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  • 1.
    Donadi, Serena
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och botanik. Stockholms universitet, Naturvetenskapliga fakulteten, Stockholms universitets Östersjöcentrum. Swedish University of Agricultural Sciences (SLU), Sweden.
    Austin, Åsa N.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och botanik.
    Bergström, U.
    Eriksson, B. K.
    Hansen, Joakim P.
    Stockholms universitet, Naturvetenskapliga fakulteten, Stockholms universitets Östersjöcentrum.
    Jacobson, P.
    Sundblad, G.
    van Regteren, M.
    Eklöf, Johan S.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och botanik.
    A cross-scale trophic cascade from large predatory fish to algae in coastal ecosystems2017Ingår i: Proceedings of the Royal Society of London. Biological Sciences, ISSN 0962-8452, E-ISSN 1471-2954, Vol. 284, nr 1859, artikel-id 20170045Artikel i tidskrift (Refereegranskat)
    Abstract [en]

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

  • 2. Soja-Woźniak, Monika
    et al.
    Craig, Susanne E.
    Kratzer, Susanne
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och botanik.
    Wojtasiewicz, Bozena
    Darecki, Miroslaw
    Jones, Chris T.
    A Novel Statistical Approach for Ocean Colour Estimation of Inherent Optical Properties and Cyanobacteria Abundance in Optically Complex Waters2017Ingår i: Remote Sensing, ISSN 2072-4292, E-ISSN 2072-4292, Vol. 9, nr 4, artikel-id 343Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Eutrophication is an increasing problem in coastal waters of the Baltic Sea. Moreover, algal blooms, which occur every summer in the Gulf of Gdansk can deleteriously impact human health, the aquatic environment, and economically important fisheries, tourism, and recreation industries. Traditional laboratory-based techniques for water monitoring are expensive and time consuming, which usually results in limited numbers of observations and discontinuity in space and time. The use of hyperspectral radiometers for coastal water observation provides the potential for more detailed remote optical monitoring. A statistical approach to develop local models for the estimation of optically significant components from in situ measured hyperspectral remote sensing reflectance in case 2 waters is presented in this study. The models, which are based on empirical orthogonal function (EOF) analysis and stepwise multilinear regression, allow for the estimation of parameters strongly correlated with phytoplankton (pigment concentration, absorption coefficient) and coloured detrital matter abundance (absorption coefficient) directly from reflectance spectra measured in situ. Chlorophyll a concentration, which is commonly used as a proxy for phytoplankton biomass, was retrieved with low error (median percent difference, MPD = 17%, root mean square error RMSE = 0.14 in log(10) space) and showed a high correlation with chlorophyll a measured in situ (R = 0.84). Furthermore, phycocyanin and phycoerythrin, both characteristic pigments for cyanobacteria species, were also retrieved reliably from reflectance with MPD = 23%, RMSE = 0.23, R-2 = 0.77 and MPD = 24%, RMSE = 0.15, R-2 = 0.74, respectively. The EOF technique proved to be accurate in the derivation of the absorption spectra of phytoplankton and coloured detrital matter (CDM), with R-2 (lambda) above 0.83 and RMSE around 0.10. The approach was also applied to satellite multispectral remote sensing reflectance data, thus allowing for improved temporal and spatial resolution compared with the in situ measurements. The EOF method tested on simulated Medium Resolution Imaging Spectrometer (MERIS) or Ocean and Land Colour Instrument (OLCI) data resulted in RMSE = 0.16 for chl-a and RMSE = 0.29 for phycocyanin. The presented methods, applied to both in situ and satellite data, provide a powerful tool for coastal monitoring and management.

  • 3. Ytreberg, Erik
    et al.
    Lagerström, Maria
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi. Chalmers University of Technology, Sweden.
    Holmqvist, Albin
    Eklund, Britta
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Elwing, Hans
    Dahlström, Magnus
    Dahl, Peter
    Dahlström, Mia
    A novel XRF method to measure environmental release of copper and zinc from antifouling paints2017Ingår i: Environmental Pollution, ISSN 0269-7491, E-ISSN 1873-6424, Vol. 225, s. 490-496Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The release of copper (Cu) and zinc (Zn) from vessels and leisure crafts coated with antifouling paints can pose a threat to water quality in semi-enclosed areas such as harbors and marinas as well as to coastal archipelagos. However, no reliable, practical and low-cost method exists to measure the direct release of metals from antifouling paints. Therefore, the paint industry and regulatory authorities are obliged to use release rate measurements derived from either mathematical models or from laboratory studies. To bridge this gap, we have developed a novel method using a handheld X-Ray Fluorescence spectrometer (XRF) to determine the cumulative release of Cu and Zn from antifouling paints. The results showed a strong linear relationship between XRF Kα net intensities and metal concentrations, as determined by ICP-MS. The release of Cu and Zn were determined for coated panels exposed in harbors located in the Baltic Sea and in Kattegat. The field study showed salinity to have a strong impact on the release of Cu, i.e. the release increased with salinity. Contrary, the effect of salinity on Zn was not as evident. As exemplified in this work, the XRF method also makes it possible to identify the governing parameters to the release of Cu and Zn, e.g. salinity and type of paint formulation. Thus, the XRF method can be used to measure environmentally relevant releases of metallic compounds to design more efficient and optimized antifouling coatings.

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

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

  • 5.
    Gewert, Berit
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Ogonowski, Martin
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi. Aquabiota Water Research, Sweden.
    Barth, Andreas
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för biokemi och biofysik.
    MacLeod, Matthew
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Abundance and composition of near surface microplastics and plastic debris in the Stockholm Archipelago, Baltic Sea2017Ingår i: Marine Pollution Bulletin, ISSN 0025-326X, E-ISSN 1879-3363, Vol. 120, nr 1-2, s. 292-302Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We collected plastic debris in the Stockholm Archipelago using a manta trawl, and additionally along a transect in the Baltic Sea from the island of Gotland to Stockholm in a citizen science study. The samples were concentrated by filtration and organic material was digested using hydrogen peroxide. Suspected plastic material was isolated by visual sorting and 59 of these were selected to be characterized with Fourier transform infrared spectroscopy. Polypropylene and polyethylene were the most abundant plastics identified among the samples (53% and 24% respectively). We found nearly ten times higher abundance of plastics near central Stockholm than in offshore areas (4.2 x 10(5) plastics km(-2) compared to 4.7 x 10(4) plastics km(-2)). The abundance of plastic debris near Stockholm was similar to urban areas in California, USA, and the overall abundance in the Stockholm Archipelago was similar to plastic abundance reported in the northwestern Mediterranean Sea.

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

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

  • 7.
    Prytherch, John
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Meteorologiska institutionen (MISU). University of Leeds, United Kingdom.
    Brooks, Ian
    Crill, Patrick
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för geologiska vetenskaper.
    Thornton, Brett
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för geologiska vetenskaper.
    Salisbury, Dominic
    Tjernström, Michael
    Stockholms universitet, Naturvetenskapliga fakulteten, Meteorologiska institutionen (MISU).
    Anderson, Leif
    Geibel, Marc C.
    Stockholms universitet, Naturvetenskapliga fakulteten, Stockholms universitets Östersjöcentrum.
    Humborg, Christoph
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Air-sea CO2and CH4 gas transfer velocity in Arctic sea-ice regions fromeddy covariance flux measurements onboard Icebreaker Oden2017Ingår i: Geophysical Research Abstracts, ISSN 1029-7006, E-ISSN 1607-7962, Vol. 19, artikel-id 697Artikel i tidskrift (Refereegranskat)
    Abstract [en]

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

  • 8.
    McCrackin, Michelle L.
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Stockholms universitets Östersjöcentrum.
    Cooter, Ellen J.
    Dennis, Robin L.
    Harrison, John A.
    Compton, Jana E.
    Alternative futures of dissolved inorganic nitrogen export from the Mississippi River Basin: influence of crop management, atmospheric deposition, and population growth2017Ingår i: Biogeochemistry, ISSN 0168-2563, E-ISSN 1573-515X, Vol. 133, nr 3, s. 263-277Artikel i tidskrift (Refereegranskat)
    Abstract [en]

