin, Michelle L.
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Stockholms universitets Östersjöcentrum.
    Gustafsson, Bo G.
    Stockholms universitet, Naturvetenskapliga fakulteten, Stockholms universitets Östersjöcentrum.
    Hong, Bongghi
    Howarth, Robert W.
    Humborg, Christoph
    Stockholms universitet, Naturvetenskapliga fakulteten, Stockholms universitets Östersjöcentrum. University of Helsinki, Finland.
    Savchuck, Oleg P.
    Stockholms universitet, Naturvetenskapliga fakulteten, Stockholms universitets Östersjöcentrum.
    Svanbäck, Annika
    Stockholms universitet, Naturvetenskapliga fakulteten, Stockholms universitets Östersjöcentrum.
    Swaney, Dennis P.
    Opportunities to reduce nutrient inputs to the Baltic Sea by improving manure use efficiency in agriculture2018Ingår i: Regional Environmental Change, ISSN 1436-3798, E-ISSN 1436-378X, Vol. 18, nr 6, s. 1843-1854Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    While progress has been made in reducing external nutrient inputs to the Baltic Sea, further actions are needed to meet the goals of the Baltic Sea Action Plan (BSAP), especially for the Baltic Proper, Gulf of Finland, and Gulf of Riga sub-basins. We used the net anthropogenic nitrogen and phosphorus inputs (NANI and NAPI, respectively) nutrient accounting approach to construct three scenarios of reduced NANI-NAPI. Reductions assumed that manure nutrients were redistributed from areas with intense animal production to areas that focus on crop production and would otherwise import synthetic and mineral fertilizers. We also used the Simple as Necessary Baltic Long Term Large Scale (SANBALTS) model to compare eutrophication conditions for the scenarios to current and BSAP-target conditions. The scenarios suggest that reducing NANI-NAPI by redistributing manure nutrients, together with improving agronomic practices, could meet 54–82% of the N reductions targets (28–43 kt N reduction) and 38–64% P reduction targets (4–6.6 kt P reduction), depending on scenario. SANBALTS output showed that even partial fulfillment of nutrient reduction targets could have ameliorating effects on eutrophication conditions. Meeting BSAP targets will require addressing additional sources, such as sewage. A common approach to apportioning sources to external nutrients loads could enable further assessment of the feasibility of eutrophication management targets.

  • 22.
    McLachlan, Michael S.
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Undeman, Emma
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi. Stockholms universitet, Naturvetenskapliga fakulteten, Stockholms universitets Östersjöcentrum.
    Zhao, Fangyuan
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    MacLeod, Matthew
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Predicting global scale exposure of humans to PCB 153 from historical emissions2018Ingår i: Environmental Science: Processes & Impacts, ISSN 2050-7887, E-ISSN 2050-7895, Vol. 20, nr 5, s. 747-756Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Predicting human exposure to an environmental contaminant based on its emissions is one of the great challenges of environmental chemistry. It has been done successfully on a local or regional scale for some persistent organic pollutants. Here we assess whether it can be done at a global scale, using PCB 153 as a test chemical. The global multimedia fate model BETR Global and the human exposure model ACC-HUMAN were employed to predict the concentration of PCB 153 in human milk for 56 countries around the world from a global historical emissions scenario. The modeled concentrations were compared with measurements in pooled human milk samples from the UNEP/WHO Global Monitoring Plan. The modeled and measured concentrations were highly correlated (r = 0.76, p < 0.0001), and the concentrations were predicted within a factor of 4 for 49 of 78 observations. Modeled concentrations of PCB 153 in human milk were higher than measurements for some European countries, which may reflect weaknesses in the assumptions made for food sourcing and an underestimation of the rate of decrease of concentrations in air during the last decades. Conversely, modeled concentrations were lower than measurements in West African countries, and more work is needed to characterize exposure vectors in this region.

  • 23.
    Bauer, Barbara
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Stockholms universitets Östersjöcentrum.
    Meier, H. E. Markus
    Casini, Michele
    Hoff, Ayoe
    Margoński, Piotr
    Orio, Alessandro
    Saraiva, Sofia
    Steenbeek, Jeroen
    Tomczak, Maciej T.
    Stockholms universitet, Naturvetenskapliga fakulteten, Stockholms universitets Östersjöcentrum.
    Reducing eutrophication increases spatial extent of communities supporting commercial fisheries: a model case study2018Ingår i: ICES Journal of Marine Science, ISSN 1054-3139, E-ISSN 1095-9289, Vol. 75, nr 4, s. 1306-1317Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this study we investigate if eutrophication management has the potential to substantially affect which areas are going to be most suitable for commercial fishing in the future. We use a spatial ecosystem model, forced by a coupled physical-biogeochemical model, to simulate the spatial distribution of functional groups within a marine ecosystem, which depends on their respective tolerances to abiotic factors, trophic interactions, and fishing. We simulate the future long-term spatial developments of the community composition and their potential implications for fisheries under three different nutrient management scenarios and changing climate. The three nutrient management scenarios result in contrasting developments of bottom oxygen concentrations and phytoplankton abundance, with substantial effects on fish production. Nutrient load reduction increases the spatial extent of the areas suitable for the commercially most valuable demersal fish predator and all types of fisheries. This suggests that strategic planning of fishery management strategies could benefit from considering future changes in species distributions due to changes in eutrophication. We show that combining approaches from climate research, physical oceanography, biogeochemistry, biogeography, and trophic ecology with economical information provides a strong foundation to produce scientific knowledge that can support a multisectoral management of ecosystems.

