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  • 1. Asmala, Eero
    et al.
    Gustafsson, Camilla
    Krause-Jensen, Dorte
    Norkko, Alf
    Stockholm University, Faculty of Science, Stockholm University Baltic Sea Centre. University of Helsinki, Finland.
    Reader, Heather
    Staehr, Peter A.
    Carstensen, Jacob
    Role of Eelgrass in the Coastal Filter of Contrasting Baltic Sea Environments2019In: Estuaries and Coasts, ISSN 1559-2723, E-ISSN 1559-2731, Vol. 42, no 7, p. 1882-1895Article in journal (Refereed)
    Abstract [en]

    Coastal ecosystems act as filters of nutrients from land to the open sea. We investigated the role of eelgrass (Zostera marina) metabolism in the coastal filter transforming nitrogen, phosphorus, and organic carbon. Field campaigns following identical methodologies were carried out at two contrasting coastal locations: the mesohaline and nutrient-rich Roskilde Fjord, Denmark, and the mesotrophic brackish Tvarminne archipelago, Finland. Over the 24-h in situ benthic incubations, we measured oxygen concentrations continuously and assessed changes in DOM characteristics and net fluxes of carbon, nitrogen, and phosphorus. Ecosystem metabolism modeled on the basis of the O-2 data showed that the systems were either net heterotrophic (Roskilde Fjord; - 1.6 and - 2.4 g O-2 m(-2) day(-1) in eelgrass meadow and bare sand, respectively) or had balanced primary production and respiration (Tvarminne; 0.0 and 0.2 g O-2 m(-2) day(-1)). Overall, initial nutrient stoichiometry was a key factor determining benthic-pelagic fluxes of nutrients, which exacerbated the deviations from Redfield ratios of N and P, indicating an efficient use of the limiting nutrient. A net diel uptake of dissolved inorganic N was observed at both locations (- 2.3 mu mol l(-1) day(-1) in Roskilde Fjord and - 0.1 mu mol l(-1) day(-1) in Tvarminne). Despite minor changes in dissolved organic carbon concentrations during the incubations, a marked increase of fluorescent DOM was observed at both locations, suggesting rapid heterotrophic processing of the DOM pool. Our results underline that the biogeochemical role of eelgrass in the coastal filter is not inherent, but strongly dependent on the environmental conditions.

  • 2. Quintana, Cintia O.
    et al.
    Raymond, Caroline
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Nascimento, Francisco J. A.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Bonaglia, Stefano
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Forster, Stefan
    Gunnarsson, Jonas S.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Kristensen, Erik
    Functional Performance of Three Invasive Marenzelleria Species Under Contrasting Ecological Conditions Within the Baltic Sea2018In: Estuaries and Coasts, ISSN 1559-2723, E-ISSN 1559-2731, Vol. 41, no 6, p. 1766-1781Article in journal (Refereed)
    Abstract [en]

    A 4-week laboratory experiment investigated the behaviour (survival and bioirrigation) and impact of the invasive polychaetes Marenzelleria viridis, M. neglecta and M. arctia on sediment-water solutes exchange, porewater chemistry, and Fe and P interactions in high-salinity sandy sediment (HSS) and low-salinity muddy sediment (LSM) from the Baltic Sea. M. viridis showed deep burrowing with efficient bioirrigation (11 L m−2 day−1) and high survival (71%) in HSS, while M. arctia exhibited shallow burrowing with high bioirrigation (12 L m−2 day−1) and survival (88%) in LSM. M. neglecta behaved poorly in both ecological settings (bioirrigation, 5–6 L m−2 day−1; survival, 21–44%). The deep M. viridis bioirrigation enhanced total microbial CO2 (TCO2) production in HSS by 175% with a net efflux of NH4+ and PO43−, at rates 3- to 27-fold higher than for the other species. Although the shallow and intense bioirrigation of M. arctia in LSM stimulated microbial TCO2 production to some extent (61% enhancement), the nutrient fluxes close to zero indicate that it effectively prevented the P release. Porewater Fe:PO43− ratios revealed that the oxidizing effect of M. arctia bioirrigation increased the PO43− adsorption capacity of LSM twofold relative to defaunated controls while no buffering of PO43− was detected in M. viridis HSS treatment. Therefore, the different behaviour of the three species in various environments and the sharp contrast between M. viridis and M. arctia effects on C, N and P cycling must be considered carefully when the ecological role of Marenzelleria species in the Baltic Sea is evaluated.

