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  • 1.
    Bergström, Lena
    et al.
    Umeå University, Faculty of Science and Technology, Ecology and Environmental Science.
    Tatarenkov, Andrei
    Jönsson, Rita B
    Johannesson, Kerstin
    Kautsky, Lena
    Morphological and genetic differentiation of Fucus vesiculosus in the brackish Baltic SeaIn: Journal of Phycology, ISSN 0022-3646, E-ISSN 1529-8817Article in journal (Refereed)
  • 2. Elvebakk, Arve
    et al.
    Papaefthimiou, Dimitra
    Stockholm University, Faculty of Science, Department of Botany.
    Robertsen, Eli Helene
    Liaimer, Anton
    Phylogenetic patterns among Nostoc cyanobionts within Bi- and tripartite lichens of the genus Pannaria2008In: Journal of Phycology, ISSN 0022-3646, E-ISSN 1529-8817, Vol. 44, no 4, p. 1049-1059Article in journal (Refereed)
    Abstract [en]

    Phylogenetic relationships between Nostoc cyanobionts in the lichen genus Pannaria were studied to evaluate their correlation to geography, habitat ecology, and other patterns previously reported. The 16S rRNA gene sequences of a total of 37 samples of 21 Pannaria species from seven countries from the Northern and Southern hemispheres were analyzed and compared with 69 free-living and symbiotic cyanobacterial strains. The sequences from Pannaria were distributed throughout a branch of Nostoc sequences previously called ""the Nephroma guild,"" and within two subgroups from another branch, referred to as the ""Peltigera guild,"" although there was a gradual transition between the two major groups. There is a more diverse pattern of relationships between Nostoc sequences from bipartite versus tripartite lichen species in Pannaria, compared with other well-studied genera, such as Nephroma and Peltigera. Cyanobionts from several tripartite Pannaria species from the Southern Hemisphere and corticolous bipartite species from both hemispheres were grouped together. Four sequences of Pannaria and Pseudocyphellaria cyanobionts from rocks in the Chilean Juan Fernandez Islands were nested within corticolous cyanobionts, whereas the terricolous ""Pannaria sphinctrina clade"" was placed with other terricolous strains. The cluster patterns derived from phylogenetic analysis were partly reflecting lichen taxonomy, in two groups of lichen species, possibly indicating coevolution. The phylogram partly also reflected lichen ecology. Three Pannaria species have very different cyanobiont strains when they grow in different habitats.

  • 3.
    Godhe, Anna
    et al.
    Department of Marine Ecology, Marine Botany, Göteborg University.
    McQuoid, Melissa R.
    Department of Marine Ecology, Marine Botany, Göteborg University.
    Karunasagar, Indrana
    Department of Fishery Microbiology, College of Fisheries, University of Agricultural Sciences, Mangalore.
    Karunasagar, Iddya
    Department of Fishery Microbiology, College of Fisheries, University of Agricultural Sciences, Mangalore.
    Rehnstam-Holm, Ann-Sofi
    Kristianstad University, School of Education and Environment, Avdelningen för Naturvetenskap. Kristianstad University, Forskningsmiljön Man and Biosphere Health (MABH).
    Comparison of three common molecular tools for distinguishing among geographically separated clones of the diatom Skeletonema marinoi Sarno et Zingone (bacillariophyceae)2006In: Journal of Phycology, ISSN 0022-3646, E-ISSN 1529-8817, Vol. 42, no 2, p. 280-291Article in journal (Refereed)
    Abstract [en]

    Skeletonema marinoi Sarno et Zingone is a planktonic marine diatom with a widespread geographic distribution. Different populations of this species may show distinct genetic signatures. We have evaluated the utility of three common molecular methods for distinguishing clones of S. marinoi from different geographic regions. Clonal cultures were isolated from the Canadian west coast, south west Portugal, and the east and west coasts of Sweden. All strains originated from resting stages in sediment. More than 90% of the individually isolated chains grew to densities suitable for DNA extraction. Genetic signatures of clones from each sample location were assessed by sequencing variable domains (D1-D3) of the nuclear large subunit (LSU) rRNA gene and internal transcriber spacer (ITS) (ITS-1, 5.8S and ITS-2) regions, and also by analysis of randomly amplified polymorphic DNA patterns. Analysis of molecular variance showed that strains from the four geographic areas were significantly separated by all three methods but that differences among European samples were best resolved by ITS 2 sequences.