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

  • 9.
    Sawicka, Joanna E.
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för geologiska vetenskaper.
    Brüchert, Volker
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för geologiska vetenskaper.
    Annual variability and regulation of methane and sulfate fluxes in Baltic Sea estuarine sediments2017Ingår i: Biogeosciences, ISSN 1726-4170, E-ISSN 1726-4189, Vol. 14, nr 2, s. 325-339Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Marine methane emissions originate largely from near-shore coastal systems, but emission estimates are often not based on temporally well-resolved data or sufficient understanding of the variability of methane consumption and production processes in the underlying sediment. The objectives of our investigation were to explore the effects of seasonal temperature, changes in benthic oxygen concentration, and historical eutrophication on sediment methane concentrations and benthic fluxes at two type localities for open-water coastal versus eutrophic, estuarine sediment in the Baltic Sea. Benthic fluxes of methane and oxygen and sediment pore-water concentrations of dissolved sulfate, methane, and S-35-sulfate reduction rates were obtained over a 12-month period from April 2012 to April 2013. Benthic methane fluxes varied by factors of 5 and 12 at the offshore coastal site and the eutrophic estuarine station, respectively, ranging from 0.1 mmol m(-2) d(-1) in winter at an open coastal site to 2.6 mmol m(-2) d(-1) in late summer in the inner eutrophic estuary. Total oxygen uptake (TOU) and S-35-sulfate reduction rates (SRRs) correlated with methane fluxes showing low rates in the winter and high rates in the summer. The highest pore-water methane concentrations also varied by factors of 6 and 10 over the sampling period with the lowest values in the winter and highest values in late summerearly autumn. The highest pore-water methane concentrations were 5.7 mM a few centimeters below the sediment surface, but they never exceeded the in situ saturation concentration. Of the total sulfate reduction, 21-24% was coupled to anaerobic methane oxidation, lowering methane concentrations below the sediment surface far below the saturation concentration. The data imply that bubble emission likely plays no or only a minor role in methane emissions in these sediments. The changes in pore-water methane concentrations over the observation period were too large to be explained by temporal changes in methane formation and methane oxidation rates due to temperature alone. Additional factors such as regional and local hydrostatic pressure changes and coastal submarine groundwater flow may also affect the vertical and lateral transport of methane.

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

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

  • 11. Kalmring, Sven
    et al.
    Runer, Johan
    Viberg, Andreas
    Stockholms universitet, Humanistiska fakulteten, Institutionen för arkeologi och antikens kultur.
    AT HOME WITH HERIGAR: A MAGNATE'S RESIDENCE FROM THE VENDEL- TO VIKING PERIOD AT KORSHAMN, BIRKA (UPPLAND/S)2017Ingår i: Archäologisches Korrespondenzblatt, ISSN 0342-734X, Vol. 47, nr 1, s. 117-140Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In September 2016 geophysical surveys were conducted at Korshamn, as one of the main harbour bays of the island of Bjorko, situated outside the town boundaries of the Viking town of Birka. The investigation of a solitarily raised plateau at Erik Steffanssons hemland revealed the outline of a large Vendel-period house. Together with further anomalies at a one-sided terrace at Kalvhagen a whole manor complex might be seizable predating the Viking-Age settlement activities on the island. The latter dwelling is superimposed by a major Viking-Age hall connecting to a fenced special area as known from e.g. Lejre and Tisso and linked to cult activities. Both the structures and the chronological depth correlate well with the ancestral property of Birka's royal bailiff Herigar as mentioned in Rimbert's Vita Anskarii. If this assumption is correct even the whereabouts of Scandinavia's first church should be located in the immediate vicinity. The consequences of this identification cannot be overestimated: In terms of the emergence of the Viking town, its royal administration and the earliest Christian mission in Scandinavia.

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

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

  • 13.
    Wennerström, Lovisa
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen.
    Jansson, Eeva
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen. Institute of Marine Research, Norway.
    Laikre, Linda
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen.
    Baltic Sea genetic biodiversity: Current knowledge relating to conservation management2017Ingår i: Aquatic conservation, ISSN 1052-7613, E-ISSN 1099-0755, Vol. 27, nr 6, s. 1069-1090Artikel, forskningsöversikt (Refereegranskat)
    Abstract [en]

    The Baltic Sea has a rare type of brackish water environment which harbours unique genetic lineages of many species. The area is highly influenced by anthropogenic activities and is affected by eutrophication, climate change, habitat modifications, fishing and stocking. Effective genetic management of species in the Baltic Sea is highly warranted in order to maximize their potential for survival, but shortcomings in this respect have been documented. Lack of knowledge is one reason managers give for why they do not regard genetic diversity in management. Here, the current knowledge of population genetic patterns of species in the Baltic Sea is reviewed and summarized with special focus on how the information can be used in management. The extent to which marine protected areas (MPAs) protect genetic diversity is also investigated in a case study of four key species. Sixty-one species have been studied genetically in the Baltic Sea, but comprehensive genetic information exists for only seven of them. Genetic monitoring shows genetic stability in some species but fluctuations and genetic changes in others. About half of the scientific studies published during the last 6years provide conservation advice, indicating a high interest in the scientific community for relating results to practical management. Populations in MPAs do not differ genetically from populations outside MPAs, indicating that MPAs in the Baltic Sea do not protect genetic diversity specifically, but that populations in MPAs are a representative subset of populations in the Baltic Sea. Recommendations are provided for cases where genetic information is available but not used in management, particularly for non-commercial species with important ecosystem function. Improved channels for effective communication between academia and practical management on Baltic Sea genetic biodiversity are needed. A web page that can be used for knowledge transfer is highlighted here.

  • 14.
    Strandmark, Alma
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och botanik.
    Baltic shore-lands facing climate change2017Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    This thesis provides new insight concerning drivers behind differences in arthropod diversity and abundance in Baltic shore ecosystems and how the arthropod communities might be affected when the conditions in the Baltic Sea are altered due to climate change.  The focus has been on climate related changes that are unique for coastal ecosystems, especially sea level rise and changes in the inflow of marine nutrients.

    As sea levels rise, features in coastal landscapes will be altered, islands and habitats will be flooded and diminished, and structural connectivity within the island landscape will therefore change. This thesis shows that arthropod diversity within the two arthropod groups, spiders and beetles, increases with island size but also that diversity is positively influenced by a high number of islands in the surroundings.

    A changed distribution and occurrence of marine species, due to climate change or eutrophication, can also affect terrestrial organisms on the shore.  In the Baltic Sea the new conditions following climate change will decrease the prevalence of bladder-wrack and benefit filamentous algae. Algal deposits on shores reflect the marine species composition and a decreased prevalence of bladder-wrack in the Baltic Sea will also be visible on the shores.  This thesis shows that a lower proportion of bladder-wrack in the algal deposits will decrease the diversity and abundance of arthropods in these deposits.

    Changes in the marine environment may also affect the inflow of insects with aquatic life stages and terrestrial adult stages.  On Baltic shores, prey species with aquatic life stages, especially chironomids, constitute a large proportion of the diet of the terrestrial predatory group, wolf spiders. In freshwater system, the inflow of chironomids is known to decrease with elevated water temperatures if this is true in the Baltic Sea prey availability of wolf spiders would decrease.  This thesis supports the importance of chironomids as a prey for coastal wolf spiders, but also shows that the diet varies over season with dominance of terrestrial prey in early summer shifting to a dominance of marine prey in late summer and autumn. This seasonal variation is primarily due to a gradual increase in the consumption of chironomids over season.

