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  • 1.
    Andersson, Agneta
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Umeå marina forskningscentrum (UMF). Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap.
    Selstam, Eva
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för fysiologisk botanik. Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Umeå Plant Science Centre (UPSC).
    Hagström, Åke
    Vertical transport of lipid in seawater1993Ingår i: Marine Ecology Progress Series, ISSN 0171-8630, E-ISSN 1616-1599, Vol. 98, nr 1-2, s. 149-155Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Lipids in seawater act as solvents and transporters of lipophilic organic pollutants. To investigate a possible transport route of lipophilic pollutants, the vertical flux of lipid was quantified during an annual cycle in the northern Baltic Sea. The lipid content in both sedimenting material and different size fractions of seawater was analyzed. During the year, 8 g lipid m-2 sedimented out from the photic zone to the benthic system. The sedimentation of lipid accounted for 300 to 400 % of the average standing stock of pelagic lipid and was concentrated in the spring bloom period (April-June) when 70 % of the total lipid sedimentation occurred. About 30 % of the produced pelagic lipid settled out from the system. In seawater the lipid maximum occurred at the end of the spring bloom, shortly after nutrient depletion, indicating a stress response in the algae. Since lipid sedimentation is concentrated in the spring bloom, removal of lipophilic organic pollutants may be important during this period.

  • 2.
    Bergmark, Paulina
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap.
    Jørgensen, Dolly
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap.
    Lophelia pertusa conservation in the North Sea using obsolete offshore structures as artificial reefs2014Ingår i: Marine Ecology Progress Series, ISSN 0171-8630, E-ISSN 1616-1599, Vol. 516, s. 275-280Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Deep-water coral reefs are classified as vulnerable marine ecosystems, with trawling identified as the primary cause of reef destruction. Lophelia pertusa is the main reef-building species in deep-water coral reefs. In addition to occurring on natural hard substrates, the species has been previously observed on standing offshore oil and gas structures in the North Sea. In this study, we review the available published information about Lophelia growth on standing offshore oil and gas industry structures in the North Sea. We discuss the potential uses of obsolete offshore structures repurposed as artificial reefs for targeted Lophelia habitat. Our survey of previous studies indicates that artificial reefs created from obsolete structures have a strong potential to form Lophelia reef communities similar to those found on natural substrates, although the absence of the polychaete worm Eunice norvegica poses some concerns about the completeness of the coral communities that develop on artificial reef structures.

  • 3.
    Båmstedt, Ulf
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Umeå marina forskningscentrum (UMF).
    Wikner, Johan
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap. Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Umeå marina forskningscentrum (UMF).
    Mixing depth and allochthonous dissolved organic carbon: controlling factors of coastal trophic balance2016Ingår i: Marine Ecology Progress Series, ISSN 0171-8630, E-ISSN 1616-1599, Vol. 561, s. 17-29Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    ABSTRACT: The interacting effects of different mixing depths and increased allochthonous dissolved organic carbon (DOC) on the ratio of heterotrophic to autotrophic production (i.e. trophic balance) was evaluated in a mesocosm study with a stratified water column. An autumn plankton community from the northern Bothnian Sea showed significantly decreased phytoplankton production and somewhat increased bacterial production with added DOC. In addition, increased mixing depth further reduced phytoplankton production. With a deep pycnocline and added DOC, the system became net-heterotrophic, with an average bacteria-to-phytoplankton production ratio of 1.24. With a deep pycnocline without added DOC, the trophic balance was changed to 0.44 (i.e. autotrophic). With a shallow pycnocline, the system remained net-autotrophic irrespective of DOC addition. We propose that increased precipitation in northern Europe due to climate change may result in changed density stratification and increased allochthonous DOC transport to the sea, leading to more heterotrophic coastal aquatic ecosystems. Such a scenario may entail reduced biological production at higher trophic levels and enhanced CO2 emission to the atmosphere.

