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  • 1.
    Berg, Florian
    et al.
    Univ Bergen, Dept Biol Sci, Post Box 7803, N-5020 Bergen, Norway;IMR, Post Box 1870 Nordnes, N-5018 Bergen, Norway.
    Slotte, Aril
    IMR, Post Box 1870 Nordnes, N-5018 Bergen, Norway.
    Andersson, Leif
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Biochemistry and Microbiology. Uppsala University, Science for Life Laboratory, SciLifeLab. Texas A&M Univ, Dept Vet Integrat Biosci, College Stn, TX 77843 USA.
    Folkvord, Arild
    Univ Bergen, Dept Biol Sci, Post Box 7803, N-5020 Bergen, Norway;IMR, Post Box 1870 Nordnes, N-5018 Bergen, Norway.
    Genetic origin and salinity history influence the reproductive success of Atlantic herring2019In: Marine Ecology Progress Series, ISSN 0171-8630, E-ISSN 1616-1599, Vol. 617, p. 81-94Article in journal (Refereed)
    Abstract [en]

    Atlantic herring populations inhabit environments ranging in salinity from fully marine to nearly freshwater, but their relative reproductive success in these respective environments remains unclear. We conducted factorial crossing experiments using parents from 3 wild populations associated with different salinity environments: the Baltic Sea (similar to 6 psu), an inland brackish lake in Norway (Landvikvannet, similar to 16 psu), and the Atlantic (similar to 30 to 35 psu). Further experiments used crosses within and between Atlantic purebreds and Atlantic/Baltic hybrids reared until first maturity at 3 yr of age. Crossing experiments were conducted at 6, 16 and 35 psu. Fertilization and hatching rates were estimated, and egg sizes were measured. Fertilization rates were highest at 16 psu for all combinations. The paternal genetic and salinity origin influenced fertilization rates at 6 and 35 psu, indicating a genetic adaptation to their original environment. Fertilization rates for males originating from 16 psu were low at 35 psu. Atlantic/Baltic hybrids had lower fertilization rates than Atlantic purebreds at 35 psu. Hatching rates were not influenced by any parental factors or salinity. Maternal effects and salinity influenced egg size. Atlantic females had significantly larger eggs than the Atlantic/Baltic hybrid females. For all genetic groups, egg size decreased with increasing salinity at incubation mainly due to osmotic effects. The observed lower fertilization success at salinities other than those of the parental fish habitat would have evolutionary consequences when herring colonize new habitats with different salinities or if interbreeding occurred between populations originating from different salinity habitats.

  • 2.
    Berglund, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Animal Ecology.
    Reproductive adaptations in two Palaemon prawn species with differing habitat requirements1984In: Marine Ecology Progress Series, ISSN 0171-8630, E-ISSN 1616-1599, Vol. 17, no 1, p. 77-83Article in journal (Refereed)
  • 3.
    Berglund, Anders
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Animal Ecology.
    Rosenqvist, Gunilla
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Animal Ecology.
    Svensson, Ingrid
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Animal Ecology.
    Reversed sex-roles and parental energy investment in zygotes of two pipefish (Syngnathidae) species1986In: Marine Ecology Progress Series, ISSN 0171-8630, E-ISSN 1616-1599, Vol. 29, no 3, p. 209-215Article in journal (Refereed)
  • 4.
    Faust, Ellika
    et al.
    Univ Gothenburg, Dept Marine Sci Tjarno, S-45296 Stromstad, Sweden..
    Andre, Carl
    Univ Gothenburg, Dept Marine Sci Tjarno, S-45296 Stromstad, Sweden..
    Meurling, Sara
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal ecology.
    Kochmann, Judith
    Senckenberg Biodiversitat & Klima Forschungszentr, Senckenberg Gesell Nat Forsch, D-60325 Frankfurt, Germany..
    Christiansen, Henrik
    Univ Gothenburg, Dept Marine Sci Tjarno, S-45296 Stromstad, Sweden.;Katholieke Univ Leuven, Lab Biodivers & Evolutionary Genom, B-3000 Leuven, Belgium..
    Jensen, Lasse Fast
    Fisheries & Maritime Museum, DK-6710 Esbjerg V, Denmark..
    Charrier, Gregory
    Univ Bretagne Occidentale, Lab Sci Environm Marin LEMAR, UMR 6539, UBO,CNRS,IRD,Ifremer,IUEM, F-29280 Plouzane, France..
    Laugen, Ane T.
    Novia Univ Appl Sci, Ekenas 10600, Finland.;Swedish Univ Agr Sci, Dept Ecol, S-75007 Uppsala, Sweden..
    Strand, Asa
    Univ Gothenburg, Dept Marine Sci Tjarno, S-45296 Stromstad, Sweden..
    Origin and route of establishment of the invasive Pacific oyster Crassostrea gigas in Scandinavia2017In: Marine Ecology Progress Series, ISSN 0171-8630, E-ISSN 1616-1599, Vol. 575, p. 95-105Article in journal (Refereed)
    Abstract [en]

