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  • 1.
    Andersson, A.
    et al.
    Umeå University;Umeå Marine Science Centre.
    Brugel, S.
    Umeå University;Umeå Marine Science Centre.
    Paczkowska, J.
    Umeå University;Umeå Marine Science Centre.
    Rowe, O. F.
    Umeå University;Umeå Marine Science Centre;Univ Helsinki, Finland.
    Figueroa, D.
    Umeå University;Umeå Marine Science Centre.
    Kratzer, S.
    Stockholm University.
    Legrand, Catherine
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Influence of allochthonous dissolved organic matter on pelagic basal production in a northerly estuary2018In: Estuarine, Coastal and Shelf Science, ISSN 0272-7714, E-ISSN 1096-0015, Vol. 204, p. 225-235Article in journal (Refereed)
    Abstract [en]

    Phytoplankton and heterotrophic bacteria are key groups at the base of aquatic food webs. In estuaries receiving riverine water with a high content of coloured allochthonous dissolved organic matter (ADOM), phytoplankton primary production may be reduced, while bacterial production is favoured. We tested this hypothesis by performing a field study in a northerly estuary receiving nutrient-poor, ADOM-rich riverine water, and analyzing results using multivariate statistics. Throughout the productive season, and especially during the spring river flush, the production and growth rate of heterotrophic bacteria were stimulated by the riverine inflow of dissolved organic carbon (DOC). In contrast, primary production and photosynthetic efficiency (i.e. phytoplankton growth rate) were negatively affected by DOC. Primary production related positively to phosphorus, which is the limiting nutrient in the area. In the upper estuary where DOC concentrations were the highest, the heterotrophic bacterial production constituted almost 100% of the basal production (sum of primary and bacterial production) during spring, while during summer the primary and bacterial production were approximately equal. Our study shows that riverine DOC had a strong negative influence on coastal phytoplankton production, likely due to light attenuation. On the other hand DOC showed a positive influence on bacterial production since it represents a supplementary food source. Thus, in boreal regions where climate change will cause increased river inflow to coastal waters, the balance between phytoplankton and bacterial production is likely to be changed, favouring bacteria. The pelagic food web structure and overall productivity will in turn be altered. (C) 2018 The Authors. Published by Elsevier Ltd.

  • 2.
    Andersson, Agneta
    et al.
    Umeå University.
    Meier, H. E. Markus
    Swedish Meteorological and Hydrological Institute.
    Ripszam, Matyas
    Umeå University.
    Rowe, Owen
    Umeå University.
    Wikner, Johan
    Umeå university.
    Haglund, Peter
    Umeå University.
    Eilola, Kari
    Swedish Meteorological and Hydrological Institute.
    Legrand, Catherine
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Figueroa, Daniela
    Umeå University.
    Paczkowska, Joanna
    Umeå University.
    Lindehoff, Elin
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Tysklind, Mats
    Umeå University.
    Elmgren, Ragnar
    Department of Ecology.
    Projected future climate change and Baltic Sea ecosystem management2015In: Ambio, ISSN 0044-7447, E-ISSN 1654-7209, Vol. 44, no Supplement 3, p. S345-S356Article in journal (Refereed)
    Abstract [en]

    Climate change is likely to have large effects on the Baltic Sea ecosystem. Simulations indicate 2-4 degrees C warming and 50-80 % decrease in ice cover by 2100. Precipitation may increase similar to 30 % in the north, causing increased land runoff of allochthonous organic matter (AOM) and organic pollutants and decreased salinity. Coupled physical-biogeochemical models indicate that, in the south, bottom-water anoxia may spread, reducing cod recruitment and increasing sediment phosphorus release, thus promoting cyanobacterial blooms. In the north, heterotrophic bacteria will be favored by AOM, while phytoplankton production may be reduced. Extra trophic levels in the food web may increase energy losses and consequently reduce fish production. Future management of the Baltic Sea must consider the effects of climate change on the ecosystem dynamics and functions, as well as the effects of anthropogenic nutrient and pollutant load. Monitoring should have a holistic approach, encompassing both autotrophic (phytoplankton) and heterotrophic (e.g., bacterial) processes.

  • 3.
    Andersson, Kajsa
    Barometern OT.
    Svensson, Fredrik (Contributor)
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Forskningsprojekt: Alger ska rena utsläpp: "Algerna är en resurs som vi knappt använder"2014In: Baromtern, no 9 augustiArticle in journal (Other (popular science, discussion, etc.))
  • 4.
    Andreas, Bendroth
    Östra Småland.
    Legrand, Catherine (Contributor)
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Algblomningens positiva sidor lyftes fram2017In: Östra Småland, no 31 Aug, p. 6-Article in journal (Other (popular science, discussion, etc.))
  • 5.
    Baltar, Federico
    et al.
    Linnéuniversitetet, Institutionen för biologi och miljö (BOM).
    Legrand, Catherine
    Linnéuniversitetet, Institutionen för biologi och miljö (BOM).
    Pinhassi, Jarone
    Linnéuniversitetet, Institutionen för biologi och miljö (BOM).
    Cell-free extracellular enzymatic activity is linked to seasonal temperature changes: a case study in the Baltic Sea2016In: Biogeosciences, ISSN 1726-4170, E-ISSN 1726-4189, Vol. 13, no 9, p. 2815-2821Article in journal (Refereed)
    Abstract [en]

    Extracellular enzymatic activities (EEA) are a crucial step on the degradation of organic matter. Dissolved (cell-free) extracellular enzymes in seawater can make up a significant contribution of the bulk EEA. However, the factors controlling the proportion of dissolved EEA in the marine environment remain unknown. Here we studied the seasonal changes in the proportion of dissolved relative to total EEA (of alkaline phosphatase [APase], β-glucosidase, [BGase], and leucine aminopeptidase, [LAPase]), in the Baltic Sea for 18 months. The proportio n of dissolved EEA ranged between 37-100%, 0-100%, 34-100% for APase, BGase and LAPase, respectively. A consistent seasonal pattern in the proportion of dissolved EEA was found among all the studied enzymes, with values up to 100% during winter and <40% du ring summer. A significant negative relation was found between the 21proportion of dissolved EEA and temperature, indicating that temperature might be a critical factor controlling the proportion of dissolved relative to total EEA in marine environments. Our results suggest a strong decoupling of hydrolysis rates from mi crobial dynamics in cold waters. This implies that under cold conditions, cell-free enzymes can contribute to substrate availability at large distances from the producing cell, increasing the dissociation between the hydrolysis of organic compounds and the actual microbes producing the enzymes. This also indicates that global warming could come to affect the hydrolysis of organic matter by reducing the hydrolytic activity of cell-free enzymes.

  • 6.
    Baltar, Federico
    et al.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science. University of Otago, New Zealand.
    Legrand, Catherine
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Pinhassi, Jarone
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Cell-free extracellular enzymatic activity is linked to seasonal temperature changes: a case study in the Baltic Sea2016In: Biogeosciences, ISSN 1726-4170, E-ISSN 1726-4189, Vol. 13, no 9, p. 2815-2821Article in journal (Refereed)
    Abstract [en]

    Extracellular enzymatic activities (EEA) are a crucial step on the degradation of organic matter. Dissolved (cell-free) extracellular enzymes in seawater can make up a significant contribution of the bulk EEA. However, the factors controlling the proportion of dissolved EEA in the marine environment remain unknown. Here we studied the seasonal changes in the proportion of dissolved relative to total EEA (of alkaline phosphatase [APase], β-glucosidase, [BGase], and leucine aminopeptidase, [LAPase]), in the Baltic Sea for 18 months. The proportio n of dissolved EEA ranged between 37-100%, 0-100%, 34-100% for APase, BGase and LAPase, respectively. A consistent seasonal pattern in the proportion of dissolved EEA was found among all the studied enzymes, with values up to 100% during winter and <40% du ring summer. A significant negative relation was found between the 21proportion of dissolved EEA and temperature, indicating that temperature might be a critical factor controlling the proportion of dissolved relative to total EEA in marine environments. Our results suggest a strong decoupling of hydrolysis rates from mi crobial dynamics in cold waters. This implies that under cold conditions, cell-free enzymes can contribute to substrate availability at large distances from the producing cell, increasing the dissociation between the hydrolysis of organic compounds and the actual microbes producing the enzymes. This also indicates that global warming could come to affect the hydrolysis of organic matter by reducing the hydrolytic activity of cell-free enzymes.

