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  • 1.
    Alegria Zufia, Javier
    et al.
    Linnéuniversitetet, Fakulteten för Hälso- och livsvetenskap (FHL), Institutionen för biologi och miljö (BOM).
    Farnelid, Hanna
    Linnéuniversitetet, Fakulteten för Hälso- och livsvetenskap (FHL), Institutionen för biologi och miljö (BOM). Linnéuniversitetet, Kunskapsmiljöer Linné, Vatten.
    Legrand, Catherine
    Linnéuniversitetet, Fakulteten för Hälso- och livsvetenskap (FHL), Institutionen för biologi och miljö (BOM). Linnéuniversitetet, Kunskapsmiljöer Linné, Vatten. Halmstad University, Sweden.
    Seasonality of Coastal Picophytoplankton Growth, Nutrient Limitation, and Biomass Contribution2021Ingår i: Frontiers in Microbiology, E-ISSN 1664-302X, Vol. 12, artikel-id 786590Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Picophytoplankton in the Baltic Sea includes the simplest unicellular cyanoprokaryotes (Synechococcus/Cyanobium) and photosynthetic picoeukaryotes (PPE). Picophytoplankton are thought to be a key component of the phytoplankton community, but their seasonal dynamics and relationships with nutrients and temperature are largely unknown. We monitored pico- and larger phytoplankton at a coastal site in Kalmar Sound (K-Station) weekly during 2018. Among the cyanoprokaryotes, phycoerythrin-rich picocyanobacteria (PE-rich) dominated in spring and summer while phycocyanin-rich picocyanobacteria (PC-rich) dominated during autumn. PE-rich and PC-rich abundances peaked during summer (1.1 x 10(5) and 2.0 x 10(5) cells mL(-1)) while PPE reached highest abundances in spring (1.1 x 10(5) cells mL(-1)). PPE was the main contributor to the total phytoplankton biomass (up to 73%). To assess nutrient limitation, bioassays with combinations of nitrogen (NO3 or NH4) and phosphorus additions were performed. PE-rich and PC-rich growth was mainly limited by nitrogen, with a preference for NH4 at >15 degrees C. The three groups had distinct seasonal dynamics and different temperature ranges: 10 degrees C and 17-19 degrees C for PE-rich, 13-16 degrees C for PC-rich and 11-15 degrees C for PPE. We conclude that picophytoplankton contribute significantly to the carbon cycle in the coastal Baltic Sea and underscore the importance of investigating populations to assess the consequences of the combination of high temperature and NH4 in a future climate.

  • 2.
    Andersen, K. H.
    et al.
    Tech Univ Denmark, Denmark.
    Berge, T.
    Tech Univ Denmark, Denmark;Univ Copenhagen, Denmark.
    Goncalves, R. J.
    Tech Univ Denmark, Denmark ;Consejo Nacl Invest Cient & Tecn, Argentina ; Estn Fotobiol Playa Union, Argentina.
    Hartvig, M.
    Tech Univ Denmark, Denmark;Univ Copenhagen, Denmark ; Univ Göttingen, Germany.
    Heuschele, J.
    Tech Univ Denmark, Denmark.
    Hylander, Samuel
    Linnéuniversitetet, Fakulteten för Hälso- och livsvetenskap (FHL), Institutionen för biologi och miljö (BOM). Tech Univ Denmark, Denmark.
    Jacobsen, N. S.
    Tech Univ Denmark, Denmark.
    Lindemann, C.
    Tech Univ Denmark, Denmark.
    Martens, E. A.
    Tech Univ Denmark, Denmark;Univ Copenhagen, Denmark.
    Neuheimer, A. B.
    Tech Univ Denmark, Denmark;Univ Hawaii Manoa, USA.
    Olsson, K.
    Tech Univ Denmark, Denmark.
    Palacz, A.
    Tech Univ Denmark, Denmark.
    Prowe, A. E. F.
    Tech Univ Denmark, Denmark;GEOMAR Helmholtz Ctr Ocean Res Kiel, Germany.
    Sainmont, J.
    Tech Univ Denmark, Denmark.
    Traving, S. J.
    Tech Univ Denmark, Denmark;Univ Copenhagen, Denmark.
    Visser, A. W.
    Tech Univ Denmark, Denmark.
    Wadhwa, N.
    Tech Univ Denmark, Denmark.
    Kiorboe, T.
    Tech Univ Denmark, Denmark.
    Characteristic Sizes of Life in the Oceans, from Bacteria to Whales2016Ingår i: Annual Review of Marine Science, ISSN 1941-1405, E-ISSN 1941-0611, Vol. 8, s. 217-241Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The size of an individual organism is a key trait to characterize its physiology and feeding ecology. Size-based scaling laws may have a limited size range of validity or undergo a transition from one scaling exponent to another at some characteristic size. We collate and review data on size-based scaling laws for resource acquisition, mobility, sensory range, and progeny size for all pelagic marine life, from bacteria to whales. Further, we review and develop simple theoretical arguments for observed scaling laws and the characteristic sizes of a change or breakdown of power laws. We divide life in the ocean into seven major realms based on trophic strategy, physiology, and life history strategy. Such a categorization represents a move away from a taxonomically oriented description toward a trait-based description of life in the oceans. Finally, we discuss life forms that transgress the simple size-based rules and identify unanswered questions.

  • 3.
    Andersson, Agneta
    et al.
    Umeå University, Sweden.
    Meier, H. E. Markus
    Swedish Meteorological and Hydrological Institute, Sweden.
    Ripszam, Matyas
    Umeå University, Sweden.
    Rowe, Owen
    Umeå University, Sweden.
    Wikner, Johan
    Umeå university, Sweden.
    Haglund, Peter
    Umeå University, Sweden.
    Eilola, Kari
    Swedish Meteorological and Hydrological Institute, Sweden.
    Legrand, Catherine
    Linnéuniversitetet, Fakulteten för Hälso- och livsvetenskap (FHL), Institutionen för biologi och miljö (BOM).
    Figueroa, Daniela
    Umeå University, Sweden.
    Paczkowska, Joanna
    Umeå University, Sweden.
    Lindehoff, Elin
    Linnéuniversitetet, Fakulteten för Hälso- och livsvetenskap (FHL), Institutionen för biologi och miljö (BOM).
    Tysklind, Mats
    Umeå University, Sweden.
    Elmgren, Ragnar
    Stockholm University, Sweden.
    Projected future climate change and Baltic Sea ecosystem management2015Ingår i: Ambio, ISSN 0044-7447, E-ISSN 1654-7209, Vol. 44, nr Supplement 3, s. S345-S356Artikel i tidskrift (Refereegranskat)
    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.