  • 4. COCHLAN, William P
    et al.
    Wikner, Johan
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för molekylärbiologi (Teknisk-naturvetenskaplig fakultet). Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Umeå marina forskningscentrum (UMF).
    Steward, Grieg F
    Smith, David C
    Azam, Farooq
    SPATIAL-DISTRIBUTION OF VIRUSES, BACTERIA AND CHLOROPHYLL-A IN NERITIC, OCEANIC AND ESTUARINE ENVIRONMENTS1993Ingår i: Marine Ecology Progress Series, ISSN 0171-8630, E-ISSN 1616-1599, Vol. 92, nr 1-2, s. 77-87Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The spatial distribution of viruses was investigated in the coastal and oceanic waters of the Southern California Bight, USA, and the brackish waters of the Gulf of Bothnia, Sweden, using the direct harvesting technique and transmission electron microscopy. The vertical and horizontal distributions of viruses were examined in relation to bacterial abundance and chlorophyll a. Total virus abundances ranged from 0.3 to 52 X 10(9) l-1; higher concentrations of viruses were found in the upper 50 m of the water column and in coastal environments. Viruses with capsid diameters less than 60 nm dominated the virus community, were morphologically characterized as bacteriophages and were responsible for most of the observed spatial variability. Bacteria abundance alone explained 67 % of the spatial variability in virus numbers, thereby suggesting that bacteria constituted the major host organisms for viruses in these physically diverse habitats.

  • 5.
    Dahlgren, Kristin
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap. Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Umeå marina forskningscentrum (UMF).
    Andersson, Agneta
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap. Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Umeå marina forskningscentrum (UMF).
    Larsson, Ulf
    Department of Systems Ecology, Stockholm University, 10691 Stockholm, Sweden.
    Hajdu, Susanna
    Department of Systems Ecology, Stockholm University, 10691 Stockholm, Sweden.
    Båmstedt, Ulf
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap. Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Umeå marina forskningscentrum (UMF).
    Planktonic production and carbon transfer efficiency along a north-south gradient in the Baltic sea2010Ingår i: Marine Ecology Progress Series, ISSN 0171-8630, E-ISSN 1616-1599, Vol. 409, s. 77-94Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A 1 yr study was conducted along a brackish-water production gradient to enhance the understanding of factors governing pelagic food web function. This was achieved by measuring carbon transfer efficiency (TE) from the basal resource to an intermediate trophic level. TE was defined as mesozooplankton carbon consumption rate divided by production at the basal trophic level, which is composed of phytoplankton and bacteria. A north–south transect in the Baltic Sea was used as a model system, with 2 stations each in the Bothnian Bay, Bothnian Sea and Baltic Proper being sampled 5 to 8× during 2006. In addition, data from monitoring programmes were used, which comprised 10 to 22 samplings stn–1. TE was expected to be governed by the size distribution of phytoplankton and due to the nutrient gradient, we expected to find an optimal cell size, and thus also a high TE, in the intermediate-productive Bothnian Sea. The basal production during summer/autumn increased 5-fold from north to south, while the mesozooplankton carbon consumption rate exhibited a peak inthe Bothnian Sea, being ~3× higher than in both Bothnian Bay and Baltic Proper. TE was found to be intermediate in the Bothnian Bay (average: 0.8), highest in the Bothnian Sea (1.6), and lowest in the Baltic Proper (0.2). We suggest that the variation in carbon transfer efficiency can be explained by the composition of the phytoplankton community, the abundance balance between copepods and cladocerans, as well as the species composition of mesozooplankton in relation to the size structure of phytoplankton.

  • 6. Dinasquet, J.
    et al.
    Titelman, J.
    Moller, L. F.
    Setala, O.
    Granhag, L.
    Andersen, T.
    Båmstedt, Ulf
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap.
    Haraldsson, M.
    Hosia, A.
    Katajisto, T.
    Kragh, T.
    Kuparinen, J.
    Schroter, M. -L
    Sondergaard, M.
    Tiselius, P.
    Riemann, L.
    Cascading effects of the ctenophore Mnemiopsis leidyi on the planktonic food web in a nutrient-limited estuarine system2012Ingår i: Marine Ecology Progress Series, ISSN 0171-8630, E-ISSN 1616-1599, Vol. 460, s. 49-61Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Increasing biomasses of gelatinous zooplankton presumably have major implications for the structure and function of marine food webs at large; however, current data on lower trophic levels are scarce, as most studies have focused on the immediate effects on zooplankton and fish larvae only. We examined the short-term impact of larvae and adults of the invasive ctenophore Mnemiopsis leidyi on a summer planktonic food web in the estuarine southern Baltic Sea, with special emphasis on the microbial loop. Grazing by M. leidyi reduced the mesozooplankton biomass, followed by increased dinoflagellate biomass in treatments with M. leidyi. While chlorophyll a increased most in the treatments with M. leidyi, small phytoplankton and ciliates decreased in all treatments. M. leidyi had a slight effect on bacterial abundance, but not on bacterial production, ectoenzymatic activities, or community composition. Undetectable levels of phosphate and a gradual accumulation of dissolved organic carbon during the experiment suggested a malfunctioning microbial loop scenario. The experiment shows that direct and indirect short-term effects of M. leidyi on the estuarine food web are limited to higher trophic levels and indicates that top-down and bottom-up consequences of M. leidyi expansions on the microbial loop will likely depend on local nutrient conditions.