    Identifying the routes and rates of introductions is fundamental for the understanding of marine invasions. Recurring introductions over the last 50 yr have led to the establishment of feral Pacific oyster Crassostrea gigas populations throughout Europe. In the northern countries, Sweden and Norway, the species first occurred in large numbers in 2006. Here, we investigated the relative importance of introduction via re-laying of cultured oysters imported for consumption from France, Ireland or the Netherlands, and dispersal of oyster larvae by ocean currents from wild oyster populations in Denmark. Using microsatellite DNA markers, we estimated genetic differentiation among Pacific oysters collected at 4 Swedish locations, 3 Norwegian locations and 9 potential source locations in Denmark, Ireland, the Netherlands and France. All Swedish samples and 1 Norwegian sample(Tromlingene) were genetically similar to each other and the Danish samples and showed significant genetic differentiation from all other populations. Consequently, it appears that the Pacific oyster populations in Sweden, Denmark and Tromlingene are closely connected and/or share a recent origin. The 2 remaining Norwegian samples(Hui and Espevik) differed from each other and all other populations, but showed similarities to wild oyster samples from Scandinavia and Ireland, respectively. Overall, the results underline a complex origin of Norwegian oysters, with gene flow from Swedish/Danish populations, as well as other unidentified sources. The apparent connectivity among most of the Scandinavian populations has implications for regional management of this invasive species, and highlights possible scenarios for other marine invasive species with a similar life history.

  • 5.
    Grubisic, Lorena M.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    Brutemark, Andreas
    Weyhenmeyer, Gesa A.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    Wikner, Johan
    Bamstedt, Ulf
    Bertilsson, Stefan
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    Effects of stratification depth and dissolved organic matter on brackish bacterioplankton communities2012In: Marine Ecology Progress Series, ISSN 0171-8630, E-ISSN 1616-1599, Vol. 453, p. 37-48Article in journal (Refereed)
    Abstract [en]

    Bacterioplankton growth is often directly or indirectly controlled by external energy subsidies via organic matter inputs or solar radiation. We carried out a mesocosm experiment to assess how bacterioplankton communities responded to elevated levels of dissolved organic matter (DOM) and experimentally controlled stratification depth. The month-long experiment consisted of 2500 l mesocosms subjected to 4 experimental manipulations in triplicate: the stratification depth was set to either 1.5 or 3.5 m, with or without experimental addition of ambient levels of chromophoric DOM. DOM addition had a significant effect on bacterial community composition as assessed by terminal restriction fragment length polymorphism of amplified 16S rRNA genes. In contrast, there were no effects of the DOM amendment on bacterial biomass or production. Mixing depth and the coupled effective light climate in the photic zone also had a significant effect on bacterial community composition. Furthermore, shallow mixing depth was associated with enhanced primary production, whereas DOM addition had a negative effect on phyto plankton biomass and productivity. Our results suggest that bacterial community composition is coupled to primary production under the studied coastal nutrient regime, and point to a key role of DOM quality in controlling bacterioplankton communities.