  • 4.
    Andersson, Kajsa
    Barometern OT.
    Svensson, Fredrik (Medarbetare/bidragsgivare)
    Linnéuniversitetet, Fakulteten för Hälso- och livsvetenskap (FHL), Institutionen för biologi och miljö (BOM).
    Forskningsprojekt: Alger ska rena utsläpp: "Algerna är en resurs som vi knappt använder"2014Ingår i: Baromtern, nr 9 augustiArtikel i tidskrift (Övrig (populärvetenskap, debatt, mm))
  • 5.
    Andreas, Bendroth
    Östra Småland.
    Legrand, Catherine (Medarbetare/bidragsgivare)
    Linnéuniversitetet, Fakulteten för Hälso- och livsvetenskap (FHL), Institutionen för biologi och miljö (BOM).
    Algblomningens positiva sidor lyftes fram2017Ingår i: Östra Småland, nr 31 Aug, s. 6-Artikel i tidskrift (Övrig (populärvetenskap, debatt, mm))
  • 6.
    Baltar, Federico
    et al.
    Linnéuniversitetet, Fakulteten för Hälso- och livsvetenskap (FHL), Institutionen för biologi och miljö (BOM). University of Otago, New Zealand.
    Legrand, Catherine
    Linnéuniversitetet, Fakulteten för Hälso- och livsvetenskap (FHL), Institutionen för biologi och miljö (BOM).
    Pinhassi, Jarone
    Linnéuniversitetet, Fakulteten för Hälso- och livsvetenskap (FHL), Institutionen för biologi och miljö (BOM).
    Cell-free extracellular enzymatic activity is linked to seasonal temperature changes: a case study in the Baltic Sea2016Ingår i: Biogeosciences, ISSN 1726-4170, E-ISSN 1726-4189, Vol. 13, nr 9, s. 2815-2821Artikel i tidskrift (Refereegranskat)
    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
    Högskolan i Kalmar, Naturvetenskapliga institutionen.
    Tamminen, T
    Lehtinen, S
    Uronen, P
    Granéli, Edna
    Högskolan i Kalmar, Naturvetenskapliga institutionen.
    Relative importance of the different negative effects of the toxic haptophyte Prymnesium parvum on Rhodomonas salina and Brachionus plicatilis2005Ingår i: Aquatic Microbial Ecology, ISSN 0948-3055, E-ISSN 1616-1564, Vol. 38, nr 3, s. 259-267Artikel i tidskrift (Refereegranskat)
    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
    Högskolan i Kalmar, Naturvetenskapliga institutionen.
    Photosynthetic capacity of the toxic dinoflagellates Dinophysis acuminata and Dinophysis acuta1994Ingår i: La Mer, Vol. 32, s. 107-117Artikel i tidskrift (Refereegranskat)
  • 9.
    Bonsdorff, Erik
    et al.
    Åbo Akademi University, Finland.
    Andersson, AgnetaUmeå University, Sweden.Elmgren, RagnarStockholm University, Sweden.Bidleman, TerryUmeå University, Sweden.Blenckner, ThorstenStockholm University, Sweden.Gorokhova, ElenaStockholm University, Sweden.Legrand, CatherineLinnéuniversitetet, Fakulteten för Hälso- och livsvetenskap (FHL), Institutionen för biologi och miljö (BOM).Wikner, JohanUmeå University, Sweden.
    Special Issue: Baltic Sea ecosystem-based management under climate change2015Samlingsverk (redaktörskap) (Refereegranskat)
  • 10.
    Broman, Elias
    et al.
    Linnéuniversitetet, Fakulteten för Hälso- och livsvetenskap (FHL), Institutionen för biologi och miljö (BOM).
    Brüsin, Martin
    Linnéuniversitetet, Fakulteten för Hälso- och livsvetenskap (FHL), Institutionen för biologi och miljö (BOM).
    Dopson, Mark
    Linnéuniversitetet, Fakulteten för Hälso- och livsvetenskap (FHL), Institutionen för biologi och miljö (BOM).
    Hylander, Samuel
    Linnéuniversitetet, Fakulteten för Hälso- och livsvetenskap (FHL), Institutionen för biologi och miljö (BOM).
    Oxygenation of anoxic sediments triggers hatching of zooplankton eggs2015Ingår i: Proceedings of the Royal Society of London. Biological Sciences, ISSN 0962-8452, E-ISSN 1471-2954, Vol. 282, nr 1817, artikel-id 20152025Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Many coastal marine systems have extensive areas with anoxic sediments and it is not well known how these conditions affect the benthic-pelagic coupling. Zooplankton lay their eggs in the pelagic zone, and some sink and lie dormant in the sediment, before hatched zooplankton return to the water column. In this study, we investigated how oxygenation of long-term anoxic sediments affects the hatching frequency of dormant zooplankton eggs. Anoxic sediments from the brackish Baltic Sea were sampled and incubated for 26 days with constant aeration whereby, the sediment surface and the overlying water were turned oxic. Newly hatched rotifers and copepod nauplii (juveniles) were observed after 5 and 8 days, respectively. Approximately 1.5 × 105 nauplii per m-2 emerged from sediment turned oxic compared to 0.02 × 105 m-2 from controls maintained anoxic. This study demonstrated that re-oxygenation of anoxic sediments activated a large pool of buried zooplankton eggs, strengthening the benthic-pelagic coupling of the system. Modelling of the studied anoxic zone suggested that a substantial part of the pelagic copepod population can derive from hatching of dormant eggs. We suggest that this process should be included in future studies to understand population dynamics and carbon flows in marine pelagic systems.

  • 11.
    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, Fakulteten för Hälso- och livsvetenskap (FHL), Institutionen för biologi och miljö (BOM).
    The interactive microbial ocean2017Ingår i: Nature Microbiology, E-ISSN 2058-5276, Vol. 2, artikel-id 16255Artikel i tidskrift (Refereegranskat)
    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.

  • 12.
    Brutemark, Andreas
    et al.
    Högskolan i Kalmar, Naturvetenskapliga institutionen.
    Lindehoff, Elin
    Högskolan i Kalmar, Naturvetenskapliga institutionen.
    Granéli, Edna
    Högskolan i Kalmar, Naturvetenskapliga institutionen.
    Granéli, Wilhelm
    Carbon isotope signature variability among cultured microalgae: Influence of species, nutrients and growth2009Ingår i: Journal of Experimental Marine Biology and Ecology, ISSN 0022-0981, E-ISSN 1879-1697, Vol. 372, nr 1-2, s. 98-105Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this study we have investigated whether the carbon isotopic signature differs between different groups and species of marine phytoplankton depending on growth phase, nutrient conditions and salinity. The 15 investigated algal species, representing the Bacillariophyceae, Chlorophyceae, Cryptophyceae, Cyanophyceae, Dinophyceae and Haptophyceae classes were grown in batch monocultures and analysed for delta(13)C in both exponential and stationary phase. For all the cultured species, delta(13)C signatures ranged from -23.5 parts per thousand (Imantonia sp.) to - 12.3 parts per thousand (Nodulania spumigena) in the exponential phase and from - 18.8 parts per thousand (Amphidinium carterae) to - 8.0 parts per thousand (Anabaena lemmermannii) in the stationary phase. Three species (Dunaliella tertiolecta, Rhodomonas sp.. Heterocapsa triquetra) were also grown under nutrient sufficient and nitrogen or phosphorus deficient conditions. Nitrogen limitation resulted in a more negative delta(13)C signature, whereas no effect could be observed during phosphorus limitation compared to nutrient sufficient conditions. Growth of Prymnesium parvum in two different salinities resulted in a more negative delta(13)C signature in the 26 parts per thousand-media compared to growth in 7 parts per thousand-media. Our results show that the carbon isotopic signature of phytoplankton may be affected by salinity, differ among different phytoplankton species, between exponential and stationary phase, as well as between nutrient treatments.

