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  • 101.
    Larsson, Ulf
    et al.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Nyberg, Svante
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Zakrisson, Anna
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Hajdu, Susanna
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Elmgren, Ragnar
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Walve, Jakob
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Rolff, Carl
    Stockholm University, Faculty of Science, Stockholm University Baltic Sea Centre.
    Baltic Sea phytoplankton: Long-term variability of major groups and primary production in spring and summer related to nutrients and temperatureManuscript (preprint) (Other academic)
  • 102. Lastra, Mariano
    et al.
    López, Jesús
    Rodil, Iván F.
    Stockholm University, Faculty of Science, Stockholm University Baltic Sea Centre. University of Helsinki, Finland.
    Warming intensify CO2 flux and nutrient release from algal wrack subsidies on sandy beaches2018In: Global Change Biology, ISSN 1354-1013, E-ISSN 1365-2486, Vol. 24, no 8, p. 3766-3779Article in journal (Refereed)
    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.

  • 103. Lehtoranta, Jouni
    et al.
    Savchuk, Oleg P.
    Stockholm University, Faculty of Science, Stockholm University Baltic Sea Centre, 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 Finland2017In: Journal of Marine Systems, ISSN 0924-7963, E-ISSN 1879-1573, Vol. 171, p. 4-20Article in journal (Refereed)
    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.

  • 104.
    Li, Zhe
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Undeman, Emma
    Stockholm University, Faculty of Science, Stockholm University Baltic Sea Centre.
    Papa, Ester
    McLachlan, Michael S.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    High-throughput evaluation of organic contaminant removal efficiency in a wastewater treatment plant using direct injection UHPLC-Orbitrap-MS/MS2018In: Environmental Science: Processes & Impacts, ISSN 2050-7887, E-ISSN 2050-7895, Vol. 20, no 3, p. 561-571Article in journal (Refereed)
    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.

  • 105. Lidström, Susanna
    et al.
    Sörlin, Sverker
    Svedäng, Henrik
    Stockholm University, Faculty of Science, Stockholm University Baltic Sea Centre. Gothenburg University, Sweden.
    Decline and diversity in Swedish seas: Environmental narratives in marine history, science and policy2020In: Ambio, ISSN 0044-7447, E-ISSN 1654-7209, Vol. 49, no 5, p. 1114-1121Article in journal (Refereed)
    Abstract [en]

    Before the mid-twentieth century, there was no comprehensive narrative about empirical conditions in Swedish seas. Around 1970, this view changed profoundly. In line with growing research and the emergence of 'the environment' as a defining concept, conditions in Swedish seas were framed as a 'narrative of decline'. Marine scientists have since recorded more diverse developments than are described by an overall declensionist narrative. Data show trends of interrupted decline, variability and even recovery, taking place at least partly in response to effective policy and legislation. We suggest that beyond the specialised fields of marine sciences and marine environmental history, the overarching narrative of decline has persisted, paying little attention to local and regional particularities as well as cultural and political dimensions of the marine environment. This overly uniform narrative risks obscuring historical reality and, hence, fails to adequately inform policy and the public about developments and outcomes of interventions in Swedish seas.

  • 106. Lohrer, Andrew M.
    et al.
    Townsend, Michael
    Hailes, Sarah F.
    Rodil, Iván F.
    Stockholm University, Faculty of Science, Stockholm University Baltic Sea Centre. National Institute of Water & Atmospheric Research, New Zealand; University of Helsinki, Finland.
    Cartner, Katie
    Pratt, Daniel R.
    Hewitt, Judi E.
    Influence of New Zealand cockles (Austrovenus stutchburyi) on primary productivity in sandflat-seagrass (Zostera muelleri) ecotones2016In: Estuarine, Coastal and Shelf Science, ISSN 0272-7714, E-ISSN 1096-0015, Vol. 181, p. 238-248Article in journal (Refereed)
    Abstract [en]

    New Zealand cockles (Austrovenus stutchburyi) are ecologically important, intertidal bivalves that have been shown to influence nutrient cycles and the productivity of microphytobenthos on sandflats. Here, we investigated the potential for cockles to impact the productivity of seagrass, Zostera muelleri, and examined interactions between these habitat-defining species where they co-occur. We sampled bivalve densities and sizes, sediment properties, and seagrass shoot densities across the boundaries of two seagrass patches on an intertidal sandflat in northern New Zealand, and measured dissolved oxygen and nutrient fluxes in light and dark benthic incubation chambers in conjunction with a 0-97% gradient in seagrass cover. Although gross primary production (GPP, mu mol O-2 m(-2) h(-1)) increased predictably with the cover of live seagrass, the density of cockles and sediment properties also contributed directly and indirectly. Seagrass cover was positively correlated with cockle density (ranging from 225 to 1350 individuals per m(2)), sediment mud percentage (0.5-9.5%), and organic matter content (0.5-2.2%), all of which can affect the efflux of ammonium (readily utilisable inorganic nitrogen) from sediments. Moreover, the cover of green seagrass blades plateaued (never exceeded 70%) in the areas of highest total seagrass cover, adding complexity to cockle-seagrass interactions and contributing to a unimodal cockleGPP relationship.

  • 107. Longo, C.
    et al.
    Hornborg, S.
    Bartolino, V.
    Tomczak, Maciej T.
    Stockholm University, Faculty of Science, Stockholm University Baltic Sea Centre.
    Ciannelli, L.
    Libralato, S.
    Belgrano, A.
    Role of trophic models and indicators in current marine fisheries management2015In: Marine Ecology Progress Series, ISSN 0171-8630, E-ISSN 1616-1599, Vol. 538, p. 257-272Article, review/survey (Refereed)
    Abstract [en]

    The previous decade has witnessed a flourishing of studies on how fisheries and marine food webs interact, and how trophic models and indicators can be used for assessment and management purposes. Acknowledging the importance of complex interactions among species, fishermen and the environment has led to a shift from single species to an ecosystem-wide approach in the science supporting fisheries management (e.g. Johannesburg Declaration, Magnuson-Stevens Act). Moreover, fisheries managers today acknowledge that fishing activities are linked to a range of societal benefits and services, and their work is necessarily a multi-objective practice (i.e. ecosystem-based management). We argue that the knowledge accumulated thus far points to tropho-dynamic models and indicators as key tools for such multi-dimensional assessments. Nevertheless, trophodynamic approaches are still underutilised in fisheries management. More specifically, most management decisions continue to rely on single species and sector-specific models. Here we review examples of applications of trophodynamic indicators within fisheries assessments in well-studied ecosystems, and discuss progress made (as well as lack thereof) towards increased integration of these metrics into marine resource management. Having clarified how trophic indicators fit within current policy and management contexts, we propose ways forward to increase their use in view of future management challenges.

  • 108.
    Lyon, Steve W.
    et al.
    Stockholm University, Faculty of Science, Department of Physical Geography. Stockholm University, Faculty of Science, Stockholm University Baltic Sea Centre, Baltic Nest Institute.
    Jantze, Elin J.
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Dahlke, Helen E.
    Jaramillo, Fernando
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Winterdahl, Mattias
    Stockholm University, Faculty of Science, Department of Physical Geography.
    WHY MONITOR CARBON IN HIGH-ALPINE STREAMS?2016In: Geografiska Annaler. Series A, Physical Geography, ISSN 0435-3676, E-ISSN 1468-0459, Vol. 98, no 3, p. 237-245Article in journal (Refereed)
    Abstract [en]

    In this short communication, we report on dissolved organic and inorganic carbon concentrations from a summer stream monitoring campaign at the main hydrological catchment of the Tarfala Research Station in northern Sweden. Further, we place these unique high-alpine observations in the context of a relevant subset of Sweden's national monitoring programme. Our analysis shows that while the monitoring programme (at least for total organic carbon) may have relatively good representativeness across a range of forest coverages, alpine/tundra environments are potentially underrepresented. As for dissolved inorganic carbon, there is currently no national monitoring in Sweden. Since the selection of stream water monitoring locations and monitored constituents at the national scale can be motivated by any number of goals (or limitations), monitoring at the Tarfala Research Station along with other research catchment sites across Fennoscandia becomes increasingly important and can offer potential complementary data necessary for improving process understanding. Research catchment sites (typically not included in national monitoring programmes) can help cover small-scale landscape features and thus complement national monitoring thereby improving the ability to capture hot spots and hot moments of biogeochemical export. This provides a valuable baseline of current conditions in high-alpine environments against which to gauge future changes in response to potential climatic and land cover shifts.

  • 109.
    Lyon, Steve W.
    et al.
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology. Stockholm University, Faculty of Science, Stockholm University Baltic Sea Centre, Baltic Nest Institute.
    Meidani, Roya
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    van der Velde, Ype
    Dahlke, Helen E.
    Swaney, Dennis P.
    Mörth, Carl-Magnus
    Stockholm University, Faculty of Science, Stockholm University Baltic Sea Centre, Baltic Nest Institute. Stockholm University, Faculty of Science, Department of Geological Sciences.
    Humborg, Christoph
    Stockholm University, Faculty of Science, Stockholm University Baltic Sea Centre, Baltic Nest Institute. Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Seasonal and Regional Patterns in Performance for a Baltic Sea Drainage Basin Hydrologic Model2015In: Journal of the American Water Resources Association, ISSN 1093-474X, E-ISSN 1752-1688, Vol. 51, no 2, p. 550-566Article in journal (Refereed)
    Abstract [en]

    This study evaluates the ability of the Catchment SIMulation (CSIM) hydrologic model to describe seasonal and regional variations in river discharge over the entire Baltic Sea drainage basin (BSDB) based on 31years of monthly simulation from 1970 through 2000. To date, the model has been successfully applied to simulate annual fluxes of water from the catchments draining into the Baltic Sea. Here, we consider spatiotemporal bias in the distribution of monthly modeling errors across the BSDB since it could potentially reduce the fidelity of predictions and negatively affect the design and implementation of land-management strategies. Within the period considered, the CSIM model accurately reproduced the annual flows across the BSDB; however, it tended to underpredict the proportion of discharge during high-flow periods (i.e., spring months) and overpredict during the summer low flow periods. While the general overpredictions during summer periods are spread across all the subbasins of the BSDB, the underprediction during spring periods is seen largely in the northern regions. By implementing a genetic algorithm calibration procedure and/or seasonal parameterization of subsurface water flows for a subset of the catchments modeled, we demonstrate that it is possible to improve the model performance albeit at the cost of increased parameterization and potential loss of parsimony.