  • 7. Barreiro, A
    et al.
    Guisande, C
    Maneiro, I
    Lien, T P
    Legrand, Catherine
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Tamminen, T
    Lehtinen, S
    Uronen, P
    Granéli, Edna
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Relative importance of the different negative effects of the toxic haptophyte Prymnesium parvum on Rhodomonas salina and Brachionus plicatilis2005In: Aquatic Microbial Ecology, ISSN 0948-3055, E-ISSN 1616-1564, Vol. 38, no 3, p. 259-267Article in journal (Refereed)
    Abstract [en]

    The aim of this study was to determine the relative importance of the different processes/mechanisms by which the toxic haptophyte Prymnesium parvum, cultured under different nutrient conditions, affects non-toxic phytoplankton competitors and microzooplankton grazers. P. parvum was cultured under steady-state growth in different nutrient conditions: nitrogen depleted (-N), phosphorus depleted (-P) and balanced nitrogen and phosphorus (+NP). Cells from each nutrient condition and culture cell-free filtrates, alone and combined with non-toxic prey (Rhodomonas salina), were used as food for the rotifer Brachionus plicatilis. An additional experiment was carried out to test the effect of P. parvum cells and culture cell-free filtrate on R. salina. The highest haemolytic activity values were achieved by -P F parvum cultures, followed by -N. However, the negative effect of R parvum on R. salina and rotifers did not correlate with haemolytic activity but with the number of P. parvum cells. -N-cultured P. parvum were the most toxic for both R. salina and rotifers, followed by +NP. Therefore, haemolytic activity is not a good indicator of the total potential toxicity of R parvum. The growth rate of R. salina was negatively affected by cell-free filtrates but the effect of P, parvum predation was greater. Rotifers fed on both toxic and non-toxic algae, indicating that they did not select against the toxic alga. The P. parvum cell-free filtrate had an effect on B. plicatilis, although this was weak, B, plicatilis was also indirectly affected by P. parvum due to the negative effects of the toxic alga on their prey (R. salina). However, the greatest negative effect of P. parvum on the rotifers was due to ingestion of the toxic cells. Therefore, the phytoplankton competitor R. salina is more affected by P. parvum predation and the grazer B. plicatilis is more affected by ingestion of the toxic cells, the effects of excreted compounds being secondary.

  • 8. Berland, B
    et al.
    Maestrini, SY
    Béchemin, C
    Legrand, Catherine
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Photosynthetic capacity of the toxic dinoflagellates Dinophysis acuminata and Dinophysis acuta1994In: La Mer, Vol. 32, p. 107-117Article in journal (Refereed)
  • 9.
    Berner, Christoffer
    et al.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Bertos-Fortis, Mireia
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Pinhassi, Jarone
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Legrand, Catherine
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Response of Microbial Communities to Changing Climate Conditions During Summer Cyanobacterial Blooms in the Baltic Sea2018In: Frontiers in Microbiology, ISSN 1664-302X, E-ISSN 1664-302X, Vol. 9, article id 1562Article in journal (Refereed)
    Abstract [en]

    Frequencies and biomass of Baltic Sea cyanobacterial blooms are expected to be higher in future climate conditions, but also of longer duration as a result of increased sea surface temperature. Concurrently, climate predictions indicate a reduced salinity in the Baltic Sea. These climate-driven changes are expected to alter not solely the phytoplankton community but also the role of microbial communities for nutrient remineralization. Here, we present the response of summer plankton communities (filamentous cyanobacteria, picocyanobacteria, and heterotrophic bacteria) to the interplay of increasing temperature (from 16 to 18 degrees C and 20 degrees C) and reduced salinity (from salinity 6.9 to 5.9) in the Baltic Proper (NW Gotland Sea) using a microcosm approach. Warmer temperatures led to an earlier peak of cyanobacterial biomass, while yields were reduced. These conditions caused a decrease of nitrogen-fixers (Dolichospermum sp.) biomass, while non nitrogen-fixers (Pseudanabaena sp.) increased. Salinity reduction did not affect cyanobacterial growth nor community composition. Among heterotrophic bacteria, Actinobacteria showed preference for high temperature, while Gammaproteobacteria thrived at in situ temperature. Heterotrophic bacteria community changed drastically at lower salinity and resembled communities at high temperature. Picocyanobacteria and heterotrophic bacterial biomass had a pronounced increase associated with the decay of filamentous cyanobacteria. This suggests that shifts in community composition of heterotrophic bacteria are influenced both directly by abiotic factors (temperature and salinity) and potentially indirectly by cyanobacteria. Our findings suggest that at warmer temperature, lower yield of photosynthetic cyanobacteria combined with lower proportion of nitrogen-fixers in the community could result in lower carbon export to the marine food web with consequences for the decomposer community of heterotrophic bacteria.

  • 10.
    Bertos-Fortis, Mireia
    et al.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Farnelid, Hanna
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Lindh, Markus V.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Casini, Michele
    Swedish University of Agricultural Sciences.
    Andersson, Agneta
    Umeå University.
    Pinhassi, Jarone
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Legrand, Catherine
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Unscrambling Cyanobacteria Community Dynamics Related to Environmental Factors2016In: Frontiers in Microbiology, ISSN 1664-302X, E-ISSN 1664-302X, Vol. 7, article id 625Article in journal (Refereed)
    Abstract [en]

    Future climate scenarios in the Baltic Sea project an increase of cyanobacterial bloom frequency and duration, attributed to eutrophication and climate change. Some cyanobacteria can be toxic and their impact on ecosystem services is relevant for a sustainable sea. Yet, there is limited understanding of the mechanisms regulating cyanobacterial diversity and biogeography. Here we unravel successional patterns and changes in cyanobacterial community structure using a 2-year monthly time series during the productive season in a 100 km coastal-offshore transect using microscopy and high-throughput sequencing of 16S rRNA gene fragments. A total of 565 cyanobacterial OTUs were found, of which 231 where filamentous/colonial and 334 picocyanobacterial. Spatial differences in community structure between coastal and offshore waters were minor. An "epidemic population structure" (dominance of a single cluster) was found for Aphanizomenon/Dolichospermum within the filamentous/colonial cyanobacterial community. In summer, this cluster simultaneously occurred with opportunistic clusters/OTUs, e.g., Nodulana spumigena and Pseudanabaena. Picocyanobacteria, Synechococcus/Cyanobium, formed a consistent but highly diverse group. Overall, the potential drivers structuring summer cyanobacterial communities were temperature and salinity. However, the different responses to environmental factors among and within genera suggest high niche specificity for individual OTUs. The recruitment and occurrence of potentially toxic filamentous/colonial clusters was likely related to disturbance such as mixing events and short-term shifts in salinity, and not solely dependent on increasing temperature and nitrogen-limiting conditions. Nutrients did not explain further the changes in cyanobacterial community composition. Novel occurrence patterns were identified as a strong seasonal succession revealing a tight coupling between the emergence of opportunistic picocyanobacteria and the bloom of filamentous/colonial clusters. These findings highlight that if environmental conditions can partially explain the presence of opportunistic picocyanobacteria, microbial and trophic interactions with filamentous/colonial cyanobacteria should also be considered as potential shaping factors for single-celled communities. Regional climate change scenarios in the Baltic Sea predict environmental shifts leading to higher temperature and lower salinity; conditions identified here as favorable for opportunistic filamentous/colonial cyanobacteria. Altogether, the diversity and complexity of cyanobacterial communities reported here is far greater than previously known, emphasizing the importance of microbial interactions between filamentous and picocyanobacteria in the context of environmental disturbances.

  • 11.
    Bonsdorff, Erik
    et al.
    Åbo Akademi University, Finland.
    Andersson, AgnetaUmeå University.Elmgren, RagnarStockholm University.Bidleman, TerryUmeå University.Blenckner, ThorstenStockholm University.Gorokhova, ElenaStockholm University.Legrand, CatherineLinnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.Wikner, JohanUmeå University.
    Special Issue: Baltic Sea ecosystem-based management under climate change2015Collection (editor) (Refereed)
  • 12.
    Broman, Elias
    et al.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Li, Lingni
    Fridlund, Jimmy
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Svensson, Fredrik
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Legrand, Catherine
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Dopson, Mark
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Eutrophication induced early stage hypoxic ‘dead zone’ sediment releases nitrate and stimulates growth of archaeaManuscript (preprint) (Other academic)
    Abstract [en]

    In the Baltic Sea, two annual algal blooms occur in spring and summer. The bloom intensity is determined by nutrient concentrations in the water column, while the period depends on weather conditions. During the course of the bloom, dead cells sink to the sediment where their degradation consumes oxygen to create hypoxic zones (< 2 mg/L dissolved oxygen, referred to as ‘dead zones’). These zones prevent the establishment of benthic communities and result in fish mortality. The aim of the study was to determine how the sediment chemistry and microbial community composition changed due to phytoplankton biomass degradation by adding cyanobacterial or diatom biomass to sediment cores from an all-year round oxic coastal Baltic Sea bay. After biomass addition, some typical anaerobic microbial processes were observed such as a decrease in NO2-+NO3- in the sediment surface (0-1 cm) and iron in the underlying layer (1-2 cm). In addition, an increase in NO2-+NO3- was observed in the water phase in all incubations (including controls without addition of phytoplankton biomass). The combination of NO2-+NO3- diffusion from the sediment plus nitrification of the available NH4+ could not account for this increase. Potential nitrogen sources that could at least partially explain this discrepancy included microbial nitrogen fixation and cycling of nitrogen compounds from deeper layers of the sediment. Based on 16S rRNA gene sequences, the addition of diatom biomass caused minor changes in the relative abundance of microbial community members while cyanobacterial biomass caused a large increase in ferrous iron-oxidizing archaea. Considering that OTUs sharing lineages with acidophilic microorganisms were present, it was suggested that specific niches developed in sediment microenvironments. These findings highlight the importance of nitrogen cycling in oxic sediments and early microbial community changes in the sediment surface due to sinking phytoplankton before major hypoxia events occur. The release of nitrate into the water could potentially enhance algal blooms and facilitate the development of ‘dead zones’.