  • 3. Rivera-Monroy, Victor H.
    et al.
    Twilley, Robert R.
    Ernesto Mancera-Pineda, J.
    Madden, Christopher J.
    Alcantara-Eguren, Ariel
    Moser, E. Barry
    Jonsson, Bror F.
    Stockholm University, Faculty of Science, Department of Meteorology .
    Castaneda-Moya, Edward
    Casas-Monroy, Oscar
    Reyes-Forero, Paola
    Restrepo, Jorge
    Salinity and Chlorophyll a as Performance Measures to Rehabilitate a Mangrove-Dominated Deltaic Coastal Region: the Cienaga Grande de Santa Marta-Pajarales Lagoon Complex, Colombia2011In: Estuaries and Coasts, ISSN 1559-2723, E-ISSN 1559-2731, Vol. 34, no 1, p. 1-19Article in journal (Refereed)
    Abstract [en]

    Salinity, water temperature, and chlorophyll a (chl-a) biomass were used as performance measures in the period 1999-2001 to evaluate the effect of a hydrological rehabilitation project in the Cienaga Grande de Santa Marta (CGSM)-Pajarales lagoon complex, Colombia where freshwater diversions were initiated in 1995 and completed in 1998. The objective of this study was to evaluate how diversions of freshwater into previously hypersaline (>80) environments changed the spatial and temporal distribution of environmental characteristics. Following the diversion, 19 surveys and transects using a flow-through system were surveyed in the CGSM-Pajarales complex to continuously measure selected water quality parameters. Geostatistical analysis indicates that hydrology and salinity regimes and water circulation patterns in the CGSM lagoon are largely controlled by freshwater discharge from the Fundacion, Aracataca, and Sevilla Rivers. Residence times in the CGSM lagoon were similar before (15.5+/-3.8 days) and after (14.2+/-2.0 days) the rehabilitation project and indicated that the system is flushed regularly. In contrast, chl-a biomass was highly variable in the CGSM-Pajarales lagoon complex and not related to discharge patterns. Mean annual chl-a biomass (44-250 mu g L(-1)) following the diversion project was similar to values recorded since the 1980s and still remains among the highest reported in coastal systems around the world owing to its unique hydrology regulated by the Magdalena River and Sierra Nevada de Santa Marta watersheds and the high teleconnection to the El Nino Southern Oscillation (ENSO). Our results confirm that the reduction in salinity in the CGSM lagoon and Pajarales complex during 1999-2000 was largely driven by high precipitation (2500 mm) induced by the ENSO-La Nina rather than by the freshwater diversions.

  • 4.
    Rodil, Iván F.
    et al.
    Stockholm University, Faculty of Science, Stockholm University Baltic Sea Centre. University of Helsinki, Finland.
    Lucena-Moya, P.
    Lastra, M.
    The Importance of Environmental and Spatial Factors in the Metacommunity Dynamics of Exposed Sandy Beach Benthic Invertebrates2018In: Estuaries and Coasts, ISSN 1559-2723, E-ISSN 1559-2731, Vol. 41, no 1, p. 206-217Article in journal (Refereed)
    Abstract [en]