  • 13.
    Carlsson, Per
    et al.
    Lunds Universitet.
    Granéli, Edna
    Linnéuniversitetet, Fakultetsnämnden för naturvetenskap och teknik, Institutionen för naturvetenskap, NV.
    Granéli, Wilhelm
    Lunds Universitet.
    Gonzalez Rodriguez, Eliane
    IEAPM, Arraial do Cabo, Brazil .
    Carvalho, Wanderson F
    IEAPM, Arraial do Cabo, Brazil .
    Brutemark, Andreas
    Linnéuniversitetet, Fakultetsnämnden för naturvetenskap och teknik, Institutionen för naturvetenskap, NV.
    Lindehoff, Elin
    Linnéuniversitetet, Fakultetsnämnden för naturvetenskap och teknik, Institutionen för naturvetenskap, NV.
    Bacterial and phytoplankton nutrient limitation in tropical marine waters, and a coastal lake in Brazil2012Ingår i: Journal of Experimental Marine Biology and Ecology, ISSN 0022-0981, E-ISSN 1879-1697, Vol. 418-419, s. 37-45Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Bioassay experiments were performed two times (with 2 years in between) in order to investigate if nitrogen(N, ammonium), phosphorus (P, phosphate) and carbon (C, glucose) additions would stimulate the growth ofbacteria and phytoplankton differently in three different tropical aquatic environments. The water and theirindigenous microbial communities were taken from a freshwater coastal lake (Cabiunas), a coastal (Anjos),and an offshore marine station (Sonar) in the Atlantic outside Cabo Frio, Rio de Janeiro State, Brazil. Ammonium,phosphate and glucose were added alone or in combination to triplicate bottles. In the lake, P seemedto be the primary limiting factor during the first experiment, since both bacterial production and phytoplanktongrowth was stimulated by the P addition. Two years later, however, addition of P inhibited phytoplanktongrowth. During both years, C was closely co-limiting for bacteria since CP additions increased the responseconsiderably. For both the coastal and offshore seawater stations, phytoplankton growth was clearly stimulatedby N addition in both years and the bacteria responded either to the P, N or C additions (alone or incombination). To conclude, the results from these tropical aquatic systems show that it is possible that phytoplanktonand bacteria may compete for a common resource (P) in lakes, but can be limited by different inorganicnutrients in marine waters as well as lakes, suggesting that phytoplankton and bacteria do notnecessarily compete for the same growth limiting nutrient in these environments.

  • 14. Chauton, M
    et al.
    Tillstone, G
    Legrand, Catherine
    Högskolan i Kalmar, Naturvetenskapliga institutionen.
    Johnsen, G
    Changes in pigmentation, bio-optical characteristics and photophysiology, during phytoflagellate succession in mesocosms2004Ingår i: Journal of Plankton Research, ISSN 0142-7873, E-ISSN 1464-3774, Vol. 26, nr 3, s. 315-324Artikel i tidskrift (Refereegranskat)
    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.

  • 15. Delmas, D
    et al.
    Legrand, Catherine
    Högskolan i Kalmar, Naturvetenskapliga institutionen.
    Béchemin, C
    Collinot, C
    Exoproteolytic activity determined by flow injection analysis: potential importance for bacterial growth in coastal marine ponds1994Ingår i: Aquatic Living Resources, ISSN 0990-7440, E-ISSN 1765-2952, Vol. 7, nr 1, s. 17-24Artikel i tidskrift (Refereegranskat)
    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.

  • 16. Doblin, M.
    et al.
    Legrand, Catherine
    Högskolan i Kalmar, Naturvetenskapliga institutionen.
    Carlsson, Per
    Hummert, Christian
    Granéli, Edna
    Högskolan i Kalmar, Naturvetenskapliga institutionen.
    Hallegraeff, G.
    Uptake of humic substances by the toxic dinoflagellate Alexandrium catenella2001Ingår i: Intergov. Oceanographic Commission of UNESCO, Paris 2001 336-339 / [ed] GM Hallegraeff, SI Blackburn, CJ Bolch, RJ Lewis, 2001Konferensbidrag (Refereegranskat)
  • 17.
    Ekvall, Mikael T.
    et al.
    Lund University.
    Hylander, Samuel
    Linnéuniversitetet, Fakulteten för Hälso- och livsvetenskap (FHL), Institutionen för biologi och miljö (BOM).
    Walles, Tim
    Lund University.
    Yang, Xi
    Lund University.
    Hansson, Lars-Anders
    Lund University.
    Diel vertical migration, size distribution and photoprotection in zooplankton as response to UV-A radiation2015Ingår i: Limnology and Oceanography, ISSN 0024-3590, E-ISSN 1939-5590, Vol. 60, nr 6, s. 2048-2058Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The transparency regulator hypothesis (TRH) proposes that ultraviolet radiation (UVR) is a main driving force behind diel vertical migration (DVM) of zooplankton in clearwater systems. While previous studies have mainly studied DVM in relation to the TRH on a spatial scale across systems we here focus on long-term trends in a single system in order to assess if UVR explains observed patterns in DVM. We show that the strength of DVM in Daphnia is to a large extent explained by UVR and we demonstrate a tipping point at which the UVR intensity drastically affects the strength of DVM in Daphnia. In contrast, the strength of DVM could not be explained by the level of UVR among calanoid copepods. The amount of photoprotective compounds did not differ between zooplankton found at different depths indicating that zooplankton do not change their vertical position in relation to the amount of accumulated photoprotective compounds. In addition, we show that both Daphnia and calanoid copepods display patterns of size structured migration.

  • 18.
    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
    Linnéuniversitetet, Fakulteten för Hälso- och livsvetenskap (FHL), Institutionen för biologi och miljö (BOM).
    Andersson, Agneta
    Umeå University ; Umeå Marine Sciences Centre.
    Allochthonous Carbon-a Major Driver of Bacterioplankton Production in the Subarctic Northern Baltic Sea2016Ingår i: Microbial Ecology, ISSN 0095-3628, E-ISSN 1432-184X, Vol. 71, nr 4, s. 789-801Artikel i tidskrift (Refereegranskat)
    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.

  • 19. Fistarol, Giovana
    et al.
    Legrand, Catherine
    Högskolan i Kalmar, Naturvetenskapliga institutionen.
    Granéli, Edna
    Högskolan i Kalmar, Naturvetenskapliga institutionen.
    Allelopathic effect of Prymnesium parvum on a natural plankton community2003Ingår i: Marine Ecology Progress Series, ISSN 0171-8630, E-ISSN 1616-1599, Vol. 255, s. 115-125Artikel i tidskrift (Refereegranskat)
    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.

  • 20. Fistarol, Giovana
    et al.
    Legrand, Catherine
    Högskolan i Kalmar, Naturvetenskapliga institutionen.
    Rengefors, Karin
    Granéli, Edna
    Högskolan i Kalmar, Naturvetenskapliga institutionen.
    Temporary cyst formation in phytoplankton: a response to allelopathic competitors?2004Ingår i: Environmental Microbiology, ISSN 1462-2912, E-ISSN 1462-2920, Vol. 6, nr 8, s. 791-798Artikel i tidskrift (Refereegranskat)
    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.