  • 13.
    Broman, Elias
    et al.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Li, Lingni
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Fridlund, Jimmy
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Svensson, Fredrik
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Legrand, Catherine
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Dopson, Mark
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Spring and Late Summer Phytoplankton Biomass Impact on the Coastal Sediment Microbial Community Structure2019In: Microbial Ecology, ISSN 0095-3628, E-ISSN 1432-184X, no 2, p. 288-303Article in journal (Refereed)
    Abstract [en]

    Two annual Baltic Sea phytoplankton blooms occur in spring and summer. The bloom intensity is determined by nutrient concentrations in the water, while the period depends on weather conditions. During the course of the bloom, dead cells sink to the sediment where their degradation consumes oxygen to create hypoxic zones (< 2 mg/L dissolved oxygen). These zones prevent the establishment of benthic communities and may result in fish mortality. The aim of the study was to determine how the spring and autumn sediment chemistry and microbial community composition changed due to degradation of diatom or cyanobacterial biomass, respectively. Results from incubation of sediment cores showed some typical anaerobic microbial processes after biomass addition such as a decrease in NO2 + NO3 in the sediment surface (0–1 cm) and iron in the underlying layer (1–2 cm). In addition, an increase in NO2 + NO3 was observed in the overlying benthic water in all amended and control incubations. The combination of NO2 + NO3 diffusion plus nitrification could not account for this increase. Based on 16S rRNA gene sequences, the addition of cyanobacterial biomass during autumn caused a large increase in ferrous iron-oxidizing archaea while diatom biomass amendment during spring caused minor changes in the microbial community. Considering that OTUs sharing lineages with acidophilic microorganisms had a high relative abundance during autumn, it was suggested that specific niches developed in sediment microenvironments. These findings highlight the importance of nitrogen cycling and early microbial community changes in the sediment due to sinking phytoplankton before potential hypoxia occurs.

  • 14.
    Brussaard, Corina P. D.
    et al.
    NIOZ Royal Netherlands Institute of Sea Research, Netherlands ; University of Utrecht, Netherlands.
    Bidle, Kay D.
    Rutgers University, USA.
    Pedrós-Alió, Carlos
    Institut de Ciències del Mar (CSIC), Spain.
    Legrand, Catherine
    Linnéuniversitetet, Institutionen för biologi och miljö (BOM).
    The interactive microbial ocean2016In: Nature Microbiology, E-ISSN 2058-5276, Vol. 2, article id 16255Article in journal (Refereed)
    Abstract [en]

    Marine microorganisms inhabit diverse environments and interact over different spatial and temporal scales. To fully understand how these interactions shape genome structures, cellular responses, lifestyles, community ecology and biogeochemical cycles, integration of diverse approaches and data is essential.

  • 15.
    Brussaard, Corina P. D.
    et al.
    NIOZ Royal Netherlands Institute of Sea Research, Netherlands;University of Utrecht, Netherlands.
    Bidle, Kay D.
    Rutgers University, USA.
    Pedrós-Alió, Carlos
    Institut de Ciències del Mar (CSIC), Spain.
    Legrand, Catherine
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    The interactive microbial ocean2017In: Nature Microbiology, E-ISSN 2058-5276, Vol. 2, article id 16255Article in journal (Refereed)
    Abstract [en]

    Marine microorganisms inhabit diverse environments and interact over different spatial and temporal scales. To fully understand how these interactions shape genome structures, cellular responses, lifestyles, community ecology and biogeochemical cycles, integration of diverse approaches and data is essential.

  • 16.
    Bunse, Carina
    et al.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Bertos-Fortis, Mireia
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Sassenhagen, Ingrid
    Lund University.
    Sildever, Sirje
    Tallinn University of Technology, Estonia.
    Sjöqvist, Conny
    Marine Research Centre, Finland;Åbo Akademi University, Finland.
    Godhe, Anna
    University of Gothenburg.
    Gross, Susanna
    University of Gothenburg.
    Kremp, Anke
    Marine Research Centre, Finland.
    Lips, Inga
    Tallinn University of Technology, Estonia.
    Lundholm, Nina
    University of Copenhagen, Denmark.
    Rengefors, Karin
    Lund University.
    Sefbom, Josefin
    University of Gothenburg.
    Pinhassi, Jarone
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Legrand, Catherine
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Spatio-Temporal Interdependence of Bacteria and Phytoplankton during a Baltic Sea Spring Bloom2016In: Frontiers in Microbiology, ISSN 1664-302X, E-ISSN 1664-302X, Vol. 7, article id 517Article in journal (Refereed)
    Abstract [en]

    In temperate systems, phytoplankton spring blooms deplete inorganic nutrients and are major sources of organic matter for the microbial loop. In response to phytoplankton exudates and environmental factors, heterotrophic microbial communities are highly dynamic and change their abundance and composition both on spatial and temporal scales. Yet, most of our understanding about these processes comes from laboratory model organism studies, mesocosm experiments or single temporal transects. Spatial -temporal studies examining interactions of phytoplankton blooms and bacterioplankton community composition and function, though being highly informative, are scarce. In this study, pelagic microbial community dynamics (bacteria and phytoplankton) and environmental variables were monitored during a spring bloom across the Baltic Proper (two cruises between North Germany to Gulf of Finland). To test to what extent bacterioplankton community composition relates to the spring bloom, we used next generation amplicon sequencing of the 16S rRNA gene, phytoplankton diversity analysis based on microscopy counts and population genotyping of the dominating diatom Skeletonema rnarinoi. Several phytoplankton bloom related and environmental variables were identified to influence bacterial community composition. Members of Bacteroidetes and Alphaproteobacteria dominated the bacterial community composition but the bacterial groups showed no apparent correlation with direct bloom related variables. The less abundant bacterial phyla Actinobacteria, Planctomycetes, and Verrucomicrobia, on the other hand, were strongly associated with phytoplankton biomass, diatom:dinoflagellate ratio, and colored dissolved organic matter (cDOM). Many bacterial operational taxonomic units (OTUs) showed high niche specificities. For example, particular Bacteroidetes OTUs were associated with two distinct genetic clusters of S. marinoi. Our study revealed the complexity of interactions of bacterial taxa with inter- and intraspecific genetic variation in phytoplankton. Overall, our findings imply that biotic and abiotic factors during spring bloom influence bacterial community dynamics in a hierarchical manner.

  • 17.
    Bunse, Carina
    et al.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science. Carl von Ossietzky Univ Oldenburg, Germany.
    Israelsson, Stina
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Baltar, Federico
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science. Univ Vienna, Austria.
    Bertos-Fortis, Mireia
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Fridolfsson, Emil
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Legrand, Catherine
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Lindehoff, Elin
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Lindh, Markus V.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science. Swedish Meteorological & Hydrological Institute.
    Martínez-García, Sandra
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science. Univ Vigo, Spain.
    Pinhassi, Jarone
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    High Frequency Multi-Year Variability in Baltic Sea Microbial Plankton Stocks and Activities2019In: Frontiers in Microbiology, ISSN 1664-302X, E-ISSN 1664-302X, Vol. 9, article id 3296Article in journal (Refereed)
    Abstract [en]

    Marine bacterioplankton are essential in global nutrient cycling and organic matter turnover. Time-series analyses, often at monthly sampling frequencies, have established the paramount role of abiotic and biotic variables in structuring bacterioplankton communities and productivities. However, fine-scale seasonal microbial activities, and underlying biological principles, are not fully understood. We report results from four consecutive years of high-frequency time-series sampling in the Baltic Proper. Pronounced temporal dynamics in most investigated microbial variables were observed, including bacterial heterotrophic production, plankton biomass, extracellular enzyme activities, substrate uptake rate constants of glucose, pyruvate, acetate, amino acids, and leucine, as well as nutrient limitation bioassays. Spring blooms consisting of diatoms and dinoflagellates were followed by elevated bacterial heterotrophic production and abundances. During summer, bacterial productivity estimates increased even further, coinciding with an initial cyanobacterial bloom in early July. However, bacterial abundances only increased following a second cyanobacterial bloom, peaking in August. Uptake rate constants for the different measured carbon compounds varied seasonally and inter-annually and were highly correlated to bacterial productivity estimates, temperature, and cyanobacterial abundances. Further, we detected nutrient limitation in response to environmental conditions in a multitude of microbial variables, such as elevated productivities in nutrient bioassays, changes in enzymatic activities, or substrate preferences. Variations among biotic variables often occurred on time scales of days to a few weeks, yet often spanning several sampling occasions. Such dynamics might not have been captured by sampling at monthly intervals, as compared to more predictable transitions in abiotic variables such as temperature or nutrient concentrations. Our study indicates that high resolution analyses of microbial biomass and productivity parameters can help out in the development of biogeochemical and food web models disentangling the microbial black box.