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

  • 5. Thang, Nguyen Manh
    et al.
    Brüchert, Volker
    Stockholm University, Faculty of Science, Department of Geological Sciences.
    Formolo, Michael
    Wegener, Gunter
    Ginters, Livija
    Stockholm University, Faculty of Science, Department of Geological Sciences.
    Jorgensen, Bo Barker
    Ferdelman, Timothy G.
    The Impact of Sediment and Carbon Fluxes on the Biogeochemistry of Methane and Sulfur in Littoral Baltic Sea Sediments (Himmerfjarden, Sweden)2013In: Estuaries and Coasts, ISSN 1559-2723, E-ISSN 1559-2731, Vol. 36, no 1, p. 98-115Article in journal (Refereed)
    Abstract [en]

    Three sediment stations in Himmerfjarden estuary (Baltic Sea, Sweden) were sampled in May 2009 and June 2010 to test how low salinity (5-7 aEuro degrees), high primary productivity partially induced by nutrient input from an upstream waste water treatment plant, and high overall sedimentation rates impact the sedimentary cycling of methane and sulfur. Rates of sediment accumulation determined using Pb-210(excess) and Cs-137 were very high (0.65-0.95 cm year(-1)), as were the corresponding rates of organic matter accumulation (8.9-9.5 mol C m(-2) year(-1)) at all three sites. Dissolved sulfate penetrated < 20 cm below the sediment surface. Although measured rates of bicarbonate methanogenesis integrated over 1 m depth were low (0.96-1.09 mol m(-2) year(-1)), methane concentrations increased to > 2 mmol L-1 below the sulfate-methane transition. A steep gradient of methane through the entire sulfate zone led to upward (diffusive and bio-irrigative) fluxes of 0.32 to 0.78 mol m(-2) year(-1) methane to the sediment-water interface. Areal rates of sulfate reduction (1.46-1.92 mol m(-2) year(-1)) integrated over the upper 0-14 cm of sediment appeared to be limited by the restricted diffusive supply of sulfate, low bio-irrigation (alpha = 2.8-3.1 year(-1)), and limited residence time of the sedimentary organic carbon in the sulfate zone. A large fraction of reduced sulfur as pyrite and organic-bound sulfur was buried and thus escaped reoxidation in the surface sediment. The presence of ferrous iron in the pore water (with concentrations up to 110 mu M) suggests that iron reduction plays an important role in surface sediments, as well as in sediment layers deep below the sulfate-methane transition. We conclude that high rates of sediment accumulation and shallow sulfate penetration are the master variables for biogeochemistry of methane and sulfur cycling; in particular, they may significantly allow for release of methane into the water column in the Himmerfjarden estuary.

  • 6.
    Tomczak, Maciej T.
    et al.
    Stockholm University, Faculty of Science, Stockholm University Baltic Sea Centre.
    Szymanek, L.
    Pastuszak, M.
    Grygiel, W.
    Zalewski, M.
    Gromisz, S.
    Ameryk, A.
    Kownacka, J.
    Psuty, I.
    Kuzebski, E.
    Grzebielec, R.
    Margonski, P.
    Evaluation of Trends and Changes in the Gulf of Gdansk Ecosystem-an Integrated Approach2016In: Estuaries and Coasts, ISSN 1559-2723, E-ISSN 1559-2731, Vol. 39, no 3, p. 593-604Article in journal (Refereed)
    Abstract [en]

    An integrated trend assessment was conducted for the Gulf of GdaAsk (GoG), Baltic Sea for the period 1994-2010 to describe changes and potentially important drivers of the ecosystem. We found changes in the biota, including an increase in open sea taxa (flatfish, sprat and cod), a decrease in typical coastal species such as eelpout and lumpfish and an increase in primary production. The analyses further suggest that changes in the food web were driven by a combination of anthropogenic pressures (e.g., nutrient loadings and fisheries) and possible interactions with climatic disturbance. Our analyses show that significant changes occurred in the GoG ecosystem between 1994 and 2010. The primary drivers and mechanisms of these changes are discussed. We describe this alteration of the GoG within the context of similar temporal patterns identified in adjacent areas.

1 - 6 of 6
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