  • 21. Fistarol, Giovana
    et al.
    Legrand, Catherine
    Högskolan i Kalmar, Naturvetenskapliga institutionen.
    Selander, Erik
    Hummert, Christian
    Stolte, Willem
    Högskolan i Kalmar, Naturvetenskapliga institutionen.
    Granéli, Edna
    Högskolan i Kalmar, Naturvetenskapliga institutionen.
    Allelopathy in Alexandrium spp.: effect on a natural plankton community and on algal monocultures2004Ingår i: Aquatic Microbial Ecology, ISSN 0948-3055, E-ISSN 1616-1564, Vol. 35, nr 1, s. 45-56Artikel i tidskrift (Refereegranskat)
    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.

  • 22. Fistarol, GO
    et al.
    Legrand, Catherine
    Högskolan i Kalmar, Naturvetenskapliga institutionen.
    Granéli, Edna
    Högskolan i Kalmar, Naturvetenskapliga institutionen.
    Allelopathic effect on a nutrient-limited phytoplankton species2005Ingår i: Aquatic Microbial Ecology, ISSN 0948-3055, E-ISSN 1616-1564, Vol. 41, nr 2, s. 153-161Artikel i tidskrift (Refereegranskat)
    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.

  • 23.
    Fridolfsson, Emil
    et al.
    Linnéuniversitetet, Fakulteten för Hälso- och livsvetenskap (FHL), Institutionen för biologi och miljö (BOM).
    Lindehoff, Elin
    Linnéuniversitetet, Fakulteten för Hälso- och livsvetenskap (FHL), Institutionen för biologi och miljö (BOM).
    Legrand, Catherine
    Linnéuniversitetet, Fakulteten för Hälso- och livsvetenskap (FHL), Institutionen för biologi och miljö (BOM).
    Hylander, Samuel
    Linnéuniversitetet, Fakulteten för Hälso- och livsvetenskap (FHL), Institutionen för biologi och miljö (BOM).
    Thiamin (vitamin B1) content in phytoplankton and zooplankton in the presence of filamentous cyanobacteria2018Ingår i: Limnology and Oceanography, ISSN 0024-3590, E-ISSN 1939-5590, Vol. 63, nr 6, s. 2423-2435Artikel i tidskrift (Refereegranskat)
    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.

  • 24. Glibert, P A
    et al.
    Legrand, Catherine
    Högskolan i Kalmar, Naturvetenskapliga institutionen.
    The diverse nutrient strategies of Hamful Algae: Focus on osmotrophy2006Ingår i: Ecology of Harmful Algae: Part C, Springer Berlin/Heidelberg, 2006, s. 163-175Kapitel i bok, del av antologi (Övrigt vetenskapligt)
  • 25. Glibert, PA
    et al.
    Granéli, Edna
    Högskolan i Kalmar, Naturvetenskapliga institutionen.
    Legrand, Catherine
    Högskolan i Kalmar, Naturvetenskapliga institutionen.
    Salomon, Paulo
    Högskolan i Kalmar, Naturvetenskapliga institutionen.
    and, 55 co-authors
    Ocean urea fertilization for carbon credits poses high ecological risks2008Ingår i: Marine Pollution Bulletin, ISSN 0025-326X, E-ISSN 1879-3363, Vol. 56, nr 6, s. 1049-1056Artikel i tidskrift (Refereegranskat)
    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.

  • 26.
    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
    Linnéuniversitetet, Fakulteten för Hälso- och livsvetenskap (FHL), Institutionen för biologi och miljö (BOM).
    Bunse, Carina
    Linnéuniversitetet, Fakulteten för Hälso- och livsvetenskap (FHL), 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, Fakulteten för Hälso- och livsvetenskap (FHL), 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.
    Physical barriers and environmental gradients cause spatial and temporal genetic differentiation of an extensive algal bloom2016Ingår i: Journal of Biogeography, ISSN 0305-0270, E-ISSN 1365-2699, Vol. 43, nr 6, s. 1130-1142Artikel i tidskrift (Refereegranskat)
    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.

  • 27.
    Granéli, Edna
    et al.
    Högskolan i Kalmar, Naturvetenskapliga institutionen.
    Carlsson, Per
    Legrand, Catherine
    Högskolan i Kalmar, Naturvetenskapliga institutionen.
    The ecology of DSP (Diarrhetic Shellfish Poisoning) toxin producing dinoflagellates1997Ingår i: Brazilian Society for Microbiology ICOME In: Martins MT, Seti MIZ, Tiedje JM, Hagler LCN, Dobereiner, J, Sanchez SS (eds) Progress in Microbial Ecol, 1997Konferensbidrag (Refereegranskat)
  • 28.
    Granéli, Edna
    et al.
    Högskolan i Kalmar, Naturvetenskapliga institutionen.
    Carlsson, Per
    Legrand, Catherine
    Högskolan i Kalmar, Naturvetenskapliga institutionen.
    The role of C, N and P in dissolved and particulate organic matter as a nutrient source for phytoplankton growth, including toxic species1999Ingår i: Aquatic Ecology, ISSN 1386-2588, E-ISSN 1573-5125, Vol. 33, s. 17-27Artikel i tidskrift (Refereegranskat)
    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.

  • 29.
    Granéli, Edna
    et al.
    Linnéuniversitetet, Fakultetsnämnden för naturvetenskap och teknik, Institutionen för naturvetenskap, NV.
    Esplund, Christina
    Linnéuniversitetet, Fakultetsnämnden för naturvetenskap och teknik, Institutionen för naturvetenskap, NV.
    Lindehoff, Elin
    Linnéuniversitetet, Fakultetsnämnden för naturvetenskap och teknik, Institutionen för naturvetenskap, NV.
    Brutemark, Andreas
    Novia University of Applied Sciences, Ekenäs, Finland.
    Minimizing economical losses with the help of “real-time” algal surveillance2012Ingår i: Eco-Tech 2012 Proceedings, 2012, s. 550-555Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    Cyanobacterial blooms covering almost the entire Baltic Sea is a yearly feature during July-August. For the tourism industry at Öland island, SE Sweden, the economical losses during the summer 2005 amounted to 17-23 million euros. Remote sensing satellite images show that all the Öland beaches are covered with decomposing algae. In reality, these blooms rarely reach the western side of the island. To more accurately inform the public on the quality of the water for swimming, with the help of volunteers, a daily real-time surveillance of the algal densities on the beaches was performed. The volunteers (from 15 years old to pensioners) were trained at the Linnaeus University, from simple laboratory techniques, to more complicated ones such as identification and enumeration of the toxic cyanobacteria species. By latest 9.00 a.m., the public had access to information on the algal situation on 17 beaches. We could show that: 1) although remote sensing images showed Öland being surrounded by the blooms, our surveillance showed no algal accumulations on the beaches 2) that the real-time warning system boosted public confidence in the local water quality and during the first “Miss Algae”-summer 2006, the economical losses by the tourism industry turned in profits, the gain amounting to 17 million euros, 3) this kind of real-time surveillance is economical feasible due to low-costs involved, but also, the project has a great social value for the volunteers who mostly were pensioners. The volunteers who participated in “Miss Algae” had a good knowledge about the area they monitored (as their houses are located nearby) and could disseminate knowledge to the public in these areas. This kind of project also render a lot of interest regional, national and international, and can be used in advertising campaigns to increase tourism in the areas affected by algal blooms.