  • 110. Matos, Marina N.
    et al.
    Lozada, Mariana
    Anselmino, Luciano E.
    Musumeci, Matías A.
    Henrissat, Bernard
    Jansson, Janet K.
    Mac Cormack, Walter P.
    Carroll, JoLynn
    Sjöling, Sara
    Lundgren, Leif
    Stockholm University, Faculty of Science, Stockholm University Baltic Sea Centre.
    Dionisi, Hebe M.
    Metagenomics unveils the attributes of the alginolytic guilds of sediments from four distant cold coastal environments2016In: Environmental Microbiology, ISSN 1462-2912, E-ISSN 1462-2920, Vol. 18, no 12, p. 4471-4484Article in journal (Refereed)
    Abstract [en]

    Alginates are abundant polysaccharides in brown algae that constitute an important energy source for marine heterotrophic bacteria. Despite the key role of alginate degradation processes in the marine carbon cycle, little information is available on the bacterial populations involved in these processes. The aim of this work was to gain a better understanding of alginate utilization capabilities in cold coastal environments. Sediment metagenomes from four high-latitude regions of both Hemispheres were interrogated for alginate lyase gene homologue sequences and their genomic context. Sediments contained highly abundant and diverse bacterial assemblages with alginolytic potential, including members of Bacteroidetes and Proteobacteria, as well as several poorly characterized taxa. The microbial communities in Arctic and Antarctic sediments exhibited the most similar alginolytic profiles, whereas brackish sediments showed distinct structures with a higher proportion of novel genes. Examination of the gene neighbourhood of the alginate lyase homologues revealed distinct patterns depending on the potential lineage of the scaffolds, with evidence of evolutionary relationships among alginolytic gene clusters from Bacteroidetes and Proteobacteria. This information is relevant for understanding carbon fluxes in cold coastal environments and provides valuable information for the development of biotechnological applications from brown algae biomass.

  • 111.
    McCrackin, Michelle L.
    et al.
    Stockholm University, Faculty of Science, Stockholm University Baltic Sea Centre.
    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 growth2017In: Biogeochemistry, ISSN 0168-2563, E-ISSN 1573-515X, Vol. 133, no 3, p. 263-277Article in journal (Refereed)
    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.

  • 112.
    McCrackin, Michelle L.
    et al.
    Stockholm University, Faculty of Science, Stockholm University Baltic Sea Centre.
    Gustafsson, Bo G.
    Stockholm University, Faculty of Science, Stockholm University Baltic Sea Centre.
    Hong, Bongghi
    Howarth, Robert W.
    Humborg, Christoph
    Stockholm University, Faculty of Science, Stockholm University Baltic Sea Centre. University of Helsinki, Finland.
    Savchuck, Oleg P.
    Stockholm University, Faculty of Science, Stockholm University Baltic Sea Centre.
    Svanbäck, Annika
    Stockholm University, Faculty of Science, Stockholm University Baltic Sea Centre.
    Swaney, Dennis P.
    Opportunities to reduce nutrient inputs to the Baltic Sea by improving manure use efficiency in agriculture2018In: Regional Environmental Change, ISSN 1436-3798, E-ISSN 1436-378X, Vol. 18, no 6, p. 1843-1854Article in journal (Refereed)
    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.

  • 113.
    McCrackin, Michelle L.
    et al.
    Stockholm University, Faculty of Science, Stockholm University Baltic Sea Centre.
    Jones, Holly P.
    Jones, Peter C.
    Moreno-Mateos, David
    Recovery of lakes and coastal marine ecosystems from eutrophication: A global meta-analysis2017In: Limnology and Oceanography, ISSN 0024-3590, E-ISSN 1939-5590, Vol. 62, no 2, p. 507-518Article in journal (Refereed)
    Abstract [en]

    In order to inform policies aimed at reducing nutrient emissions to surface waters, it is essential to understand how aquatic ecosystems respond to eutrophication management. Using data from 89 studies worldwide, we examined responses to the reduction or cessation of anthropogenic nutrient inputs relative to baseline conditions. Baseline conditions were pre-disturbance conditions, undisturbed reference sites, restoration targets, or experimental controls. We estimated recovery completeness (% baseline conditions reached) and recovery rate (annual % change relative to baseline conditions) for plant and animal abundance and diversity and for ecosystem functions. Categories were considered fully recovered if the 95% confidence interval (CI) of recovery completeness overlapped 100% and partially recovered if the CI did not overlap either 100% or zero. Cessation of nutrient inputs did not result in more complete or faster recovery than partial nutrient reductions, due likely to insufficient passage of time, nutrients from other sources, or shifting baselines. Together, lakes and coastal marine areas achieved 34% (+/- 16% CI) and 24% (+/- 15% CI) of baseline conditions decades after the cessation or partial reduction of nutrients, respectively. One third of individual response variables showed no change or worsened conditions, suggesting that achieving baseline conditions may not be possible in all cases. Implied recovery times after cessation of nutrient inputs varied widely, from < 1 yr to nearly a century, depending on response. Our results suggest that long-term monitoring is needed to better understand recovery timescales and trajectories and that policy measures must consider the potential for slow and partial recovery.

  • 114.
    McCrackin, Michelle L.
    et al.
    Stockholm University, Faculty of Science, Stockholm University Baltic Sea Centre.
    Muller-Karulis, Bärbel
    Stockholm University, Faculty of Science, Stockholm University Baltic Sea Centre.
    Gustafsson, Bo G.
    Stockholm University, Faculty of Science, Stockholm University Baltic Sea Centre. University of Helsinki, Finland.
    Howarth, Robert W.
    Humborg, Christoph
    Stockholm University, Faculty of Science, Stockholm University Baltic Sea Centre. University of Helsinki, Finland.
    Svanbäck, Annika
    Stockholm University, Faculty of Science, Stockholm University Baltic Sea Centre.
    Swaney, Dennis P.
    A Century of Legacy Phosphorus Dynamics in a Large Drainage Basin2018In: Global Biogeochemical Cycles, ISSN 0886-6236, E-ISSN 1944-9224, Vol. 32, no 7, p. 1107-1122Article in journal (Refereed)
    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.

  • 115.
    McLachlan, Michael S.
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Undeman, Emma
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry. Stockholm University, Faculty of Science, Stockholm University Baltic Sea Centre.
    Zhao, Fangyuan
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    MacLeod, Matthew
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Predicting global scale exposure of humans to PCB 153 from historical emissions2018In: Environmental Science: Processes & Impacts, ISSN 2050-7887, E-ISSN 2050-7895, Vol. 20, no 5, p. 747-756Article in journal (Refereed)
    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.

  • 116. Meier, H. E. Markus
    et al.
    Andersson, Helen C.
    Arheimer, Berit
    Donnelly, Chantal
    Eilola, Kari
    Gustafsson, Bo G.
    Stockholm University, Faculty of Science, Stockholm University Baltic Sea Centre, Baltic Nest Institute.
    Kotwicki, Lech
    Neset, Tina-Simone
    Niiranen, Susa
    Stockholm University, Faculty of Science, Stockholm Resilience Centre.
    Piwowarczyk, Joanna
    Savchuk, Oleg P.
    Stockholm University, Faculty of Science, Stockholm University Baltic Sea Centre, Baltic Nest Institute.
    Schenk, Frederik
    Weslawski, Jan Marcin
    Zorita, Eduardo
    Ensemble Modeling of the Baltic Sea Ecosystem to Provide Scenarios for Management2014In: Ambio, ISSN 0044-7447, E-ISSN 1654-7209, Vol. 43, no 1, p. 37-48Article in journal (Refereed)
    Abstract [en]

    We present a multi-model ensemble study for the Baltic Sea, and investigate the combined impact of changing climate, external nutrient supply, and fisheries on the marine ecosystem. The applied regional climate system model contains state-of-the-art component models for the atmosphere, sea ice, ocean, land surface, terrestrial and marine biogeochemistry, and marine food-web. Time-dependent scenario simulations for the period 1960-2100 are performed and uncertainties of future projections are estimated. In addition, reconstructions since 1850 are carried out to evaluate the models sensitivity to external stressors on long time scales. Information from scenario simulations are used to support decision-makers and stakeholders and to raise awareness of climate change, environmental problems, and possible abatement strategies among the general public using geovisualization. It is concluded that the study results are relevant for the Baltic Sea Action Plan of the Helsinki Commission.