  • 7.
    Eriksson Wiklund, Ann-Kristin
    et al.
    Department of Applied Environmental Science, ITM, Stockholm University, 106 91 Stockholm, Sweden.
    Dahlgren, Kristin
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap. Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Umeå marina forskningscentrum (UMF).
    Sundelin, Britta
    Department of Applied Environmental Science, ITM, Stockholm University, 106 91 Stockholm, Sweden.
    Andersson, Agneta
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap. Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Umeå marina forskningscentrum (UMF).
    Effects of warming and shifts of pelagic food web structure on benthic productivity in a coastal marine system2009Ingår i: Marine Ecology Progress Series, ISSN 0171-8630, E-ISSN 1616-1599, Vol. 396, s. 13-25Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    It has been predicted that climate change will lead to increased temperature and precipitation in northern latitudes, which in turn may lead to brownification of coastal sea areas. This will increase the importance of the heterotrophic microbial food web in areas like the northern Baltic Sea. Such a structural change in the pelagic food web would hamper benthic productivity, since microheterotrophs have lower settling rates than phytoplankton. We tested how variation in temperature and alteration of the pelagic food web structure affected the productivity of a key benthic species, the amphipod Monoporeia affinis, and the pelagic-benthic food web efficiency (FWE). Using water from the northern Baltic Sea, a mesocosm experiment was performed in which the temperature was altered by 5°C. The structure of the pelagic food web changed from one based on algae to one based on bacteria. Amphipod productivity was 3 times higher and FWE was 25 times higher in the algae than in the bacteria-based food web, showing that an altered pelagic food web will have severe effects on benthic productivity. Temperature variation, on the other hand, did not cause any changes in either growth of M. affinis or FWE. Our data indicate that indirect effects of climate change, leading to structural changes in the pelagic food web, will have much more severe effects on benthic productivity than the direct effect of increased temperature.

  • 8. Grubisic, Lorena M.
    et al.
    Brutemark, Andreas
    Weyhenmeyer, Gesa A.
    Wikner, Johan
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Umeå marina forskningscentrum (UMF).
    Båmstedt, Ulf
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Umeå marina forskningscentrum (UMF).
    Bertilsson, Stefan
    Effects of stratification depth and dissolved organic matter on brackish bacterioplankton communities2012Ingår i: Marine Ecology Progress Series, ISSN 0171-8630, E-ISSN 1616-1599, Vol. 453, s. 37-48Artikel i tidskrift (Refereegranskat)
    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.

  • 9.
    Hagström, Åke
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för molekylärbiologi (Teknisk-naturvetenskaplig fakultet).
    Azam, Farooq
    Andersson, Agneta
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för molekylärbiologi (Teknisk-naturvetenskaplig fakultet).
    Wikner, Johan
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för molekylärbiologi (Teknisk-naturvetenskaplig fakultet).
    Raassoulzadegan, Fereidoun
    Microbial loop in an oligothropic pelagic marine ecosystem: Possible roles of cyanobacteria and nanoflagellates in the organic fluxes1988Ingår i: Marine Ecology Progress Series, ISSN 0171-8630, E-ISSN 1616-1599, Vol. 49, nr 1-2, s. 171-178Artikel i tidskrift (Refereegranskat)
  • 10. Hellemann, Dana
    et al.
    Tallberg, Petra
    Bartl, Ines
    Voss, Maren
    Hietanen, Susanna
    Denitrification in an oligotrophic estuary: a delayed sink for riverine nitrate2017Ingår i: Marine Ecology Progress Series, ISSN 0171-8630, E-ISSN 1616-1599, Vol. 583, s. 63-80Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Estuaries are often seen as natural filters of riverine nitrate, but knowledge of this nitrogen sink in oligotrophic systems is limited. We measured spring and summer dinitrogen production (denitrification, anammox) in muddy and non-permeable sandy sediments of an oligotrophic estuary in the northern Baltic Sea, to estimate its function in mitigating the riverine nitrate load. Both sediment types had similar denitrification rates, and no anammox was detected. In spring at high nitrate loading, denitrification was limited by likely low availability of labile organic carbon. In summer, the average denitrification rate was similar to 138 mu mol N m(-2) d(-1). The corresponding estuarine nitrogen removal for August was similar to 1.2 t, of which similar to 93% was removed by coupled nitrification-denitrification. Particulate matter in the estuary was mainly phytoplankton derived (> 70% in surface waters) and likely based on the riverine nitrate which was not removed by direct denitrification due to water column stratification. Subsequently settling particles served as a link be tween the otherwise uncoupled nitrate in surface waters and benthic nitrogen removal. We suggest that the riverine nitrate brought into the oligotrophic estuary during the spring flood is gradually, and with a time delay, removed by benthic denitrification after being temporarily ` trapped' in phytoplankton particulate matter. The oligotrophic system is not likely to face eutrophication from increasing nitrogen loading due to phosphorus limitation. In response, coupled nitrification-denitrification rates are likely to stay constant, which might increase the future export of nitrate to the open sea and decrease the estuary's function as a nitrogen sink relative to the load.