  • 4.
    Gylle, A. Maria
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Rantamäki, Susanne
    Univ Turku, Dept Biochem & Food Chem, FI-20014 Turku, Finland.
    Ekelund, Nils G.A.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Tyystjärvi, Esa
    Univ Turku, Dept Biochem & Food Chem, FI-20014 Turku, Finland.
    Fluorescence emission spectra of marine and brackish-water ecotypes of Fucus vesiculosus and Fucus radicans (Phaeophyceae) reveal differences in light-harvesting apparatus: emission spectra in Fucus2011In: Journal of Phycology, ISSN 0022-3646, E-ISSN 1529-8817, Vol. 47, no 1, p. 98-105Article in journal (Refereed)
    Abstract [en]

    The Bothnian Sea in the northerly part of the Baltic Sea is a geologically recent brackish-water environment, and rapid speciation is occurring in the algal community of the Bothnian Sea. We measured low-temperature fluorescence emission spectra from the Bothnian Sea and the Norwegian Sea ecotypes of Fucus vesiculosus L., a marine macroalga widespread in the Bothnian Sea. Powdered, frozen thallus was used to obtain undistorted emission spectra. The spectra were compared with spectra measured from the newly identified species Fucus radicans L.Bergström et L. Kautsky, which is a close relative of F. vesiculosusand endemic to the Bothnian Sea. The spectrum of variable fluorescence was used to identify fluorescence peaks originating in PSI and PSII in this chl c–containing alga. The spectra revealed much higher PSII emission, compared to PSI emission, in the Bothnian Sea ecotype of F. vesiculosus than in F. radicans or in the Norwegian Sea ecotype of F. vesiculosus. The results suggest that more lightharvesting chl a ⁄ c proteins serve PSII in the Bothnian Sea ecotype of F. vesiculosusthan in the two other algal strains. Treatment of the Bothnian Sea ecotype of F. vesiculosusin high salinity (10, 20, and 35 practical salinity units) for 1 week did not lead to spectral changes, indicating that the measured features of the Bothnian Sea F. vesiculosus are stable and not simply a direct result of exposure to low salinity.

  • 5.
    Haubner, Norbert
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics.
    Sylvander, Peter
    Vuori, Kristiina
    Snoeijs, Pauline
    Abiotic Stress Modifies the Synthesis of Alpha-Tocopherol and Beta-Carotene in Phytoplankton Species2014In: Journal of Phycology, ISSN 0022-3646, E-ISSN 1529-8817, Vol. 50, no 4, p. 753-759Article in journal (Refereed)
    Abstract [en]

    We performed laboratory experiments to investi-gate whether the synthesis of the antioxidants -tocopherol (vitamin E) and -carotene in phytoplankton depends on changes in abiotic factors. Cultures of Nodularia spumigena, Phaeodactylum tricornutum, Skeletonema costatum, Dunaliella tertiolecta, Prorocentrum cordatum, and Rhodomonas salina were incubated at different tempe-ratures, photon flux densities and salinities for 48h. We found that abiotic stress, within natural ecological ranges, affects the synthesis of the two antioxidants in different ways in different species. In most cases antioxidant production was stimulated by increased abiotic stress. In P.tricornutumKAC 37 and D.tertiolectaSCCAP K-0591, both good producers of this compound, -tocopherol accumulation was negatively affected by environmentally induced higher photosystem II efficiency (F-v/F-m). On the other hand, -carotene accumulation was positively affected by higher F-v/F-m in N.spumigena KAC 7, P.tricornutum KAC 37, D.tertiolecta SCCAP K-0591 and R.salina SCCAP K-0294. These different patterns in the synthesis of the two compounds may be explained by their different locations and functions in the cell. While -tocopherol is heavily involved in the protection of prevention of lipid peroxidation in membranes, -carotene performs immediate photo-oxidative protection in the antennae complex of photosystem II. Overall, our results suggest a high variability in the antioxidant pool of natural aquatic ecosystems, which can be subject to short-term temperature, photon flux density and salinity fluctuations. The antioxidant levels in natural phytoplankton communities depend on species composition, the physiological condition of the species, and their respective strategies to deal with reactive oxygen species. Since -tocopherol and -carotene, as well as many other nonenzymatic antioxidants, are exclusively produced by photo-synthetic organisms, and are required by higher trophic levels through dietary intake, regime shifts in the phytoplankton as a result of large-scale environmental changes, such as climate change, may have serious consequences for aquatic food webs.