  • 6.
    Henderiks, Jorijntje
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Palaeobiology.
    Winter, Amos
    Elbraechter, Malte
    Feistel, Rainer
    van der Plas, Anja
    Nausch, Guenther
    Barlow, Ray
    Environmental controls on Emiliania huxleyi morphotypes in the Benguela coastal upwelling system (SE Atlantic)2012In: Marine Ecology Progress Series, ISSN 0171-8630, E-ISSN 1616-1599, Vol. 448, p. 51-66Article in journal (Refereed)
    Abstract [en]

    Two distinct morphotypes of the coccolithophore Emiliania huxleyi were observed as part of the phytoplankton succession offshore of Namibia, where coastal upwelling created strong gradients in sea surface temperature (SST), salinity, and nutrient conditions. The sampled surface waters hosted a characteristic succession of phytoplankton communities: diatoms bloomed in newly upwelled waters above the shelf, whereas dense coccolithophore communities dominated by E. huxleyi were found farther offshore, in progressively aging upwelled waters. A substantially calcified E. huxleyi morphotype (labeled Type A*) dominated plankton assemblages at stations influenced by upwelling, that immediately succeeded coastal diatom blooms. This morphotype caused a chlorophyll and 19'-hexanoyloxyfucoxanthin (19'-HF) maximum with >1 x 10(6) cells l(-1), straddling a pycnocline at 17 m depth where the in situ N:P ratio was approximate to 13. Farther offshore, within <20 nautical miles distance, populations of Type A* drastically declined, and a more delicate morphotype with thin distal shield elements and open central area (Type B/C) was found. This morphotype was most abundant (similar to 0.2 x 10(6) cells l(-1)) in high-phosphate, nitrogen-depleted surface waters (N:P approximate to 8), where it co-existed with other coccolithophores, most notably Syracosphaera spp. Extensive surface blooms of coccolithophores observed by satellites in the same region in the past were identified by microscopy as being produced by E. huxleyi and S. pulchra. However, blooms of E. huxleyi at greater depths in the euphotic zone, such as those observed in this study, will go undetected by satellites and thus underestimate coccolithophore biomass and calcification within upwelling regions.

  • 7.
    Häubner, Norbert
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Ecological Botany.
    Tallmark, Bo
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal Ecology.
    Snoeijs, Pauli
    Department of Systems Ecology, Stockholm University.
    Phytoplankton biomass controls tocopherol concentrations in Baltic Sea zooplanktonIn: Marine Ecology Progress Series, ISSN 0171-8630, E-ISSN 1616-1599Article in journal (Refereed)
    Abstract [en]

    Nearly all organisms are constantly exposed to oxidative threat, because every reaction where oxygen is involved gives rise to oxidants. Efficient protection is provided by antioxidants. Vitamin E (tocopherol) is an essential plant-derived antioxidant and poorly studied so far in marine food webs. In 2004 and 2005 eight offshore expeditions were conducted in the Baltic Sea to explore the dynamics of α-tocopherol in the pelagic food web. In order to analyze tocopherol production and transition to the next food web level, two plankton size classes were sampled; <100 µm (dominated by phytoplankton) and >200 µm (dominated by calanoid copepods). HPLC analysis revealed lowest values of α-tocopherol per L seawater in March in both size classes and highest in May for <100 µm (31.5 ng L-1) and August for >200 µm (1.3 ng L-1). No consistent seasonal pattern could be observed in α-tocopherol per unit biomass for the zooplankton. Concentrations ranged in <100 µm from 0.05 to 0.10 ng µg C-1 and in >200 µm from 0.05 to 0.11 ng µg C-1.  Partial least square regression (PLS) revealed nutrional status and species composition of the phytoplankton biomass as driving factors of α-tocopherol production in phytoplankton. Abiotic factors, as depth and temperature were only of significant influence in May. In zooplankton, the α-tocopherol concentration was negatively associated with phytoplankton biomass in May. Therefore we concluded that assimilation efficiency of zooplankton in combination with high phytoplankton biomass is the bottle-neck in tocopherol transport from phytoplankton to higher levels in the food web.

