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  • 1. Brinza, Loredana
    et al.
    Nygård, Charlotta A
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap, teknik och matematik.
    Dring, Matthew J
    Gavrilescu, Maria
    Benning, Liane G
    Cadmium tolerance and adsorption by the marine brown alga Fucus vesiculosus from the Irish Sea and the Bothnian Sea2009Ingår i: Bioresource Technology, ISSN 0960-8524, E-ISSN 1873-2976, Vol. 100, nr 5, s. 1727-1733Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Cadmium (Cd) uptake capacities and Cd tolerance of the marine alga Fucus vesiculosus from the Irish Sea (salinity 35 psu) and from the Bothnian Sea (northern Baltic, 5 psu) were quantified. These data were complemented by measurements of changes in maximal photosynthetic rate (Pmax), dark respiration rate and variable fluorescence vs. maximal fluorescence (Fv:Fm). At concentrations between 0.01 and 1 mmol Cd l−1, F. vesiculosus from the Bothnian Sea adsorbed significantly more (about 98%) Cd compared with F. vesiculosus from the Irish Sea. The photosynthetic measurements showed that the Bothnian Sea F. vesiculosus were more sensitive to Cd exposure than the Irish Sea algae. The algae from the Irish Sea showed negative photosynthetic effects only at 1 mmol Cd l−1, which was expressed as a decreased Pmax (−12.3%) and Fv:Fm (−4.6%). On the contrary, the algae from the Bothnian Sea were negatively affected already at Cd concentrations as low at 0.1 mmol Cd l−1. They exhibited increased dark respiration (+11.1%) and decreased Fv:Fm (−13.9%). The results show that F. vesiculosus from the Bothnian Sea may be an efficient sorption substrate for Cd removal from Cd contaminated seawater and this algae type may also have applications for wastewater treatment.

  • 2.
    Ekelund, Nils G. A.
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap, teknik och matematik.
    Nygård, Charlotta A
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap, teknik och matematik.
    Nordström, R
    Gylle, Maria
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap, teknik och matematik.
    In situ study of relative electron transport rates (ETR) in the marine macroalga Fucus vesiculosus from the Baltic Sea at different depths and times of the year.2008Ingår i: Journal of Applied Phycology, ISSN 0921-8971, E-ISSN 1573-5176, Vol. 20, nr 5, s. 751-756Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The brown alga Fucus vesiculous is one of the few marine species in the Baltic Sea. F. vesiculosus shows high morphological and physiological variability as a response to its environmental conditions. The salinity in the Baltic Sea is 4-5 psu in comparison to 35 psu in the Atlantic. Photosynthesis of algae is usually measured after collection and transportation to constant culture conditions. However, in this study the relative photosynthetic electron transport rate (rETR), calculated from chl a fluorescence parameters were compared for algae from 1 and 4 m depths by SCUBA divers. Measurements of light response curves from the same individuals of F. vesiculosus at different depths and times of the year have to our knowledge never been made before. Measurements were performed at four different occasions during the spring (February 25, April 3 and 29 and May 26 in 2005) in the Baltic Sea, using rapid light curves (RLCs) generated with a Diving PAM. In addition, samples were collected for photoinhibition studies in the laboratory. The light response curves obtained in situ at 1 and 4 m depths for F. vesiculosus showed lower values of light saturation with depth. When algae from 1 and 4 m depths were exposed to high irradiances of PAR (1400 µmol photons m-2 s-1), algae from 1 m depth showed a higher degree of photoinhibition in comparison to algae from the 4 m depth.