  • 6. Haubner, Norbert
    et al.
    Sylvander, Peter
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Vuori, Kristiina
    Snoeijs, Pauline
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    ABIOTIC STRESS MODIFIES THE SYNTHESIS OF ALPHA-TOCOPHEROL AND BETA-CAROTENE IN PHYTOPLANKTON SPECIES2014In: Journal of Phycology, ISSN 0022-3646, E-ISSN 1529-8817, Vol. 50, no 4, p. 753-759Article in journal (Refereed)
    Abstract [en]

    We performed laboratory experiments to investi-gate whether the synthesis of the antioxidants -tocopherol (vitamin E) and -carotene in phytoplankton depends on changes in abiotic factors. Cultures of Nodularia spumigena, Phaeodactylum tricornutum, Skeletonema costatum, Dunaliella tertiolecta, Prorocentrum cordatum, and Rhodomonas salina were incubated at different tempe-ratures, photon flux densities and salinities for 48h. We found that abiotic stress, within natural ecological ranges, affects the synthesis of the two antioxidants in different ways in different species. In most cases antioxidant production was stimulated by increased abiotic stress. In P.tricornutumKAC 37 and D.tertiolectaSCCAP K-0591, both good producers of this compound, -tocopherol accumulation was negatively affected by environmentally induced higher photosystem II efficiency (F-v/F-m). On the other hand, -carotene accumulation was positively affected by higher F-v/F-m in N.spumigena KAC 7, P.tricornutum KAC 37, D.tertiolecta SCCAP K-0591 and R.salina SCCAP K-0294. These different patterns in the synthesis of the two compounds may be explained by their different locations and functions in the cell. While -tocopherol is heavily involved in the protection of prevention of lipid peroxidation in membranes, -carotene performs immediate photo-oxidative protection in the antennae complex of photosystem II. Overall, our results suggest a high variability in the antioxidant pool of natural aquatic ecosystems, which can be subject to short-term temperature, photon flux density and salinity fluctuations. The antioxidant levels in natural phytoplankton communities depend on species composition, the physiological condition of the species, and their respective strategies to deal with reactive oxygen species. Since -tocopherol and -carotene, as well as many other nonenzymatic antioxidants, are exclusively produced by photo-synthetic organisms, and are required by higher trophic levels through dietary intake, regime shifts in the phytoplankton as a result of large-scale environmental changes, such as climate change, may have serious consequences for aquatic food webs.

  • 7. Johannesson, Kerstin
    et al.
    Johansson, Daniel
    Larsson, Karl H.
    Huenchunir, Cecilia J.
    Perus, Jens
    Forslund, Helena
    Stockholm University, Faculty of Science, Department of Botany.
    Kautsky, Lena
    Stockholm University, Faculty of Science, Department of Botany.
    Pereyra, Ricardo T.
    FREQUENT CLONALITY IN FUCOIDS (FUCUS RADICANS AND FUCUS VESICULOSUS; FUCALES, PHAEOPHYCEAE) IN THE BALTIC SEA2011In: Journal of Phycology, ISSN 0022-3646, E-ISSN 1529-8817, Vol. 47, no 5, p. 990-998Article in journal (Refereed)
    Abstract [en]

    Asexual reproduction by cloning may affect the genetic structure of populations, their potential to evolve, and, among foundation species, contributions to ecosystem functions. Macroalgae of the genus Fucus are known to produce attached plants only by sexual recruitment. Recently, however, clones of attached plants recruited by asexual reproduction were observed in a few populations of Fucus radicans Bergstrom et L. Kautsky and F. vesiculosus L. inside the Baltic Sea. Herein we assess the distribution and prevalence of clonality in Baltic fucoids using nine polymorphic microsatellite loci and samples of F. radicans and F. vesiculosus from 13 Baltic sites. Clonality was more common in F. radicans than in F. vesiculosus, and in both species it tended to be most common in northern Baltic sites, although variation among close populations was sometimes extensive. Individual clonal lineages were mostly restricted to single or nearby locations, but one clonal lineage of F. radicans dominated five of 10 populations and was widely distributed over 550 x 100 km of coast. Populations dominated by a few clonal lineages were common in F. radicans, and these were less genetically variable than in other populations. As thalli recruited by cloning produced gametes, a possible explanation for this reduced genetic variation is that dominance of one or a few clonal lineages biases the gamete pool resulting in a decreased effective population size and thereby loss of genetic variation by genetic drift. Baltic fucoids are important habitat-forming species, and genetic structure and presence of clonality have implications for conservation strategies.

  • 8. Johnsen, G
    et al.
    Eikrem, W
    Dalloekken, R
    Legrand, Catherine
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Aure, J
    Skjoldal, HR
    Eco-physiology, bio-optics and toxicity of the ichthyotoxic prymnesiophyte Chrysochromulina leadbeateri1999In: Journal of Phycology, ISSN 0022-3646, E-ISSN 1529-8817, Vol. 35, no 6, p. 1465-1476Article in journal (Refereed)
    Abstract [en]