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  • 30.
    Granéli, Edna
    et al.
    Högskolan i Kalmar, Naturvetenskapliga institutionen.
    Esplund-Lindquist, Christina
    Högskolan i Kalmar, Naturvetenskapliga institutionen.
    Legrand, Catherine
    Högskolan i Kalmar, Naturvetenskapliga institutionen.
    Franzén, H
    Granéli, C
    Minimizing economical losses with the help of “real-time” HAB surveillance2008Ingår i: ISSHA and IOC of UNESCO / [ed] Moestrup Ø, Enevoldsen H, Sellner K, Tester P, Copenhagen, 2008Konferensbidrag (Refereegranskat)
  • 31.
    Granéli, Edna
    et al.
    Högskolan i Kalmar, Naturvetenskapliga institutionen.
    Legrand, Catherine
    Högskolan i Kalmar, Naturvetenskapliga institutionen.
    FATE-Transfer and fate of Harmful Algal Bloom (HAB) toxins in European marine waters2005Rapport (Övrigt vetenskapligt)
  • 32.
    Granéli, Edna
    et al.
    Högskolan i Kalmar, Naturvetenskapliga institutionen.
    Legrand, Catherine
    Högskolan i Kalmar, Naturvetenskapliga institutionen.
    Harmful algal blooms: causes, consequences for the economy, human health and the European Policy2001Ingår i: European Commission, EUR 19408 Research in enclosed seas series / [ed] Barthel K-G and 12 other authors, Hamburg, 2001Konferensbidrag (Refereegranskat)
  • 33.
    Granéli, Edna
    et al.
    Högskolan i Kalmar, Naturvetenskapliga institutionen.
    Legrand, Catherine
    Högskolan i Kalmar, Naturvetenskapliga institutionen.
    Interactions between nitrogen: phosphorus ratios and concentrations and the growth and toxin production of harmful phytoplankton2000Ingår i: European Commission. Project synopses I. Marine processes, ecosystems and interactions, Hamburg, 2000Konferensbidrag (Refereegranskat)
  • 34.
    Hansson, Lars-Anders
    et al.
    Lund University.
    Bianco, Giuseppe
    Lund University.
    Ekvall, Mikael
    Lund University.
    Heuschele, Jan
    Lund University.
    Hylander, Samuel
    Linnéuniversitetet, Fakulteten för Hälso- och livsvetenskap (FHL), Institutionen för biologi och miljö (BOM).
    Yang, Xi
    Lund University.
    Instantaneous threat escape and differentiated refuge demand among zooplankton taxa2016Ingår i: Ecology, ISSN 0012-9658, E-ISSN 1939-9170, Vol. 97, nr 2, s. 279-285Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Most animals, including aquatic crustacean zooplankton, perform strong avoidance movements when exposed to a threat, such as ultraviolet radiation (UVR). We here show that the genera Daphnia and Bosmina instantly adjust their vertical position in the water in accordance with the present UVR threat, i.e., seek refuge in deeper waters, whereas other taxa show less response to the threat. Moreover, Daphnia repeatedly respond to UVR pulses, suggesting that they spend more energy on movement than more stationary taxa, for example, during days with fluctuating cloud cover, illustrating nonlethal effects in avoiding UVR threat. Accordingly, we also show that the taxa with the most contrasting behavioral responses differ considerably in photoprotection, suggesting different morphological and behavioral strategies in handling the UVR threat. In a broader context, our studies on individual and taxa specific responses to UVR provide insights into observed spatial and temporal distribution in natural ecosystems.

  • 35.
    Hansson, Lars-Anders
    et al.
    Lunds universitet.
    Hylander, Samuel
    Lunds universitet.
    Effects of ultraviolet radiation on pigmentation, photoenzymatic repair, behavior, and community ecology of zooplankton2009Ingår i: Photochemical and Photobiological Sciences, ISSN 1474-905X, E-ISSN 1474-9092, Vol. 8, nr 9, s. 1266-1275Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this report, we provide a perspective on how zooplankton are able to respond to present and future levels of ultraviolet (UV) radiation, a threat that has been present throughout evolutionary time. To cope with this threat, zooplankton have evolved several adaptations including behavioral responses, repair systems, and accumulation of photoprotective compounds. Common photoprotective compounds include melanins and carotenoids, which are true pigments, but also mycosporine-like amino acids (MAAs) and several other substances, and different taxa use different blends of these compounds. It is not only the level of UV radiation, however, that determines the amount of photoprotective compounds incorporated by the zooplankton, but also other environmental factors, such as predation and supply rate of the compounds. Furthermore, compared to taxa that are less pigmented, those taxa with ample pigmentation are generally less likely to exhibit diel migration. The photoenzymatic repair of UV damages seems to be more efficient at intermediate temperature than at low and high temperatures, suggesting that it is less useful at high and low latitudes, where UV radiation is often extremely high. While predicted future increases in UV radiation are expected to substantially affect many processes, recent studies show that most zooplankton taxa are well adapted to cope with such increases, either by UV avoidance behavior or by incorporation of photoprotective compounds. Hence, we conclude that future increase in UV radiation will have only moderate direct effects on zooplankton biomass and community dynamics.

  • 36.
    Hansson, Lars-Anders
    et al.
    Lunds universitet.
    Hylander, Samuel
    Lunds universitet.
    Size-structured risk assessments govern Daphnia migration2009Ingår i: Proceedings of the Royal Society of London. Biological Sciences, ISSN 0962-8452, E-ISSN 1471-2954, Vol. 276, nr 1655, s. 331-336Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    One of the more fascinating phenomena in nature is animal mass migrations and in oceans and freshwaters, diel variations in depth distribution of zooplankton are a phenomenon that has intrigued scientists for more than a century. In our study, we show that zooplankton are able to assess the threat level of ultraviolet radiation and adjust their depth distribution to this level at a very fine tuned scale. Moreover, predation risk induces a size-structured depth separation, such that small individuals, which we show are less vulnerable to predation than larger, make a risk assessment and continue feeding in surface waters during day, offering a competitive release from down-migrating larger animals. Hence, we mechanistically show that such simple organisms as invertebrate zooplankton are able to make individual, size-specific decisions regarding how to compromise between threats from both predators and UV radiation, and adjust their diel migratory patterns accordingly.