    Climate change has the potential to alter the biogeographical conditions in coastal landscapes as well as the density and quality of marine nutrient inflow. Sea level rise will diminish and flood islands and this thesis shows that a moderate sea level rise of 0.5 meters would make the total number of islands in the outer part of Stockholm archipelago decrease with about 25 %. Sea level rise could thus have consequences for arthropod diversity in Baltic shore meadows in the near future. The combined effects of sea level rise and changed prevalence of marine species in the Baltic Sea will affect the abundance and diversity of arthropods substantially. The abundance and diversity of spiders and beetles will decrease on shores that today have a high occurrence of bladder-wrack and prey availability for coastal predators might decrease due to a decreased inflow of chironomids. Changes in the arthropod communities could have consequences also further up in the food chain, such as for shore birds feeding on these arthropods.

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

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

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

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

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

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

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

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

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

  • 16.
    Snoeijs-Leijonmalm, Pauline
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och botanik.
    Schubert, HendrikRadziejewska, Teresa
    Biological Oceanography of the Baltic Sea2017Samlingsverk (redaktörskap) (Refereegranskat)
    Abstract [en]

    This is the first comprehensive science-based textbook on the biology and ecology of the Baltic Sea, one of the world’s largest brackish water bodies. The aim of this book is to provide students and other readers with knowledge about the conditions for life in brackish water, the functioning of the Baltic Sea ecosystem and its environmental problems and management. It highlights biological variation along the unique environmental gradients of the brackish Baltic Sea Area (the Baltic Sea, Belt Sea and Kattegat), especially those in salinity and climate.

    The first part of the book presents the challenges for life processes and ecosystem dynamics that result from the Baltic Sea’s highly variable recent geological history and geographical isolation. The second part explains interactions between organisms and their environment, including biogeochemical cycles, patterns of biodiversity, genetic diversity and evolution, biological invasions and physiological adaptations. In the third part, the subsystems of the Baltic Sea ecosystem – the pelagic zone, the sea ice, the deep soft sea beds, the phytobenthic zone, the sandy coasts, and estuaries and coastal lagoons – are treated in detail with respect to the structure and function of communities and habitats and consequences of natural and anthropogenic constraints, such as climate change, discharges of nutrients and hazardous substances. Finally, the fourth part of the book discusses monitoring and ecosystem-based management to deal with contemporary and emerging threats to the ecosystem’s health.

  • 17.
    Lindqvist, Dennis
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Dahlgren, Elin
    Asplund, Lillemor
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Biosynthesis of hydroxylated polybrominated diphenyl ethers and the correlation with photosynthetic pigments in the red alga Ceramium tenuicorne2017Ingår i: Phytochemistry, ISSN 0031-9422, E-ISSN 1873-3700, Vol. 133, s. 51-58Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Hydroxylated polybrominated diphenyl ethers (OH-PBDEs) have been identified in a variety of marine organisms from different trophic levels indicating a large spread in the environment. There is much evidence pointing towards natural production as the major source of these compounds in nature. However, much is still not known about the natural production of these compounds. Seasonal trend studies have shown large fluctuations in the levels of OH-PBDEs in Ceramium tenuicorne from the Baltic Sea. Yet, even though indications of stimuli that can induce the production of these compounds have been observed, none, neither internal nor external, has been assigned to be responsible for the recorded fluctuations. In the present study the possible relationship between the concentration of pigments and that of OH-PBDEs in C. tenuicorne has been addressed. Significant correlations were revealed between the concentrations of all OH-PBDEs quantified and the concentrations of both chlorophyll a and Σxanthophylls + carotenoids. All of which displayed a concentration peak in mid-July. The levels of OH-PBDEs may be linked to photosynthetic activity, and hence indirectly to photosynthetic pigments, via bromoperoxidase working as a scavenger for hydrogen peroxide formed during photosynthesis. Yet the large apparent investment in producing specific OH-PBDE congeners point towards an targeted production, with a more specific function than being a waste product of photosynthesis. The OH-PBDE congener pattern observed in this study is not agreeable with some currently accepted models for the biosynthesis of these compounds, and indicates a more selective route than previously considered in C. tenuicorne.

  • 18.
    Gustafsson, Erik
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Stockholms universitets Östersjöcentrum, Baltic Nest Institute.
    Humborg, Christoph
    Stockholms universitet, Naturvetenskapliga fakulteten, Stockholms universitets Östersjöcentrum. Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Björk, Göran
    Stranne, Christian
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för geologiska vetenskaper. University of New Hampshire, USA.
    Andersson, Leif G.
    Geibel, Marc C.
    Stockholms universitet, Naturvetenskapliga fakulteten, Stockholms universitets Östersjöcentrum. Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Mörth, Carl-Magnus
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för geologiska vetenskaper.
    Sundbom, Marcus
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Semiletov, Igor P.
    Thornton, Brett F.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för geologiska vetenskaper.
    Gustafsson, Bo G.
    Stockholms universitet, Naturvetenskapliga fakulteten, Stockholms universitets Östersjöcentrum, Baltic Nest Institute.
    Carbon cycling on the East Siberian Arctic Shelf – a change in air-sea CO2 flux induced by mineralization of terrestrial organic carbon2017Ingår i: Biogeosciences, ISSN 1726-4170, E-ISSN 1726-4189Artikel i tidskrift (Refereegranskat)
    Abstract [en]

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

  • 19.
    Bradshaw, Clare
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och botanik. Södertörn University, Sweden.
    Golz, Anna-Lea
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och botanik.
    Gustafsson, Kerstin
    Coastal Ecosystem Effects of Increased Summer Temperature and Contamination by the Flame Retardant HBCDD2017Ingår i: Journal of Marine Science and Engineering, E-ISSN 2077-1312, Vol. 5, nr 2, artikel-id 18Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The combined effects of ocean warming and contaminants on marine ecosystems are poorly understood. In this study, we exposed model ecosystems comprising typical shallow coastal Baltic Sea communities to elevated temperature (+5 °C) and the flame retardant hexabromocyclododecane (HBCDD), both singly and in combination, for 13 days. Higher temperatures caused the release of PO4 from the sediment, which in turn stimulated the growth of the cyanobacteria Dolichospermum sp. This in turn led to an increase in the copepod Acartia bifilosa and other indirect effects in the plankton, interpreted as being caused by changes in predation, grazing, and competition. Elevated temperatures also stimulated benthic primary production and increased production of benthic mollusk larvae. Although increased temperature was the dominant driver of effects in these systems, HBCDD also appeared to have some effects, mainly in the zooplankton (both direct and indirect effects) and benthic meiofauna (an interactive effect with temperature). Although the study used model ecosystems, which are an approximation of field conditions, it highlights that interactive ecosystem effects between two stressors are possible and demonstrates the ecological and temporal complexity of such responses. Such unpredictable responses to warming and contaminants are a major challenge for ecosystem management to deal with multistressor situations in the Baltic Sea.

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

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

  • 21.
    Mustajärvi, Lukas
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Contaminated sediments: Methods to assess release and toxicity of organic chemical mixtures2017Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Bottom sediments around the world store large amounts of legacy hydrophobic organic contaminants (HOCs), forming mixtures of unknown chemical composition. Primary emissions to the environment of many HOCs have been reduced as a consequence of regulation. However, HOCs may be released from the sediments to water and biota, and there is therefore a risk of negative effects on local ecosystems. The activity of benthic organisms can enhance the sediment-to-water flux of HOCs, a process called bioturbation. Few in situ assessments of the sediment-to-water flux are available in the scientific literature, and the effect of bioturbation on the sediment-to-water flux of HOCs has not been studied in the field. Thus, there is a need to improve in situ methods for direct determination of sediments as a source of HOCs to water, and thereby include the effect of bioturbation. In Paper I, a benthic flow-through chamber was developed for environmentally realistic in situ assessments of the sediment-to-water flux. In Paper II, the sediment-to-water flux of polycyclic aromatic hydrocarbons (PAHs) was assessed using the flow-through chamber at four sites on the Swedish Baltic Sea coast. The sediments at all four sites acted as sources of PAHs to water. In the same study, potential effects of bioturbation, with an increase of the sediment-to-water flux by up to one order of magnitude, were observed at sites with bioturbating organisms. In the past, assessing the toxicity of HOCs has been challenging due to difficulties in maintaining stable exposure concentrations of the test chemical. In Paper III, a passive dosing method, where the test chemical partitions from a polymer (silicone) to the aquatic exposure medium, was developed and tested for chronic exposure. A stable exposure concentration could be maintained, and the chronic toxicity to the sediment-dwelling harpacticoid Nitocra spinipes of chronic exposure to triclosan was assessed in a 6-week population development test. In Paper IV, a passive sampling and dosing method was developed and used to assess the toxicity of an environmental chemical mixture of bioavailable sediment-associated HOCs transferred from a contaminated sediment to the laboratory-based bioassay. The passive sampling and dosing method can be used to assess the toxicity of environmental mixtures of chemicals at environmentally realistic concentrations to which ecosystems are constantly exposed.