  • 24. Jones, Holly P.
    et al.
    Jones, Peter C.
    Barbier, Edward B.
    Blackburn, Ryan C.
    Benayas, Jose M. Rey
    Holl, Karen D.
    McCrackin, Michelle
    Stockholms universitet, Naturvetenskapliga fakulteten, Stockholms universitets Östersjöcentrum.
    Meli, Paula
    Montoya, Daniel
    Mateos, David Moreno
    Restoration and repair of Earth's damaged ecosystems2018Ingår i: Proceedings of the Royal Society of London. Biological Sciences, ISSN 0962-8452, E-ISSN 1471-2954, Vol. 285, nr 1873, artikel-id 20172577Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Given that few ecosystems on the Earth have been unaffected by humans, restoring them holds great promise for stemming the biodiversity crisis and ensuring ecosystem services are provided to humanity. Nonetheless, few studies have documented the recovery of ecosystems globally or the rates at which ecosystems recover. Even fewer have addressed the added benefit of actively restoring ecosystems versus allowing them to recover without human intervention following the cessation of a disturbance. Our meta-analysis of 400 studies worldwide that document recovery from large-scale disturbances, such as oil spills, agriculture and logging, suggests that though ecosystems are progressing towards recovery following disturbances, they rarely recover completely. This result reinforces conservation of intact ecosystems as a key strategy for protecting biodiversity. Recovery rates slowed down with time since the disturbance ended, suggesting that the final stages of recovery are the most challenging to achieve. Active restoration did not result in faster or more complete recovery than simply ending the disturbances ecosystems face. Our results on the added benefit of restoration must be interpreted cautiously, because few studies directly compared different restoration actions in the same location after the same disturbance. The lack of consistent value added of active restoration following disturbance suggests that passive recovery should be considered as a first option; if recovery is slow, then active restoration actions should be better tailored to overcome specific obstacles to recovery and achieve restoration goals. We call for a more strategic investment of limited restoration resources into innovative collaborative efforts between scientists, local communities and practitioners to develop restoration techniques that are ecologically, economically and socially viable.

  • 25. Kauppi, L.
    et al.
    Norkko, Alf
    Stockholms universitet, Naturvetenskapliga fakulteten, Stockholms universitets Östersjöcentrum. University of Helsinki, Finland.
    Norkko, J.
    Seasonal population dynamics of the invasive polychaete genus Marenzelleria spp. in contrasting soft-sediment habitats2018Ingår i: Journal of Sea Research, ISSN 1385-1101, E-ISSN 1873-1414, Vol. 131, s. 46-60Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Three species of the invasive polychaete genus Marenzelleria are among the dominant benthic taxa in many, especially deeper, areas in the Baltic Sea. The population dynamics of the polychaetes in the Baltic are, however, still largely unknown. We conducted monthly samplings of the benthic communities and environmental parameters at five sites with differing depths and sediment characteristics in the northern Baltic Sea (59 degrees 50.896', 23 degrees 15.092') to study the population dynamics, productivity and growth of Marenzelleria spp. from April 2013 to June 2014. The species of Marenzelleria occurring at the study sites were identified by genetic analyses. At the deepest site (33 m) only M. arctia was present, while all three species were found at the shallower, muddy sites (up to 20 m depth). At the shallow (6 m) sandy site only M. viridis and M. neglecta occurred. The sites differed in the seasonal dynamics of the Marenzelleria spp. population, reflecting the different species identities. The muddy sites up to 20 m depth showed clear seasonal dynamics, with the population practically disappearing by winter, whereas more stable populations occurred at the deepest site and at the sandy site. The highest density, biomass and production were observed at the 20 m deep, organic-rich muddy site where all three species recruited. The seasonally very high densities are likely to have important consequences for organic matter processing, and species interactions at these sites. The observed high productivity of the populations has possibly facilitated their establishment, and considerably increased secondary production in especially the deeper areas.

  • 26. Joensuu, M.
    et al.
    Pilditch, C. A.
    Harris, R.
    Hietanen, S.
    Pettersson, H.
    Norkko, Alf
    Stockholms universitet, Naturvetenskapliga fakulteten, Stockholms universitets Östersjöcentrum. University of Helsinki, Finland.
    Sediment properties, biota, and local habitat structure explain variation in the erodibility of coastal sediments2018Ingår i: Limnology and Oceanography, ISSN 0024-3590, E-ISSN 1939-5590, Vol. 63, nr 1, s. 173-186Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Sediment resuspension is a frequent phenomenon in coastal areas and a key driver for many ecosystem functions. Sediment resuspension is often linked to biological and anthropogenic activities, which in combination with hydrodynamic forcing initiate sediment erosion and resuspension, if the erosion threshold (tau(c)) is exceeded. Despite its importance to ecosystem functions very few studies have provided measurements on natural assemblages for subtidal sediments. The aim of this study was to determinate key environmental variables regulating sediment resuspension potential across a sedimentary gradient in a subtidal coastal environment. In order to explore this, we sampled 16 sites encompassing a wide variety in environmental variables (e.g., grain size distribution, macrofaunal communities, vegetation) in the Gulf of Finland, Baltic Sea. A core-based erosion device (EROMES) was used to determine sediment resuspension potential measures of erosion threshold, erosion rate (ER), and erosion constant (m(e)). Based on abiotic and biotic properties sampled, sediments diverged into two distinct groups; cohesive (muddy) and noncohesive (sandy) sediments. Results showed that abiotic sediment properties explained 38-53% and 15-36% of the total variation in resuspension potential measures in muddy and sandy sediments, respectively. In cumulative models, biota accounted for 12-26% and 6-24% to the total variation in muddy and sandy sediments, respectively. Sediment erodibility and resuspension potential of natural sediments is highly variable from local habitats to a larger seascape scale. Our results underline the importance of biota to resuspension potential measures in spatially variable environments.