    A toxic phytoplankton bloom, dominated by the prymnesiophyte Chrysochromulina leadbeateri Estep, developed in the Ofotfjord-Tysfjord area (North Norway) in mid-May and ended in late June 1991 in Vestfjorden and the adjacent fjord areas, Chrysochromulina leadbeateri dominated at total cell densities of >2 x 10(6) cells . L-1; at lower total cell densities, C. leadbeateri was accompanied by other Chrysochromulina species, peridinin-containing dinoflagellates, and diatoms, Bio-optical characteristics and pigmentation in laboratory and field strains of C. leadbeateri allowed for the interpretation of the optical signatures within the bloom. The bio-optical data suggested healthy and actively growing cells during the bloom. About 600 metric tons of pen-raised Atlantic salmon were killed by the C. leadbeateri bloom. A laboratory study was conducted to assess the potential impact of finfish on C. leadbeaferi growth. It was found that the polyamine putrescine enhanced cell biomass and hemolytic activity. Given this, a possible scenario for the development of this bloom and the level of toxicity is hypothesized: (1) The nutrient loading in the Ofotfjord area was enhanced during the winter of 1990-1991 due to the overwintering of 1.5 x 10(6) metric tons of herring from a depth of 0-250 m, This may have sustained a large stock of the mixotrophic C. leadbeateri in early spring before light regime (irradiance, spectral irradiance, and day length) made net photosynthesis possible, (2) The release of polyamines during; the decay of dead fish (e.g. putrescine, cadaverine, and histamine) may have acted as cofactors with ichthyotoxins making "hypertoxic complexes" with the polyamines enhancing growth in the mixotrophic C, leadbeateri.

  • 9. Kamjunke, Norbert
    et al.
    Koehler, Birgit
    Wannicke, Nicola
    Tittel, Jörg
    Algae as competitors of heterotrophic bacteria for glucose2008In: Journal of Phycology, ISSN 0022-3646, E-ISSN 1529-8817, Vol. 44, p. 616-623Article in journal (Refereed)
  • 10.
    Karlsson-Elfgren, Irene
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Evolutionary Biology, Limnology.
    Brunberg, Anna-Kristina
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Limnology.
    The Importance of Shallow Sediments in the Recruitment of Anabaena and Aphanizomenon (Cyanophyceae)2004In: Journal of Phycology, ISSN 0022-3646, E-ISSN 1529-8817, Vol. 40, no 5, p. 831-836Article in journal (Refereed)
    Abstract [en]

    Recruitment of Anabaena and Aphanizomenon from the sediments to the water column was investigated in shallow (1-2 m) and deep (6-7 m) areas of Lake Limmaren, central Sweden. Recruitment traps attached to the bottom were sampled weekly throughout the summer season (June through September). A comparison between the two sites shows that the largest part of the recruited cells originated from the shallow site, although recruitment occurred at all depths in the lake. There were also differences between the species, regarding the site as well as the timing of the recruitment. The contribution of the inoculum to the pelagic population was calculated to vary between 0.003% and 0.05% for the different species. From these results we conclude that shallow sediments are more important than deep ones for the recruitment and that the inoculum in Lake Limmaren is small but may still be an important factor in the population dynamics.

  • 11.
    Karlsson-Elfgren, Irene
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Evolutionary Biology, Limnology.
    Rydin, Emil
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Limnology.
    Hyenstrand, Per
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Limnology.
    Pettersson, Kurt
    Recruitment and pelagic growth of Gloeotrichia echinulata (Chyanophyceae) in Lake Erken2003In: Journal of Phycology, ISSN 0022-3646, E-ISSN 1529-8817, Vol. 39, no 6, p. 1050-1056Article in journal (Refereed)
    Abstract [en]

    Different parameters in the life cycle of the colony forming cyanobacterium Gloeotrichia echinulata (J.E. Smith) Richter was evaluated in Lake Erken, Sweden. Recruitment of colonies from the sediments and pelagic abundance were measured during 2 years. These data were then used in a model to evaluate and estimate parameters of the life cycle. In our study, recruitment alone only contributed to a small part (<5%) of the maximum G. echinulata abundance that occurred during late summer. However, recruitment from shallow sediments forms the important seed for the pelagic population. Together with measured rates of migration from the sediment, variations in either pelagic colony division rate or pelagic residence time could explain variations in the measured abundance of G. echinulata in situ.

  • 12.
    Lebret, Karen
    et al.
    Department of Biology, Lund University, Lund, Sweden.
    Tesson, Sylvie V. M.
    Kritzberg, Emma S.
    Tomas, Carmelo
    Rengefors, Karin
    Phylogeography of the freshwater raphidophyte Gonyostomum semen confirms a recent expansion in northern Europe by a single haplotype2015In: Journal of Phycology, ISSN 0022-3646, E-ISSN 1529-8817, Vol. 51, no 4, p. 768-781Article in journal (Refereed)
  • 13.
    Lebret, Karen
    et al.
    Lund University.
    Tesson, Sylvie V. M.
    Lund University.
    Kritzberg, Emma S.
    Lund University.
    Tomas, Carmelo
    University of North Carolina at Wilmington, USA.
    Rengefors, Karin
    Lund University.
    Phylogeography of the freshwater raphidophyte Gonyostomum semen confirms a recent expansion in northern Europe by a single haplotype2015In: Journal of Phycology, ISSN 0022-3646, E-ISSN 1529-8817, Vol. 51, no 4, p. 768-781Article in journal (Refereed)
    Abstract [en]