  • 117. Meier, H. E. Markus
    et al.
    Edman, Moa
    Eilola, Kari
    Placke, Manja
    Neumann, Thomas
    Andersson, Helen C.
    Brunnabend, Sandra-Esther
    Dieterich, Christian
    Frauen, Claudia
    Friedland, Rene
    Gröger, Matthias
    Gustafsson, Bo G.
    Stockholm University, Faculty of Science, Stockholm University Baltic Sea Centre. University of Helsinki, Finland.
    Gustafsson, Erik
    Stockholm University, Faculty of Science, Stockholm University Baltic Sea Centre.
    Isaev, Alexey
    Kniebusch, Madline
    Kuznetsov, Ivan
    Müller-Karulis, Bärbel
    Stockholm University, Faculty of Science, Stockholm University Baltic Sea Centre.
    Naumann, Michael
    Omstedt, Anders
    Ryabchenko, Vladimir
    Saraiva, Sofia
    Savchuk, Oleg P.
    Stockholm University, Faculty of Science, Stockholm University Baltic Sea Centre.
    Assessment of Uncertainties in Scenario Simulations of Biogeochemical Cycles in the Baltic Sea2019In: Frontiers in Marine Science, E-ISSN 2296-7745, Vol. 6, article id 46Article, review/survey (Refereed)
    Abstract [en]

    Following earlier regional assessment studies, such as the Assessment of Climate Change for the Baltic Sea Basin and the North Sea Region Climate Change Assessment, knowledge acquired from available literature about future scenario simulations of biogeochemical cycles in the Baltic Sea and their uncertainties is assessed. The identification and reduction of uncertainties of scenario simulations are issues for marine management. For instance, it is important to know whether nutrient load abatement will meet its objectives of restored water quality status in future climate or whether additional measures are required. However, uncertainties are large and their sources need to be understood to draw conclusions about the effectiveness of measures. The assessment of sources of uncertainties in projections of biogeochemical cycles based on authors' own expert judgment suggests that the biggest uncertainties are caused by (1) unknown current and future bioavailable nutrient loads from land and atmosphere, (2) the experimental setup (including the spin up strategy), (3) differences between the projections of global and regional climate models, in particular, with respect to the global mean sea level rise and regional water cycle, (4) differing model-specific responses of the simulated biogeochemical cycles to long-term changes in external nutrient loads and climate of the Baltic Sea region, and (5) unknown future greenhouse gas emissions. Regular assessments of the models' skill (or quality compared to observations) for the Baltic Sea region and the spread in scenario simulations (differences among projected changes) as well as improvement of dynamical downscaling methods are recommended.

  • 118. Meier, H. E. Markus
    et al.
    Edman, Moa K.
    Eilola, Kari J.
    Placke, Manja
    Neumann, Thomas
    Andersson, Helén C.
    Brunnabend, Sandra-Esther
    Dieterich, Christian
    Frauen, Claudia
    Friedland, René
    Gröger, Matthias
    Gustafsson, Bo G.
    Stockholm University, Faculty of Science, Stockholm University Baltic Sea Centre, Baltic Nest Institute. University of Helsinki, Finland.
    Gustafsson, Erik
    Stockholm University, Faculty of Science, Stockholm University Baltic Sea Centre, Baltic Nest Institute.
    Isaev, Alexey
    Kniebusch, Madline
    Kuznetsov, Ivan
    Müller-Karulis, Bärbel
    Stockholm University, Faculty of Science, Stockholm University Baltic Sea Centre, Baltic Nest Institute.
    Omstedt, Anders
    Ryabchenko, Vladimir
    Saraiva, Sofia
    Savchuk, Oleg P.
    Stockholm University, Faculty of Science, Stockholm University Baltic Sea Centre, Baltic Nest Institute.
    Assessment of Eutrophication Abatement Scenarios for the Baltic Sea by Multi-Model Ensemble Simulations2018In: Frontiers in Marine Science, E-ISSN 2296-7745, Vol. 5, article id 440Article in journal (Refereed)
    Abstract [en]

    To assess the impact of the implementation of the Baltic Sea Action Plan (BSAP) on the future environmental status of the Baltic Sea, available uncoordinated multi-model ensemble simulations for the Baltic Sea region for the twenty-first century were analyzed. 

    The scenario simulations were driven by regionalized global general circulation model (GCM) data using several regional climate system models and forced by various future greenhouse gas emission and air- and river-borne nutrient load scenarios following either reference conditions or the BSAP. To estimate uncertainties in projections, the largest ever multi-model ensemble for the Baltic Sea comprising 58 transient simulations for the twenty-first century was assessed. Data from already existing simulations from different projects including regionalized GCM simulations of the third and fourth assessment reports of the Intergovernmental Panel on Climate Change based on the corresponding Coupled Model Intercomparison Projects, CMIP3 and CMIP5, were collected.

    Various strategies to weigh the ensemble members were tested and the results for ensemble mean changes between future and present climates are shown to be robust with respect to the chosen metric. Although (1) the model simulations during the historical period are of different quality and (2) the assumptions on nutrient load levels during present and future periods differ between models considerably, the ensemble mean changes in biogeochemical variables in the Baltic proper with respect to nutrient load reductions are similar between the entire ensemble and a subset consisting only of the most reliable simulations.

    Despite the large spread in projections, the implementation of the BSAP will lead to a significant improvement of the environmental status of the Baltic Sea according to both weighted and unweighted ensembles. The results emphasize the need for investigating ensembles with many members and rigorous assessments of models’ performance.

  • 119. Meysick, Lukas
    et al.
    Ysebaert, Tom
    Jansson, Anna
    Montserrat, Francesc
    Valanko, Sebastian
    Villnäs, Anna
    Boström, Christoffer
    Norkko, Joanna
    Norkko, Alf
    Stockholm University, Faculty of Science, Stockholm University Baltic Sea Centre. University of Helsinki, Finland.
    Context-dependent community facilitation in seagrass meadows along a hydrodynamic stress gradient2019In: Journal of Sea Research, ISSN 1385-1101, E-ISSN 1873-1414, Vol. 150, p. 8-23Article in journal (Refereed)
    Abstract [en]

    Foundation species host diverse associated communities by ameliorating environmental stress. The strength of this facilitative effect can be highly dependent on the underlying biotic and abiotic context. We investigated community level patterns of macrofauna associated with and adjacent to the marine foundation species eelgrass (Zostera marina) along a hydrodynamic stress gradient. We could demonstrate that the relative importance of this foundation species for its infaunal community increases with environmental variables associated with increasing hydrodynamic stress (depth, sand ripples formation, sediment grain size and organic content). Faunal assemblages in proximity to the Zostera patch edges, however, showed no (infauna) or negative (epifauna) response to hydrodynamic stress. Our study highlights that the facilitative outcome of a foundation species is conditional to the faunal assemblage in question and can be highly variable even between positions within the habitat.

  • 120. Moellmann, Christian
    et al.
    Lindegren, Martin
    Blenckner, Thorsten
    Stockholm University, Faculty of Science, Stockholm Resilience Centre.
    Bergström, Lena
    Casini, Michele
    Diekmann, Rabea
    Flinkman, Juha
    Muller-Karulis, Bärbel
    Stockholm University, Faculty of Science, Stockholm University Baltic Sea Centre.
    Neuenfeldt, Stefan
    Schmidt, Joern O.
    Tomczak, Maciej
    Stockholm University, Faculty of Science, Stockholm University Baltic Sea Centre.
    Voss, Ruediger
    Gårdmark, Anna
    Implementing ecosystem-based fisheries management: from single-species to integrated ecosystem assessment and advice for Baltic Sea fish stocks2014In: ICES Journal of Marine Science, ISSN 1054-3139, E-ISSN 1095-9289, Vol. 71, no 5, p. 1187-1197Article in journal (Refereed)
    Abstract [en]

    Theory behind ecosystem-based management (EBM) and ecosystem-based fisheries management (EBFM) is now well developed. However, the implementation of EBFM exemplified by fisheries management in Europe is still largely based on single-species assessments and ignores the wider ecosystem context and impact. The reason for the lack or slow implementation of EBM and specifically EBFM is a lack of a coherent strategy. Such a strategy is offered by recently developed integrated ecosystem assessments (IEAs), a formal synthesis tool to quantitatively analyse information on relevant natural and socio-economic factors, in relation to specified management objectives. Here, we focus on implementing the IEA approach for Baltic Sea fish stocks. We combine both tactical and strategic management aspects into a single strategy that supports the present Baltic Sea fish stock advice, conducted by the International Council for the Exploration of the Sea (ICES). We first review the state of the art in the development of IEA within the current management framework. We then outline and discuss an approach that integrates fish stock advice and IEAs for the Baltic Sea. We intentionally focus on the central Baltic Sea and its three major fish stocks cod (Gadus morhua), herring (Clupea harengus), and sprat (Sprattus sprattus), but emphasize that our approach may be applied to other parts and stocks of the Baltic, as well as other ocean areas.

  • 121. Momigliano, Paolo
    et al.
    Jokinen, Henri
    Fraimout, Antoine
    Florin, Ann-Britt
    Norkko, Alf
    Stockholm University, Faculty of Science, Stockholm University Baltic Sea Centre. University of Helsinki, Finland.
    Merila, Juha
    Extraordinarily rapid speciation in a marine fish2017In: Proceedings of the National Academy of Sciences of the United States of America, ISSN 0027-8424, E-ISSN 1091-6490, Vol. 114, no 23, p. 6074-6079Article in journal (Refereed)
    Abstract [en]

    Divergent selection may initiate ecological speciation extremely rapidly. How often and at what pace ecological speciation proceeds to yield strong reproductive isolation is more uncertain. Here, we document a case of extraordinarily rapid speciation associated with ecological selection in the postglacial Baltic Sea. European flounders (Platichthys flesus) in the Baltic exhibit two contrasting reproductive behaviors: pelagic and demersal spawning. Demersal spawning enables flounders to thrive in the low salinity of the Northern Baltic, where eggs cannot achieve neutral buoyancy. We show that demersal and pelagic flounders are a species pair arising from a recent event of speciation. Despite having a parapatric distribution with extensive overlap, the two species are reciprocally monophyletic and show strongly bimodal genotypic clustering and no evidence of contemporary migration, suggesting strong reproductive isolation. Divergence across the genome is weak but shows strong signatures of selection, a pattern suggestive of a recent ecological speciation event. We propose that spawning behavior in Baltic flounders is the trait under ecologically based selection causing reproductive isolation, directly implicating a process of ecological speciation. We evaluated different possible evolutionary scenarios under the approximate Bayesian computation framework and estimate that the speciation process started in allopatry similar to 2,400 generations ago, following the colonization of the Baltic by the demersal lineage. This is faster than most known cases of ecological speciation and represents the most rapid event of speciation ever reported for any marine vertebrate.