  • 27.
    Sun, Xiaole
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Stockholms universitets Östersjöcentrum. Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Mörth, Carl-Magnus
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för geologiska vetenskaper.
    Porcelli, Don
    Kutscher, Liselott
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för geologiska vetenskaper. Swedish Museum of Natural History, Sweden.
    Hirst, Catherine
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för geologiska vetenskaper. Swedish Museum of Natural History, Sweden.
    Murphy, Melissa J.
    Maximov, Trofim
    Petrov, Roman E.
    Humborg, Christoph
    Stockholms universitet, Naturvetenskapliga fakulteten, Stockholms universitets Östersjöcentrum. Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Schmitt, Melanie
    Andersson, Per S.
    Stable silicon isotopic compositions of the Lena River and its tributaries: Implications for silicon delivery to the Arctic Ocean2018Ingår i: Geochimica et Cosmochimica Acta, ISSN 0016-7037, E-ISSN 1872-9533, Vol. 241, s. 120-133Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Silicon isotope values (delta Si-30(DSi)) of dissolved silicon (DSi) have been analyzed in the Lena River and its tributaries, one of the largest Arctic watersheds in the world. The geographical and temporal variations of delta Si-30(DSi) range from +0.39 to +1.86% with DSi concentrations from 34 to 121 mu M. No obvious patterns of DSi concentrations and delta Si-30(DSi) values were observed along over 200 km of the two major tributaries, the Viliui and Aldan Rivers. In summer, the variations of DSi concentrations and delta Si-30(DSi) values in the water are either caused by biological uptake by higher plants and phytoplankton or by mixing of water masses carrying different DSi concentrations and delta Si-30(DSi) values. DSi in tributaries from the Verkhoyansk Mountain Range seems to be associated with secondary clay formation that increased the delta Si-30(DSi) values, while terrestrial biological production is likely more prevalent in controlling delta Si-30(DSi) values in Central Siberian Plateau and Lena Amganski Inter-River Area. In winter, when soils were frozen, the delta Si-30(DSi) values in the river appeared to be controlled by weathering and clay formation in deep intrapermafrost groundwater. During the spring flood, dissolved silicate materials and phytoliths were flushed from the upper thawed soils into rivers, which reset delta Si-30(DSi) values to the values observed prior to the biological bloom in summer. The results indicate that the Si isotope values reflect the changing processes controlling Si outputs to the Lena River and to the Arctic Ocean between seasons. The annual average delta Si-30(DSi) value of the Lena Si flux is calculated to be +0.86 +/- 0.3 parts per thousand using measured delta Si-30(DSi) values from each season. Combined with the estimate of + 1.6 +/- 0.25 parts per thousand for the Yenisey River, an updated delta Si-30(DSi) value of the major river Si inputs to the Arctic Ocean is estimated to be + 1.3 +/- 0.3 parts per thousand. This value is expected to shift towards higher values in the future because of the impacts from a variety of biological and geochemical processes and sources under global warming.

  • 28. Villnäs, Anna
    et al.
    Hewitt, Judi
    Snickars, Martin
    Westerbom, Mats
    Norkko, Alf
    Stockholms universitet, Naturvetenskapliga fakulteten, Stockholms universitets Östersjöcentrum. University of Helsinki, Finland.
    Template for using biological trait groupings when exploringlarge-scale variation in seafloor multifunctionality2018Ingår i: Ecological Applications, ISSN 1051-0761, E-ISSN 1939-5582, Vol. 28, nr 1, s. 78-94Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Understanding large-scale spatial variation in ecosystem properties and associated functionality is key for successful conservation of ecosystems. This study provides a template for how to estimate differences in ecosystem functionality over large spatial scales by using groupings of biological traits. We focus on trait groupings that describe three important benthic ecosystem properties, namely bioturbation, community stability, and juvenile dispersal. Recognizing that groups of traits interact and are constrained within an organism, we statistically define important functional trait subgroups that describe each ecosystem property. The sub-groups are scored according to their weighted ecological impact to gain an overall estimation of the cumulative expression of each ecosystem property at individual sites. Furthermore, by assigning each property a value relative to its observed maximum, and by summing up the individual property values, we offer an estimate of benthic ecosystem multi-functionality. Based on a spatially extensive benthic data set, we were able to identify coastal areas with high and low potential for the considered benthic ecosystem properties and the measure of ecosystem multifunctionality. Importantly, we show that a large part of the spatial variation in functional trait sub-groups and in benthic ecosystem multifunctionality was explained by environmental change. Our results indicate that through this simplification it is possible to estimate the functionality of the seafloor. Such information is vital in marine spatial planning efforts striving to balance the utilization with the preservation of natural resources.

  • 29.
    Rodil, Iván F.
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Stockholms universitets Östersjöcentrum. University of Helsinki, Finland.
    Lucena-Moya, P.
    Lastra, M.
    The Importance of Environmental and Spatial Factors in the Metacommunity Dynamics of Exposed Sandy Beach Benthic Invertebrates2018Ingår i: Estuaries and Coasts, ISSN 1559-2723, E-ISSN 1559-2731, Vol. 41, nr 1, s. 206-217Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We studied the contribution of environmental and spatial factors in determining the metacommunity dynamics of benthic macroinvertebrates in ocean-exposed sandy beaches. A combination of different metacommunity models contributed to the structure of the benthic species, suggesting that the interplay of environmental and spatial factors played a key role in determining the beach community structure. Our study highlights the sensitivity of beach invertebrates to environmental factors such as morphodynamic descriptors, and to oceanographic-related variables (e.g., sea-water temperature). The results also suggest significant spatial signals at a large geographical scale. We applied two different species categorizations, high dispersive vs low dispersive and generalist vs specialist, to disentangle the roles of dispersal mode and habitat specialization in the beach metacommunity structure. The strength of the environmental and spatial factors varied depending on the category of species traits considered, emphasizing the value of using different groups of species in explaining variation in metacommunity dynamics. Low dispersive species showed a better ability to track environmental variability than high dispersive species, which were more spatially constrained. Habitat specialists were better able to track environmental variability than generalists, which were mainly predicted by pure spatial factors. A better understanding of the metacommunity dynamics using different species categorizations can help to improve our predictions about exposed beach community structure, and to prioritize management actions to cope with biodiversity loss in such superlative marine environment.