    Gonyostmum semen is a freshwater raphidophyte that has increased in occurrence and abundance in several countries in northern Europe since the 1980s. More recently, the species has expanded rapidly also in north-eastern Europe, and it is frequently referred to as invasive. To better understand the species history, we have explored the phylogeography of G. semen using strains from northern Europe, United States, and Japan. Three regions of the ribosomal RNA gene (small subunit [SSU], internal transcribed spacer [ITS] and large subunit [LSU]) and one mitochondrial DNA marker (cox1) were analyzed. The SSU and partial LSU sequences were identical in all strains, confirming that they belong to the same species. The ITS region differentiated the American from the other strains, but showed high intra-strain variability. In contrast, the mitochondrial marker cox1 showed distinct differences between the European, American, and Japanese strains. Interestingly, only one cox1 haplotype was detected in European strains. The overall low diversity and weak geographic structure within northern European strains supported the hypothesis of a recent invasion of new lakes by G. semen. Our data also show that the invasive northern European lineage is genetically distinct from the lineages from the other continents. Finally, we concluded that the mitochondrial cox1 was the most useful marker in determining large-scale biogeographic patterns in this species.

  • 14. Morgan-Kiss, R M
    et al.
    Ivanov, A G
    Pocock, Tessa
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Krol, M
    Gudynaite-Savitch, L
    Huner, N P A
    The Antarctic psychrophile, Chlamydomonas raudensis Ettl (UWO241) (Chlorophyceae, Chlorophyta), exhibits a limited capacity to photoacclimate to red light2005In: Journal of Phycology, ISSN 0022-3646, E-ISSN 1529-8817, Vol. 41, no 4, p. 791-800Article in journal (Refereed)
    Abstract [en]

    The psychrophilic Antarctic alga, Chlamydomonas raudensis Ettl (UWO241), grows under an extreme environment of low temperature and low irradiance of a limited spectral quality (blue-green). We investigated the ability of C. raudensis to acclimate to long-term imbalances in excitation caused by light quality through adjustments in photosystem stoichiometry. Log-phase cultures of C. raudensis and C. reinhardtii grown under white light were shifted to either blue or red light for 12 h. Previously, we reported that C. raudensis lacks the ability to redistribute light energy via the short-term mechanism of state transitions. However, similar to the model of mesophilic alga, C. reinhardtii, the psychrophile retained the capacity for long-term adjustment in energy distribution between PSI and PSII by modulating the levels of PSI reaction center polypeptides, PsaA/PsaB, with minimal changes in the content of the PSII polypeptide, D1, in response to changes in light quality. The functional consequences of the modulation in PSI/PSII stoichiometry in the psychrophile were distinct from those observed in C. reinhardtii. Exposure of C. raudensis to red light caused 1) an inhibition of growth and photosynthetic rates, 2) an increased reduction state of the intersystem plastoquinone pool with concomitant increases in nonphotochemical quenching, 3) an uncoupling of the major light-harvesting complex from the PSII core, and 4) differential thylakoid protein phosphorylation profiles compared with C. reinhardtii. We conclude that the characteristic low levels of PSI relative to PSII set the limit in the capacity of C. raudensis to photoacclimate to an environment enriched in red light.

  • 15.
    Pocock, Tessa
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Koziak, Alexandra
    Rosso, Dominic
    Falk, Stefan
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Hüner, Norman
    Chlamydomonas raudensis Ettl. (UWO241) exhibits the capacity for rapid D1 repair in response to chronic photoinhibition at low temperature2007In: Journal of Phycology, ISSN 0022-3646, E-ISSN 1529-8817, Vol. 43, no 5, p. 924-936Article in journal (Refereed)
    Abstract [en]