  • 122. Moreno-Mateos, David
    et al.
    Barbier, Edward B.
    Jones, Peter C.
    Jones, Holly P.
    Aronson, James
    López-López, José A.
    McCrackin, Michelle L.
    Stockholm University, Faculty of Science, Stockholm University Baltic Sea Centre.
    Meli, Paula
    Montoya, Daniel
    Rey Benayas, José M.
    Anthropogenic ecosystem disturbance and the recovery debt2017In: Nature Communications, ISSN 2041-1723, E-ISSN 2041-1723, Vol. 8, article id 14163Article in journal (Refereed)
    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.

  • 123.
    Mustajärvi, Lukas
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Eek, Espen
    Cornelissen, Gerard
    Eriksson-Wiklund, Ann-Kristin
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Undeman, Emma
    Stockholm University, Faculty of Science, Stockholm University Baltic Sea Centre.
    Sobek, Anna
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    In situ benthic flow-through chambers to determine sediment-to-water fluxes of legacy hydrophobic organic contaminants2017In: Environmental Pollution, ISSN 0269-7491, E-ISSN 1873-6424, Vol. 231, p. 854-862Article in journal (Refereed)
    Abstract [en]

    Contaminated sediment can release hydrophobic organic contaminants (HOCs) and thereby act as a secondary source of primarily legacy hazardous substances to the water column. There is therefore a need for assessments of the release of HOCs from contaminated sediment for prioritization of management actions. In situ assessment of HOC sediment-to-water flux is currently done with (closed) benthic flux chambers, which have a sampling time exceeding one month. During this time, the water inside the chamber is depleted of oxygen and the effect of bioturbation on the sediment-to-water release of HOCs is largely ignored. Here we present a novel benthic flux chamber, which measures sediment-to-water flux of legacy HOCs within days, and includes the effect of bioturbation since ambient oxygen levels inside the chamber are maintained by continuous pumping of water through the chamber. This chamber design allows for sediment-to-water flux measurements under more natural conditions. The chamber design was tested in a contaminated Baltic Sea bay. Measured fluxes were 62–2300 ng m−2 d−1 for individual polycyclic aromatic hydrocarbons (PAHs), and 5.5–150 ng m−2 d−1 for polychlorinated biphenyls (PCBs). These fluxes were 3–23 times (PAHs) and 12–74 times (PCBs) higher than fluxes measured with closed benthic chambers deployed in parallel at the same location. We hypothesize that the observed difference in HOC flux between the two chamber designs are partly an effect of bioturbation. This hypothesized effect of bioturbation was in accordance with literature data from experimental studies.

  • 124. 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.
    Stockholm University, Faculty of Science, Stockholm University Baltic Sea Centre.
    Ulrich, Clara
    van Dijk, Diana
    Vermard, Youen
    Voss, Rudi
    Waldo, Staffan
    Integrated ecological–economic fisheries models—Evaluation, review and challenges for implementation2018In: Fish and Fisheries, ISSN 1467-2960, E-ISSN 1467-2979, Vol. 19, no 1, p. 1-29Article, review/survey (Refereed)
    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.

  • 125.
    Niiranen, Susa
    et al.
    Stockholm University, Faculty of Science, Stockholm Resilience Centre. Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Yletyinen, Johanna
    Stockholm University, Faculty of Science, Stockholm Resilience Centre. University of Olso, Norway.
    Tomczak, Maciej T.
    Stockholm University, Faculty of Science, Stockholm University Baltic Sea Centre, Baltic Nest Institute.
    Blenckner, Thorsten
    Stockholm University, Faculty of Science, Stockholm Resilience Centre.
    Hjerne, Olle
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    MacKenzie, Brian R.
    Müller-Karulis, Bärbel
    Stockholm University, Faculty of Science, Stockholm University Baltic Sea Centre, Baltic Nest Institute.
    Neumann, Thomas
    Meier, H. E. Markus
    Stockholm University, Faculty of Science, Department of Meteorology . Swedish Meteorological and Hydrological Institute, Sweden.
    Combined effects of global climate change and regional ecosystem drivers on an exploited marine food web2013In: Global Change Biology, ISSN 1354-1013, E-ISSN 1365-2486, Vol. 19, no 11, p. 3327-3342Article in journal (Refereed)
    Abstract [en]

    Changes in climate, in combination with intensive exploitation of marine resources, have caused large-scale reorganizations in many of the world's marine ecosystems during the past decades. The Baltic Sea in Northern Europe is one of the systems most affected. In addition to being exposed to persistent eutrophication, intensive fishing, and one of the world's fastest rates of warming in the last two decades of the 20th century, accelerated climate change including atmospheric warming and changes in precipitation is projected for this region during the 21st century. Here, we used a new multi-model approach to project how the interaction of climate, nutrient loads and cod fishing may affect the future of the open Central Baltic Sea food web. Regionally downscaled global climate scenarios were, in combination with three nutrient load scenarios, used to drive an ensemble of three regional biogeochemical models (BGMs). An Ecopath with Ecosim food web model was then forced with the BGM results from different nutrient-climate scenarios in combination with two different cod fishing scenarios. The results showed that regional management is likely to play a major role in determining the future of the Baltic Sea ecosystem. By the end of the 21st century, for example, the combination of intensive cod fishing and high nutrient loads projected a strongly eutrophicated and sprat-dominated ecosystem, while low cod fishing in combination with low nutrient loads resulted in a cod-dominated ecosystem with eutrophication levels close to present. Also, non-linearities were observed in the sensitivity of different trophic groups to nutrient loads or fishing depending on the combination of the two. Finally, many climate variables and species biomasses were projected to levels unseen in the past. Hence, the risk for ecological surprises needs to be addressed, particularly when the results are discussed in the ecosystem-based management context.

  • 126.
    Nilsson Austin, Åsa
    et al.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Hansen, Joakim P.
    Stockholm University, Faculty of Science, Stockholm University Baltic Sea Centre.
    Donadi, Serena
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Eklöf, Johan S.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Relationships between aquatic vegetation and water turbidity: A field survey across seasons and spatial scales2017In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 12, no 8, article id e0181419Article in journal (Refereed)
    Abstract [en]

    Field surveys often show that high water turbidity limits cover of aquatic vegetation, while many small-scale experiments show that vegetation can reduce turbidity by decreasing water flow, stabilizing sediments, and competing with phytoplankton for nutrients. Here we bridged these two views by exploring the direction and strength of causal relationships between aquatic vegetation and turbidity across seasons (spring and late summer) and spatial scales (local and regional), using causal modeling based on data from a field survey along the central Swedish Baltic Sea coast. The two best-fitting regional-scale models both suggested that in spring, high cover of vegetation reduces water turbidity. In summer, the relationships differed between the two models; in the first model high vegetation cover reduced turbidity; while in the second model reduction of summer turbidity by high vegetation cover in spring had a positive effect on summer vegetation which suggests a positive feedback of vegetation on itself. Nitrogen load had a positive effect on turbidity in both seasons, which was comparable in strength to the effect of vegetation on turbidity. To assess whether the effect of vegetation was primarily caused by sediment stabilization or a reduction of phytoplankton, we also tested models where turbidity was replaced by phytoplankton fluorescence or sediment-driven turbidity. The best-fitting regional-scale models suggested that high sediment-driven turbidity in spring reduces vegetation cover in summer, which in turn has a negative effect on sediment-driven turbidity in summer, indicating a potential positive feedback of sediment-driven turbidity on itself. Using data at the local scale, few relationships were significant, likely due to the influence of unmeasured variables and/or spatial heterogeneity. In summary, causal modeling based on data from a large-scale field survey suggested that aquatic vegetation can reduce turbidity at regional scales, and that high vegetation cover vs. high sediment-driven turbidity may represent two self-enhancing, alternative states of shallow bay ecosystems.

  • 127. Norkko, Joanna
    et al.
    Pilditch, Conrad A.
    Gammal, Johanna
    Rosenberg, Rutger
    Enemar, Arvid
    Magnusson, Marina
    Granberg, Maria E.
    Lindgren, J. Fredrik
    Agrenius, Stefan
    Norkko, Alf
    Stockholm University, Faculty of Science, Stockholm University Baltic Sea Centre. University of Helsinki, Finland.
    Ecosystem functioning along gradients of increasing hypoxia and changing soft-sediment community types2019In: Journal of Sea Research, ISSN 1385-1101, E-ISSN 1873-1414, Vol. 153, article id 101781Article in journal (Refereed)
    Abstract [en]

    Marine ecosystems world-wide are threatened by oxygen deficiency, with potential serious consequences for ecosystem functioning and the goods and services they provide. While the effects of hypoxia on benthic species diversity are well documented, the effects on ecosystem function have only rarely been assessed in real-world settings. To better understand the links between structural changes in macro- and meiofaunal communities, hypoxic stress and benthic ecosystem function (benthic nutrient fluxes, community metabolism), we sampled a total of 11 sites in Haystensfjord and Askerofjord (Swedish west coast) in late summer, coinciding with the largest extent and severity of seasonal hypoxia in the area. The sites spanned oxic to anoxic bottom water, and a corresponding gradient in faunal diversity. Intact sediment cores were incubated to measure fluxes of oxygen and nutrients (NO3-, NO2-, NH4+, PO43-, SiO4) across the sediment-water interface. Sediment profile imaging (SPI) footage was obtained from all sites to assess structural elements and the bioturbadon depth, and additional samples were collected to characterise sediment properties and macro- and meiofaunal community composition. Bottom-water O-2 concentration was the main driver of macrofauna communities, with highest abundance and biomass, as well as variability, at the sites with intermediate O-2 concentration. Meiofauna on the other hand was less sensitive to bottom-water O-2 concentration. Oxygen was the main driver of nutrient fluxes too, but macrofauna as well meiofauna were also significant predictors; DistLM analyses indicated that O-2 concentration, macrofaunal abundance or biomass, and meiofaunal abundance collectively explained 63%, 30% and 28% of the variation in sediment O-2 consumption, NH4+ flux and PO43+ flux, respectively. The study provides a step towards a more realistic understanding of the link between benthic fauna and ecosystem functioning, and the influence of disturbance on this relationship, which is important for management decisions aimed at protecting the dwindling biodiversity in the coastal zones around the world.