  • 30. Westerbom, Mats
    et al.
    Lappalainen, Antti
    Mustonen, Olli
    Norkko, Alf
    Stockholms universitet, Naturvetenskapliga fakulteten, Stockholms universitets Östersjöcentrum. Tvärminne Zoological Station, Finland.
    Trophic overlap between expanding and contracting fish predators in a range margin undergoing change2018Ingår i: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 8, artikel-id 7895Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Climate change is predicted to cause a freshening of the Baltic Sea, facilitating range expansions of freshwater species and contractions of marine. Resident marine flounders (Platichthys flesus) and expansive freshwater roach (Rutilus rutilus) are dominant consumers in the Baltic Sea sublittoral where they occur in partial sympatry. By comparing patterns of resource use by flounders and roach along a declining resource gradient of blue mussels (Mytilus trossulus) our aim was to explore predator functional responses and the degree of trophic overlap. Understanding the nature of density-dependent prey acquisition has important implications for predicting population dynamics of both predators and their shared prey. Results showed a highly specialized diet for both species, high reliance on blue mussels throughout the range, similar prey size preference and high trophic overlap. Highest overlap occurred where blue mussels were abundant but overlap was also high where they were scarce. Our results highlight the importance of a single food item - the blue mussel - for both species, likely promoting high population size and range expansion of roach. Findings also suggest that range expansion of roach may have a top-down structuring force on mussels that differ in severity and location from that originating from resident flounders.

  • 31. Kahru, Mati
    et al.
    Elmgren, Ragnar
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och botanik.
    Di Lorenzo, Emanuele
    Savchuck, Oleg
    Stockholms universitet, Naturvetenskapliga fakulteten, Stockholms universitets Östersjöcentrum, Baltic Nest Institute.
    Unexplained interannual oscillations of cyanobacterial blooms in the Baltic Sea2018Ingår i: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 8, artikel-id 6365Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Population oscillations in multi-species or even single species systems are well-known but have rarely been detected at the lower trophic levels in marine systems. Nitrogen fixing cyanobacteria are a major component of the Baltic Sea ecosystem and sometimes form huge surface accumulations covering most of the sea surface. By analysing a satellite-derived 39-year (1979–2017) data archive of surface cyanobacteria concentrations we have found evidence of strikingly regular interannual oscillations in cyanobacteria concentrations in the northern Baltic Sea. These oscillations have a period of ~3 years with a high-concentration year generally followed by one or two low-concentration years. Changes in abiotic factors known to influence the growth and survival of cyanobacteria could not provide an explanation for the oscillations. We therefore assume that these oscillations are intrinsic to the marine system, caused by an unknown, probably mainly biological mechanism that may be triggered by a combination of environmental factors. Interactions between different life cycle stages of cyanobacteria as well as between predator-prey or host-parasite are possible candidates for causing the oscillations.

  • 32. Lastra, Mariano
    et al.
    López, Jesús
    Rodil, Iván F.
    Stockholms universitet, Naturvetenskapliga fakulteten, Stockholms universitets Östersjöcentrum. University of Helsinki, Finland.
    Warming intensify CO2 flux and nutrient release from algal wrack subsidies on sandy beaches2018Ingår i: Global Change Biology, ISSN 1354-1013, E-ISSN 1365-2486, Vol. 24, nr 8, s. 3766-3779Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Algal wrack subsidies underpin most of the food web structure of exposed sandy beaches and are responsible of important biogeochemical processes that link marine and terrestrial ecosystems. The response in decomposition of algal wrack deposits to global warming has not been studied in ocean-exposed sandy beaches to date. With this aim, passive open top chambers (OTCs) were used to increase soil temperature within the range predicted by the IPCC for western Europe (between 0.5 and 1.5 degrees C), following the hypothesis that the biogeochemical processing of macroalgal wrack subsidies would accelerate in response to temperature increase. The effect of temperature manipulation on three target substrates: fresh and aged macroalgae, and bare sand, was tested. Results indicated that a small warming (< 0.5 degrees C) affected the wrack decomposition process through traceable increases in soil respiration through CO2 flux, inorganic nutrients within the interstitial environment (N and P), sediment organic contents measured through the amount of proteins and microbial pool through the total soil DNA. The different responses of soil variables in the studied substrates indicated that the decomposition stage of stranded macroalgae influences the biogeochemical processing of organic matter in sandy beaches. Thus, CO2 fluxes, releases of organic and inorganic nutrients and microbial activity intensify in aged wrack deposits. Our results predict that expected global warming will increase the release of inorganic nutrients to the coastal ocean by 30% for the N (21 Gg/year) and 5.9% for P (14 Gg/year); that increase for the flow of C to the atmosphere as CO2 was estimated in 8.2% (523 Gg/year). This study confirms the key role of sandy beaches in recycling ocean-derived organic matter, highlighting their sensitivity to a changing scenario of global warming that predicts significant increases in temperature over the next few decades.