  • 37.
    Hansson, Lars-Anders
    et al.
    Lunds universitet.
    Hylander, Samuel
    Lunds universitet.
    Dartnall, Herbert J. G.
    Lidstrom, Sven
    Svensson, Jan-Erik
    High zooplankton diversity in the extreme environments of the McMurdo Dry Valley lakes, Antarctica2012Ingår i: Antarctic Science, ISSN 0954-1020, E-ISSN 1365-2079, Vol. 24, nr 2, s. 131-138Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The McMurdo Dry Valley lakes of Antarctica constitute some of the harshest and most isolated freshwater environments on Earth which might be expected to limit the biogeographical expansion of many organisms. Despite this, we found that the biodiversity of rotifer zooplankton is the highest ever recorded on the Antarctic mainland. We identified in total nine rotifer taxa, of which six are new to the Antarctic continent, in Lake Hoare, and also the first sub- adult crustacean copepod belonging to the genus Boeckella. A possible explanation for the high biodiversity is that many of the recorded species have arrived in the region in relatively recent times and then established invasive populations, suggesting that their distribution pattern was previously limited only by biogeographical borders. Interestingly, we show that the cosmopolitan rotifer taxa identified are relatively abundant, suggesting that they have established viable populations. Hence, our study suggests that the biogeographical maps have to be redrawn for several species.

  • 38.
    Hansson, Lars-Anders
    et al.
    Lund University.
    Hylander, Samuel
    Lund University.
    Sommaruga, Ruben
    University of Innsbruck.
    Escape from UV threats in zooplankton: A cocktail of behavior and protective pigmentation2007Ingår i: Ecology, ISSN 0012-9658, E-ISSN 1939-9170, Vol. 88, nr 8, s. 1932-1939Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In order to avoid environmental threats, organisms may respond by altering behavior or phenotype. Using experiments performed in high-latitude Siberia and in temperate Sweden, we show for the first time that, among freshwater crustacean zooplankton, the defense against threats from ultraviolet radiation (UV) is a system where phenotypic plasticity and behavioral escape mechanisms function as complementary traits. Freshwater copepods relied mainly on accumulating protective pigments when exposed to UV radiation, but Daphnia showed strong behavioral responses. Pigment levels for both Daphnia and copepods were generally higher at higher latitudes, mirroring different UV threat levels. When released from the UV threat, Daphnia rapidly reduced (within 10 days) their UV protecting pigmentation—by as much as 40%—suggesting a cost in maintaining UV protective pigmentation. The evolutionary advantage of protective pigments is, likely, the ability to utilize the whole water column during daytime; conversely, since the amount of algal food is generally higher in surface waters, unpigmented individuals are restricted to a less preferred feeding habitat in deeper waters. Our main conclusion is that different zooplankton taxa, and similar taxa at different latitudes, use different mixes of behavior and pigments to respond to UV radiation.

  • 39.
    Heuschele, Jan
    et al.
    Tech Univ Denmark, Denmark.
    Ceballos, Sara
    Tech Univ Denmark, Denmark;Spanish Inst Oceanog, Spain.
    Borg, Christian Marc Andersen
    Tech Univ Denmark, Denmark.
    Bjaerke, Oda
    Univ Oslo, Norway.
    Isari, Stamatina
    CSIC, Spain;Hellenic Centre for Marine Research, Greece.
    Lasley-Rasher, Rachel
    Georgia Inst Technol, USA;Univ Maine, USA.
    Lindehoff, Elin
    Linnéuniversitetet, Fakulteten för Hälso- och livsvetenskap (FHL), Institutionen för biologi och miljö (BOM). Umeå university.
    Souissi, Anissa
    University of Lille Nord de France, France.
    Souissi, Sami
    University of Lille Nord de France, France.
    Titelman, Josefin
    Univ Oslo, Norway.
    Non-consumptive effects of predator presence on copepod reproduction: insights from a mesocosm experiment2014Ingår i: Marine Biology, ISSN 0025-3162, E-ISSN 1432-1793, Vol. 161, nr 7, s. 1653-1666Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Reproduction in planktonic animals depends on numerous biotic and abiotic factors. One of them is predation pressure, which can have both directconsumptive effects on population density and sex ratio, and non-consumptive effects, for example on mating and migration behaviour. In copepods, predatorvulnerability depends on their sex, motility pattern and mating behaviour. Therefore, copepods can be affected at multiple stages during the mating process. We investigated the reproductive dynamics of the estuarine copepod Eurytemora affinis in the presence and absence of its predator the mysid Neomysis integer in a mesocosm experiment. We found that the proportion of ovigerous females decreased in the presence of predators. This shift was not caused by differential predation as the absolute number of females was unaffected by mysid presence. Presence of predators reduced the ratio of males to non-ovigerous females, but not by predation of males. Our combined results suggest that the shift from ovigerous to non-ovigerous females under the presence of predators was caused by either actively delayed egg production or by shedding of egg sacs. Nauplii production was initially suppressed in the predation treatment, but increased towards the end of the experiment. The proportion of fertilized females was similar in both treatments, but constantly fell behind model predictions using a random mating model. Our results highlight the importance of non-consumptive effects of predators on copepod reproduction and hence on population dynamics.

  • 40.
    Hogland, William
    et al.
    Högskolan i Kalmar, Naturvetenskapliga institutionen.
    Pohl, Eva
    Högskolan i Kalmar, Naturvetenskapliga institutionen.
    MARQUES, MARCIA
    Högskolan i Kalmar, Naturvetenskapliga institutionen.
    The resurrection of used thermoplastics to minimize the lifecycle environmental impact of building materials2001Ingår i: Cleaner Production Proceedings 7th Roundtable on Cleaner Production, Sustainable Production and Consumption Systems-Cooperation for Change, Lund, 2-4 May, 2001Konferensbidrag (Refereegranskat)
  • 41.
    Hugerth, Luisa W.
    et al.
    KTH Royal Institute of Technology, Sweden.
    Larsson, John
    Linnéuniversitetet, Fakulteten för Hälso- och livsvetenskap (FHL), Institutionen för biologi och miljö (BOM).
    Alneberg, Johannes
    KTH Royal Institute of Technology, Sweden.
    Lindh, Markus V.
    Linnéuniversitetet, Fakulteten för Hälso- och livsvetenskap (FHL), Institutionen för biologi och miljö (BOM).
    Legrand, Catherine
    Linnéuniversitetet, Fakulteten för Hälso- och livsvetenskap (FHL), Institutionen för biologi och miljö (BOM).
    Pinhassi, Jarone
    Linnéuniversitetet, Fakulteten för Hälso- och livsvetenskap (FHL), Institutionen för biologi och miljö (BOM).
    Andersson, Anders F.
    KTH Royal Institute of Technology, Sweden.
    Metagenome-assembled genomes uncover a global brackish microbiome2015Ingår i: Genome Biology, ISSN 1465-6906, E-ISSN 1474-760X, Vol. 16, artikel-id 279Artikel i tidskrift (Refereegranskat)
    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.

  • 42.
    Hultman, Birgitta
    Barometern OT .
    Hållbara transporter nästa mål för Linné2018Ingår i: Barometern OT, Vol. 16 April, s. 8-Artikel i tidskrift (Övrig (populärvetenskap, debatt, mm))
  • 43. Hummert, Christian
    et al.
    Reichelt, M
    Legrand, Catherine
    Högskolan i Kalmar, Naturvetenskapliga institutionen.
    Granéli, Edna
    Högskolan i Kalmar, Naturvetenskapliga institutionen.
    Luckas, B
    Rapid clean-up and effective sample preparation procedure for unambiguous determination of the cyclic peptides microcystin and nodularin1999Ingår i: Chromatographia, ISSN 0009-5893, E-ISSN 1612-1112, Vol. 50, nr 3-4, s. 173-180Artikel i tidskrift (Refereegranskat)
    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..