    Maximum photosynthetic capacity indicates that the Antarctic psychrophile Chlamydomonas raudensis H. Ettl UWO 241 is photosynthetically adapted to low temperature. Despite this finding, C. raudensis UWO 241 exhibited greater sensitivity to low-temperature photoinhibition of PSII than the mesophile Chlamydomonas reinhardtii P. A. Dang. However, in contrast with results for C. reinhardtii, the quantum requirement to induce 50% photoinhibition of PSII in C. raudensis UWO 241 (50 μmol photons) was comparable at either 8°C or 29°C. To our knowledge, this is the first report of a photoautotroph whose susceptibility to photoinhibition is temperature independent. In contrast, the capacity of the psychrophile to recover from photoinhibition of PSII was sensitive to temperature and inhibited at 29°C. The maximum rate of recovery from photoinhibition of the psychrophile at 8°C was comparable to the maximum rate of recovery of the mesophile at 29°C. We provide evidence that photoinhibition in C. raudensis UWO 241 is chronic rather than dynamic. The photoinhibition-induced decrease in the D1 content in C. raudensis recovered within 30 min at 8°C. Both the recovery of the D1 content as well as the initial fast phase of the recovery of Fv/Fm at 8°C were inhibited by lincomycin, a chloroplast protein synthesis inhibitor. We conclude that the susceptibility of C. raudensis UWO 241 to low-temperature photoinhibition reflects its adaptation to low growth irradiance, whereas the unusually rapid rate of recovery at low temperature exhibited by this psychrophile is due to a novel D1 repair cycle that is adapted to and is maximally operative at low temperature.

  • 16.
    Roleda, Michael Y.
    et al.
    Inst Polar Ecol, D-24148 Kiel, Germany..
    Campana, Gabriela L.
    Consejo Nacl Invest Cient & Tecn, Inst Antartico Argentino, RA-1033 Buenos Aires, DF, Argentina..
    Wiencke, Christian
    Alfred Wegener Inst Polar & Marine Res, Dept Seaweed Biol, Sect Funct Ecol, D-27570 Bremerhaven, Germany..
    Hanelt, Dieter
    Univ Hamburg, Biozentrum Klein Flottbek, D-22609 Hamburg, Germany..
    Quartino, Maria Liliana
    Wulff, Angela
    Gothenburg Univ, Dept Marine Ecol, SE-40530 Gothenburg, Sweden..
    SENSITIVITY OF ANTARCTIC UROSPORA PENICILLIFORMIS (ULOTRICHALES, CHLOROPHYTA) TO ULTRAVIOLET RADIATION IS LIFE-STAGE DEPENDENT2009In: Journal of Phycology, ISSN 0022-3646, E-ISSN 1529-8817, Vol. 45, no 3, p. 600-609Article in journal (Refereed)
    Abstract [en]

    The sensitivity of different life stages of the eulittoral green alga Urospora penicilliformis (Roth) Aresch. to ultraviolet radiation (UVR) was examined in the laboratory. Gametophytic filaments and propagules (zoospores and gametes) released from filaments were separately exposed to different fluence of radiation treatments consisting of PAR (P = 400-700 nm), PAR + ultraviolet A (UVA) (PA, UVA = 320-400 nm), and PAR + UVA + ultraviolet B (UVB) (PAB, UVB = 280-320 nm). Photophysiological indices (ETR(max), E(k), and alpha) derived from rapid light curves were measured in controls, while photosynthetic efficiency and amount of DNA lesions in terms of cyclobutane pyrimidine dimers (CPDs) were measured after exposure to radiation treatments and after recovery in low PAR; pigments of propagules were quantified after exposure treatment only. The photosynthetic conversion efficiency (alpha) and photosynthetic capacity (rETR(max)) were higher in gametophytes compared with the propagules. The propagules were slightly more sensitive to UVB-induced DNA damage; however, both life stages of the eulittoral inhabiting turf alga were not severely affected by the negative impacts of UVR. Exposure to a maximum of 8 h UVR caused mild effects on the photochemical efficiency of PSII and induced minimal DNA lesions in both the gametophytes and propagules. Pigment concentrations were not significantly different between PAR-exposed and PAR + UVR-exposed propagules. Our data showed that U. penicilliformis from the Antarctic is rather insensitive to the applied UVR. This amphi-equatorial species possesses different protective mechanisms that can cope with high UVR in cold-temperate waters of both hemispheres and in polar regions under conditions of increasing UVR as a consequence of further reduction of stratospheric ozone.

  • 17.
    Sassenhagen, Ingrid
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    Rengefors, Karin
    Richardson, Tammi L.
    Pinckney, James L.
    Pigment composition and photoacclimation as keys to the ecological success of Gonyostomum semen (Raphidophyceae, Stramenopiles)2014In: Journal of Phycology, ISSN 0022-3646, E-ISSN 1529-8817, Vol. 50, no 6, p. 1146-1154Article in journal (Refereed)
  • 18.
    Sundström, Annica M.
    et al.
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Kremp, Anke
    Finnish Environment Institute.
    Daugbjerg, Niels
    Phycology Laboratory, Department of Biology, University of Copenhagen.
    Moestrup, Øjvind
    Phycology Laboratory, Department of Biology, University of Copenhagen.
    Ellegaard, Marianne
    Phycology Laboratory, Department of Biology, University of Copenhagen.
    Hansen, Regina
    Leibniz Institute for Baltic Sea Research Warnemünde.
    Hajdu, Susanna
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    GYMNODINIUM COROLLARIUM SP. NOV. (DINOPHYCEAE)—A NEW COLD-WATER DINOFLAGELLATE RESPONSIBLE FOR CYST SEDIMENTATION EVENTS IN THE BALTIC SEA2009In: Journal of Phycology, ISSN 0022-3646, E-ISSN 1529-8817, Vol. 45, p. 938-952Article in journal (Refereed)
    Abstract [en]