  • 128.
    Norström, Albert
    et al.
    Stockholm University, Faculty of Science, Stockholm Resilience Centre.
    Cvitanovic, Christopher
    Löf, Marie F.
    Stockholm University, Faculty of Science, Stockholm University Baltic Sea Centre.
    West, Simon
    Stockholm University, Faculty of Science, Stockholm Resilience Centre. Australian National University, Australia; Charles Darwin University, Australia.
    Wyborn, Carina
    Balvanera, Patricia
    Bednarek, Angela T.
    Bennett, Elena M.
    Biggs, Reinette
    Stockholm University, Faculty of Science, Stockholm Resilience Centre. Stellenbosch University, South Africa.
    de Bremond, Ariane
    Campbell, Bruce M.
    Canadell, Josep G.
    Carpenter, Stephen R.
    Folke, Carl
    Stockholm University, Faculty of Science, Stockholm Resilience Centre. Royal Swedish Academy of Sciences, Sweden.
    Fulton, Elizabeth A.
    Gaffney, Owen
    Stockholm University, Faculty of Science, Stockholm Resilience Centre. Potsdam Institute for Climate Impact Research, Germany.
    Gelcich, Stefan
    Jouffray, Jean-Baptiste
    Stockholm University, Faculty of Science, Stockholm Resilience Centre. Royal Swedish Academy of Sciences, Sweden.
    Leach, Melissa
    Le Tissier, Martin
    Martin-López, Berta
    Louder, Elena
    Loutre, Marie-France
    Meadow, Alison M.
    Nagendra, Harini
    Payne, Davnah
    Peterson, Garry D.
    Stockholm University, Faculty of Science, Stockholm Resilience Centre.
    Reyers, Belinda
    Stockholm University, Faculty of Science, Stockholm Resilience Centre. Stellenbosch University, South Africa.
    Scholes, Robert
    Speranza, Chinwe Ifejika
    Spierenburg, Marja
    Stafford-Smith, Mark
    Tengö, Maria
    Stockholm University, Faculty of Science, Stockholm Resilience Centre.
    van der Hel, Sandra
    van Putten, Ingrid
    Österblom, Henrik
    Stockholm University, Faculty of Science, Stockholm Resilience Centre.
    Principles for knowledge co-production in sustainability research2020In: Nature Sustainability, E-ISSN 2398-9629, Vol. 3, no 3, p. 182-190Article in journal (Refereed)
    Abstract [en]

    Research practice, funding agencies and global science organizations suggest that research aimed at addressing sustainability challenges is most effective when 'co-produced' by academics and non-academics. Co-production promises to address the complex nature of contemporary sustainability challenges better than more traditional scientific approaches. But definitions of knowledge co-production are diverse and often contradictory. We propose a set of four general principles that underlie high-quality knowledge co-production for sustainability research. Using these principles, we offer practical guidance on how to engage in meaningful co-productive practices, and how to evaluate their quality and success. Research addressing sustainability issues is more effective if 'co-produced' by academics and non-academics, but definitions of co-production vary. This Perspective presents four knowledge co-production principles for sustainability research and guides on how to engage in co-productive practices.

  • 129. Odom Green, Olivia
    et al.
    Schultz, Lisen
    Stockholm University, Faculty of Science, Stockholm Resilience Centre.
    Nekoro, Marmar
    Stockholm University, Faculty of Science, Stockholm University Baltic Sea Centre.
    Garmestani, Ahjond G.
    The Role of Bridging Organizations in Enhancing Ecosystem Services and Facilitating Adaptive Management of Social-Ecological Systems2015In: Adaptive Management of Social-Ecological Systems / [ed] Craig R. Allen, Ahjond S. Garmestani, Springer Netherlands, 2015, p. 107-122Chapter in book (Refereed)
    Abstract [en]

    The nested nature of social-ecological systems across scales requires a multi-scale approach for monitoring and response. However, in many cases this flow is hindered by hierarchical structures and bureaucratic procedures. Recent research suggests that bridging organizations that facilitate collaboration and learning across sectors and scales are key to adaptive governance. Bridging organizations can facilitate cross-scale linkages, enabling formal management entities operating at discrete scales to improve communication channels and create opportunities for collaboration. This allows for management to set new target levels and modify policy to reach those target levels as new information is generated on scale-specific system attributes. Bridging organizations also incubate new ideas for environmental management, provide a forum for coming to agreement on contentious issues, and foster the capacity to manage for resilience of social-ecological systems and the provisioning of ecosystem services that are directly and indirectly important on a regional and international scale.

  • 130. Olsson, Jens
    et al.
    Tomczak, Maciej T.
    Stockholm University, Faculty of Science, Stockholm University Baltic Sea Centre.
    Ojaveer, Henn
    Gårdmark, Anna
    Pöllumäe, Arno
    Muller-Karulis, Bärbel
    Stockholm University, Faculty of Science, Stockholm University Baltic Sea Centre.
    Ustups, Didzis
    Dinesen, Grete E.
    Peltonen, Heikki
    Putnis, Ivars
    Szymanek, Lena
    Simm, Mart
    Heikinheimo, Outi
    Gasyukov, Pavel
    Axe, Philip
    Bergström, Lena
    Temporal development of coastal ecosystems in the Baltic Sea over the past two decades2015In: ICES Journal of Marine Science, ISSN 1054-3139, E-ISSN 1095-9289, Vol. 72, no 9, p. 2539-2548Article in journal (Refereed)
    Abstract [en]

    Coastal areas are among the most biologically productive aquatic systems worldwide, but face strong and variable anthropogenic pressures. Few studies have, however, addressed the temporal development of coastal ecosystems in an integrated context. This study represents an assessment of the development over time in 13 coastal ecosystems in the Baltic Sea region during the past two decades. The study covers between two to six trophic levels per system and time-series dating back to the early 1990s. We applied multivariate analyses to assess the temporal development of biological ecosystem components and relate these to potential driving variables associated with changes in climate, hydrology, nutrient status, and fishing pressure. Our results show that structural change often occurred with similar timing in the assessed coastal systems. Moreover, in 10 of the 13 systems, a directional development of the ecosystem components was observed. The variables representing key ecosystem components generally differed across systems, due to natural differences and limitation to available data. As a result of this, the correlation between the temporal development of the biological components in each area and the driving variables assessed was to some extent area-specific. However, change in nutrient status was a common denominator of the variables most often associated with changes in the assessed systems. Our results, additionally, indicate existing strengths as well as future challenges in the capacity of currently available monitoring data to support integrated assessments and the implementation of an integrated ecosystem-based approach to the management of the Baltic Sea coastal ecosystems.

  • 131.
    Palomino-Ángel, Sebastián
    et al.
    Stockholm University, Faculty of Science, Department of Physical Geography. Universidad de Medellín, Colombia.
    Anaya-Acevedo, Jesús A.
    Simard, Marc
    Liao, Tien-Hao
    Jaramillo, Fernando
    Stockholm University, Faculty of Science, Department of Physical Geography. Stockholm University, Faculty of Science, Stockholm University Baltic Sea Centre. Stockholm University, Faculty of Science, Stockholm Resilience Centre.
    Analysis of Floodplain Dynamics in the Atrato River Colombia Using SAR Interferometry2019In: Water, ISSN 2073-4441, E-ISSN 2073-4441, Vol. 11, no 5, article id 875Article in journal (Refereed)
    Abstract [en]

    Floodplain water flows have large volumetric flowrates and high complexity in space and time that are difficult to understand using water level gauges. We here analyze the spatial and temporal fluctuations of surface water flows in the floodplain of the Atrato River, Colombia, in order to evaluate their hydrological connectivity. The basin is one of the rainiest areas of the world with wetland ecosystems threatened by the expansion of agriculture and mining activities. We used 16 Differential Interferometric Synthetic Aperture Radars (DInSAR) phase observations from the ALOS-PALSAR L-band instrument acquired between 2008-2010 to characterize the flow of surface water. We were able to observe water level change in vegetated wetland areas and identify flooding patterns. In the lower basin, flow patterns are conditioned by fluctuations in the levels of the main river channel, whereas in the middle basin, topography and superficial channels strongly influence the flow and connectivity. We found that the variations in water level in a station on the main channel 87 km upstream explained more than 56% of the variations in water level in the floodplain. This result shows that, despite current expansion of agriculture and mining activities, there remain significant hydrological connectivity between wetlands and the Atrato River. This study demonstrates the use of DInSAR for a spatially comprehensive monitoring of the Atrato River basin hydrology. For the first time, we identified the spatiotemporal patterns of surface water flow of the region. We recommend these observations serve as a baseline to monitor the potential impact of ongoing human activities on surface water flows across the Atrato River basin.