  • 44.
    Hylander, Samuel
    Länsstyrelsen i Skåne län.
    Biotopkartering av Bivarödsån 2003: Naturvärden och behov av restaureringsåtgärder i ett biflöde till Helge å2005Rapport (Övrigt vetenskapligt)
    Abstract [sv]

    Denna rapport beskriver resultaten från en biotopkartering av Bivarödsån. Den karterade vattendragssträckan är en del av Helge ås avrinningsområde och flyter genom Osby och Östra Göinge kommuner. Huvudsyftet med projektet var att ge ett underlag för att kunna bedöma vilka biologiska återställningsåtgärder som är nödvändiga i vattendraget för att återfå den fauna som försvunnit på grund av försurning. Genom kalkning av vattendraget ges möjlighet för utslagna arter att återkomma till området. För att detta ska vara möjligt behöver dock även andra hotfaktorer som förändrad markanvändning, vandringhinder, rensning mm. identifieras och eventuellt åtgärdas. Denna biotopkartering ger en god översikt av Bivarödsån både vad det gäller restaureringsbehov och naturvärden.

    Fältarbetet utfördes september 2003 av Ekologgruppen i Landskrona AB på uppdrag av Länsstyrelsen i Skåne län. Flygbildstolkning har utförts av Marie Eriksson på Länsstyrelsen i Skåne län. Rapportskrivning, beräkningar och kvalitetssäkring av materialet har utförts av Samuel Hylander på Länsstyrelsen i Skåne län. Projektet är bekostat med medel från Naturvårdsverket inom ramen för arbetet med biologisk återställning.

    Biotopkarteringar av vattendrag utgör dessutom viktiga kunskapsunderlag inom arbetet med EU:s ramdirektiv för vatten där utgångspunkten är att ”god ekologisk status” ska upprätthållas i våra sjöar och vattendrag. Resultaten beskriver bl.a. åtgärdsbehov och identifierade nyckelbiotoper och kan därmed användas för att realisera miljökvalitetsmålet ”Levande sjöar och vattendrag”. Rapporten riktar sig främst till handläggare vid kommuner och länsstyrelser men även andra intresserade.

  • 45.
    Hylander, Samuel
    Länsstyrelsen i Skåne län.
    Biotopkartering av Klingstorpabäcken 2003: Naturvärden och behov av restaureringsåtgärder i ett biflöde till Rönne å2005Rapport (Övrigt vetenskapligt)
    Abstract [sv]

    Denna rapport beskriver resultaten från biotopkarteringen av Klingstorpabäcken i Klippans kommun, 2003. Vattendraget, som är en del av Rönne ås avrinningsområde, anses vara relativt naturligt och rent och hyser ett bestånd av den sällsynta och fridlysta arten flodpärlmussla (Margaritifera margaritifera). Arten är klassad som sårbar (VU) i ArtDatabankens rödlista.

    Huvudsyftet med biotopkarteringen var att ge ett underlag för att kunna bedöma vilka biologiska återställningsåtgärder som är nödvändiga i Klingstorpabäcken för att återfå ett reproducerande bestånd av flodpärlmussla. Projektet skulle även ge en bild av vilka naturvärden och skyddsvärda biotoper som finns i området samt ge underlag till bedömningen om vattendraget har potential att bli upptaget som nationellt särskilt värdefullt vattendrag.

    Biotopkarteringar av vattendrag utgör viktiga kunskapsunderlag inom arbetet med EU:s ramdirektiv för vatten där utgångspunkten är att ”god ekologisk status” ska upprätthållas i våra sjöar och vattendrag. Resultaten kan även användas för att realisera miljökvalitetsmålet ”Levande sjöar och vattendrag”.

    Fältarbetet utfördes juni-juli 2003 av Samuel Hylander inom ramen för en praktikkurs vid Lunds universitet. Handledare var Marie Eriksson på Länsstyrelsen i Skåne län.

  • 46.
    Hylander, Samuel
    Länsstyrelsen i Skåne län.
    Biotopkartering av Röke å och Humlesjöbäcken 2002: Naturvärden och behov av restaureringsåtgärder i ett biflöde till Almaån/Helge å2005Rapport (Övrigt vetenskapligt)
    Abstract [sv]

    Denna rapport beskriver resultaten av en biotopkartering i Röke å och Humlesjöbäcken i Helge ås vattensystem. Huvudsyftet med projektet var att ge ett underlag för att kunna bedöma vilka biologiska återställningsåtgärder som är nödvändiga i vattendragen för att återfå den fauna som försvunnit på grund av försurning. Ett exempel på en sådan försvunnen art är flodpärlmusslan (Margaritifera margaritifera) som finns nedströms i Hörlingeån och som tidigare troligen även har funnits i Röke å. Genom kalkning av vattendraget ges möjlighet för utslagna arter att återkomma till området. För att detta ska vara möjligt behöver dock även andra hotfaktorer som förändrad markanvändning, vandringhinder, rensning mm. identifieras och eventuellt åtgärdas. Denna biotopkartering ger en god översikt av Röke å och Humlesjöbäcken både vad det gäller restaureringsbehov och naturvärden.

    Fältarbetet utfördes under augusti och september 2002 av Ekologgruppen i Landskrona AB, på uppdrag av Länsstyrelsen i Skåne län. Flygbildstolkning och digitalisering av närmiljö och omgivning har utförts av Marie Eriksson på Länsstyrelsen i Skåne län. Övrig digitalisering har utförts av Johan Bendtsen på Länsstyrelsen i Skåne län. Rapportskrivning, GIS-hantering, beräkningar och kvalitetssäkring av materialet har utförts av Samuel Hylander på Länsstyrelsen i Skåne län.

    Projektet är bekostat med medel från Naturvårdsverket inom ramen för arbetet med biologisk återställning.

    Biotopkarteringar av vattendrag utgör dessutom viktiga kunskapsunderlag inom arbetet med EU:s ramdirektiv för vatten där utgångspunkten är att ”god ekologisk status” ska upprätthållas i våra sjöar och vattendrag. Resultaten beskriver bl.a. åtgärdsbehov och identifierade nyckelbiotoper och kan därmed användas för att realisera miljökvalitetsmålet ”Levande sjöar och vattendrag”. Rapporten riktar sig främst till handläggare vid kommuner och länsstyrelser men även andra intresserade.

  • 47.
    Hylander, Samuel
    Lund University, Sweden.
    Flodpärlmusslans känslighet för predation från kräftor: effekt i jämförelse med andra hotfaktorer i ett skånskt vattendrag2004Rapport (Övrigt vetenskapligt)
    Abstract [sv]

    Flodpärlmusslan (Margaritifera margaritifera) är idag en utrotningshotad art. I Sverige har den försvunnit från ca en tredjedel av de sedan tidigare kända lokalerna och dess rekrytering är utslagen på ca 75 % av dessa lokaler. Tidigare försvann musslan på grund av omfattande pärlfiske men idag är andra faktorer så som t. ex. försurning och övergödning viktigare och många studier har beaktat dessa problem. Denna studie tar upp effekten av predation från kräftor, i synnerhet från signalkräfta (Pacifastacus lenisculus), på juvenila musslor. Detta är ett område som tidigare ignorerats.