  • 22.
    Jensen, Kurt Villads
    Stockholms universitet, Humanistiska fakulteten, Historiska institutionen. Stockholms universitet, Humanistiska fakulteten, Centrum för medeltidsstudier.
    Crusading at the Edges of Europe: Denmark and Portugal c. 1000 - c. 12502017Bok (Refereegranskat)
    Abstract [en]

    Communication in the Middle Ages was better developed than often assumed and institutions, ideas, and military technology was exchanged rapidly, meaning it was possible to coordinate great military expeditions across the geographical periphery of Western Europe. Both Denmark and Portugal were closely connected to the sea and developed strong fleets, at the entrance to the Baltic and in the Mediterranean Seas respectively. They also both had religious borders, to the pagan Wends and to the Muslims, that were pushed forward in almost continuous crusades throughout the centuries. Crusading at the Edges of Europe follows the major campaigns of the kings and crusaders in Denmark and Portugal and compares war-technology and crusading ideology, highlighting how the countries learned from each other and became organised for war.

  • 23. Patton, Henry
    et al.
    Hubbard, Alun
    Andreassen, Karin
    Auriac, Amandine
    Whitehouse, Pippa L.
    Stroeven, Arjen P.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi.
    Shackleton, Calvin
    Winsborrow, Monica
    Heyman, Jakob
    Hall, Adrian M.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi.
    Deglaciation of the Eurasian ice sheet complex2017Ingår i: Quaternary Science Reviews, ISSN 0277-3791, E-ISSN 1873-457X, Vol. 169, s. 148-172Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The Eurasian ice sheet complex (EISC) was the third largest ice mass during the Last Glacial Maximum with a span of over 4500 km and responsible for around 20 m of eustatic sea-level lowering. Whilst recent terrestrial and marine empirical insights have improved understanding of the chronology, pattern and rates of retreat of this vast ice sheet, a concerted attempt to model the deglaciation of the EISC honouring these new constraints is conspicuously lacking. Here, we apply a first-order, thermo-mechanical ice sheet model, validated against a diverse suite of empirical data, to investigate the retreat of the EISC after 23 ka BP, directly extending the work of Patton et al. (2016) who modelled the build-up to its maximum extent. Retreat of the ice sheet complex was highly asynchronous, reflecting contrasting regional sensitivities to climate forcing, oceanic influence, and internal dynamics. Most rapid retreat was experienced across the Barents Sea sector after 17.8 ka BP when this marine-based ice sheet disintegrated at a rate of similar to 670 gigatonnes per year (Gt a(-1)) through enhanced calving and interior dynamic thinning, driven by oceanic/atmospheric warming and exacerbated by eustatic sea-level rise. From 14.9 to 12.9 ka BP the EISC lost on average 750 Gt a(-1), peaking at rates >3000 Gt a(-1), roughly equally partitioned between surface melt and dynamic losses, and potentially contributing up to 2.5 m to global sea-level rise during Meltwater Pulse 1A. Independent glacio-isostatic modelling constrained by an extensive inventory of relative sea-level change corroborates our ice sheet loading history of the Barents Sea sector. Subglacial conditions were predominately temperate during deglaciation, with over 6000 subglacial lakes predicted along with an extensive subglacial drainage network. Moreover, the maximum EISC and its isostatic footprint had a profound impact on the proglacial hydrological network, forming the Fleuve Manche mega-catchment which had an area of similar to 2.5 x 10(6) km(2) and drained the present day Vistula, Elbe, Rhine and Thames rivers through the Seine Estuary. During the Bolling/Allerod oscillation after c. 14.6 ka BP, two major proglacial lakes formed in the Baltic and White seas, buffering meltwater pulses from eastern Fennoscandia through to the Younger Dryas when these massive proglacial freshwater lakes flooded into the North Atlantic Ocean. Deglaciation temporarily abated during the Younger Dryas stadial at 12.9 ka BP, when remnant ice across Svalbard, Franz Josef Land, Novaya Zemlya, Fennoscandia and Scotland experienced a short-lived but dynamic re-advance. The final stage of deglaciation converged on present day ice cover around the Scandes mountains and the Barents Sea by 8.7 ka BP, although the phas-lagged isostatic recovery still continues today.

  • 24.
    Prytherch, John
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Meteorologiska institutionen (MISU). University of Leeds, UK.
    Brooks, Ian M.
    Crill, Patrick M.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för geologiska vetenskaper.
    Thornton, Brett F.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för geologiska vetenskaper.
    Salisbury, Dominic J.
    Tjernström, Michael
    Stockholms universitet, Naturvetenskapliga fakulteten, Meteorologiska institutionen (MISU).
    Anderson, Leif G.
    Geibel, Marc C.
    Stockholms universitet, Naturvetenskapliga fakulteten, Stockholms universitets Östersjöcentrum.
    Humborg, Christoph
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Direct determination of the air-sea CO2 gas transfer velocity in Arctic sea ice regions2017Ingår i: Geophysical Research Letters, ISSN 0094-8276, E-ISSN 1944-8007, Vol. 44, nr 8, s. 3770-3778Artikel i tidskrift (Refereegranskat)
    Abstract [en]

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

  • 25. Bauer, Susanne
    et al.
    Blomqvist, Sven
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och botanik.
    Ingri, Johan
    Distribution of dissolved and suspended particulate molybdenum, vanadium, and tungsten in the Baltic Sea2017Ingår i: Marine Chemistry, ISSN 0304-4203, E-ISSN 1872-7581, Vol. 196, s. 135-147Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In natural waters, dissolved oxyanions often dominate over the particle-bound element fraction. Still, the scavenging of oxyanions by suspended particles might contribute significantly to their dynamic cycling and distribution. To investigate how oxyanions are affected by manganese (Mn) redox cycling, detailed depth profiles across the pelagic redox zone at the Landsort Deep, Baltic Sea, were collected for molybdenum (Mo), vanadium (V), and tungsten (W), for both dissolved (< 0.22 mu m) and suspended particulate (> 0.22 mu m) fractions. All three oxyanions show a non-conservative behavior in the stratified Landsort Deep. Strong linear correlations with Mn in the particulate fraction in the redox zone of the Landsort Deep suggest that Mn redox cycling influences their distribution. In the dissolved fraction, Mo, V, and W exhibited rather different behavior. Molybdenum was depleted below the redox zone, while V was depleted only within the redox zone. Tungsten concentrations increased within the redox zone, being three times higher in the sulfidic zone than in the surface water. Unlike Mo, W shows no tendency for adsorption or co-precipitation under the prevailing weak sulfidic conditions in the deep water of the Landsort Deep and is, therefore, not exported to the underlying sediment. The Landsort Deep data were compared with data from the northern Baltic Sea (Bothnian Bay, Kalix River and Rane River estuaries), where particulate iron (Fe) occurs in high abundance. The particulate fractions of Mo, V, and W decreased during mixing in these estuaries. Vanadium showed the most drastic reduction, with a decrease in dissolved and particulate fractions, indicating that different processes influence the distribution of these oxyanions.