  • 33.
    Undeman, Emma
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi. Stockholms universitet, Naturvetenskapliga fakulteten, Stockholms universitets Östersjöcentrum.
    Brown, Trevor N.
    McLachlan, Michael S.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Wania, Frank
    Who in the world is most exposed to polychlorinated biphenyls? Using models to identify highly exposed populations2018Ingår i: Environmental Research Letters, ISSN 1748-9326, E-ISSN 1748-9326, Vol. 13, nr 6, artikel-id 064036Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Human subpopulations experience different exposure to persistent organic pollutants (POPs) because of differences in the structure of their food webs and the extent of environmental contamination. Here we quantify the time-variant exposure of different human populations around the world to one representative POP, namely the polychlorinated biphenyl (PCB) congener 153, based on a dynamic simulation of both global environmental fate (using the model BETR-Global) and human food chain bioaccumulation (using the model ACC-HUMAN). The approach identifies subpopulations whose diets include a carnivorous mammal as experiencing the world's highest PCB-153 exposure, i.e. the very large biomagnification potential of their food web more than makes up for the remoteness of their living environment. However, for subpopulations that do not eat warm-blooded carnivores, the proximity to sources of PCBs is more important than food web structure and environmental conditions for differentiating their exposure to PCBs.

  • 34.
    Donadi, Serena
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och botanik. Stockholms universitet, Naturvetenskapliga fakulteten, Stockholms universitets Östersjöcentrum. Swedish University of Agricultural Sciences (SLU), Sweden.
    Austin, Åsa N.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och botanik.
    Bergström, U.
    Eriksson, B. K.
    Hansen, Joakim P.
    Stockholms universitet, Naturvetenskapliga fakulteten, Stockholms universitets Östersjöcentrum.
    Jacobson, P.
    Sundblad, G.
    van Regteren, M.
    Eklöf, Johan S.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och botanik.
    A cross-scale trophic cascade from large predatory fish to algae in coastal ecosystems2017Ingår i: Proceedings of the Royal Society of London. Biological Sciences, ISSN 0962-8452, E-ISSN 1471-2954, Vol. 284, nr 1859, artikel-id 20170045Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Trophic cascades occur in many ecosystems, but the factors regulating them are still elusive. We suggest that an overlooked factor is that trophic interactions (TIs) are often scale-dependent and possibly interact across spatial scales. To explore the role of spatial scale for trophic cascades, and particularly the occurrence of cross-scale interactions (CSIs), we collected and analysed food-web data from 139 stations across 32 bays in the Baltic Sea. We found evidence of a four-level trophic cascade linking TIs across two spatial scales: at bay scale, piscivores (perch and pike) controlled mesopredators (three-spined stickleback), which in turn negatively affected epifaunal grazers. At station scale (within bays), grazers on average suppressed epiphytic algae, and indirectly benefitted habitat-forming vegetation. Moreover, the direction and strength of the grazer-algae relationship at station scale depended on the piscivore biomass at bay scale, indicating a cross-scale interaction effect, potentially caused by a shift in grazer assemblage composition. In summary, the trophic cascade from piscivores to algae appears to involve TIs that occur at, but also interact across, different spatial scales. Considering scale-dependence in general, and CSIs in particular, could therefore enhance our understanding of trophic cascades.

  • 35. Enge, Swantje
    et al.
    Sagerman, Josefin
    Stockholms universitet, Naturvetenskapliga fakulteten, Stockholms universitets Östersjöcentrum.
    Wikström, Sofia A.
    Stockholms universitet, Naturvetenskapliga fakulteten, Stockholms universitets Östersjöcentrum.
    Pavia, Henrik
    A Review of Herbivore Effects on Seaweed Invasions2017Ingår i: Oceanography and Marine Biology: An Annual Review, Volume 55 / [ed] S. J. Hawkins, A. J. Evans, A.C. Dale, L. B. Firth, D. J. Hughes, I. P. Smith, BOCA RATON: CRC PRESS-TAYLOR & FRANCIS GROUP , 2017, Vol. 55, s. 421-440Kapitel i bok, del av antologi (Refereegranskat)
    Abstract [en]

    Almost 300 non-native seaweeds are identified worldwide and an increasing number of these are classified as invasive with potential negative effects on the diversity and functioning of native ecosystems. Marine herbivores affect seaweed biomass and community structure in marine habitats across the globe. Consequently, herbivore-seaweed interactions are expected to be important for the establishment and invasion success of non-native seaweeds. To synthesize current knowledge of consumer effects on non-native seaweeds, we performed a meta-analysis on feeding preferences of native herbivores for non-native versus native seaweeds. Data were included from 35 studies, published from 1992-2015 and comprising 18 non-native seaweeds. Results showed that overall, native herbivores tended to prefer to feed on native rather than non-native seaweeds. Preferences were, however, variable across studies with significant differences between taxonomic and functional groups of seaweeds. In particular, filamentous red non-native seaweeds were of low palatability to native herbivores. No general feeding preferences were apparent between natives and non-natives for brown and green seaweeds, or for leathery and corticated seaweeds. In addition, we reviewed the existing studies on the effects of consumers on the performance of native and non-native seaweeds in invaded communities. This indicated that non-native seaweeds performed better than their native competitors in the presence of grazers, but in many cases had superior competitive abilities also in the absence of herbivory. To achieve a comprehensive evaluation of consumers' role in seaweed invasion success, future research should have a larger focus on manipulative community experiments, ideally on time scales that include seasonal changes and complete life cycles of the seaweeds.