  • 132.
    Piemontese, Luigi
    et al.
    Stockholm University, Faculty of Science, Stockholm Resilience Centre.
    Fetzer, Ingo
    Stockholm University, Faculty of Science, Stockholm Resilience Centre.
    Rockström, Johan
    Stockholm University, Faculty of Science, Stockholm Resilience Centre. Potsdam Institute for Climate Impact Research, Germany.
    Jaramillo, Fernando
    Stockholm University, Faculty of Science, Stockholm Resilience Centre. Stockholm University, Faculty of Science, Department of Physical Geography. Stockholm University, Faculty of Science, Stockholm University Baltic Sea Centre.
    Future Hydroclimatic Impacts on Africa: Beyond the Paris Agreement2019In: Earth's Future, ISSN 1384-5160, E-ISSN 2328-4277, Vol. 7, no 7, p. 748-761Article in journal (Refereed)
    Abstract [en]

    Projections of global warming in Africa are generally associated with increasing aridity and decreasing water availability. However, most freshwater assessments focus on single hydroclimatic indicators (e.g., runoff, precipitation, or aridity), lacking analysis on combined changes in evaporative demand, and water availability on land. There remains a high degree of uncertainty over water implications at the basin scale, in particular for the most water-consuming sector-food production. Using the Budyko framework, we perform an assessment of future hydroclimatic change for the 50 largest African basins, finding a consistent pattern of change in four distinct regions across the two main emission scenarios corresponding to the Paris Agreement, and the business as usual. Although the Paris Agreement is likely to lead to less intense changes when compared to the business as usual, both scenarios show the same pattern of hydroclimatic shifts, suggesting a potential roadmap for hydroclimatic adaptation. We discuss the social-ecological implications of the projected hydroclimatic shifts in the four regions and argue that climate policies need to be complemented by soil and water conservation practices to make the best use of future water resources.

  • 133. Pinnegar, John K.
    et al.
    Tomczak, Maciej T.
    Stockholm University, Faculty of Science, Stockholm Resilience Centre. Stockholm University, Faculty of Science, Stockholm University Baltic Sea Centre, Baltic Nest Institute.
    Link, Jason S.
    How to determine the likely indirect food-web consequences of a newly introduced non-native species: A worked example2014In: Ecological Modelling, ISSN 0304-3800, E-ISSN 1872-7026, Vol. 272, p. 379-387Article in journal (Refereed)
    Abstract [en]

    In this paper we demonstrate through a worked case-study that it is possible to make an assessment of the indirect food-web consequences that might occur as a result of the arrival of a hither-to not observed non-native species. We also explore implications for commercial fisheries catches, through the application of a suite of complimentary ecosystem modelling tools. Fistularia commersonii is a lessepsian migrant (introduced via the Suez Canal) that was first recorded in the Mediterranean in January 2000. It has since spread throughout the basin and has been described as the fastest and farthest spreading lessepsian fish migrant ever recorded'. We have used a Rank Proportion Algorithm (RPA) model to predict the theoretical diet composition of F. commersonii in the Bay of Calvi, Corsica. We did so based on potential prey abundances, as well as morphological and behavioural characteristics of both the prey and this novel predator. The 'predicted' diet composition of F. commersonii derived from the RPA analysis was then used as input to an Ecopath with Ecosim (EwE) model. This model was used to simulate possible consequences of introducing this invasive species, assuming different rates of expansion of F. commersonii populations in the region. Increases in the F. commersonii population resulted in a marked decline in certain prey types (notably planktivorous fish, Mullus surmuletus and Symphodus tinca). By contrast, seabirds and piscivorous fish were suggested as possible beneficiaries, although this depended heavily on model and scenario assumptions. Overall fisheries catches were projected to increase, and this reflected an anticipated 'bottom up' increase in piscivorous fish that are the main target of the commercial fishery in the Bay of Calvi region.

  • 134. Pope, John G.
    et al.
    Bartolino, Valerio
    Kulatska, Nataliia
    Bauer, Barbara
    Stockholm University, Faculty of Science, Stockholm University Baltic Sea Centre.
    Horbowy, Jan
    Ribeiro, Joana P. C.
    Sturludottir, Erla
    Thorpe, Robert
    Comparing the steady state results of a range of multispecies models between and across geographical areas by the use of the jacobian matrix of yield on fishing mortality rate2019In: Fisheries Research, ISSN 0165-7836, E-ISSN 1872-6763, Vol. 209, p. 259-270Article in journal (Refereed)
    Abstract [en]

    Like other fisheries models, multispecies models are subject to various sources of error. However, with regard to their use for ecosystem-based fisheries management (EBFM) between model errors are likely to be most important. As multispecies models are by definition many-dimensional, comparing them is potentially a complex task. The paper uses a simple approach. This is to calculate the Jacobian matrix of long term steady state catch by species with respect to the fishing mortality relative to status quo levels on all species. This enables the comparison of the relative strength of species interactions among models both within and between regions. This Jacobian matrix approach to comparing multispecies models is applied to available models for the North Sea, the Baltic Sea and from Icelandic waters. Moreover, this information is used to provide the basis for estimating a multidimensional quadratic yield surface for each model in the near field. Used this way it is possible to compare different model estimations of fishing mortality rate changes needed to approach yield-related management goals. The results suggest considerable variation between models in their detailed results but more coherence in suggesting directions for changing fishing mortality rate. Thus the approach is of considerable importance in specifying the confidence with which it is possible to make multispecies predictions for EBFM.

  • 135. Powers, S. M.
    et al.
    Chowdhury, R. B.
    MacDonald, G. K.
    Metson, G. S.
    Beusen, A. H. W.
    Bouwman, A. F.
    Hampton, S. E.
    Mayer, B. K.
    McCrackin, M. L.
    Stockholm University, Faculty of Science, Stockholm University Baltic Sea Centre.
    Vaccari, D. A.
    Global Opportunities to Increase Agricultural Independence Through Phosphorus Recycling2019In: Earth's Future, ISSN 1384-5160, E-ISSN 2328-4277, Vol. 7, no 4, p. 370-383Article in journal (Refereed)
    Abstract [en]

    Food production hinges largely upon access to phosphorus (P) fertilizer. Most fertilizer P used in the global agricultural system comes from mining of nonrenewable phosphate rock deposits located within few countries. However, P contained in livestock manure or urban wastes represents a recyclable source of P. To inform development of P recycling technologies and policies, we examined subnational, national, and global spatial patterns for two intersections of land use affording high P recycling potential: (a) manure-rich cultivated areas and (b) populous cultivated areas. In turn, we examined overlap between P recycling potential and nation-level P fertilizer import dependency. Populous cultivated areas were less abundant globally than manure-rich cultivated areas, reflecting greater segregation between crops and people compared to crops and livestock, especially in the Americas. Based on a global hexagonal grid (290-km(2) grid cell area), disproportionately large shares of subnational hot spots for P recycling potential occurred in India, China, Southeast Asia, Europe, and parts of Africa. Outside of China, most of the remaining manure-rich or pulous cultivated areas occurred within nations that had relatively high imports of P fertilizer (net P import:consumption ratios >= 0.4) or substantial increases in fertilizer demand between the 2000s (2002-2006) and 2010s (2010-2014). Manure-rich cultivated grid cells (those above the 75th percentiles for both manure and cropland extent) represented 12% of the global grid after excluding cropless cells. Annually, the global sum of animal manure P was at least 5 times that contained in human excreta, and among cultivated cells the ratio was frequently higher (median = 8.9). The abundance of potential P recycling hot spots within nations that have depended on fertilizer imports or experienced rising fertilizer demand could prove useful for developing local P sources and maintaining agricultural independence.

  • 136.
    Prytherch, John
    et al.
    Stockholm University, Faculty of Science, Department of Meteorology . University of Leeds, United Kingdom.
    Brooks, Ian
    Crill, Patrick
    Stockholm University, Faculty of Science, Department of Geological Sciences.
    Thornton, Brett
    Stockholm University, Faculty of Science, Department of Geological Sciences.
    Salisbury, Dominic
    Tjernström, Michael
    Stockholm University, Faculty of Science, Department of Meteorology .
    Anderson, Leif
    Geibel, Marc C.
    Stockholm University, Faculty of Science, Stockholm University Baltic Sea Centre.
    Humborg, Christoph
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Air-sea CO2and CH4 gas transfer velocity in Arctic sea-ice regions fromeddy covariance flux measurements onboard Icebreaker Oden2017In: Geophysical Research Abstracts, ISSN 1029-7006, E-ISSN 1607-7962, Vol. 19, article id 697Article in journal (Refereed)
    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.

  • 137.
    Prytherch, John
    et al.
    Stockholm University, Faculty of Science, Department of Meteorology . University of Leeds, UK.
    Brooks, Ian M.
    Crill, Patrick M.
    Stockholm University, Faculty of Science, Department of Geological Sciences.
    Thornton, Brett F.
    Stockholm University, Faculty of Science, Department of Geological Sciences.
    Salisbury, Dominic J.
    Tjernström, Michael
    Stockholm University, Faculty of Science, Department of Meteorology .
    Anderson, Leif G.
    Geibel, Marc C.
    Stockholm University, Faculty of Science, Stockholm University Baltic Sea Centre.
    Humborg, Christoph
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Direct determination of the air-sea CO2 gas transfer velocity in Arctic sea ice regions2017In: Geophysical Research Letters, ISSN 0094-8276, E-ISSN 1944-8007, Vol. 44, no 8, p. 3770-3778Article in journal (Refereed)
    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 that the gas transfer velocity increases near linearly with decreasing sea ice concentration. We also show that previous modeling approaches overestimate gas transfer rates in sea ice regions.