  • 18.
    Bunse, Carina
    et al.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Lundin, Daniel
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Lindh, Markus V.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science. Lund University.
    Sjöstedt, Johanna
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Israelsson, Stina
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Martínez-García, Sandra
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science. Universidade de Vigo, Spain.
    Baltar, Federico
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science. University of Otago, New Zealand.
    Muthusamy, Sarala Devi
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Pontiller, Benjamin
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Karlsson, Christofer M. G.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Legrand, Catherine
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Pinhassi, Jarone
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Seasonality and co-occurrences of free-living Baltic Sea bacterioplanktonManuscript (preprint) (Other academic)
  • 19. Chauton, M
    et al.
    Tillstone, G
    Legrand, Catherine
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Johnsen, G
    Changes in pigmentation, bio-optical characteristics and photophysiology, during phytoflagellate succession in mesocosms2004In: Journal of Plankton Research, ISSN 0142-7873, E-ISSN 1464-3774, Vol. 26, no 3, p. 315-324Article in journal (Refereed)
    Abstract [en]

    Pigmentation, bio-optical characteristics and photophysiology, were studied in mesocosms with different N:P ratios. No significant difference in biomass or species composition was seen under different nitrogen to phosphorus ratios (N:P), but a temporal succession of different flagellate groups was observed in all mesocosms. An initial bloom of prymnesiophytes containing chlorophyll (Chl) c and 19' hexanoyloxyfucoxanthin (19' HOF) was followed by prasinophytes containing Chl b. Electron microscope analysis confirmed the presence of genera such as Chrysochromulina (Prymnesiophyceae), Tetraselmis and Pyramimonas (Prasinophyceae). Traces of prasinoxanthin in the pigment samples showed that smaller prasinophytes were also present. Chl b influenced the photophysiology of the prasinophytes resulting in higher Chl a-specific absorption, but a greater difference between absorption and scaled fluorescence excitation spectra indicated that light absorbed by Chl b is associated with photosystem I (PSI). Since a larger fraction of the light was absorbed by chlorophyll in PSI and/or photoprotective carotenoids, the light-saturated Chl a-specific rate of photosynthesis (P-m(B)) and maximum light utilization coefficient (alpha(B)) decreased when [Chl b] increased. The highest P-m(B) values were seen when the ratios of fucoxanthins to Chl a were high, indicating that prymnesiophytes might be more efficient in light harvesting and electron transport through photosystem II (PSII) by fucoxanthins and Chl c. Our results therefore indicate different light acclimation strategies in prasinophytes versus prymnesiophytes, which may be reflected in the successional appearance of these communities in the natural environment. We also suggest that grazing by ciliates and rotifers caused periodic decreases in phytoplankton biomass, which in turn gave rise to the phytoflagellate succession observed in the mesocosms.

  • 20. Delmas, D
    et al.
    Legrand, Catherine
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Béchemin, C
    Collinot, C
    Exoproteolytic activity determined by flow injection analysis: potential importance for bacterial growth in coastal marine ponds1994In: Aquatic Living Resources, ISSN 0990-7440, E-ISSN 1765-2952, Vol. 7, no 1, p. 17-24Article in journal (Refereed)
    Abstract [en]

    The measurement of the fluorescent 4-methyl-7-coumarinylamine released from the hydrolysis of a non-fluorescent peptide model substrate by exoproteolytic enzymes has been adapted to flow injection analysis (FIA). FIA allows samples to be processed very quickly (less than 2 min. for triplicate determinations) with good sensitivity (< 0.1 muM) and reproducibility (relative standard deviation < 3 % at the 0.2 muM level). In a coastal marine pond, exoproteolytic activity was closely related to bacterioplankton biomass. The high activity measured in pond water (maximum velocity: V(M) almost-equal-to 1.46 to 2.54 muM.h-1) emphasizes the importance of dissolved protein hydrolysis for bacterial growth and for dissolved organic nitrogen cycling. The mean turnover time of dissolved peptides was 7.6 days, and amino acids liberated by exoproteolytic activity could potentially support, on average, 40 % of the bacterial nitrogen demand.

  • 21. Doblin, M.
    et al.
    Legrand, Catherine
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Carlsson, Per
    Hummert, Christian
    Granéli, Edna
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Hallegraeff, G.
    Uptake of humic substances by the toxic dinoflagellate Alexandrium catenella2001In: Intergov. Oceanographic Commission of UNESCO, Paris 2001 336-339 / [ed] GM Hallegraeff, SI Blackburn, CJ Bolch, RJ Lewis, 2001Conference paper (Refereed)
  • 22.
    Figueroa, Daniela
    et al.
    Umeå University ; Umeå Marine Sciences Centre.
    Rowe, O. F.
    Umeå University ; University of Helsinki, Finland.
    Paczkowska, Joanna
    Umeå University.
    Legrand, Catherine
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Andersson, Agneta
    Umeå University ; Umeå Marine Sciences Centre.
    Allochthonous Carbon-a Major Driver of Bacterioplankton Production in the Subarctic Northern Baltic Sea2016In: Microbial Ecology, ISSN 0095-3628, E-ISSN 1432-184X, Vol. 71, no 4, p. 789-801Article in journal (Refereed)
    Abstract [en]

    Heterotrophic bacteria are, in many aquatic systems, reliant on autochthonous organic carbon as their energy source. One exception is low-productive humic lakes, where allochthonous dissolved organic matter (ADOM) is the major driver. We hypothesized that bacterial production (BP) is similarly regulated in subarctic estuaries that receive large amounts of riverine material. BP and potential explanatory factors were measured during May-August 2011 in the subarctic Råne Estuary, northern Sweden. The highest BP was observed in spring, concomitant with the spring river-flush and the lowest rates occurred during summer when primary production (PP) peaked. PLS correlations showed that ∼60 % of the BP variation was explained by different ADOM components, measured as humic substances, dissolved organic carbon (DOC) and coloured dissolved organic matter (CDOM). On average, BP was threefold higher than PP. The bioavailability of allochthonous dissolved organic carbon (ADOC) exhibited large spatial and temporal variation; however, the average value was low, ∼2 %. Bioassay analysis showed that BP in the near-shore area was potentially carbon limited early in the season, while BP at seaward stations was more commonly limited by nitrogen-phosphorus. Nevertheless, the bioassay indicated that ADOC could contribute significantly to the in situ BP, ∼60 %. We conclude that ADOM is a regulator of BP in the studied estuary. Thus, projected climate-induced increases in river discharge suggest that BP will increase in subarctic coastal areas during the coming century.

  • 23. Fistarol, Giovana
    et al.
    Legrand, Catherine
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Granéli, Edna
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Allelopathic effect of Prymnesium parvum on a natural plankton community2003In: Marine Ecology Progress Series, ISSN 0171-8630, E-ISSN 1616-1599, Vol. 255, p. 115-125Article in journal (Refereed)
    Abstract [en]

    The allelopathic effect of Prymnesium parvum (Prymnesiophyta), which produces toxins with haemolytic, ichthyotoxic and cytotoxic properties, was investigated on a natural plankton community. Under controlled conditions, 3 laboratory bioassays were performed by adding cell-free filtrate from a P. parvum culture into different size fractions (<150, <100 and 20 to 150 mum) of a natural Baltic Sea plankton community. The effect of P. parvum cell-free filtrate was determined by measuring chlorophyll a, cell numbers (phytoplankton, ciliates, bacteria), carbon (C-14) uptake by phytoplankton and the incorporation of H-3-leucine by bacteria. P. parvum cell-free filtrate affected the whole phytoplankton community, resulting in a decrease in both chlorophyll a and carbon uptake. Furthermore, the plankton groups present in the community exhibited different sensitivity to the cell-free filtrate. While growth of cyanobacteria and dinoflagellates was inhibited, that of diatoms and ciliates was not only completely suppressed, but no cells were present at the end of the experiment in the bottles with P. parvum filtrate. In all experiments, therefore, cyanobacteria and dinoflagellates were the most resistant groups, which led to their dominance in the treatments with filtrate compared to controls. Bacterial production was also negatively affected by P. parvum filtrate. The results show that compounds released by P. parvum induce changes in the plankton community structure, killing other members of the marine food-web, especially other phytoplankton (allelopathy), and suggest that secreted compounds of P. parvum are inhibitory to potential grazers (ciliates). It is proposed that allelopathy is an important process in the ecology of P. parvum.

  • 24. Fistarol, Giovana
    et al.
    Legrand, Catherine
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Rengefors, Karin
    Granéli, Edna
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Temporary cyst formation in phytoplankton: a response to allelopathic competitors?2004In: Environmental Microbiology, ISSN 1462-2912, E-ISSN 1462-2920, Vol. 6, no 8, p. 791-798Article in journal (Refereed)
    Abstract [en]

    Competition among phytoplankton for limiting resources may involve direct or indirect interactions. A direct interaction of competitors is the release of chemicals that inhibit other species, a process known as allelopathy. Here, we investigated the allelopathic effect of three toxic microalgae species (Alexandrium tamarense, Karenia mikimotoi and Chrysochromulina polylepis) on a natural population of the dinoflagellate Scrippsiella trochoidea. Our major findings were that in addition to causing death of S. trochoidea cells, the allelopathic species also induced the formation of temporary cysts in S. trochoidea. Because cysts were not lysed, encystment may act as a defence mechanism for S. trochoidea to resist allelochemicals, especially when the allelopathic effect is moderate. By forming temporary cysts, S. trochoidea may be able to overcome the effect of allelochemicals, and thereby have an adaptive advantage over other organisms unable to do so.