  • 26. Jakubavičiūtė, Eglė
    et al.
    Bergström, Ulf
    Eklöf, Johan S.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och botanik.
    Haenel, Quiterie
    Bourlat, Sarah J.
    DNA metabarcoding reveals diverse diet of the three-spined stickleback in a coastal ecosystem2017Ingår i: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 12, nr 10, artikel-id e0186929Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The three-spined stickleback (Gasterosteus aculeatus L., hereafter 'stickleback') is a common mesopredatory fish in marine, coastal and freshwater areas. In large parts of the Baltic Sea, stickleback densities have increased > 10-fold during the last decades, and it is now one of the dominating fish species both in terms of biomass and effects on lower trophic levels. Still, relatively little is known about its diet-knowledge which is essential to understand the increasing role sticklebacks play in the ecosystem. Fish diet analyses typically rely on visual identification of stomach contents, a labour-intensive method that is made difficult by prey digestion and requires expert taxonomic knowledge. However, advances in DNA-based metabarcoding methods promise a simultaneous identification of most prey items, even from semi-digested tissue. Here, we studied the diet of stickleback from the western Baltic Sea coast using both DNA metabarcoding and visual analysis of stomach contents. Using the cytochrome oxidase (CO1) marker we identified 120 prey taxa in the diet, belonging to 15 phyla, 83 genera and 84 species. Compared to previous studies, this is an unusually high prey diversity. Chironomids, cladocerans and harpacticoids were dominating prey items. Large sticklebacks were found to feed more on benthic prey, such as amphipods, gastropods and isopods. DNA metabarcoding gave much higher taxonomic resolution (median rank genus) than visual analysis (median rank order), and many taxa identified using barcoding could not have been identified visually. However, a few taxa identified by visual inspection were not revealed by barcoding. In summary, our results suggest that the three-spined stickleback feeds on a wide variety of both pelagic and benthic organisms, indicating that the strong increase in stickleback populations may affect many parts of the Baltic Sea coastal ecosystem.

  • 27. Voss, Rudi
    et al.
    Quaas, Martin F.
    Stoeven, Max T.
    Schmidt, Jörn O.
    Tomczak, Maciej T.
    Stockholms universitet, Naturvetenskapliga fakulteten, Stockholms universitets Östersjöcentrum.
    Möllmann, Christian
    Ecological-Economic Fisheries Management Advice—Quantification of Potential Benefits for the Case of the Eastern Baltic COD Fishery2017Ingår i: Frontiers in Marine Science, E-ISSN 2296-7745, Vol. 4, artikel-id 209Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Fishing is a social and economic activity, and consequently socio-economic considerations are important for resource management. While this is acknowledged in the theory of Ecosystem-Based Management (EBM) and its sector-specific development Ecosystem-Based Fisheries Management (EBFM), currently applied fishery management objectives often ignore economic considerations. Year-to-year management, however, implicitly responds to short-term economic interests, and consequently, regularly resorts to tactical short-term rather than strategic long-term decisions. The aim of this article is to introduce a new way of estimating management advice referred to as an “ecologically-constrained Maximum Economic Yield” (eMEY) strategy, which takes into account ecological criteria as well as short- to medium-term economic costs. We further illustrate what net cost reductions per year are possible applying the eMEY strategy compared with the existing way of setting total allowable catches (TACs). The eMEY approach aims at maximizing the economic benefits for the fishery as well as society (consumers), while safeguarding precautionary stock sizes. Using an age-structured optimization model parameterized for the Eastern Baltic cod case study, we find that application of eMEY advice results in more stability in catch advice. Quantification and visualization of the costs of deviating from eMEY advice offers a transparent basis for evaluating decision-making outcomes. The costs of overfishing are mainly borne by the commercial fishery, while fishing less than optimal is particularly costly for the processing industry and consumers. To foster the uptake of our eMEY approach in current advice given by the International Council for the Exploration of the Sea (ICES) and the EU fishery management system, we suggest an easy-to-implement scheme of providing integrated advice, also accounting for economic considerations.

  • 28. Lundmark, Carina
    et al.
    Andersson, Klas
    Sandström, Annica
    Laikre, Linda
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen.
    Effectiveness of short-term knowledge communication on Baltic Sea marine genetic biodiversity to public managers2017Ingår i: Regional Environmental Change, ISSN 1436-3798, E-ISSN 1436-378X, Vol. 17, nr 3, s. 841-849Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The aim of this study is to assess the impact of two forms of short-term knowledge communication-lectures and group deliberations-on public managers' policy beliefs regarding genetic biodiversity in the Baltic Sea. Genetic biodiversity is a key component of biological variation, but despite scientific knowledge and far-reaching political goals, genetic biodiversity remains neglected in marine management. Previous research highlights lack of knowledge among managers as one explanation to the implementation deficit. This multidisciplinary study builds on the identified need for an improved knowledge transfer between science and ongoing management. A basic knowledge package on genetic biodiversity in the Baltic Sea was presented as either a lecture or a deliberative group discussion to two separate samples of public managers who are involved in Baltic Sea and other biodiversity management at the regional level in Sweden. The empirical findings show that the communicated information has an impact on the public managers' beliefs on genetic biodiversity of the Baltic Sea. Lectures seem more efficient to transfer knowledge on this theme. Those who received information through a lecture strengthen their confidence in area protection as a management tool to conserve genetic diversity. They were also more convinced of the obligation of authorities at national and regional level to take on larger responsibility for genetic conservation than those managers who participated in a deliberative discussion.

  • 29. Legradi, Jessica
    et al.
    van Pomeren, Marinda
    Dahlberg, Anna-Karin
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi. Swedish University of Agricultural Sciences, Sweden.
    Legler, Juliette
    Effects of Hydroxylated Polybrominated Diphenyl Ethers in Developing Zebrafish Are Indicative of Disruption of Oxidative Phosphorylation2017Ingår i: International Journal of Molecular Sciences, ISSN 1422-0067, E-ISSN 1422-0067, Vol. 18, nr 5, artikel-id 970Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Hydroxylated polybrominated diphenyl ethers (OH-PBDEs) have been detected in humans and wildlife. Using in vitro models, we recently showed that OH-PBDEs disrupt oxidative phosphorylation (OXPHOS), an essential process in energy metabolism. The goal of the current study was to determine the in vivo effects of OH-PBDE reported in marine wildlife. To this end, we exposed zebrafish larvae to 17 OH-PBDEs from fertilisation to 6 days of age, and determined developmental toxicity as well as OXPHOS disruption potential with a newly developed assay of oxygen consumption in living embryos. We show here that all OH-PBDEs tested, both individually and as mixtures, resulted in a concentration-dependant delay in development in zebrafish embryos. The most potent substances were 6'-OH-BDE47 and 6-OH-BDE49 (No-Effect-Concentration: 0.1 and 0.05 mu M). The first 24 h of development were the most sensitive, resulting in significant and irreversible developmental delay. All substances increased oxygen consumption, an effect indicative of OXPHOS disruption. Our results suggest that the induced developmental delay may be caused by disruption of OXPHOS. Though further studies are needed, our findings suggest that the environmental concentrations of some OH-PBDEs found in Baltic Sea wildlife in the Baltic Sea may be of toxicological concern.