    A naked dinoflagellate with a unique arrangement of chloroplasts in the center of the cell was isolated from the northern Baltic proper during a spring dinoflagellate bloom (March 2005). Morphological, ultrastructural, and molecular analyses revealed this dinoflagellate to be undescribed and belonging to the genus Gymnodinium F. Stein. Gymnodinium corollarium A. M. Sundström, Kremp et Daugbjerg sp. nov. possesses features typical of Gymnodinium sensu stricto, such as nuclear chambers and an apical groove running in a counterclockwise direction around the apex. Phylogenetic analyses based on partial nuclear-encoded LSU rDNA sequences place the species in close proximity to G. aureolum, but significant genetic distance, together with distinct morphological features, such as the position of chloroplasts, clearly justifies separation from this species. Temperature and salinity experiments revealed a preference of G. corollarium for low salinities and temperatures, confirming it to be a cold-water species well adapted to the brackish water conditions in the Baltic Sea. At nitrogen-deplete conditions, G. corollarium cultures produced small, slightly oval cysts resembling a previously unidentified cyst type commonly found in sediment trap samples collected from the northern and central open Baltic Sea. Based on LSU rDNA comparison, these cysts were assigned to G. corollarium. The cysts have been observed in many parts of the Baltic Sea, indicating the ecologic versatility of the species and its importance for the Baltic ecosystem.

  • 19. Turk-Kubo, Kendra A.
    et al.
    Farnelid, Hanna M.
    Shilova, Irina N.
    Henke, Britt
    Zehr, Jonathan P.
    DISTINCT ECOLOGICAL NICHES OF MARINE SYMBIOTIC N-2-FIXING CYANOBACTERIUM CANDIDATUS ATELOCYANOBACTERIUM THALASSA SUBLINEAGES2017In: Journal of Phycology, ISSN 0022-3646, E-ISSN 1529-8817, Vol. 53, no 2, p. 451-461Article in journal (Refereed)
    Abstract [en]

    A recently described symbiosis between the metabolically streamlined nitrogen-fixing cyanobacterium UCYN-A and a single-celled eukaryote prymnesiophyte alga is widely distributed throughout tropical and subtropical marine waters, and is thought to contribute significantly to nitrogen fixation in these regions. Several UCYN-A sublineages have been defined based on UCYN-A nitrogenase (nifH) sequences. Due to the low abundances of UCYN-A in the global oceans, currently existing molecular techniques are limited for detecting and quantifying these organisms. A targeted approach is needed to adequately characterize the diversity of this important marine cyanobacterium, and to advance understanding of its ecological importance. We present findings on the distribution of UCYN-A sublineages based on high throughput sequencing of UCYN-A nifH PCR amplicons from 78 samples distributed throughout many major oceanic provinces. These UCYN-A nifH fragments were used to define oligotypes, alternative taxonomic units defined by nucleotide positions with high variability. The data set was dominated by a single oligotype associated with the UCYN-A1 sublineage, consistent with previous observations of relatively high abundances in tropical and subtropical regions. However, this analysis also revealed for the first time the widespread distribution of the UCYN-A3 sublineage in oligotrophic waters. Furthermore, distinct assemblages of UCYN-A oligotypes were found in oligotrophic and coastally influenced waters. This unique data set provides a framework for determining the environmental controls on UCYN-A distributions and the ecological importance of the different sublineages.

  • 20.
    Turk-Kubo, Kendra A.
    et al.
    University of California, USA.
    Farnelid, Hanna
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science. University of California, USA.
    Shilova, Irina N.
    University of California, USA.
    Henke, Britt
    University of California, USA.
    Zehr, Jonathan P.
    University of California, USA.
    Distinct ecological niches of marine symbiotic N2-fixing cyanobacterium Candidatus Atelocyanobacterium thalassa sublineages2017In: Journal of Phycology, ISSN 0022-3646, E-ISSN 1529-8817, Vol. 53, no 2, p. 451-461Article in journal (Refereed)
    Abstract [en]