  • 25. Fistarol, Giovana
    et al.
    Legrand, Catherine
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Selander, Erik
    Hummert, Christian
    Stolte, Willem
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Granéli, Edna
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Allelopathy in Alexandrium spp.: effect on a natural plankton community and on algal monocultures2004In: Aquatic Microbial Ecology, ISSN 0948-3055, E-ISSN 1616-1564, Vol. 35, no 1, p. 45-56Article in journal (Refereed)
    Abstract [en]

    We studied allelopathy in the dinoflagellate genus Alexandrium by testing the effect of A. tamarense on a natural plankton community from Hopavagen Bay, Trondheimsfjord, Norway, and the effect of toxic and non-toxic strains of A. tamarense and a toxic strain of A. minutum on algal monocultures. Also, a possible relation between the allelopathic effect and the production of paralytic shellfish poison (PSP) toxin was investigated. A. tamarense affected the whole phytoplankton community by decreasing the growth rate and changing the community structure (relative abundance of each species, dominant species). A negative effect of A. tamarense was also observed on ciliates, but not on bacteria numbers, In the bioassay with algal monocultures, the diatom Thalassiosira weissflogii and the cryptophyte Rhodomonas sp. were exposed to the filtrate of Alexandrium spp. All tested Alexandrium strains negatively affected T weissflogii and Rhodomonas sp. cultures, independent of whether PSP toxins were produced. The compounds released by Alexandrium caused lysis of natural and cultured algal cells, suggesting that the allelopathic effect may be connected with previously described ichthyotoxic and haemolytic properties of Alexandrium. Furthermore, the observation that several components of the plankton community were affected by compounds released by A. tamarense emphasizes the importance of allelopathy for the ecology of this species.

  • 26. Fistarol, GO
    et al.
    Legrand, Catherine
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Granéli, Edna
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Allelopathic effect on a nutrient-limited phytoplankton species2005In: Aquatic Microbial Ecology, ISSN 0948-3055, E-ISSN 1616-1564, Vol. 41, no 2, p. 153-161Article in journal (Refereed)
    Abstract [en]

    For aquatic systems, studies on allelopathic interactions among phytoplankton have increased over recent years, with the main focus on the role of the donor organism. In this study, we report on the response of a target organism to allelochemicals and whether this response was affected by stress conditions (nutrient limitation). We exposed the diatom Thalassiosira weissflogii, grown under different nitrogen (N) and phosphorus (P) conditions (NP, -N, or -P), to single or daily additions of a cell-free filtrate of Prymnesium parvum (grown with no nutrient limitation). When we exposed T weissflogii to a single addition of filtrate, all 3 treatments were inhibited by P. parvum. However, T weissflogii NP was the most resistant, while T weissflogii -N showed the highest sensitivity to P. parvum filtrate, followed by T weissflogii -P. When T weissflogii was exposed. to daily additions of P. parvum, the degree of inhibition of all T weissflogii treatments was higher than when only 1 initial addition was made. In this case, even the treatment that had the highest resistance (T weissflogii NP) was not only inhibited by the filtrate, but also showed a decrease in cell numbers. Nevertheless, T weissflogii -N was still more sensitive than the other treatments. Therefore, nutrient-limiting conditions may increase allelopathic effects, by making the target more susceptive to allelopathic compounds. Under these conditions, allelopathy may play a strong role in phytoplankton competition, especially in natural environments where the allelochemicals are continuously released and, thus, the target species do not have time to recover.

  • 27.
    Fridolfsson, Emil
    et al.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Bunse, Carina
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science. University of Oldenburg, Germany.
    Legrand, Catherine
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Lindehoff, Elin
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Majaneva, Sanna
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science. The Arctic University of Norway, Norway.
    Hylander, Samuel
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Seasonal variation and species-specific concentrations of the essential vitamin B₁ (thiamin) in zooplankton and seston2019In: Marine Biology, ISSN 0025-3162, E-ISSN 1432-1793, Vol. 166, no 6, p. 1-13, article id 70Article in journal (Refereed)
    Abstract [en]

    Thiamin (vitamin B1) is mainly produced by bacteria and phytoplankton and then transferred to zooplankton and higher trophic levels but knowledge on the dynamics of these processes in aquatic ecosystems is lacking. Hence, the seasonal variation in thiamin content was assessed in field samples of copepods and in pico-, nano- and micro-plankton of two size classes (0.7–3 µm and > 3 µm) collected monthly in the Baltic Sea during 3 years and in the Skagerrak during 1 year. Copepods exhibited species-specific concentrations of thiamin and Acartia sp. had the highest carbon-specific thiamin content, at both locations. Even members of the same genus, but from different systems contained different levels of thiamin, with higher thiamin content per specimen in copepods from the Skagerrak compared to congeners from the Baltic Sea. Furthermore, our results show that the small plankton (0.7–3 µm) had a higher carbon-specific thiamin content compared to the large (> 3 µm). Additionally, there was a large seasonal variation and thiamin content was highly correlated comparing the two size fractions. Finally, there was an overall positive correlation between thiamin content in copepods and plankton. However, for periods of high thiamin content in the two size fractions, this correlation was negative. This suggests a decoupling between thiamin availability in pico-, nano- and micro-plankton and zooplankton in the Baltic Sea. Knowledge about concentrations of this essential micronutrient in the aquatic food web is limited and this study constitutes a foundation for further understanding the dynamics of thiamin in aquatic environments.

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  • 28.
    Fridolfsson, Emil
    et al.
    Linnéuniversitetet, Institutionen för biologi och miljö (BOM).
    Bunse, Carina
    Linnéuniversitetet, Institutionen för biologi och miljö (BOM).
    Legrand, Catherine
    Linnéuniversitetet, Institutionen för biologi och miljö (BOM).
    Lindehoff, Elin
    Linnéuniversitetet, Institutionen för biologi och miljö (BOM).
    Majaneva, Sanna
    Linnéuniversitetet, Institutionen för biologi och miljö (BOM).
    Hylander, Samuel
    Linnéuniversitetet, Institutionen för biologi och miljö (BOM).
    Seasonal variation and species-specific concentrations of the essential vitamin B₁ (thiamin) in zooplankton and seston2019In: Marine Biology, ISSN 0025-3162, E-ISSN 1432-1793, Vol. 166, no 6, p. 1-13, article id 70Article in journal (Refereed)
    Abstract [en]

    Thiamin (vitamin B1) is mainly produced by bacteria and phytoplankton and then transferred to zooplankton and higher trophic levels but knowledge on the dynamics of these processes in aquatic ecosystems is lacking. Hence, the seasonal variation in thiamin content was assessed in field samples of copepods and in pico-, nano- and micro-plankton of two size classes (0.7–3 µm and > 3 µm) collected monthly in the Baltic Sea during 3 years and in the Skagerrak during 1 year. Copepods exhibited species-specific concentrations of thiamin and Acartia sp. had the highest carbon-specific thiamin content, at both locations. Even members of the same genus, but from different systems contained different levels of thiamin, with higher thiamin content per specimen in copepods from the Skagerrak compared to congeners from the Baltic Sea. Furthermore, our results show that the small plankton (0.7–3 µm) had a higher carbon-specific thiamin content compared to the large (> 3 µm). Additionally, there was a large seasonal variation and thiamin content was highly correlated comparing the two size fractions. Finally, there was an overall positive correlation between thiamin content in copepods and plankton. However, for periods of high thiamin content in the two size fractions, this correlation was negative. This suggests a decoupling between thiamin availability in pico-, nano- and micro-plankton and zooplankton in the Baltic Sea. Knowledge about concentrations of this essential micronutrient in the aquatic food web is limited and this study constitutes a foundation for further understanding the dynamics of thiamin in aquatic environments.

    Download full text (pdf)
    fulltext
  • 29.
    Fridolfsson, Emil
    et al.
    Linnéuniversitetet, Institutionen för biologi och miljö (BOM).
    Lindehoff, Elin
    Linnéuniversitetet, Institutionen för biologi och miljö (BOM).
    Legrand, Catherine
    Linnéuniversitetet, Institutionen för biologi och miljö (BOM).
    Hylander, Samuel
    Linnéuniversitetet, Institutionen för biologi och miljö (BOM).
    Species-specific content of thiamin (vitamin B1) in phytoplankton and the transfer to copepodsManuscript (preprint) (Other academic)
  • 30.
    Fridolfsson, Emil
    et al.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Lindehoff, Elin
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Legrand, Catherine
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Hylander, Samuel
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Species-specific content of thiamin (vitamin B1) in phytoplankton and the transfer to copepods2020In: Journal of Plankton Research, ISSN 0142-7873, E-ISSN 1464-3774Article in journal (Refereed)
    Abstract [en]

    Thiamin (vitamin B1) is primarily produced by bacteria and phytoplankton in aquatic food webs and transferred by ingestion to higher trophic levels. However, much remains unknown regarding production, content and transfer of this water-soluble, essential micronutrient. Hence, the thiamin content of six phytoplankton species from different taxa was investigated, along with the effect of thiamin amendment on thiamin content. Furthermore, thiamin transfer to copepods was estimated in feeding experiments. Prey type, not phytoplankton thiamin content per se, was the most important factor for the transfer of thiamin, as it was lowest from filamentous Cyanophyceae and highest from more easily ingested prey like Dunaliella tertiolecta and Rhodomonas salina. Cyanophyceae had the highest thiamin content of the investigated species, eightfold higher than the lowest. Phytoplankton varied in thiamin content related to the supply of thiamin, where thiamin addition enabled higher thiamin content in some species, while copepod thiamin content was less variable. In all, thiamin transfer is not only dependent on the prey thiamin content, but also the edibility and/or digestibility is of importance. Thiamin is essential for all organisms, and this study constitutes an important building block to understanding the dynamics and transfer of thiamin in the aquatic food web.