  • 30.
    Eriksson, Niklas
    Stockholms universitet, Humanistiska fakulteten, Institutionen för arkeologi och antikens kultur.
    Eftermedeltida skeppsvrak: reflektioner kring marinarkeologi och historisk arkeologi med exempel från Östersjö2017Ingår i: Nordisk marinarkæologi fast forankret / [ed] Otto Uldum, Morten Sylvester, Rudkøbing: Langelands Museum , 2017, s. 101-116Kapitel i bok, del av antologi (Övrigt vetenskapligt)
    Abstract [en]

    Postmedieval shipwrecks: reflections on maritime archaeology and historical archaeology with examples from the Baltic Sea That the brackish water of the Baltic Sea provides ideal conditions for preservation of organic material is a well-known fact. With this in mind it is a bit surprising just how little archaeological efforts that has been put into surveying these wrecks. The majority of these remains date to the early modern period. The study of these remains are thus associated with the assets as well as problems associated with historical archaeology. This paper reviews some of the research efforts carried out on wrecks in the past with focus on the relationship between history and archaeology. It is argued that the often claimed unique archaeological potential of the Baltic wrecks, tend to become overshadowed by narratives sprung out of written sources. The paper ends with a couple of examples of discussions that are only possible to raise from well-preserved shipwrecks. Inspired by phenomenology and the current research on historical buildings it is argued that ‘the lived experience’ is a possible way forward to raise other questions and to highlight other aspects of the past. The examples discussed are the everyday environment onboard fluits, a very common type of merchant ship, and the famous naval ship Svärdet that went down during a fierce battle in 1676.

  • 31. Krogseth, Ingjerd S.
    et al.
    Undeman, Emma
    Stockholms universitet, Naturvetenskapliga fakulteten, Stockholms universitets Östersjöcentrum. Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Evenset, Anita
    Christensen, Guttorm N.
    Whelan, Mick J.
    Breivik, Knut
    Warner, Nicholas A.
    Elucidating the Behavior of Cyclic Volatile Methylsiloxanes in a Subarctic Freshwater Food Web: A Modeled and Measured Approach2017Ingår i: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 51, nr 21, s. 12489-12497Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Cyclic volatile methylsiloxanes (cVMS) are used in personal care products and emitted to aquatic environments through wastewater effluents, and their bioaccumulation potential is debated. Here, a new bentho-pelagic version of the ACC-HUMAN model was evaluated for polychlorinated biphenyls (PCBs) and applied to cVMS in combination with measurements to explore their bioaccumulation behavior in a subarctic lake. Predictions agreed better with measured PCB concentrations in Arctic char (Salvelinus alpinus) and brown trout (Salmo trutta) when the benthic link was included than in the pelagic-only model. Measured concentrations of decamethylcyclopentasiloxane (D5) were 60 +/- 1.2 (Chironomidae larvae), 107 +/- 4.5 (pea clams Pisidium sp.), 131 +/- 105 (three-spined sticklebacks: Gasterosteus aculeatus), 41 +/- 38 (char), and 9.9 +/- 5.9 (trout) ng g(-1) wet weight. Concentrations were lower for octamethylcyclotetrasiloxane (D4) and dodecamethylcyclohexasiloxane (D6), and none of the cVMS displayed trophic magnification. Predicted cVMS concentrations were lower than measured in benthos, but agreed well with measurements in fish. cVMS removal through ventilation was an important predicted loss mechanism for the benthic-feeding fish. Predictions were highly sensitive to the partition coefficient between organic carbon and water (K-OC) and its temperature dependence, as this controlled bioavailability for benthos (the main source of cVMS for fish).

  • 32. Anderson, Leif G.
    et al.
    Ek, Jörgen
    Stockholms universitet, Naturvetenskapliga fakulteten, Stockholms universitets Östersjöcentrum.
    Ericson, Ylva
    Humborg, Christoph
    Stockholms universitet, Naturvetenskapliga fakulteten, Stockholms universitets Östersjöcentrum. Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Semiletov, Igor
    Sundbom, Marcus
    Stockholms universitet, Naturvetenskapliga fakulteten, Stockholms universitets Östersjöcentrum.
    Ulfsbo, Adam
    Export of calcium carbonate corrosive waters from the East Siberian Sea2017Ingår i: Biogeosciences, ISSN 1726-4170, E-ISSN 1726-4189, Vol. 14, nr 7, s. 1811-1823Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The Siberian shelf seas are areas of extensive biogeochemical transformation of organic matter, both of marine and terrestrial origin. This in combination with brine production from sea ice formation results in a cold bottom water of relative high salinity and partial pressure of carbon dioxide (pCO(2)). Data from the SWERUS-C3 expedition compiled on the icebreaker Oden in July to September 2014 show the distribution of such waters at the outer shelf, as well as their export into the deep central Arctic basins. Very high pCO(2) water, up to similar to 1000 mu atm, was observed associated with high nutrients and low oxygen concentrations. Consequently, this water had low saturation state with respect to calcium carbonate down to less than 0.8 for calcite and 0.5 for aragonite. Waters undersaturated in aragonite were also observed in the surface in waters at equilibrium with atmospheric CO2; however, at these conditions the cause of undersaturation was low salinity from river runoff and/or sea ice melt. The calcium carbonate corrosive water was observed all along the continental margin and well out into the deep Makarov and Canada basins at a depth from about 50 m depth in the west to about 150 m in the east. These waters of low aragonite saturation state are traced in historic data to the Canada Basin and in the waters flowing out of the Arctic Ocean north of Greenland and in the western Fram Strait, thus potentially impacting the marine life in the North Atlantic Ocean.

  • 33. Horbowy, Jan
    et al.
    Tomczak, Maciej T.
    Stockholms universitet, Naturvetenskapliga fakulteten, Stockholms universitets Östersjöcentrum.
    Extension of biomass estimates to pre-assessment periods using density dependent surplus production approach2017Ingår i: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 12, nr 11, artikel-id e0186830Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Biomass reconstructions to pre-assessment periods for commercially important and exploitable fish species are important tools for understanding long-term processes and fluctuation on stock and ecosystem level. For some stocks only fisheries statistics and fishery dependent data are available, for periods before surveys were conducted. The methods for the backward extension of the analytical assessment of biomass for years for which only total catch volumes are available were developed and tested in this paper. Two of the approaches developed apply the concept of the surplus production rate (SPR), which is shown to be stock density dependent if stock dynamics is governed by classical stock-production models. The other approach used a modified form of the Schaefer production model that allows for backward biomass estimation. The performance of the methods was tested on the Arctic cod and North Sea herring stocks, for which analytical biomass estimates extend back to the late 1940s. Next, the methods were applied to extend biomass estimates of the North-east Atlantic mackerel from the 1970s (analytical biomass estimates available) to the 1950s, for which only total catch volumes were available. For comparison with other methods which employs a constant SPR estimated as an average of the observed values, was also applied. The analyses showed that the performance of the methods is stock and data specific; the methods that work well for one stock may fail for the others. The constant SPR method is not recommended in those cases when the SPR is relatively high and the catch volumes in the reconstructed period are low.

  • 34. Momigliano, Paolo
    et al.
    Jokinen, Henri
    Fraimout, Antoine
    Florin, Ann-Britt
    Norkko, Alf
    Stockholms universitet, Naturvetenskapliga fakulteten, Stockholms universitets Östersjöcentrum. University of Helsinki, Finland.
    Merila, Juha
    Extraordinarily rapid speciation in a marine fish2017Ingår i: Proceedings of the National Academy of Sciences of the United States of America, ISSN 0027-8424, E-ISSN 1091-6490, Vol. 114, nr 23, s. 6074-6079Artikel i tidskrift (Refereegranskat)
    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.

  • 35.
    Bergendahl, I. Ahlbeck
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och botanik.
    Holliland, Per Benjamin
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och botanik.
    Hansson, Sture
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och botanik.
    Karlöf, Oliver
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och botanik.
    Feeding range of age 1+year Eurasian perch Perca fluviatilis in the Baltic Sea2017Ingår i: Journal of Fish Biology, ISSN 0022-1112, E-ISSN 1095-8649, Vol. 90, nr 5, s. 2060-2072Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Using the widespread Eurasian perch Perca fluviatilis as a model organism, feeding ranges were investigated using stable-isotope ratios (N-15 and C-13) and body condition. Differences were found between closely located sampling sites in a littoral area without obvious migration barriers, indicating that individual fish had small feeding ranges. Body condition differences between sampled stations were consistent over 4 years. Such sedentary behaviour is important to consider in, e.g. fisheries management and environmental monitoring, as local catch regulations may be meaningful or geographic stability in sampling locations may reduce noise in data.