    Eftersom flodpärlmusslan är fridlyst användes i försöken istället den spetsiga målarmusslan (Unio tumidus) som har liknande morfologi och skaltjocklek (vid skånska förhållanden) som flodpärlmusslan. Även den stora dammsnäckan (Lymnaea stagnalis) har använts i vissa jämförande försök. För att sätta in resultaten i ett större sammanhang har även inventeringar utförts i ett vattendrag i Skåne med förekomst av flodpärlmussla (Klingstorpabäcken). Inventeringarna har syftat till att förstå flodpärlmusslans reproduktionsproblem och har bland annat inneburit musselinventering, kräftprovfiske, elfiske, bottensubstratprovtagning och provtagning gällande kemiska och fysikaliska parametrar.

    Resultaten visade att kräftor och i synnerhet signalkräfta äter musslor upp till en storlek av ca 2 cm. De långa hanterings- och konsumtionstiderna indikerar dock på att kräftorna har svårt att öppna musslorna. Skadade musslor verkade dock mer utsatta för predation än hela. Om kräftorna fick välja mellan att äta snäckor eller musslor valde de i samtliga fall att äta snäckor, vilket tyder på att kräftorna väljer annan föda än musslor om de har tillgång till det. Vidare visade experimenten att signalkräfta åt ett i genomsnitt större antal snäckor än flodkräfta under försökstiden vilket indikerar att signalkräftan kan utöva ett större predationstryck än vad flodkräftan kan. Detta illustreras även av att flodkräftan generellt sett krävde längre tider av svält innan den börjande äta musslor.

    Inventeringarna i fält visade att det i princip endast finns adulta musslor kvar i bäcken (medellängd 109 mm). Det som karakteriserade en flodpärlmussellokal i vattendraget var god krontäckning, högt pH och hög konduktivitet. Vidare visade bottensubstratmätningarna att andelen finpartikulärt material är relativt hög vilket troligen missgynnar flodpärlmusslans reproduktion. Provfiskena visade att det finns signalkräfta på två områden i vattendraget men tätheterna är relativt låga och kräftorna antas ej påverka musselpopulationerna i någon större utsträckning. Elfisket visade på en relativt god tillgång på öring. Infektioner från glochidier hittades men infektionsgraden var relativt låg. Med hjälp av DNA-analys konstaterades att glochidierna var av arten flodpärlmussla.

    Hotbilden för flodpärlmusslan är komplex i Klingstorpabäcken. Påverkan från signalkräfta bedöms vara liten men kombinationen med flera andra faktorer gör att flodpärlmusslan har mycket begränsade föryngringsmöjligheter i vattendraget. De största hoten mot musselpopulationerna i Klingstorpabäcken utgörs troligen av skogsbruket och grustäktsverksamheten i avrinningsområdet.

  • 48. Hylander, Samuel
    Zooplankton responses to threats from UV and predation2009Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Ladda ner (pdf)
    Abstract
  • 49.
    Hylander, Samuel
    et al.
    Lunds universitet.
    Boeing, Wiebke J.
    Graneli, Wilhelm
    Karlsson, Jan
    von Einem, Jessica
    Gutseit, Kelly
    Hansson, Lars-Anders
    Complementary UV protective compounds in zooplankton2009Ingår i: Limnology and Oceanography, ISSN 0024-3590, E-ISSN 1939-5590, Vol. 54, nr 6, s. 1883-1893Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Zooplankton accumulate several groups of photoprotective compounds to shield against damaging ultraviolet radiation (UV). One of these groups, the carotenoids, makes the animals more conspicuous to visually hunting predators, whereas others, such as the mycosporine-like amino acids (MAAs) may not. The blend of photoprotective compounds is therefore important for the UV defense but also for the ability to escape predation through crypsis. Here we assess laboratory and field data from different latitudes to examine how UV, predation threat, and pigment availability ( in food) affects the mixture of UV-protective compounds in copepods. Overall, the blend of MAAs and carotenoids was partly explained by the availability of MAAs in the food, the UV-threat, and the presence of predators. Copepods upregulated their MAA content when UV threat was increasing (i.e., if MAAs were abundant in food), and in field data this accumulation only occurred at high levels of predation threat. If MAAs were scarce, copepods instead compensated with higher carotenoid accumulation. However, when there was a high predation threat this carotenoid compensatory effect was disadvantageous, and low concentrations of both MAAs and carotenoids at high UV-threat resulted in lower reproduction. In all, these results showed that carotenoids and MAAs are complementary substances, i.e., one is high when the other is low, and copepods are, hence, able to adjust their blend of different UV-protective compounds to optimize their defenses to the threats of UV and predation. These defense systems may buffer against direct food-web interactions and help the zooplankton to survive in environments with high UV threat.

  • 50.
    Hylander, Samuel
    et al.
    Tech Univ Denmark.
    Cornelius Grenvald, Julie
    Tech Univ Denmark.
    Kiørboe, Thomas
    Tech Univ Denmark.
    Fitness costs and benefits of ultraviolet radiation exposure in marine pelagic copepods2014Ingår i: Functional Ecology, ISSN 0269-8463, E-ISSN 1365-2435, Vol. 28, nr 1, s. 149-158Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    1Life-history theory predicts that organisms should allocate energy throughout their life such that they maximize their fitness. Copepod zooplankton are known to accumulate sunscreens (so-called mycosporine-like amino acids, MAAs) and antioxidant carotenoids to mitigate negative effects of ultraviolet radiation (UVR), but it is not well known how this affects their fitness. We followed cohorts of the marine copepod Acartia tonsa and assessed how fitness was affected by UVR exposure and a diet rich in UVR-protective sunscreens. Several fitness components including somatic growth, egg quality and nauplii production (larvae) were negatively affected by UVR, whereas other components such as size at maturity, survival and length of life were not. Nauplii production through low egg quality was the most influential life-history parameter that changed in response to UVR. There was interaction between fitness costs and food source. If copepods were fed a diet rich in UVR-screening MAAs, they were able to maintain and even increase their fitness even though they were exposed to otherwise detrimental radiation. Levels of UVR-protective carotenoids were low in the studied species and a meta-analysis revealed that marine copepods in general have much lower - by an order of magnitude - levels of carotenoids than freshwater species, while levels of MAAs are similar between the two habitats. We conclude that allocation to different fitness components to some extent is plastic although egg quality is by far the most influential factor, and this is an example of how environmental variability affects overall fitness. Fitness costs associated with UVR exposure in the absence of UVR-screening MAAs were present. Other costs such as costs for accumulating MAAs were not detected, and if present, they were outweighed by a stimulated fitness in combined UVR and MAA treatments challenging the common model that inducible defences (such as accumulation of MAAs) should come with a cost. Low levels of carotenoids in marine systems suggest high predation pressures on pigmented specimens. Accumulation of nonpigmented MAAs could hence be a key adaptation for surface-dwelling marine zooplankton to maintain or even increase their fitness when exposed to detrimental radiation.

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