  • 36. Hong, Bongghi
    et al.
    Swaney, Dennis P.
    McCrackin, Michelle
    Stockholms universitet, Naturvetenskapliga fakulteten, Stockholms universitets Östersjöcentrum.
    Svanbäck, Annika
    Stockholms universitet, Naturvetenskapliga fakulteten, Stockholms universitets Östersjöcentrum.
    Humborg, Christoph
    Stockholms universitet, Naturvetenskapliga fakulteten, Stockholms universitets Östersjöcentrum.
    Gustafsson, Bo
    Stockholms universitet, Naturvetenskapliga fakulteten, Stockholms universitets Östersjöcentrum.
    Yershova, Alexandra
    Pakhomau, Aliaksandr
    Advances in NANI and NAPI accounting for the Baltic drainage basin: spatial and temporal trends and relationships to watershed TN and TP fluxes2017Ingår i: Biogeochemistry, ISSN 0168-2563, E-ISSN 1573-515X, Vol. 133, nr 3, s. 245-261Artikel i tidskrift (Refereegranskat)
    Abstract [en]

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

  • 37.
    Prytherch, John
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Meteorologiska institutionen (MISU). University of Leeds, United Kingdom.
    Brooks, Ian
    Crill, Patrick
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för geologiska vetenskaper.
    Thornton, Brett
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för geologiska vetenskaper.
    Salisbury, Dominic
    Tjernström, Michael
    Stockholms universitet, Naturvetenskapliga fakulteten, Meteorologiska institutionen (MISU).
    Anderson, Leif
    Geibel, Marc C.
    Stockholms universitet, Naturvetenskapliga fakulteten, Stockholms universitets Östersjöcentrum.
    Humborg, Christoph
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Air-sea CO2and CH4 gas transfer velocity in Arctic sea-ice regions fromeddy covariance flux measurements onboard Icebreaker Oden2017Ingår i: Geophysical Research Abstracts, ISSN 1029-7006, E-ISSN 1607-7962, Vol. 19, artikel-id 697Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The Arctic Ocean is an important sink for atmospheric CO2, and there is ongoing debate on whether seafloor seeps in the Arctic are a large source of CH4 to the atmosphere. The impact of warming waters, decreasing sea-ice extent and expanding marginal ice zones on Arctic air-sea gas exchange depends on the rate of gas transfer in the presence of sea ice. Sea ice acts as a near-impermeable lid to air-sea gas exchange, but is also hypothesised to enhance gas transfer rates through physical processes such as increased surface-ocean turbulence from ice-water shear and ice-edge form drag. The dependence of the gas transfer rate on sea-ice concentration remains uncertain due to a lack of in situ measurements. Here we present the first direct estimates of gas transfer rate in a wide range of Arctic sea-ice conditions. The estimates were derived from eddy covariance CO2 and CH4 fluxes, measured from the Swedish Icebreaker Oden during two expeditions: the 3-month duration Arctic Clouds in Summer Experiment (ACSE) in 2014, a component of the Swedish-Russian-US Arctic Ocean Investigation on Climate-Cryosphere-Carbon Interactions (SWERUS-C3) in the eastern Arctic Ocean shelf region; and the Arctic Ocean 2016 expedition to the high latitude Arctic Ocean. Initial CO2 results from ACSE showed that the gas transfer rate has a near-linear dependence on sea-ice concentration, and that some previous indirect measurements and modelling estimates overestimate gas transfer rates in sea-ice regions. This supports a linear sea-ice scaling approach for assessments of polar ocean carbon fluxes. Air-sea gas transfer model assumptions (e.g. Schmidt number dependence) will be examined using simultaneous CO2 and CH4 measurements, and observations in different ice conditions (e.g. summer melt, autumn freeze up, central Arctic and marginal ice zones) will be compared.

  • 38.
    McCrackin, Michelle L.
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Stockholms universitets Östersjöcentrum.
    Cooter, Ellen J.
    Dennis, Robin L.
    Harrison, John A.
    Compton, Jana E.
    Alternative futures of dissolved inorganic nitrogen export from the Mississippi River Basin: influence of crop management, atmospheric deposition, and population growth2017Ingår i: Biogeochemistry, ISSN 0168-2563, E-ISSN 1573-515X, Vol. 133, nr 3, s. 263-277Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Nitrogen (N) export from the Mississippi River Basin contributes to seasonal hypoxia in the Gulf of Mexico (GOM). We explored monthly dissolved inorganic N (DIN) export to the GOM for a historical year (2002) and two future scenarios (year 2022) by linking macroeonomic energy, agriculture market, air quality, and agriculture land management models to a DIN export model. Future scenarios considered policies aimed at encouraging bioenergy crop production and reducing atmospheric N-emissions, as well as the effect of population growth and the states' infrastructure plans on sewage fluxes. Model-derived DIN export decreased by about 9% (from 279 to 254 kg N km(-2) year(-1)) between 2002 and 2022 due to a 28% increase in area planted with corn, 24% improvement in crop N-recovery efficiency (NRE, to 0.52), 22% reduction in atmospheric N deposition, and 23% increase in sewage inputs. Changes in atmospheric and sewage inputs had a relatively small effect on DIN export and the effect of bioenergy crop production depended on nutrient management practices. Without improved NRE, increased production of corn would have increased DIN export by about 14% (to 289 kg N km(-2) year(-1)) between 2002 and 2022. Model results suggest that meeting future crop demand while reducing the areal extent of hypoxia could require aggressive actions, such improving basin-level crop NRE to 0.62 or upgrading N-removal capabilities in waste water treatment plants beyond current plans. Tile-drained cropland could contribute up to half of DIN export; thus, practices that reduce N losses from tile drains could also have substantial benefit.

  • 39. Moreno-Mateos, David
    et al.
    Barbier, Edward B.
    Jones, Peter C.
    Jones, Holly P.
    Aronson, James
    López-López, José A.
    McCrackin, Michelle L.
    Stockholms universitet, Naturvetenskapliga fakulteten, Stockholms universitets Östersjöcentrum.
    Meli, Paula
    Montoya, Daniel
    Rey Benayas, José M.
    Anthropogenic ecosystem disturbance and the recovery debt2017Ingår i: Nature Communications, ISSN 2041-1723, E-ISSN 2041-1723, Vol. 8, artikel-id 14163Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Ecosystem recovery from anthropogenic disturbances, either without human intervention or assisted by ecological restoration, is increasingly occurring worldwide. As ecosystems progress through recovery, it is important to estimate any resulting deficit in biodiversity and functions. Here we use data from 3,035 sampling plots worldwide, to quantify the interim reduction of biodiversity and functions occurring during the recovery process (that is, the 'recovery debt'). Compared with reference levels, recovering ecosystems run annual deficits of 46-51% for organism abundance, 27-33% for species diversity, 32-42% for carbon cycling and 31-41% for nitrogen cycling. Our results are consistent across biomes but not across degrading factors. Our results suggest that recovering and restored ecosystems have less abundance, diversity and cycling of carbon and nitrogen than 'undisturbed' ecosystems, and that even if complete recovery is reached, an interim recovery debt will accumulate. Under such circumstances, increasing the quantity of less-functional ecosystems through ecological restoration and offsetting are inadequate alternatives to ecosystem protection.