  • 31.
    Fridolfsson, Emil
    et al.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Lindehoff, Elin
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Legrand, Catherine
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Hylander, Samuel
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Thiamin (vitamin B1) content in phytoplankton and zooplankton in the presence of filamentous cyanobacteria2018In: Limnology and Oceanography, ISSN 0024-3590, E-ISSN 1939-5590, Vol. 63, no 6, p. 2423-2435Article in journal (Refereed)
    Abstract [en]

    Top predators in several aquatic food webs regularly display elevated reproductive failure, caused by thiamin(vitamin B1)deficiency. The reasons for these low-thiamin levels are not understood and information about the transfer of thiamin from the producers (bacteria and phytoplankton) to higher trophic levels is limited. One main concern is whether cyanobacterial blooms could negatively affect thiamin transfer in aquatic systems. Laboratory experiments with Baltic Sea plankton communities and single phytoplankton species were used to study the effect of filamentous cyanobacteria on the transfer of thiamin from phytoplankton to zooplankton. Experiments showed that the thiamin content in copepods was reduced when exposed to elevated levels of cyanobacteria, although filamentous cyanobacteria had higher levels of thiamin than any other analyzed phytoplankton species. Filamentous cyanobacteria also had a negative effect on copepod egg production despite high concentrations of non-cyanobacterial food. Phytoplankton species composition affected overall thiamin concentration with relatively more thiamin available for transfer when the relative abundance of Dinophyceae was higher. Finally, phytoplankton thiamin levels were lower when copepods were abundant, indicating that grazers affect thiamin levels in phytoplankton community, likely by selective feeding. Overall, high levels of thiamin in phytoplankton communities are not reflected in the copepod community. We conclude that presence of filamentous cyanobacteria during summer potentially reduces the transfer of thiamin to higher trophic levels by negatively affecting phytoplankton and copepod thiamin content as well as copepod reproduction, thereby lowering the absolute capacity of the food web to transfer thiamin through copepods to higher trophic levels.

  • 32. Glibert, P A
    et al.
    Legrand, Catherine
    University of Kalmar, School of Pure and Applied Natural Sciences.
    The diverse nutrient strategies of Hamful Algae: Focus on osmotrophy2006In: Ecology of Harmful Algae: Part C, Springer Berlin/Heidelberg, 2006, p. 163-175Chapter in book (Other academic)
  • 33. Glibert, PA
    et al.
    Granéli, Edna
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Legrand, Catherine
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Salomon, Paulo
    University of Kalmar, School of Pure and Applied Natural Sciences.
    and, 55 co-authors
    Ocean urea fertilization for carbon credits poses high ecological risks2008In: Marine Pollution Bulletin, ISSN 0025-326X, E-ISSN 1879-3363, Vol. 56, no 6, p. 1049-1056Article in journal (Refereed)
    Abstract [en]

    The proposed plan for enrichment of the Sulu Sea, Philippines, a region of rich marine biodiversity, with thousands of tonnes of urea in order to stimulate algal blooms and sequester carbon is flawed for multiple reasons. Urea is preferentially used as a nitrogen source by some cyanobacteria and dinoflagellates, many of which are neutrally or positively buoyant. Biological pumps to the deep sea are classically leaky, and the inefficient burial of new biomass makes the estimation of a net loss of carbon from the atmosphere questionable at best. The potential for growth of toxic dinoflagellates is also high, as many grow well on urea and some even increase their toxicity when grown on urea. Many toxic dinoflagellates form cysts which can settle to the sediment and germinate in subsequent years, forming new blooms even without further fertilization. If large-scale blooms do occur, it is likely that they will contribute to hypoxia in the bottom waters upon decomposition. Lastly, urea production requires fossil fuel usage, further limiting the potential for net carbon sequestration. The environmental and economic impacts are potentially great and need to be rigorously assessed.

  • 34.
    Godhe, Anna
    et al.
    University of Gothenburg.
    Sjoekvist, Conny
    Åbo Akademi University, Finland.
    Sildever, Sirje
    Tallinn University of Technology, Estonia.
    Sefbom, Josefin
    University of Gothenburg.
    Harðardóttir, Sara
    Natural History Museum of Denmark, Denmark ; University of Copenhagen, Denmark.
    Bertos-Fortis, Mireia
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Bunse, Carina
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Gross, Susanna
    University of Gothenburg.
    Johansson, Emma
    University of Gothenburg.
    Jonsson, Per R.
    University of Gothenburg.
    Khandan, Saghar
    Lund University.
    Legrand, Catherine
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Lips, Inga
    Tallinn University of Technology, Estonia.
    Lundholm, Nina
    Natural History Museum of Denmark, Denmark ; University of Copenhagen, Denmark.
    Rengefors, Karin E.
    Lund University.
    Physical barriers and environmental gradients cause spatial and temporal genetic differentiation of an extensive algal bloom2016In: Journal of Biogeography, ISSN 0305-0270, E-ISSN 1365-2699, Vol. 43, no 6, p. 1130-1142Article in journal (Refereed)
    Abstract [en]

    Aim

    To test if a phytoplankton bloom is panmictic, or whether geographical and environmental factors cause spatial and temporal genetic structure.

    Location

    Baltic Sea.

    Method

    During four cruises, we isolated clonal strains of the diatom Skeletonema marinoifrom 9 to 10 stations along a 1132 km transect and analysed the genetic structure using eight microsatellites. Using F-statistics and Bayesian clustering analysis we determined if samples were significantly differentiated. A seascape approach was applied to examine correlations between gene flow and oceanographic connectivity, and combined partial Mantel test and RDA based variation partitioning to investigate associations with environmental gradients.

    Results

    The bloom was initiated during the second half of March in the southern and the northern- parts of the transect, and later propagated offshore. By mid-April the bloom declined in the south, whereas high phytoplankton biomass was recorded northward. We found two significantly differentiated populations along the transect. Genotypes were significantly isolated by distance and by the south–north salinity gradient, which illustrated that the effects of distance and environment were confounded. The gene flow among the sampled stations was significantly correlated with oceanographic connectivity. The depletion of silica during the progression of the bloom was related to a temporal population genetic shift.

    Main conclusions

    A phytoplankton bloom may propagate as a continuous cascade and yet be genetically structured over both spatial and temporal scales. The Baltic Sea spring bloom displayed strong spatial structure driven by oceanographic connectivity and geographical distance, which was enhanced by the pronounced salinity gradient. Temporal transition of conditions important for growth may induce genetic shifts and different phenotypic strategies, which serve to maintain the bloom over longer periods.

  • 35.
    Godhe, Anna
    et al.
    University of Gothenburg.
    Sjöqvist, Conny
    Åbo Akademi University, Finland.
    Sildever, Sirje
    Tallinn University of Technology, Estonia.
    Sefbom, Josefin
    University of Gothenburg.
    Harðardóttir, Sara
    Natural History Museum of Denmark, Denmark ; University of Copenhagen, Denmark.
    Bertos-Fortis, Mireia
    Linnéuniversitetet, Institutionen för biologi och miljö (BOM).
    Bunse, Carina
    Linnéuniversitetet, Institutionen för biologi och miljö (BOM).
    Gross, Susanna
    University of Gothenburg.
    Johansson, Emma
    University of Gothenburg.
    Jonsson, Per R.
    University of Gothenburg.
    Khandan, Saghar
    Lund University.
    Legrand, Catherine
    Linnéuniversitetet, Institutionen för biologi och miljö (BOM).
    Lips, Inga
    Tallinn University of Technology, Estonia.
    Lundholm, Nina
    Natural History Museum of Denmark, Denmark ; University of Copenhagen, Denmark.
    Rengefors, Karin E.
    Lund University.
    Sassenhagen, Ingrid
    Suikkanen, Sanna
    Sundqvist, Lisa
    Kremp, Anke
    Physical barriers and environmental gradients cause spatial and temporal genetic differentiation of an extensive algal bloom2016In: Journal of Biogeography, ISSN 0305-0270, E-ISSN 1365-2699, Vol. 43, no 6, p. 1130-1142Article in journal (Refereed)
    Abstract [en]

    Aim: To test if a phytoplankton bloom is panmictic, or whether geographical and environmental factors cause spatial and temporal genetic structure.

    Location: Baltic Sea.