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  • 138. Reed, Daniel C.
    et al.
    Gustafsson, Bo G.
    Stockholm University, Faculty of Science, Stockholm University Baltic Sea Centre, Baltic Nest Institute.
    Slomp, Caroline P.
    Shelf-to-basin iron shuttling enhances vivianite formation in deep Baltic Sea sediments2016In: Earth and Planetary Science Letters, ISSN 0012-821X, E-ISSN 1385-013X, Vol. 434, p. 241-251Article in journal (Refereed)
    Abstract [en]

    Coastal hypoxia is a growing and persistent problem largely attributable to enhanced terrestrial nutrient (i.e., nitrogen and phosphorus) loading. Recent studies suggest phosphorus removal through burial of iron (II) phosphates, putatively vivianite, plays an important role in nutrient cycling in the Baltic Sea the world's largest anthropogenic dead zone yet the dynamics of iron (II) phosphate formation are poorly constrained. To address this, a reactive-transport model was used to reconstruct the diagenetic and depositional history of sediments in the Faro basin, a deep anoxic and sulphidic region of the Baltic Sea where iron (II) phosphates have been observed. Simulations demonstrate that transport of iron from shelf sediments to deep basins enhances vivianite formation while sulphide concentrations are low, but that pyrite forms preferentially over vivianite when sulphate reduction intensifies due to elevated organic loading. Episodic reoxygenation events, associated with major inflows of oxic waters, encourage the retention of iron oxyhydroxides and iron-bound phosphorus in sediments, increasing vivianite precipitation as a result. Results suggest that artificial reoxygenation of the Baltic Sea bottom waters could sequester up to 3% of the annual external phosphorus loads as iron (II) phosphates, but this is negligible when compared to potential internal phosphorus loads due to dissolution of iron oxyhydroxides when low oxygen conditions prevail. Thus, enhancing vivianite formation through artificial reoxygenation of deep waters is not a viable engineering solution to eutrophication in the Baltic Sea. Finally, simulations suggest that regions with limited sulphate reduction and hypoxic intervals, such as eutrophic estuaries, could act as important phosphorus sinks by sequestering vivianite. This could potentially alleviate eutrophication in shelf and slope environments.

  • 139. Rivera-Monroy, Victor H.
    et al.
    Elliton, Courtney
    Narra, Siddhartha
    Meselhe, Ehab
    Zhao, Xiaochen
    White, Eric
    Sasser, Charles E.
    Visser, Jenneke M.
    Meng, Xuelian
    Wang, Hongqing
    Xue, Zuo
    Jaramillo, Fernando
    Stockholm University, Faculty of Science, Department of Physical Geography. Stockholm University, Faculty of Science, Stockholm University Baltic Sea Centre.
    Wetland Biomass and Productivity in Coastal Louisiana: Base Line Data (1976-2015) and Knowledge Gaps for the Development of Spatially Explicit Models for Ecosystem Restoration and Rehabilitation Initiatives2019In: Water, ISSN 2073-4441, Vol. 11, no 10, article id 2054Article in journal (Refereed)
    Abstract [en]

    Coastal Louisiana hosts 37% of the coastal wetland area in the conterminous US, including one of the deltaic coastal regions more susceptible to the synergy of human and natural impacts causing wetland loss. As a result of the construction of flood protection infrastructure, dredging of channels across wetlands for oil/gas exploration and maritime transport activities, coastal Louisiana has lost approximately 4900 km(2) of wetland area since the early 1930s. Despite the economic relevance of both wetland biomass and net primary productivity (NPP) as ecosystem services, there is a lack of vegetation simulation models to forecast the trends of those functional attributes at the landscape level as hydrological restoration projects are implemented. Here, we review the availability of peer-reviewed biomass and NPP wetland data (below and aboveground) published during the period 1976-2015 for use in the development, calibration and validation of high spatial resolution (<200 m x 200 m) vegetation process-based ecological models. We discuss and list the knowledge gaps for those species that represent vegetation community associations of ecological importance, including the long-term research issues associated to limited number of paired belowground biomass and productivity studies across hydrological basins currently undergoing different freshwater diversions management regimes and hydrological restoration priorities.

  • 140.
    Rodil, Iván F.
    et al.
    Stockholm University, Faculty of Science, Stockholm University Baltic Sea Centre. University of Helsinki, Finland.
    Attard, K. M.
    Norkko, J.
    Glud, R. N.
    Norkko, Alf
    Stockholm University, Faculty of Science, Stockholm University Baltic Sea Centre. University of Helsinki, Finland.
    Estimating Respiration Rates and Secondary Production of Macrobenthic Communities Across Coastal Habitats with Contrasting Structural Biodiversity2020In: Ecosystems (New York. Print), ISSN 1432-9840, E-ISSN 1435-0629, Vol. 23, no 3, p. 630-647Article in journal (Refereed)
    Abstract [en]

    A central goal of benthic ecology is to describe the pathways and quantities of energy and material flow in seafloor communities over different spatial and temporal scales. We examined the relative macrobenthic contribution to the seafloor metabolism by estimating respiration and secondary production based on seasonal measurements of macrofauna biomass across key coastal habitats of the Baltic Sea archipelago. Then, we compared the macrofauna estimates with estimates of overall seafloor gross primary production and respiration obtained from the same habitats using the aquatic eddy covariance technique. Estimates of macrobenthic respiration rates suggest habitat-specific macrofauna contribution (%) to the overall seafloor respiration ranked as follows: blue mussel reef (44.5) > seagrass meadow (25.6) > mixed meadow (24.1) > bare sand (17.8) > Fucus-bed (11.1). In terms of secondary production (g C m(-2) y(-1)), our estimates suggest ranking of habitat value as follows: blue mussel reef (493.4) > seagrass meadow (278.5) > Fucus-bed (102.2) > mixed meadow (94.2) > bare sand (52.1). Our results suggest that approximately 12 and 10% of the overall soft-sediment metabolism translated into macrofauna respiration and secondary production, respectively. The hard-bottoms exemplified two end-points of the coastal metabolism, with the Fucus-bed as a high producer and active exporter of organic C (that is, net autotrophy), and the mussel reef as a high consumer and active recycler of organic C (that is, net heterotrophy). Using a combination of metrics of ecosystem functioning, such as respiration rates and secondary production, in combination with direct habitat-scale measurements of O-2 fluxes, our study provides a quantitative assessment of the role of macrofauna for ecosystem functioning across heterogeneous coastal seascapes.

  • 141.
    Rodil, Iván F.
    et al.
    Stockholm University, Faculty of Science, Stockholm University Baltic Sea Centre. University of Helsinki, Finland.
    Attard, Karl M.
    Norkko, Joanna
    Glud, Ronnie N.
    Norkko, Alf
    Stockholm University, Faculty of Science, Stockholm University Baltic Sea Centre. University of Helsinki, Finland.
    Towards a sampling design for characterizing habitat-specific benthic biodiversity related to oxygen flux dynamics using Aquatic Eddy Covariance2019In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 14, no 2, article id e0211673Article in journal (Refereed)
    Abstract [en]

    The Aquatic Eddy Covariance (AEC) technique has emerged as an important method to quantify in situ seafloor metabolism over large areas of heterogeneous benthic communities, enabling cross-habitat comparisons of seafloor productivity. However, the lack of a corresponding sampling protocol to perform biodiversity comparisons across habitats is impeding a full assessment of marine ecosystem metabolism. Here, we study a range of coastal benthic habitats, from rocky-bed communities defined by either perennial macroalgae or blue mussel beds to soft-sediment communities comprised of either seagrass, patches of different macrophyte species or bare sand. We estimated that the maximum contribution to the AEC metabolic flux can be found for a seafloor area of approximately 80 m(2) with a 5 meter upstream distance of the instrument across all the habitats. We conducted a sampling approach to characterize and quantify the dominant features of biodiversity (i.e., community biomass) within the main seafloor area of maximum metabolic contribution (i.e., gross primary production and community respiration) measured by the AEC. We documented a high biomass contribution of the macroalgal Fucus vesiculosus, the seagrass Zostera marina and the macroinvertebrate Mytilus edulis to the net ecosystem metabolism of the habitats. We also documented a significant role of the bare sediments for primary productivity compared to vegetated canopies of the soft sediments. The AEC also provided insight into dynamic short-term drivers of productivity such as PAR availability and water flow velocity for the productivity estimate. We regard this study as an important step forward, setting a framework for upcoming research focusing on linking biodiversity metrics and AEC flux measurements across habitats.

  • 142.
    Rodil, Iván F.
    et al.
    Stockholm University, Faculty of Science, Stockholm University Baltic Sea Centre. University of Porto, Portugal; University of Helsinki, Finland.
    Jaramillo, Eduardo
    Acuna, Emilio
    Manzano, Mario
    Velasquez, Carlos
    Long-term responses of sandy beach crustaceans to the effects of coastal armouring after the 2010 Maule earthquake in South Central Chile2016In: Journal of Sea Research, ISSN 1385-1101, E-ISSN 1873-1414, Vol. 108, p. 10-18Article in journal (Refereed)
    Abstract [en]

    Earthquakes and tsunamis are large physical disturbances frequently striking the coast of Chile with dramatic effects on intertidal habitats. Armouring structures built as societal responses to beach erosion and shoreline retreat are also responsible of coastal squeeze and habitat loss. The ecological implications of interactions between coastal armouring and earthquakes have recently started to be studied for beach ecosystems. How long interactive impacts persist is still unclear because monitoring after disturbance generally extends for a few months. During five years after the Maule earthquake (South Central Chile, February 27th 2010) we monitored the variability in population abundances of the most common crustacean inhabitants of different beach zones (i.e. upper, medium, and lower intertidal) at two armoured (one concrete seawall and one rocky revetment) and one unarmoured sites along the sandy beach of Llico. Beach morphology changed after the earthquake-mediated uplift, restoring upper-and mid-shore armoured levels that were rapidly colonized by typical crustacean species. However, post-earthquake increasing human activities affected the colonization process of sandy beach crustaceans in front of the seawall. Lower-shore crab Emerita analoga was the less affected by armouring structures, and it was the only crustacean species present at the three sites before and after the earthquake. This study shows that field sampling carried out promptly after major disturbances, and monitoring of the affected sites long after the disturbance is gone are effective approaches to increase the knowledge on the interactive effects of large-scale natural phenomena and artificial defences on beach ecology.