  • 40. Lehtoranta, Jouni
    et al.
    Savchuk, Oleg P.
    Stockholms universitet, Naturvetenskapliga fakulteten, Stockholms universitets Östersjöcentrum, Baltic Nest Institute.
    Elken, Juri
    Dahlbo, Kim
    Kuosa, Harri
    Raateoja, Mika
    Kauppila, Pirkko
    Raike, Antti
    Pitkanen, Heikki
    Atmospheric forcing controlling inter-annual nutrient dynamics in the open Gulf of Finland2017Ingår i: Journal of Marine Systems, ISSN 0924-7963, E-ISSN 1879-1573, Vol. 171, s. 4-20Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The loading of P into the Gulf of Finland has decreased markedly, but no overall trend in the concentration of P has been observed in the open Gulf, where the concentrations of both inorganic N and P still have a pronounced inter annual variability. Our main aim was to study whether the internal processes driven by atmospheric forcing can explain the variation in the nutrient conditions in the Gulf during the period 1992-2014. We observed that the long-term salinity variation of the bottom water in the northern Baltic Proper controls that in the Gulf, and that the deep-water concentrations of oxygen and nutrients are significantly correlated between the basins. This imposes preconditions regarding how atmospheric forcing may influence deep water flows and stratification in the Gulf on a long-term scale. We found that over short timescales, winter winds in particular can control the in- and outflows of water and the vertical stratification and mixing, which to a large extent explained the inter-annual variation in the DIN and TP pools in the Gulf. We conclude that the inter-annual variation in the amounts, ratios, and spatial distribution of nutrients sets variable preconditions for the spring and potential blue-green algae blooms, and that internal processes were able to mask the effects of the P load reductions implemented across the whole Gulf. The transportation of P along the bottom from the northern Baltic Proper and its evident uplift in the Gulf highlights the fact that the nutrient reductions are also needed in the entire catchment of the Baltic Sea to improve the trophic status of the open Gulf.

  • 41. Schneider, Bernd
    et al.
    Dellwig, Olaf
    Kuliński, Karol
    Omstedt, Anders
    Pollehne, Falk
    Rehder, Gregor
    Savchuck, Oleg P.
    Stockholms universitet, Naturvetenskapliga fakulteten, Stockholms universitets Östersjöcentrum.
    Biogeochemical cycles2017Ingår i: Biological Oceanography of the Baltic Sea / [ed] Pauline Snoeijs-Leijonmalm, Hendrik Schubert, Teresa Radziejewska, Dordrecht: Springer Science+Business Media B.V., 2017, s. 87-122Kapitel i bok, del av antologi (Refereegranskat)
    Abstract [en]

    1. The internal cycles of carbon, nitrogen and phosphorus in the Baltic Sea are, like in other seas, mainly controlled by biological production and degradation of organic matter (OM).

    2. Biological activity also modulates the acid/base balance (pH), which is mainly a function of alkalinity and the total CO2 concentration.

    3. Particulate organic matter (POM) produced in the photic zone sinks into deeper water layers and is deposited on the sediment surface, where it is mineralised. Mineralisation is a form of microbial oxidation and thus leads to oxygen depletion. Due to its semi-enclosed position and its bottom topography, large-scale oxygen depletion of deep bottoms is common in the Baltic Sea.

    4. Under anoxic conditions, the burial of phosphorus bound to ferric oxide is inhibited and the availability of phosphate for incorporation in new OM production increases.

    5. In stagnant waters, the oxic/anoxic interface may migrate from the sediment into the water column, forming a pelagic redoxcline. Such a redoxcline occurs in large areas of the Baltic Sea.

    6. At oxygen concentrations close to zero, nitrate acts as an oxidant and is reduced to elemental nitrogen (denitrification). After the exhaustion of both oxygen and nitrate, OM is oxidised by sulphate, which is reduced to toxic hydrogen sulphide.

    7. The final step in the mineralisation process is the microbial formation of methane in deeper sediment layers, which reflects the internal oxidation/reduction of OM.

    8. A significant fraction of the organic carbon, nitrogen and phosphorus escapes mineralisation and is permanently buried in the sediment. On a long-term basis, this loss, together with export to the North Sea and internal sinks, is mainly balanced by riverine inputs and atmospheric deposition to the Baltic Sea.