  • 8.
    Johansson, G
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Evolutionary Biology, Plant Ecology.
    Snoeijs, P
    Macroalgal photosynthetic responses to light in relation to thallus morphology and depth zonation2002In: Marine Ecology Progress Series, ISSN 0171-8630, E-ISSN 1616-1599, Vol. 244, p. 63-72Article in journal (Refereed)
    Abstract [en]

    We show how photosynthesis and UV sensitivity of algae are related to thallus morphology and depth distributions. This was studied for typical depth zonations of red and brown macroalgae in the Skagerrak (ca. 25 psu) and the Baltic Sea (6.5 psu). The algae were collected from the water surface down to 20.5 m of depth, whereby each species was sampled at its maximum abundance depth. Altogether, we measured photosynthetic and respiratory rates of 19 red and 13 brown algal species as O2 evolution at different light intensities. Photosynthesis versus irradiance curves (PI curves) showed that light-saturated net photosynthetic rates (Pmax), respiratory rates in darkness (Rd) and the initial slope (α) were strongly related to algal morphology with higher values for thinner species. The compensation irradiance (Ic) and saturating irradiance (Ik) were strongly related to water depth with lower values at greater depth. A novel approach to analyse PI data with principal component analysis (PCA) is presented. The method makes it possible to assign a quantitative morphological gradient to algal species based on photosynthetic properties. Such a gradient can be used in ecological studies as an alternative to more subjective discrete subdivisions into functional-form groups. Another type of PCA analysis, with the relative shapes of the PI curves as input data, summarises α and convexity but discards all interference of morphology. This results in a gradient of genuine physiological responses, which in our study was strongly correlated to maximum abundance depth. The UV sensitivity of the same 32 algal species was determined as the change in net O2 evolution after exposure to UV light and the recovery after this treatment. Deeper-growing algae were more sensitive to UV and species with thinner thalli recovered better after UV treatment in the Skagerrak. No such trends were observed for the algae in the northern Baltic Sea, which suggests that no real deep-water species occur here. This is further supported by the lack of a clear pattern in Ic and Ik values with depth for the algae in the Baltic Sea. Our results advocate that the reduced species diversity of the Baltic Sea is also coupled to a loss of functional groups in the sense of general photosynthetic performance and not only in the sense of pure morphology (loss of canopy-forming species).

  • 9.
    Lönnstedt, Oona
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    Frisch, Achley J.
    Habitat bleaching disrupts threat responses and persistence in anemonefish2014In: Marine Ecology Progress Series, ISSN 0171-8630, E-ISSN 1616-1599, Vol. 517, p. 265-270Article in journal (Refereed)
    Abstract [en]

    Climate-induced habitat bleaching is linked to dramatic declines in diversity and abundance of coral reef fish; however, mechanisms underlying these declines are poorly understood. Here, we used in situ studies to demonstrate that bleaching can influence persistence of reef fish by affecting behaviours, including responses to a potential predation threat. When encountering the predatory rock cod Cephalophalis cyanostigma, anemonefish Amphiprion akindynos occupying healthy unbleached host anemones Heteractis crispa respond by feeding less and spending more time within the anemone tentacles. When the host anemone was experimentally bleached, these visual risk responses were compromised: A. akindynos continued to feed and did not seek shelter. The impaired behavioural response may prove detrimental to anemonefish populations as abundance levels of fish on bleached anemones was reduced by 60% within 3 d, which may have been the result of increased predation. Our data illustrate how climate-induced habitat degradation can drive declines of reef fish by potentially altering outcomes of predator–prey interactions.

  • 10. Snickars, Martin
    et al.
    Sundblad, Göran
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Limnology.
    Sandström, Alfred
    Ljunggren, Lars
    Bergström, Ulf
    Johansson, Gustav
    Mattila, Johanna
    Habitat selectivity of substrate-spawning fish: modelling requirements for the Eurasian perch Perca fluviatilis2010In: Marine Ecology Progress Series, ISSN 0171-8630, E-ISSN 1616-1599, Vol. 398, p. 235-243Article in journal (Refereed)
    Abstract [en]