  • 143.
    Rodil, Iván F.
    et al.
    Stockholm University, Faculty of Science, Stockholm University Baltic Sea Centre. University of Helsinki, Finland; University of Porto, Portugal.
    Lastra, Mariano
    López, Jesús
    Mucha, Ana P.
    Fernandes, Joana P.
    Fernandes, Sara V.
    Olabarria, Celia
    Sandy Beaches as Biogeochemical Hotspots: The Metabolic Role of Macroalgal Wrack on Low-productive Shores2019In: Ecosystems (New York. Print), ISSN 1432-9840, E-ISSN 1435-0629, Vol. 22, no 1, p. 49-63Article in journal (Refereed)
    Abstract [en]

    Sandy beaches, which represent the most common type of land-sea interface, harbor distinctive biotic communities and regulate the flow of energy between marine and terrestrial ecosystems. Accumulations of sea wrack on sandy beaches are of crucial importance for recycling beach nutrients and for regulating trophic connectivity and coastal functioning. We investigated the role of beaches as biogeochemical hotspots by examining the metabolic activity in accumulations of different species of wrack on two exposed beaches affected by different levels of human pressure. Experimental wrack patches provided large amounts of different sedimentary nutrients over time due to remineralization of the algae. Unsurprisingly, the variation in the nutrients present in the beach sediments was related to the species of wrack considered. Macroalgal wrack was metabolically very active and supported high respiration rates represented by intense CO2 fluxes. Importantly, we demonstrated that the wrack metabolic rate differed significantly depending on the algal species considered. Different macrofauna and bacterial assemblages were identified in the different wrack patches and on the different beaches. We suggest that human activities such as beach grooming can modify the wrack-associated communities, thus contributing to the variability in the biogeochemical processes and metabolic rates. Significant changes in the type and amount of wrack deposited on beaches can change fundamental processes related to the marine-terrestrial transfer of nutrients and energy and to the marine-atmospheric transfer of CO2 emissions, with ecological consequences for nearshore environments.

  • 144.
    Rodil, Iván F.
    et al.
    Stockholm University, Faculty of Science, Stockholm University Baltic Sea Centre. 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 Invertebrates2018In: Estuaries and Coasts, ISSN 1559-2723, E-ISSN 1559-2731, Vol. 41, no 1, p. 206-217Article in journal (Refereed)
    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.

  • 145.
    Rodil, Iván F.
    et al.
    Stockholm University, Faculty of Science, Stockholm University Baltic Sea Centre. University of Helsinki, Finland.
    Lucena-Moya, Paloma
    Jokinen, Henri
    Ollus, Victoria
    Wennhage, Håkan
    Villnäs, Anna
    Norkko, Alf
    Stockholm University, Faculty of Science, Stockholm University Baltic Sea Centre. University of Helsinki, Finland.
    The role of dispersal mode and habitat specialization for metacommunity structure of shallow beach invertebrates2017In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 12, no 2, article id e0172160Article in journal (Refereed)
    Abstract [en]

    Metacommunity ecology recognizes the interplay between local and regional patterns in contributing to spatial variation in community structure. In aquatic systems, the relative importance of such patterns depends mainly on the potential connectivity of the specific system. Thus, connectivity is expected to increase in relation to the degree of water movement, and to depend on the specific traits of the study organism. We examined the role of environmental and spatial factors in structuring benthic communities from a highly connected shallow beach network using a metacommunity approach. Both factors contributed to a varying degree to the structure of the local communities suggesting that environmental filters and dispersal-related mechanisms played key roles in determining abundance patterns. We categorized benthic taxa according to their dispersal mode (passive vs. active) and habitat specialization (generalist vs. specialist) to understand the relative importance of environment and dispersal related processes for shallow beach metacommunities. Passive dispersers were predicted by a combination of environmental and spatial factors, whereas active dispersers were not spatially structured and responded only to local environmental factors. Generalists were predicted primarily by spatial factors, while specialists were only predicted by local environmental factors. The results suggest that the role of the spatial component in metacommunity organization is greater in open coastal waters, such as shallow beaches, compared to less-connected environmentally controlled aquatic systems. Our results also reveal a strong environmental role in structuring the benthic metacommunity of shallow beaches. Specifically, we highlight the sensitivity of shallow beach macrofauna to environmental factors related to eutrophication proxies.

  • 146.
    Rolff, Carl
    et al.
    Stockholm University, Faculty of Science, Stockholm University Baltic Sea Centre.
    Elfwing, Tina
    Stockholm University, Faculty of Science, Stockholm University Baltic Sea Centre.
    Increasing nitrogen limitation in the Bothnian Sea, potentially caused by inflow of phosphate-rich water from the Baltic Proper2015In: Ambio, ISSN 0044-7447, E-ISSN 1654-7209, Vol. 44, no 7, p. 601-611Article in journal (Refereed)
    Abstract [en]

    The study showed that the open water of the Bothnian Sea (BS) is likely to have shifted from altering nitrogen and phosphorous limitations of the spring bloom to more nitrogen-limited conditions during the last 20 years. This is affected by the by inflow of phosphate-rich and oxygen-depleted water from depths near the halocline in the northern Baltic Proper, where severe oxygen conditions currently cause extreme phosphate concentrations in the deep water. The change in relation between inorganic nitrogen and phosphorous in the BS occurs first in the deep water and then progresses to the surface water. The change can potentially cause increased production in the BS and more frequent cyanobacterial blooms. There does not appear to be any immediate concern in the short-term perspective for the state of the BS, but a progression of the processes may lead to a more eutrophic state of the BS.

  • 147. Ryabchenko, V. A.
    et al.
    Karlin, L. N.
    Isaev, A. V.
    Vankevich, R. E.
    Eremina, T. R.
    Molchanov, M. S.
    Savchuk, Oleg P.
    Stockholm University, Faculty of Science, Stockholm University Baltic Sea Centre. St. Petersburg State University, Russia.
    Model estimates of the eutrophication of the Baltic Sea in the contemporary and future climate2016In: Oceanology (Washington. 1965), ISSN 0001-4370, E-ISSN 0001-4370, Vol. 56, no 1, p. 36-45Article in journal (Refereed)
    Abstract [en]

    The St. Petersburg Baltic eutrophication model (SPBEM) is used to assess the ecological condition of the sea under possible changes in climate and nutrient loads in the 21st century. According to model estimates, in the future climate water quality will worsen, compared to modern conditions. This deterioration is stronger in the climate warming scenario with a stronger change in future near-surface air temperature. In the considered scenarios of climate change, climate warming will lead to an increase in the area of anoxic and hypoxic zones. Reduction of nutrient loading, estimated in accordance with the Baltic Sea Action Plan, will only be able to partially compensate for the negative effects of global warming.

  • 148. Rydin, Emil
    et al.
    Kumblad, Linda
    Stockholm University, Faculty of Science, Stockholm University Baltic Sea Centre.
    Capturing past eutrophication in coastal sediments - Towards water-quality goals2019In: Estuarine, Coastal and Shelf Science, ISSN 0272-7714, E-ISSN 1096-0015, Vol. 221, p. 184-188Article in journal (Refereed)
    Abstract [en]

    Bjornofjarden is a semi-enclosed brackish bay located in the Stockholm archipelago (Baltic Sea, Sweden). Anthropogenic phosphorus (P) loading to the bay over the past century has overwhelmed the largely unchanged natural supply of elements and compounds that permanently sequester P in sediments. At the same time, eutrophication has shifted surface sediments from oxic to anoxic conditions and reduced their P-retention capacity. Consequently, the release of P from anoxic sediments has become the main P source to the water column. Here we report on a long-term remediation program to reverse eutrophication in Bjornofjarden. After the implementation of measures that reduced the land-based external load to the bay, sediment-P retention was increased by mixing a solution of aluminum (Al) chloride into the anoxic and azoic sediments (> 6 m water depth) at a dose of 50 g Al/m(2), a first in a brackish environment. As a result, P accumulation in the surface sediment reached 2.0 gP/m(2) after 14 years, corresponding to 1.6 mg P/m(2)-day. This is the first time that the P accumulation rate has been determined in aquatic sediments following the addition of P-sequestering material, such as Al. The P that accumulated was dissolved P that mainly migrated from below the layer of P accumulation. The aim of the Al-addition was to sequester legacy P that had accumulated during the past century and to return Bjornofjarden to a low productivity regime, which would allow the surface sediment to become oxic and enable natural P binding by iron.

  • 149. Rydin, Emil
    et al.
    Kumblad, Linda
    Wulff, Fredrik
    Stockholm University, Faculty of Science, Stockholm University Baltic Sea Centre.
    Larsson, Per
    Remediation of a Eutrophic Bay in the Baltic Sea2017In: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 51, no 8, p. 4559-4566Article in journal (Refereed)
    Abstract [en]

    Eutrophication of coastal ecosystems is a global problem that often results in bottom water oxygen deficiency and in turn promotes sediment phosphorus (P) release (A). In order to increase sediment P retention, we injected dissolved aluminum into the anoxic sediment of a eutrophic semienclosed bay in the Baltic Sea, thereby inhibiting P recycling and further eutrophication (B). The P concentration in the bay remained at half, as did phytoplankton biomass (C), compared to pretreatment conditions and compared to the reference bay. Four years after treatment the water column transparency was increased, allowing submerged vegetation to penetrate deeper, and the habitat suitable for fish and benthic fauna had expanded (D). The lowered P concentration in the bay decreased the P export to the surrounding archipelago. This is the first full-scale marine remediation project using a geo-engineering method that demonstrates a quick recovery. For successful remediation in coastal areas, permanent binding of mobile P in anoxic sediments may be needed together with measures in the catchment area to obtain faster recovery of eutrophicated marine ecosystems.

  • 150.
    Sagerman, Josefin
    et al.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Enge, Swantje
    Pavia, Henrik
    Wikström, Sofia
    Stockholm University, Faculty of Science, Stockholm University Baltic Sea Centre. Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Low feeding preference of native herbivores for the successful non-native seaweed Heterosiphonia japonicaManuscript (preprint) (Other academic)
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