  • 36. Torres, Maria A.
    et al.
    Casini, Michele
    Huss, Magnus
    Otto, Saskia A.
    Stockholms universitet, Naturvetenskapliga fakulteten, Stockholm Resilience Centre. University of Hamburg, Germany.
    Kadin, Martina
    Stockholms universitet, Naturvetenskapliga fakulteten, Stockholm Resilience Centre.
    Gårdmark, Anna
    Food-web indicators accounting for species interactions respond to multiple pressures2017Ingår i: Ecological Indicators, ISSN 1470-160X, E-ISSN 1872-7034, Vol. 77, s. 67-79Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Food-web indicators for marine management are required to describe the functioning and structure of marine food-webs. In Europe, the Marine Strategy Framework Directive (MSFD), intended to lead to a 'good environmental status' of the marine waters, requires indicators of the status of the marine environment that also respond to manageable anthropogenic pressures. Identifying such relationships to pressures is particularly challenging for food-web indicators, as they need to be disentangled from linkages between indicators of different functional groups caused by species interactions. Still, such linkages have not been handled in the indicator development. Here we used multivariate autoregressive time series models to identify how fish indicators in an exploited food-web relate to fishing, climate and eutrophication, while accounting for the linkages between indicators caused by species interactions. We assembled 31-year long time series of indicators of key functional groups of fish in the Central Baltic Sea pelagic food-web, which is characterized by strong trophic links between cod (Gadus morhua) and its main fish prey sprat (Sprattus sprattus) and herring (Clupea harengus). These food-web indicators were either abundance-based indicators of key piscivores (cod) and zooplanktivores (sprat and herring) or size-based indicators of the corresponding trophic groups (biomass of large predatory fish (cod >= 38 cm) and biomass of small prey fish (sprat and herring <10 cm)). Comparative analyses of models with and without linkages among indicators showed that for both types of indicators, linkages corresponding to predator-prey feedbacks and intra-specific density-dependence were essential to explain temporal variation in the indicators. Thus, no indicator-pressure relationships could be found that explained the indicators' variation unless such linkages were accounted for. When accounting for these, we found that the indicators overall respond to multiple pressures acting simultaneously rather than to single pressures, as no pressure alone could explain how the indicators developed over time. The manageable pressures fishing and eutrophication, as well as the prevailing hydrological conditions influenced by climate, were all needed to reproduce the inter-annual changes in these food-web indicators combined, although individual relationships differed between the indicators. We conclude that our innovative indicator-testing framework can therefore be used to identify responses of food-web indicators to manageable pressures while accounting for the biotic interactions in food-webs linking such indicators.

  • 37.
    Lade, Steven J.
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Stockholm Resilience Centre. The Australian National University, Australia.
    Niiranen, Susa
    Stockholms universitet, Naturvetenskapliga fakulteten, Stockholm Resilience Centre.
    Generalized modeling of empirical social-ecological systems2017Ingår i: Natural Resource Modeling, ISSN 0890-8575, E-ISSN 1939-7445, Vol. 30, nr 3, artikel-id e12129Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Modeling social-ecological systems is difficult due to the complexity of ecosystems and of individual and collective human behavior. Key components of the social-ecological system are often over-simplified or omitted. Generalized modeling is a dynamical systems approach that can overcome some of these challenges. It can rigorously analyze qualitative system dynamics such as regime shifts despite incomplete knowledge of the model's constituent processes. Here, we review generalized modeling and use a recent study on the Baltic Sea cod fishery's boom and collapse to demonstrate its application to modeling the dynamics of empirical social-ecological systems. These empirical applications demand new methods of analysis suited to larger, more complicated generalized models. Generalized modeling is a promising tool for rapidly developing mathematically rigorous, process-based understanding of a social-ecological system's dynamics despite limited knowledge of the system. Recommendations for Resource Managers Understanding empirical social-ecological dynamics requires integrating quantitative and qualitative data Generalized modeling can analyze qualitative dynamics, such as regime shifts, by integrating both qualitative and quantitative data Generalized modeling is well-suited to use in participatory or collaborative settings

  • 38.
    Vigil-Stenman, Theoden
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och botanik.
    Ininbergs, Karolina
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och botanik.
    Bergman, Birgitta
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och botanik.
    Ekman, Martin
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och botanik.
    High abundance and expression of transposases in bacteria from the Baltic Sea2017Ingår i: The ISME Journal, ISSN 1751-7362, E-ISSN 1751-7370, Vol. 11, nr 11, s. 2611-2623Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Transposases are mobile genetic elements suggested to have an important role in bacterial genome plasticity and host adaptation but their transcriptional activity in natural bacterial communities is largely unexplored. Here we analyzed metagenomes and -transcriptomes of size fractionated (0.1-0.8, 0.8-3.0 and 3.0-200 mu m) bacterial communities from the brackish Baltic Sea, and adjacent marine waters. The Baltic Sea transposase levels, up to 1.7% of bacterial genes and 2% of bacterial transcripts, were considerably higher than in marine waters and similar to levels reported for extreme environments. Large variations in expression were found between transposase families and groups of bacteria, with a two-fold higher transcription in Cyanobacteria than in any other phylum. The community-level results were corroborated at the genus level by Synechococcus transposases reaching up to 5.2% of genes and 6.9% of transcripts, which is in contrast to marine Synechococcus that largely lack these genes. Levels peaked in Synechococcus from the largest size fraction, suggesting high frequencies of lateral gene transfer and high genome plasticity in colony-forming picocyanobacteria. Together, the results support an elevated rate of transposition-based genome change and adaptation in bacterial populations of the Baltic Sea, and possibly also of other highly dynamic estuarine waters.

  • 39. Alikas, Krista
    et al.
    Kratzer, Susanne
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och botanik.
    Improved retrieval of Secchi depth for optically-complex waters using remote sensing data2017Ingår i: Ecological Indicators, ISSN 1470-160X, E-ISSN 1872-7034, Vol. 77, s. 218-227Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Water transparency is one of the ecological indicators for describing water quality and the underwater light field which determines its productivity. In the European Water Framework Directive (WFD) as well as in the European Marine Strategy Framework Directive (MSFD) water transparency is used for ecological status classification of inland, coastal and open sea waters and it is regarded as an indicator for eutrophication in Baltic Sea management (HELCOM, 2007). We developed and compared different empirical and semi-analytical algorithms for lakes and coastal Nordic waters to retrieve Secchi depth (Z(SD)) from remote sensing data (MERIS, 300 m resolution).The algorithms were developed in water bodies with high coloured dissolved organic matter absorption (a(CNOM)(442) ranging 1.7-4.0 m(-1)), Chl a concentration (0.5-73 mg m(-3)) and total suspended matter (0.7-37.5 g m(-3)) and validated against an independent data set over inland and coastal waters (0.6 m < Z(SD) < 14.8 m). The results indicate that for empirical algorithms, using longer wavelengths in the visible spectrum as a reference band decreases the RMSE and increases the coefficient of determination (R-2). The accuracy increased (R-2 = 0.75, RMSE = 1.33 m, n = 134) when Z(SD) was retrieved via an empirical relationship between Z(SD) and K-d (490). The best agreement with in situ data was attained when Z(SD) was calculated via both the diffuse and the beam attenuation coefficient (R-2 = 0.89, RMSE = 0.77 m, n = 89). The results demonstrate that transparency can be retrieved with high accuracy over various optical water types by the means of ocean color remote sensing, improving both the spatial and temporal coverage. The satellite derived Z(SD) product could be therefore used as an additional source of information for WFD and MSFD reporting purposes.