    Method: During four cruises, we isolated clonal strains of the diatom Skeletonema marinoifrom 9 to 10 stations along a 1132 km transect and analysed the genetic structure using eight microsatellites. Using F-statistics and Bayesian clustering analysis we determined if samples were significantly differentiated. A seascape approach was applied to examine correlations between gene flow and oceanographic connectivity, and combined partial Mantel test and RDA based variation partitioning to investigate associations with environmental gradients.

    Results: The bloom was initiated during the second half of March in the southern and the northern- parts of the transect, and later propagated offshore. By mid-April the bloom declined in the south, whereas high phytoplankton biomass was recorded northward. We found two significantly differentiated populations along the transect. Genotypes were significantly isolated by distance and by the south–north salinity gradient, which illustrated that the effects of distance and environment were confounded. The gene flow among the sampled stations was significantly correlated with oceanographic connectivity. The depletion of silica during the progression of the bloom was related to a temporal population genetic shift.

    Main conclusions: A phytoplankton bloom may propagate as a continuous cascade and yet be genetically structured over both spatial and temporal scales. The Baltic Sea spring bloom displayed strong spatial structure driven by oceanographic connectivity and geographical distance, which was enhanced by the pronounced salinity gradient. Temporal transition of conditions important for growth may induce genetic shifts and different phenotypic strategies, which serve to maintain the bloom over longer periods.

  • 36.
    Granéli, Edna
    et al.
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Carlsson, Per
    Legrand, Catherine
    University of Kalmar, School of Pure and Applied Natural Sciences.
    The ecology of DSP (Diarrhetic Shellfish Poisoning) toxin producing dinoflagellates1997In: Brazilian Society for Microbiology ICOME In: Martins MT, Seti MIZ, Tiedje JM, Hagler LCN, Dobereiner, J, Sanchez SS (eds) Progress in Microbial Ecol, 1997Conference paper (Refereed)
  • 37.
    Granéli, Edna
    et al.
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Carlsson, Per
    Legrand, Catherine
    University of Kalmar, School of Pure and Applied Natural Sciences.
    The role of C, N and P in dissolved and particulate organic matter as a nutrient source for phytoplankton growth, including toxic species1999In: Aquatic Ecology, ISSN 1386-2588, E-ISSN 1573-5125, Vol. 33, p. 17-27Article in journal (Refereed)
    Abstract [en]

    Phytoplankton have traditionally been regarded as strictly phototrophic, with a well defined position at the base of pelagic food webs. However, recently we have learned that the nutritional demands of a growing number of phytoplankton species can be met, at least partially, or under specific environmental conditions, through heterotrophy. Mixotrophy is the ability of an organism to be both phototrophic and heterotrophic, in the latter case utilizing either organic particles (phagotrophy) or dissolved organic substances (osmotrophy). This finding has direct implications for our view on algal survival strategies, particularly for harmful species, and energy- and nutrient flow in pelagic food webs. Mixotrophic species may outcompete strict autotrophs, e.g. in waters poor in inorganic nutrients or under low light. In the traditional view of the ‘microbial loop’ DOC is thought to be channeled from algal photosynthesis to bacteria and then up the food chain through heterotrophic flagellates, ciliates and mesozooplankton. Are mixotrophic phytoplankton that feed on bacteria also significantly contributing to this transport of photosynthetic carbon up the food chain? How can we estimate the fluxes of carbon and nutrients between different trophic levels in the plankton food web involving phagotrophic algae? These questions largely remain unanswered. In this review we treat evidence for both osmotrophy and phagotrophy in phytoplankton, especially toxic marine species, and some ecological implications of mixotrophy.

  • 38.
    Granéli, Edna
    et al.
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Esplund-Lindquist, Christina
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Legrand, Catherine
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Franzén, H
    Granéli, C
    Minimizing economical losses with the help of “real-time” HAB surveillance2008In: ISSHA and IOC of UNESCO / [ed] Moestrup Ø, Enevoldsen H, Sellner K, Tester P, Copenhagen, 2008Conference paper (Refereed)
  • 39.
    Granéli, Edna
    et al.
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Legrand, Catherine
    University of Kalmar, School of Pure and Applied Natural Sciences.
    FATE-Transfer and fate of Harmful Algal Bloom (HAB) toxins in European marine waters2005Report (Other academic)
  • 40.
    Granéli, Edna
    et al.
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Legrand, Catherine
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Harmful algal blooms: causes, consequences for the economy, human health and the European Policy2001In: European Commission, EUR 19408 Research in enclosed seas series / [ed] Barthel K-G and 12 other authors, Hamburg, 2001Conference paper (Refereed)
  • 41.
    Granéli, Edna
    et al.
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Legrand, Catherine
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Interactions between nitrogen: phosphorus ratios and concentrations and the growth and toxin production of harmful phytoplankton2000In: European Commission. Project synopses I. Marine processes, ecosystems and interactions, Hamburg, 2000Conference paper (Refereed)
  • 42.
    Gross, Elisabeth
    et al.
    University of Konstanz, Germany.
    Legrand, Catherine
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Rengefors, Karin
    Lund University.
    Tillmann, Urban
    Alfred Wegener Institute for Polar Research, Germany.
    Allelochemical interactions among aquatic primary producers2012In: Chemical Ecology in Aquatic Systems / [ed] Christer Brönmark, Lars Anders Hansson, Oxford: Oxford University Press, 2012, 1, p. 196-209Chapter in book (Refereed)
    Abstract [en]

    Allelopathy is the study of biochemically-driven organismic interactions among primary producers. One organism affects others by the release of allelochemicals that are transported to the target cells, and cause a negative (or positive) response. Most aquatic allelochemicals are amphiphilic, thus have a sufficient solubility in the water, and at the same time can bind to and penetrate lipophilic cell membranes. Allelopathic interactions are not static but are influenced by variable environmental stressors. Resource availability can both affect the production and release of allelochemicals by the producing organism, but also influence the susceptibility of the target cells. The biosynthesis and excretion of allelochemicals might involve costs for the producing organism, and these costs will only be balanced if a net gain, i.e. better resource availability such as space or nutrients or secondary benefits, e.g. predator deterrence, are achieved. Allelopathic effects against cooccurring organisms might lead to coevolutionary responses, i.e. a lower susceptibility of target cells or to more advanced allelochemicals. Target organisms from different habitats might be more susceptible, especially if they are not acquainted with the allelochemicals. The transfer of laboratory results on allelopathy to realistic field conditions is complex, and might in the long run benefit from advanced analytical and molecular methods identifying specific target cell responses in situ.

  • 43.
    Hugerth, Luisa W.
    et al.
    KTH Royal Institute of Technology.
    Larsson, John
    Linnéuniversitetet, Institutionen för biologi och miljö (BOM).
    Alneberg, Johannes
    KTH Royal Institute of Technology.
    Lindh, Markus V.
    Linnéuniversitetet, Institutionen för biologi och miljö (BOM).
    Legrand, Catherine
    Linnéuniversitetet, Institutionen för biologi och miljö (BOM).
    Pinhassi, Jarone
    Linnéuniversitetet, Institutionen för biologi och miljö (BOM).
    Andersson, Anders F.
    KTH Royal Institute of Technology.
    Metagenome-assembled genomes uncover a global brackish microbiome2015In: Genome Biology, ISSN 1465-6906, E-ISSN 1474-760X, Vol. 16, article id 279Article in journal (Refereed)
    Abstract [en]

    Background: Microbes are main drivers of biogeochemical cycles in oceans and lakes. Although the genome is a foundation for understanding the metabolism, ecology and evolution of an organism, few bacterioplankton genomes have been sequenced, partly due to difficulties in cultivating them. Results: We use automatic binning to reconstruct a large number of bacterioplankton genomes from a metagenomic time-series from the Baltic Sea, one of world's largest brackish water bodies. These genomes represent novel species within typical freshwater and marine clades, including clades not previously sequenced. The genomes' seasonal dynamics follow phylogenetic patterns, but with fine-grained lineage-specific variations, reflected in gene-content. Signs of streamlining are evident in most genomes, and estimated genome sizes correlate with abundance variation across filter size fractions. Comparing thegenomes with globally distributed metagenomes reveals significant fragment recruitment at high sequence identity from brackish waters in North America, but little from lakes or oceans. This suggests the existence of a global brackish metacommunity whose populations diverged from freshwater and marine relatives over 100,000 years ago, long before the Baltic Sea was formed (8000 years ago). This markedly contrasts to most Baltic Sea multicellular organisms, which are locally adapted populations of freshwater or marine counterparts. Conclusions: We describe the gene content, temporal dynamics and biogeography of a large set of new bacterioplankton genomes assembled from metagenomes. We propose that brackish environments exert such strong selection that lineages adapted to them flourish globally with limited influence from surrounding aquatic communities.