  • 11. Magnhagen, Carin
    et al.
    Johansson, Kajsa
    Sigray, Peter
    Effects of motorboat noise on foraging behaviour in Eurasian perch and roach: a field experiment2017Ingår i: Marine Ecology Progress Series, ISSN 0171-8630, E-ISSN 1616-1599, Vol. 564, s. 115-125Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The negative impact of anthropogenic noise on marine animals is receiving increasing attention. In order to study the effect of motorboat noise on foraging behaviour in fish, we chose 2 species with different hearing abilities. The roach Rutilus rutilus has a better developed sense of hearing than the Eurasian perch Perca fluviatilis. The study took place in an inlet of the Bothnian Sea where boat traffic is almost absent. Groups of 6 fish were placed in field enclosures containing either one of the species or equal numbers of perch and roach. Half of each enclosure was covered with artificial vegetation. The fish were fed with pieces of saithe twice a day, both with and without the disturbance of an outboard motor. Sound pressure level and particle acceleration were measured for the motor, which was run at 2000 rpm. The trials were repeated for 5 d. Perch made fewer feeding attempts during noise exposure compared to controls in the single-species enclosures. As the experiment progressed, they gradually increased feeding and time spent in the open area, both with and without noise, indicating habituation. Habitat utilization was affected by the interaction of noise exposure and day. Roach responded to noise exposure with fewer feeding attempts, higher latency to enter the open area, and longer time spent in the vegetation compared to the controls without noise. Roach behaviour changed with time only when housed together with perch. This study, using authentic sound in a natural habitat, shows that noise exposure may affect the feeding behaviour of fish, that the response is species-specific, and that habituation and the presence of other species may modify the effects.

  • 12.
    Md Amin, Roswati
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap. Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Umeå marina forskningscentrum (UMF).
    Båmstedt, Ulf
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap. Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Umeå marina forskningscentrum (UMF).
    Nejstgaard, Jens C
    Skidaway Institute of Oceanography, USA.
    Di Capua, Iole
    Ecology and Evolution of Plankton, Stazione Zoologica, Italy.
    Partition of planktonic respiratory carbon requirements during a phytoplankton spring bloom2012Ingår i: Marine Ecology Progress Series, ISSN 0171-8630, E-ISSN 1616-1599, Vol. 451, s. 15-29Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We studied the effect of variable phytoplankton biomass and dominance of the diatom Skeletonema marinoi on the planktonic community respiratory carbon requirement over a period of 14 days (14-28 April, 2008) in 3 different mesocosms filled with natural water at Espegrend marine biological field station by Raunefjord, Norway. The carbon requirement was measured on mesozooplankton (the calanoid copepod Calanus finmarchicus) and three different size fraction; <200 µm (dominated by microzooplankton), <15 µm (dominated by nanoplankton including most of the phytoplankton) and particles passing GF/C (dominated by bacterioplankton) by measuring oxygen consumption with an optode system with two SensorDish Readers. The respiratory carbon requirement showed no clear trend over time for any of the four groups. The mesozooplankton contributed the least to the total community carbon requirement, corresponding to less than 6% of primary production. In contrast, microzooplankton and nanoplankton consistently dominated the community carbon requirement, corresponding to > 50% of the primary production, while bacterioplankton showed an intermediate and variable contribution (ca <20% with a max of 50%). Feeding experiments on mesozooplankton (C. finmarchicus) two days before the peak in phytoplankton biomass, showed that the copepods ingested 2.4-4.3 times their respiratory carbon requirements, thus giving a high potential for growth. Respiratory carbon requirements of mesozooplankton were not significantly related to dominance or quantity of food available, whereas the respiratory carbon requirements of other groups were all related to the production of 22:6(n-3) fatty acid. The study confirms the important role of microorganisms in the biological carbon transformation through the food web during a phytoplankton spring bloom.