  • 40.
    Mustajärvi, Lukas
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Eek, Espen
    Cornelissen, Gerard
    Eriksson-Wiklund, Ann-Kristin
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Undeman, Emma
    Stockholms universitet, Naturvetenskapliga fakulteten, Stockholms universitets Östersjöcentrum.
    Sobek, Anna
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    In situ benthic flow-through chambers to determine sediment-to-water fluxes of legacy hydrophobic organic contaminants2017Ingår i: Environmental Pollution, ISSN 0269-7491, E-ISSN 1873-6424, Vol. 231, s. 854-862Artikel i tidskrift (Refereegranskat)
    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.

  • 41.
    Svensson, Filip
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och botanik. Swedish University of Agricultural Sciences, Sweden.
    Karlsson, Erik
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och botanik. Institute of Coastal Research, Sweden.
    Gårdmark, Anna
    Olsson, Jens
    Adill, Anders
    Zie, Jenny
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och botanik.
    Snoeijs-Leijonmalm, Pauline
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och botanik.
    Eklöf, Johan S.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och botanik.
    In situ warming strengthens trophic cascades in a coastal food web2017Ingår i: Oikos, ISSN 0030-1299, E-ISSN 1600-0706, Vol. 126, nr 8, s. 1150-1161Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Global warming may affect most organisms and their interactions. Theory and simple mesocosm experiments suggest that consumer top-down control over primary producer biomass should strengthen with warming, since consumer respiration increases faster with warming than plant photosynthesis. However, these predictions have so far not been tested on natural communities that have experienced warming over many generations. Natural systems display a higher diversity, heterogeneity and complexity than mesocosms, which could alter predicted effects of warming. Here we used an artificially heated part of the northern Baltic Sea (the Forsmark Biotest basin) to test how warming influences trophic interactions in a shallow coastal food web with four trophic levels: omnivorous fish, invertivorous fish, herbivorous invertebrates, and filamentous macroalgae. Monitoring of fish assemblages over six years showed that small invertivorous fish (gobiids, sticklebacks and minnows) were much less abundant in the heated basin than in unheated references areas. Stomach content analyses of the dominating omnivorous fish - Eurasian perch Perca fluviatilis - revealed a strikingly different diet within and outside the Biotest basin; gammarid crustaceans were the dominating prey at heated sites, whereas invertivorous fish (e.g. gobiids) dominated at unheated sites. A 45-day cage experiment showed that fish exclusion did not affect the biomass of algal herbivores (gastropods and gammarids), but reduced algal biomass in heated sites (but not unheated). This suggests that warming induced a trophic cascade from fish to algae, and that this effect was mediated by predator-induced changes in herbivore behavior, rather than number. Overall, our study suggests that warming has effectively compressed the food chain from four to three trophic levels (algae, gammarids and perch), which have benefitted the primary producers by reducing grazing pressure. Consequently, warming appears to have restructured this coastal food web through a combination of direct (physiological) and indirect (species interactions) effects.

  • 42. Sampaio, E.
    et al.
    Rodil, Iván F.
    Stockholms universitet, Naturvetenskapliga fakulteten, Stockholms universitets Östersjöcentrum. University of Porto, Portugal; University of Helsinki, Finland.
    Vaz-Pinto, F.
    Fernandez, A.
    Arenas, F.
    Interaction strength between different grazers and macroalgae mediated by ocean acidification over warming gradients2017Ingår i: Marine Environmental Research, ISSN 0141-1136, E-ISSN 1879-0291, Vol. 125, s. 25-33Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Since the past century, rising CO2 levels have led to global changes (ocean warming and acidification) with subsequent effects on marine ecosystems and organisms. Macroalgae-herbivore interactions have a main role in the regulation of marine community structure (top-down control). Gradients of warming prompt complex non-linear effects on organism metabolism, cascading into altered trophic interactions and community dynamics. However, not much is known on how will acidification and grazer assemblage composition shape these effects. Within this context, we aimed to assess the combined effects of warming gradients and acidification on macroalgae-herbivore interactions, using three cosmopolitan species, abundant in the Iberian Peninsula and closely associated in nature: the amphipod Melita palmata, the gastropod Gibbula umbilicalis, and the green macroalga Ulva rigida. Under two CO2 treatments (triangle CO2 similar or equal to 450 mu atm) across a temperature gradient (13.5, 16.6, 19.9 and 22.1 degrees C), two mesocosm experiments were performed to assess grazer consumption rates and macroalgae-herbivore interaction, respectively. Warming (Experiment I and II) and acidification (Experiment II) prompted negative effects in grazer's survival and species-specific differences in consumption rates. M. palmata was shown to be the stronger grazer per biomass (but not per capita), and also the most affected by climate stressors. Macroalgae-herbivore interaction strength was markedly shaped by the temperature gradient, while simultaneous acidification lowered thermal optimal threshold. In the near future, warming and acidification are likely to strengthen top-down control, but further increases in disturbances may lead to bottom-up regulated communities. Finally, our results suggest that grazer assemblage composition may modulate future macroalgae-herbivore interactions.

  • 43.
    Rundgren, Carl-Johan
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för matematikämnets och naturvetenskapsämnenas didaktik.
    Eriksson, Martin
    Chang Rundgren, Shu-Nu
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för pedagogik och didaktik.
    Investigating the intertwinement of knowledge, value, and experience of upper secondary students’ argumentation concerning socioscientific issues2017Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    This study aims to explore students’ argumentation and decision-making relating toan authentic socioscientific issue (SSI)—the problem of environmental toxins in fish from theBaltic Sea. A multi-disciplinary instructional module, designed in order to develop students’skills to argue about complex SSI, was successfully tested. Seven science majors in the finalyear of their upper secondary studies participated in this study. Their argumentation anddecision-making processes were followed closely, and data were collected during multiplestages of the instructional module: group discussions were audio recorded, the participantswrote reports on their decision making, and postexercise interviews were conducted withindividual students. The analysis focused on the skill of evaluation demonstrated by thestudents during the exercise and the relationships between the knowledge, values, andexperiences that they used in their argumentation. Even though all of the students had accessto the same information and agreed on the factual aspects of the issue, they came to differentdecisions. All of the students took counter-arguments and the limitations of their claims intoaccount and were able to extend their claims where appropriate. However, their decisionsdiffered depending on their background knowledge, values, and experiences (i.e., theirintellectual baggage). The implication to SSI teaching and learning is discussed.

  • 44.
    Rundgren, Carl-Johan
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för matematikämnets och naturvetenskapsämnenas didaktik.
    Eriksson, Martin
    Chang Rundgren, Shu-Nu
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för pedagogik och didaktik.
    Investigating the intertwinement of knowledge, value and experience of upper secondary students' argumentation concerning socioscientific issues2017Ingår i: Science & Education, ISSN 0926-7220, E-ISSN 1573-1901, Vol. 25, nr 9-10, s. 1049-1071Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This study aims to explore students’ argumentation and decision-making relating to an authentic socioscientific issue (SSI)—the problem of environmental toxins in fish from the Baltic Sea. A multi-disciplinary instructional module, designed in order to develop students’ skills to argue about complex SSI, was successfully tested. Seven science majors in the final year of their upper secondary studies participated in this study. Their argumentation and decision-making processes were followed closely, and data were collected during multiple stages of the instructional module: group discussions were audio recorded, the participants wrote reports on their decision making, and postexercise interviews were conducted with individual students. The analysis focused on the skill of evaluation demonstrated by the students during the exercise and the relationships between the knowledge, values, and experiences that they used in their argumentation. Even though all of the students had access to the same information and agreed on the factual aspects of the issue, they came to different decisions. All of the students took counter-arguments and the limitations of their claims into account and were able to extend their claims where appropriate. However, their decisions differed depending on their background knowledge, values, and experiences (i.e., their intellectual baggage). The implication to SSI teaching and learning is discussed.