  • 44.
    Hugerth, Luisa W.
    et al.
    KTH Royal Institute of Technology.
    Larsson, John
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Alneberg, Johannes
    KTH Royal Institute of Technology.
    Lindh, Markus V.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Legrand, Catherine
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Pinhassi, Jarone
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Andersson, Anders F.
    KTH Royal Institute of Technology.
    Metagenome-assembled genomes uncover a global brackish microbiome2015In: Genome Biology, ISSN 1465-6906, E-ISSN 1474-760X, Vol. 16, article id 279Article in journal (Refereed)
    Abstract [en]

    Background: Microbes are main drivers of biogeochemical cycles in oceans and lakes. Although the genome is a foundation for understanding the metabolism, ecology and evolution of an organism, few bacterioplankton genomes have been sequenced, partly due to difficulties in cultivating them. Results: We use automatic binning to reconstruct a large number of bacterioplankton genomes from a metagenomic time-series from the Baltic Sea, one of world's largest brackish water bodies. These genomes represent novel species within typical freshwater and marine clades, including clades not previously sequenced. The genomes' seasonal dynamics follow phylogenetic patterns, but with fine-grained lineage-specific variations, reflected in gene-content. Signs of streamlining are evident in most genomes, and estimated genome sizes correlate with abundance variation across filter size fractions. Comparing thegenomes with globally distributed metagenomes reveals significant fragment recruitment at high sequence identity from brackish waters in North America, but little from lakes or oceans. This suggests the existence of a global brackish metacommunity whose populations diverged from freshwater and marine relatives over 100,000 years ago, long before the Baltic Sea was formed (8000 years ago). This markedly contrasts to most Baltic Sea multicellular organisms, which are locally adapted populations of freshwater or marine counterparts. Conclusions: We describe the gene content, temporal dynamics and biogeography of a large set of new bacterioplankton genomes assembled from metagenomes. We propose that brackish environments exert such strong selection that lineages adapted to them flourish globally with limited influence from surrounding aquatic communities.

  • 45.
    Hultman, Birgitta
    Barometern OT .
    Hållbara transporter nästa mål för Linné2018In: Barometern OT, Vol. 16 April, p. 8-Article in journal (Other (popular science, discussion, etc.))
  • 46. Hummert, Christian
    et al.
    Reichelt, M
    Legrand, Catherine
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Granéli, Edna
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Luckas, B
    Rapid clean-up and effective sample preparation procedure for unambiguous determination of the cyclic peptides microcystin and nodularin1999In: Chromatographia, ISSN 0009-5893, E-ISSN 1612-1112, Vol. 50, no 3-4, p. 173-180Article in journal (Refereed)
    Abstract [en]

    A new sample preparation strategy has been established to improve the identification and determination of nodularin and microcystins. The sample preparation consisted of enrichment of the analytes by solid phase extraction with C18 cartridges followed by clean-up of the enriched raw extracts by high performance size exclusion gel permeation chromatography. In contrast to established clean-up procedures based on polarity, related distribution of microcystins and nodularin in non-miscible phases (e.g. a C18 cartridge as stationary phase and a water-containing eluent as mobile phase) this strategy separates microcystins from interfering compounds by molecular size differences.The sample preparation procedure can be automated easily and was validated for both water samples as well as raw extracts of algal cells. The method was successfully applied during an experiment with natural algae communities from the Baltic Sea to investigate the influence of different nutrient limitations on toxicity of Nodularia sp..

  • 47.
    Ianora, Adrianna
    et al.
    Stazione Zoologica Anton Dohrn, Italy.
    Bentley, Matthew G
    Newcastle University, UK.
    Caldwell, Gary S
    Newcastle University, UK.
    Casotti, Rafaella
    Stazione Zoologica Anton Dohrn, Italy.
    Cembella, Allan D
    Alfred Wegener Institute for Polar Research, Germany.
    Engström Öst, Jonna
    Novia University of Applied Sciences, Finland ; Åbo Akademi University, Finland.
    Halsband, Claudia
    Plymouth Marine Laboratory, UK.
    Sonnenschein, Eva
    International Max Planck Research School of Marine Microbiology, Germany.
    Legrand, Catherine
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Llewellyn, Carole
    Plymouth Marine Laboratory, UK.
    Paldaviciene, Aiste
    Klaipeda University, Lithuania.
    Pilkaityte, Renata
    Klaipeda University, Lithuania.
    Pohnert, Georg
    Friedrich Schiller University Jena, Germany.
    Razinkovas, Arthur
    Klaipeda University, Lithuania.
    Romano, Giovanna
    Stazione Zoologica Anton Dohrn, Italy.
    Tillmann, Urban
    Alfred Wegener Institute for Polar Research, Germany.
    Vaiciute, Diana
    Klaipeda University, Lithuania.
    The Relevance of Marine Chemical Ecology to Plankton and Ecosystem Function: An Emerging Field2011In: Marine Drugs, ISSN 1660-3397, E-ISSN 1660-3397, Vol. 9, no 9, p. 1625-1648Article in journal (Refereed)
    Abstract [en]

    Marine chemical ecology comprises the study of the production and interaction of bioactive molecules affecting organism behavior and function. Here we focus on bioactive compounds and interactions associated with phytoplankton, particularly bloom-forming diatoms, prymnesiophytes and dinoflagellates. Planktonic bioactive metabolites are structurally and functionally diverse and some may have multiple simultaneous functions including roles in chemical defense (antipredator, allelopathic and antibacterial compounds), and/or cell-to-cell signaling (e.g., polyunsaturated aldehydes (PUAs) of diatoms). Among inducible chemical defenses in response to grazing, there is high species-specific variability in the effects on grazers, ranging from severe physical incapacitation and/or death to no apparent physiological response, depending on predator susceptibility and detoxification capability. Most bioactive compounds are present in very low concentrations, in both the producing organism and the surrounding aqueous medium. Furthermore, bioactivity may be subject to synergistic interactions with other natural and anthropogenic environmental toxicants. Most, if not all phycotoxins are classic secondary metabolites, but many other bioactive metabolites are simple molecules derived from primary metabolism (e.g., PUAs in diatoms, dimethylsulfoniopropionate (DMSP) in prymnesiophytes). Producing cells do not seem to suffer physiological impact due to their synthesis. Functional genome sequence data and gene expression analysis will provide insights into regulatory and metabolic pathways in producer organisms, as well as identification of mechanisms of action in target organisms. Understanding chemical ecological responses to environmental triggers and chemically-mediated species interactions will help define crucial chemical and molecular processes that help maintain biodiversity and ecosystem functionality.

  • 48.
    Israelsson, Stina
    et al.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Bunse, Carina
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Baltar, Federico
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science. University of Otago, New Zealand.
    Bertos-Fortis, Mireia
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Fridolfsson, Emil
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Legrand, Catherine
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Lindehoff, Elin
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Lindh, Markus V.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science. Lund University.
    Martinez-Garcia, Sandra
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science. Universidade de Vigo, Spain.
    Pinhassi, Jarone
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Seasonal dynamics of Baltic Sea plankton activities: heterotrophic bacterial function under different biological and environmental conditionsManuscript (preprint) (Other academic)
  • 49.
    Johansson, Emma
    et al.
    Lund University, Sweden.
    Legrand, Catherine
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Bjorneras, Caroline
    Lund University, Sweden.
    Godhe, Anna
    University of Gothenburg, Sweden.
    Mazur-Marzec, Hanna
    Univ Gdansk, Poland.
    Säll, Torbjörn
    Lund University, Sweden.
    Rengefors, Karin
    Lund University, Sweden.
    High Diversity of Microcystin Chemotypes within a Summer Bloom of the Cyanobacterium Microcystis botrys2019In: Toxins, ISSN 2072-6651, E-ISSN 2072-6651, Vol. 11, no 12, p. 1-16, article id 698Article in journal (Refereed)
    Abstract [en]

    The fresh-water cyanobacterium Microcystis is known to form blooms world-wide, and is often responsible for the production of microcystins found in lake water. Microcystins are non-ribosomal peptides with toxic effects, e.g. on vertebrates, but their function remains largely unresolved. Moreover, not all strains produce microcystins, and many different microcystin variants have been described. Here we explored the diversity of microcystin variants within Microcystis botrys, a common bloom-former in Sweden. We isolated a total of 130 strains through the duration of a bloom in eutrophic Lake Vomb, and analyzed their microcystin profiles with tandem mass spectrometry (LC-MS/MS). We found that microcystin producing (28.5%) and non-producing (71.5%) M. botrys strains, co-existed throughout the bloom. However, microcystin producing strains were more prevalent towards the end of the sampling period. Overall, 26 unique M. botrys chemotypes were identified, and while some chemotypes re-occurred, others were found only once. The M. botrys chemotypes showed considerable variation both in terms of number of microcystin variants, as well as in what combinations the variants occurred. To our knowledge, this is the first report on microcystin chemotype variation and dynamics in M. botrys. In addition, our study verifies the co-existence of microcystin and non-microcystin producing strains, and we propose that environmental conditions may be implicated in determining their composition.

  • 50. Johansson, N
    et al.
    Granéli, Edna
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Yasumoto, T
    Carlsson, Per
    Legrand, Catherine
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Toxin production by Dinophysis acuminata and D. acuta cells grown under nutrient sufficient and deficient conditions1996In: Intergovernmental Oceanographic Commission of UNESCO In: Yasumoto, T, Oshima Y, Fukuyo Y (eds) Harmful and Toxic Algal Blooms, Paris, 1996Conference paper (Refereed)
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