  • 13. Rosenberg, Rutger
    et al.
    Dahl, E
    Edler, Lars
    Fyrberg, Lotta
    Graneli, Edna
    Graneli, Wilhelm
    Hagström, Åke
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för molekylärbiologi (Teknisk-naturvetenskaplig fakultet). Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Umeå marina forskningscentrum (UMF).
    Lindahl, Odd
    Matos, MO
    Pettersson, Karin
    Sahlsten, Elisabeth
    Tiselius, Peter
    Turk, Valentina
    Wikner, Johan
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Umeå marina forskningscentrum (UMF). Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för molekylärbiologi (Teknisk-naturvetenskaplig fakultet).
    PELAGIC NUTRIENT AND ENERGY-TRANSFER DURING SPRING IN THE OPEN AND COASTAL SKAGERRAK1990Ingår i: Marine Ecology Progress Series, ISSN 0171-8630, E-ISSN 1616-1599, Vol. 61, nr 3, s. 215-231Artikel i tidskrift (Refereegranskat)
  • 14. Sommer, Ulrich
    et al.
    Lengfellner, Kathrin
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap.
    Lewandowska, Aleksandra
    Experimental induction of a coastal spring bloom early in the year by intermittent high-light episodes2012Ingår i: Marine Ecology Progress Series, ISSN 0171-8630, E-ISSN 1616-1599, Vol. 446, s. 61-71Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Through the use of mesocosm experiments, we show that an unusually early spring pbytoplankton bloom can be induced by intermittent high-light periods. We performed mesocosm experiments where plankton assemblages from Kiel Bight (Western Baltic Sea) received a light regime based on the natural seasonal irradiance dimmed to 43% of surface irradiance of cloudless days, starting with irradiance levels of mid-January (6 mesocosms) and mid-February (6 mesocosms). After 6 d, half of the mesocosms received a ca. 2-fold increase in irradiance. In the January mesocosms, a phytoplankton bloom developed only in the treatments with the high-light episode, whereas in the February mesocosms a phytoplankton bloom also developed in the controls. Phytoplankton net growth rates, production:biomass ratios and biomass at the end of the high irradiance episodes were positively correlated to the daily light dose. The relative biomass of diatoms increased with increasing light, whereas the relative biomass of cryptophytes decreased. A bottom-up transmission to mesozooplankton (mainly copepods of the genera Acartia and Oithona) was evident by increased densities of copepod nauplii and egg production under higher light conditions, whereas copepodids and adults showed no responses during the experimental period. The taxonomic composition of the nauplii was shifted to the advantage of Acartia/Centropages (not distinguished at the naupliar stage) under higher light conditions.

  • 15. Titelman, J
    et al.
    Riemann, L
    Sørnes, T
    Griekspoor, P
    Båmstedt, U
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap.
    Turnover of dead jellyfish: stimulation and retardation of microbial activity2006Ingår i: Marine Ecology Progress Series, ISSN 0171-8630, E-ISSN 1616-1599, Vol. 325, s. 43-58Artikel i tidskrift (Refereegranskat)
  • 16.
    Wikner, Johan
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Umeå marina forskningscentrum (UMF). Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för molekylärbiologi (Teknisk-naturvetenskaplig fakultet).
    Hagström, Åke
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för molekylärbiologi (Teknisk-naturvetenskaplig fakultet). Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Umeå marina forskningscentrum (UMF).
    Evidence for a tightly coupled nanoplanktonic predator-prey link regulating the bacterivores in the marine-environment1988Ingår i: Marine Ecology Progress Series, ISSN 0171-8630, E-ISSN 1616-1599, Vol. 50, nr 1-2, s. 137-145Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A coupled predator-prey chain, starting with bactenvores, was invest~gated using the mlnicell recapture technique (MiniCap) Water samples were subjected to slze fract~onation wth decreasing filter pore sue in order to obtain a successive truncation of the microbial food chaln Our results showed that the malor bacterivores were flagellates in the size range of 1 to 3 pm The truncation of the food chain caused increased or decreased predation on the bactena, d e p e n d~n go n whether the bacterivores 'ivere released from or subjected to increased predat~on pressure We present a model describing trophic interactions between organisms less than 12 pm In size This model suggests 4 trophic levels to form a regulatory chain exer t~nga tight control on major bacterivores.

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