    A recently described symbiosis between the metabolically streamlined nitrogen-fixing cyanobacterium UCYN-A and a single-celled eukaryote prymnesiophyte alga is widely distributed throughout tropical and subtropical marine waters, and is thought to contribute significantly to nitrogen fixation in these regions. Several UCYN-A sublineages have been defined based on UCYN-A nitrogenase (nifH) sequences. Due to the low abundances of UCYN-A in the global oceans, currently existing molecular techniques are limited for detecting and quantifying these organisms. A targeted approach is needed to adequately characterize the diversity of this important marine cyanobacterium, and to advance understanding of its ecological importance. We present findings on the distribution of UCYN-A sublineages based on high throughput sequencing of UCYN-A nifH PCR amplicons from 78 samples distributed throughout many major oceanic provinces. These UCYN-A nifH fragments were used to define oligotypes, alternative taxonomic units defined by nucleotide positions with high variability. The data set was dominated by a single oligotype associated with the UCYN-A1 sublineage, consistent with previous observations of relatively high abundances in tropical and subtropical regions. However, this analysis also revealed for the first time the widespread distribution of the UCYN-A3 sublineage in oligotrophic waters. Furthermore, distinct assemblages of UCYN-A oligotypes were found in oligotrophic and coastally influenced waters. This unique data set provides a framework for determining the environmental controls on UCYN-A distributions and the ecological importance of the different sublineages.

  • 21.
    Ulanova, Anna
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Ecological Botany.
    Busse, Svenja
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Ecological Botany.
    Snoeijs, Pauli
    Coastal diatom-environment relationships in the brackish Baltic Sea2009In: Journal of Phycology, ISSN 0022-3646, E-ISSN 1529-8817, Vol. 45, no 1, p. 54-68Article in journal (Refereed)
    Abstract [en]

    High-quality calibration data sets are required when diatom assemblages are used for monitoring ecological change or reconstructing palaeo-environments. The quality of such data sets can be validated, in addition to other criteria, by the percentage of significant unimodal species responses as a measure of the length of an environmental gradient. This study presents diatom-environment relationships analyzed from a robust data set of diatom communities living on submerged stones along a 2,000 km long coastline in the Baltic Sea area, including 524 samples taken at 135 sites and covering a salinity gradient from 0.4 to 11.4. Altogether, 487 diatom taxa belonging to 102 genera were recorded. Detrended canonical correspondence analysis showed that salinity was the overriding environmental factor regulating diatom community composition, while exposure to wave action and nutrient concentrations were of secondary importance. Modeling the abundances of the 58 most common diatom taxa yielded significant relationships with salinity for 57 taxa. Twenty-three taxa showing monotonic responses were species with optimum distributions in freshwater or marine waters. Thirty-four taxa showing unimodal responses were brackish-water species with maximum distributions at different salinities. Separate analyses for small (cell biovolume <1,000 μm3) and large (≥1,000 μm3) taxa yielded similar results. In previous studies along shorter salinity gradients, large and small epilithic diatom taxa responded differently. From our large data, we conclude that counts of large diatom taxa alone seem sufficient for indicating salinity changes in coastal environments with high precision.

  • 22.
    Ulanova, Anna
    et al.
    Department of Ecology and Evolution, Evolutionary Biology Centre, Uppsala University.
    Busse, Svenja
    Department of Ecology and Evolution, Evolutionary Biology Centre, Uppsala University.
    Snoeijs, Pauli
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    COASTAL DIATOM-ENVIRONMENT RELATIONSHIPS IN THE BRACKISH BALTIC SEA2009In: Journal of Phycology, ISSN 0022-3646, E-ISSN 1529-8817, Vol. 45, p. 54-68Article in journal (Refereed)
    Abstract [en]

    High-quality calibration data sets are required when diatom assemblages are used for monitoring ecological change or reconstructing palaeo-environments. The quality of such data sets can be validated, in addition to other criteria, by the percentage of significant unimodal species responses as a measure of the length of an environmental gradient. This study presents diatom-environment relationships analyzed from a robust data set of diatom communities living on submerged stones along a 2,000 km long coastline in the Baltic Sea area, including 524 samples taken at 135 sites and covering a salinity gradient from 0.4 to 11.4. Altogether, 487 diatom taxa belonging to 102 genera were recorded. Detrended canonical correspondence analysis showed that salinity was the overriding environmental factor regulating diatom community composition, while exposure to wave action and nutrient concentrations were of secondary importance. Modeling the abundances of the 58 most common diatom taxa yielded significant relationships with salinity for 57 taxa. Twenty-three taxa showing monotonic responses were species with optimum distributions in freshwater or marine waters. Thirty-four taxa showing unimodal responses were brackish-water species with maximum distributions at different salinities. Separate analyses for small (cell biovolume <1,000 μm3) and large (≥1,000 μm3) taxa yielded similar results. In previous studies along shorter salinity gradients, large and small epilithic diatom taxa responded differently. From our large data, we conclude that counts of large diatom taxa alone seem sufficient for indicating salinity changes in coastal environments with high precision.

1 - 22 of 22
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