  • 42.
    Gustafsson, Erik
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Stockholms universitets Östersjöcentrum, Baltic Nest Institute.
    Humborg, Christoph
    Stockholms universitet, Naturvetenskapliga fakulteten, Stockholms universitets Östersjöcentrum. Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Björk, Göran
    Stranne, Christian
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för geologiska vetenskaper. University of New Hampshire, USA.
    Andersson, Leif G.
    Geibel, Marc C.
    Stockholms universitet, Naturvetenskapliga fakulteten, Stockholms universitets Östersjöcentrum. Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Mörth, Carl-Magnus
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för geologiska vetenskaper.
    Sundbom, Marcus
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Semiletov, Igor P.
    Thornton, Brett F.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för geologiska vetenskaper.
    Gustafsson, Bo G.
    Stockholms universitet, Naturvetenskapliga fakulteten, Stockholms universitets Östersjöcentrum, Baltic Nest Institute.
    Carbon cycling on the East Siberian Arctic Shelf – a change in air-sea CO2 flux induced by mineralization of terrestrial organic carbon2017Ingår i: Biogeosciences, ISSN 1726-4170, E-ISSN 1726-4189Artikel i tidskrift (Övrigt vetenskapligt)
    Abstract [en]

    Measurements from the SWERUS-C3 and ISSS-08 Arctic expeditions were used to calibrate and validate a new physical-biogeochemical model developed to quantify key carbon cycling processes on the East Siberian Arctic Shelf (ESAS). The model was used in a series of experimental simulations with the specific aim to investigate the pathways of terrestrial dissolved and particulate organic carbon (DOCter and POCter) supplied to the shelf. Rivers supply on average 8.5 Tg C yr−1 dissolved inorganic carbon (DIC), and further 8.5 and 1.1 Tg C yr−1 DOCter and POCter respectively. Based on observed and simulated DOC concentrations and stable isotope values (δ13CDOC) in shelf waters, we estimate that only some 20 % of the riverine DOCter is labile. According to our model results, an additional supply of approximately 14 Tg C yr−1 eroded labile POCter is however required to describe the observed stable isotope values of DIC (δ13CDIC). Degradation of riverine DOCter and POCter results in a 1.8 Tg C yr−1 reduction in the uptake of atmospheric CO2, while degradation of eroded POCter results in an additional 10 Tg C yr−1 reduction. Our calculations indicate nevertheless that the ESAS is an overall small net sink for atmospheric CO2 (1.7 Tg C yr−1). The external carbon sources are largely compensated by a net export from the shelf to the Arctic Ocean (31 Tg C yr−1), and to a smaller degree by a permanent burial in the sediments (2.7 Tg C yr−1).

  • 43. Seidel, Michael
    et al.
    Manecki, Marcus
    Herlemann, Daniel P. R.
    Deutsch, Barbara
    Stockholms universitet, Naturvetenskapliga fakulteten, Stockholms universitets Östersjöcentrum.
    Schulz-Bull, Detlef
    Jürgens, Klaus
    Dittmar, Thorsten
    Composition and Transformation of Dissolved Organic Matter in the Baltic Sea2017Ingår i: Frontiers in Earth Science, ISSN 2296-6463, Vol. 5, artikel-id UNSP 31Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The processing of terrestrial dissolved organic matter (DOM) in coastal shelf seas is an important part of the global carbon cycle, yet, it is still not well understood. One of the largest brackish shelf seas, the Baltic Sea in northern Europe, is characterized by high freshwater input from sub-arctic rivers and limited water exchange with the Atlantic Ocean via the North Sea. We studied the molecular and isotopic composition and turnover of solid-phase extractable (SPE) DOM and its transformation along the salinity and redox continuum of the Baltic Sea during spring and autumn. We applied ultrahigh-resolution mass spectrometry and other geochemical and biological approaches. Our data demonstrate a large influx of terrestrial riverine DOM, especially into the northern part of the Baltic Sea. The DOM composition in the central Baltic Sea changed seasonally and was mainly related to autochthonous production by phytoplankton in spring. Especially in the northern, river-dominated basins, a major fraction of riverine DOM was removed, likely by bio- and photo-degradation. We estimate that the removal rate of terrestrial DOM in the Baltic Sea (Bothnian Bay to the Danish Straits/Kattegat area) is 1.6-1.9 Tg C per year which is 43-51% of the total riverine input. The export of terrestrial DOM from the Danish Straits/Kattegat area toward the North Sea is 1.8-2.1 Tg C per year. Due to the long residence time of terrestrial DOMin the Baltic Sea (total of ca. 12 years), seasonal variations caused by bio- and photo-transformations and riverine discharge are dampened, resulting in a relatively invariant DOM molecular and isotopic signature exported to the North Sea. In the deep stagnant basins of the Baltic Sea, the DOM composition and dissolved organic nitrogen concentrations changed seasonally, likely because of vertical particle transport and subsequent degradation releasing DOM. DOM in the deep anoxic basins was also enriched in sulfur-containing organic molecules, pointing to abiotic sulfurization of DOM under sulfidic conditions.

  • 44.
    Prytherch, John
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Meteorologiska institutionen (MISU). University of Leeds, UK.
    Brooks, Ian M.
    Crill, Patrick M.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för geologiska vetenskaper.
    Thornton, Brett F.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för geologiska vetenskaper.
    Salisbury, Dominic J.
    Tjernström, Michael
    Stockholms universitet, Naturvetenskapliga fakulteten, Meteorologiska institutionen (MISU).
    Anderson, Leif G.
    Geibel, Marc C.
    Stockholms universitet, Naturvetenskapliga fakulteten, Stockholms universitets Östersjöcentrum.
    Humborg, Christoph
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Direct determination of the air-sea CO2 gas transfer velocity in Arctic sea ice regions2017Ingår i: Geophysical Research Letters, ISSN 0094-8276, E-ISSN 1944-8007, Vol. 44, nr 8, s. 3770-3778Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The Arctic Ocean is an important sink for atmospheric CO2. The impact of decreasing sea ice extent and expanding marginal ice zones on Arctic air-sea CO2 exchange depends on the rate of gas transfer in the presence of sea ice. Sea ice acts to limit air-sea gas exchange by reducing contact between air and water but is also hypothesized to enhance gas transfer rates across surrounding open-water surfaces through physical processes such as increased surface-ocean turbulence from ice-water shear and ice-edge form drag. Here we present the first direct determination of the CO2 air-sea gas transfer velocity in a wide range of Arctic sea ice conditions. We show