    Substrate spawning fish are believed to be selective in their choice of spawning habitat,yet few studies have shown the relative importance of different characteristics in terms of habitatquality. We used an extensive and detailed dataset to identify the factors that govern both large-scale(1 000 to 100 000 m) and local-scale (10 to 100 m) selection by a substrate-spawning fish, the Eurasian perchPerca fluviatilis L. Distribution of spawning habitat was strongly dependent on habitat characteristicsdefined by substrate, wave exposure, temperature and depth. The most important predictor was thetype of spawning substrate, which generally consisted of different types of vegetation. Substratesproviding rigidity and structural complexity were preferred, despite abundant presence of other substratetypes. Shallow depth and sheltered areas were also selected habitat characteristics. Theresponse to temperature was scale-dependent, with a stronger selection expressed at the local scale.The specific selectivity suggests that spawning patterns can be successfully modelled with sufficientdetail using only a few fundamental environmental variables. Wave exposure and depth are readilyavailable for large-scale spatial predictions, while temperature and substrate require further developmentin most coastal areas. The high specificity of the characteristics determining habitat qualitysuggests that it should be possible to apply this modelling approach for identification and conservationof spawning habitats of Eurasian perch and other substrate-spawning fishes in coastal waters.

  • 11.
    Sylvander, Peter
    et al.
    Department of Systems Ecology, Stockholm University.
    Häubner, Norbert
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Ecological Botany.
    Snoeijs, Pauli
    Department of Systems Ecology, Stockohlm University.
    The thiamine (vitamin B1) content of phytoplankton is affected by temperature, photon density and salinityIn: Marine Ecology Progress Series, ISSN 0171-8630, E-ISSN 1616-1599Article in journal (Refereed)
    Abstract [en]

    Thiamine (vitamin B1) is produced by plants, algae and bacteria and must be acquired through the food web by higher trophic levels. In this study we investigate the biosynthesis of thiamine in six phytoplankton species belonging to five different phyla under different environmental conditions. The chlorophyte Dunaliella tertiolecta, the dinoflagellate Prorocentrum minimum and the prymnesiophyte Rhodomonas salina were found to be thiamine auxotrophs, while the cyanobacterium Nodularia spumigena and the diatoms Phaeodactylum tricornutum and Skeletonema costatum were capable of thiamine synthesis. Measured net thiamine production in the latter three species varied with temperature, photon density and salinity. These effects were different for the cyanobacterium and the diatoms and strongest for salinity. In N. spumigena, the total thiamine concentration increased threefold with increased salinity. P. tricornutum accumulated seven times more thiamine diphosphate when salinity was decreased. Temperature also had pronounced effects on thiamine concentration, while photon density only affected thiamine levels in combination with temperature. In N. spumigena and P. tricornutum, total thiamine levels increased with higher temperature. We demonstrate a high variability among phytoplankton species in thiamine biosynthesis, as well as in the level of thiamine production in response to environmental factors. Thus, regime shifts in phytoplankton community composition through large-scale environmental change can alter the vitamin B1 availability for higher trophic levels. This may have serious consequences for the access of zooplankton, fish, birds and mammals to this essential vitamin in changing ecosystems.

     

  • 12.
    Westin, Lars
    Gotland University, Department of Biology.
    Migration failure in stocked eels Anguilla anguilla2003In: Marine Ecology Progress Series, ISSN 0171-8630, E-ISSN 1616-1599, Vol. 254, p. 307-311Article in journal (Refereed)
    Abstract [en]

    Silver eels Anguilla anguilla L., stocked as elvers in a freshwater lake on the island of Gotland, were caught in an outlet stream leading to the Baltic Sea. After tagging, they were released either into the lake or into the stream above a fine-meshed trap, and were recaptured after a period of 3 to 120 mo. During the period between tagging and recapture, the majority lost weight and decreased in length and fat content. It is hypothesized that the stocked eels had had no opportunity to imprint the directional cues necessary for migration; i.e. they were unable to recognize the outlet stream as the starting point of migration and lacked the orientation mechanism necessary to locate the outlet to the Baltic Sea. The lake itself comprises an initial trap, and the Baltic Sea a secondary trap. It is concluded that stocked eels lack imprinting, and that consequently their contribution to recruitment is null.

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