  • 3. Figueroa, Felix
    et al.
    Nygård, Charlotta
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Ekelund, Nils
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Gomez, Ivan
    Photobiological characteristics and photosynthetic UV responses in two Ulva species (Chlorophyta) from southern Spain.2003Ingår i: Journal of Photochemistry and Photobiology. B: Biology, ISSN 1011-1344, E-ISSN 1873-2682, Vol. 72, nr 1-3, s. 35-44Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The effect of different wavebands of artificial UV (UVB and UVA) and photosynthetically active radiation (PAR) was assessed in two species of the genus Ova, U. olivascens and U rotundata, from southern Spain in order to test for possible differences in acclimation of photosynthesis. Both species share similar morphology but are subject to different light environments: U. rotundata is an estuarine alga, inhabiting subtidal locations, while U. olivascens is an intertidal, sun-adapted organism. Algae were exposed to three different UV conditions, PAR + UVA + UVB, PAR + UVA and PAR for 7 d. Short-term exposure (6 h) was also carried out, using two PAR levels, 150 and 700 mumol m(-2) s(-1). Pigment contents and photosynthesis vs. irradiance curves from oxygen evolution were used to contrast sun- and shade adaptation between these species. O-2-based net photosynthesis (P-max) and PAM-chlorophyll fluorescence (optimal quantum yield, F-v/F-m) were used as parameters to evaluate photoinhibition of photosynthesis in the experiments. The results underline different photobiological characteristics among species: the subtidal U rotundata had higher contents of pigments (Chl a, Chl b and carotenoids) than the sun-adapted U olivascens, which resulted in higher thallus absorptance and P-I parameters characterized by higher photosynthetic efficiency at limiting irradiances (alpha) and lower saturating points for photosynthesis (E-k). After 7 d exposure, photoinhibition of F-v/F-m was close to 40-45% in both species. Differences between UV treatments were seen in U. rotundata after 5 0 and after 7 d in U olivascens, in which PAR + UVA impaired strongly photosynthesis (80%). Such patterns were correlated with a progressive decrease in pigment contents, specially chlorophylls. In short-term (6 h) exposures, combinations of UVA + UVB and high PAR level resulted in high rates of photoinhibition of chlorophyll fluorescence (68-92%) in U rotundata, whereas in U. olivascens photoinhibition ranged between 42% and 53%. Photoinhibition under low PAR combined to UV radiation was lower than observed under high PAR. Net O-2-P-max revealed similar response among the species, with maximal photoinhibition rates close to 60% in algae incubated under high PAR + UVA + UVB. In the case of UV exposure in combination with low PAR, the highest photoinhibition rates were measured in U. rotundata. 

  • 4.
    Gylle, A Maria
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap, teknik och matematik.
    Nygård, Charlotta A
    Länsstyrelsen Västernorrland.
    Ekelund, Nils GA
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap, teknik och matematik.
    Desiccation and salinity effects on marine and brackhish Fucus vesiculosus L. (Phaeophyceae).2009Ingår i: Phycologia, ISSN 0031-8884, E-ISSN 2330-2968, Vol. 48, nr 3, s. 156-164Artikel i tidskrift (Övrigt vetenskapligt)
    Abstract [en]

    Ecotypes of Fucus vesiculosus L. from the Norwegian Sea (34 psu, marine ecotype) and Bothnian Sea (5 psu, brackish ecotype) have been compared with respect to the ability to withstand desiccation at different temperatures (0, 10, and 20°C). The aim was also to investigate the importance of salinity and light for the availably energy reserves, osmotic adjustment, and pigment content. The maximum quantum yield of photosystem II photochemistry (Fv/Fm) values revealed that the marine ecotype was more able to resist desiccation. The brackish algae showed a decrease in Fv/Fm as a response to desiccation at all temperatures, but the decrease was most pronounced at 20°C. The brackish ecotype recovered from desiccation within 5 h only when treated at 0°C. When the two ecotypes were treated at different levels of salinity in darkness and light, the results suggested that both salinity and irradiance are main factors in the differences in mannitol content between the two ecotypes. Chlorophyll (Chl) measurements showed 25% higher Chl α and 60% higher Chl c in the brackish ecotype in comparison to the marine ecotype. Darkness had a more pronounced effect on the Chl content than the salinity and initiated an increase in the amount of Chl, especially Chl c in the brackish ecotype.

  • 5.
    Gylle, A. Maria
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Nygård, Charlotta A
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Pocock, Tessa
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Ekelund, Nils G. A.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Salinity effect on oxygen evolution and the relative amount of RuBisCO in the brackish Fucus vesiculosus L. (Phaeophyceae)2007Ingår i: Pysiological responses of marine and brackish Fucuc vesiculosus L with respect to salinity, Sundsvall: Mittuniversitetet , 2007, s. 1-8Kapitel i bok, del av antologi (Övrigt vetenskapligt)
    Abstract [en]

    The sublittoral Fucus vesiculosus from the brackish Bothnian Sea is adapted to a salinity of 4-5 practical salinity units (psu). This study investigated the effect of different salinities (5, 10, 20 and 35 psu) on maximum photosynthetic capacity (Pmax) and the relative amount of ribulose 1,5-bisphosphate carboxylase/oxygenase (Rubisco). The results revealed a higher Pmax at higher salinities with the maximum at 10 psu. Higher salinities also resulted in increased relative amounts of Rubisco but this was not well correlated with the increased Pmax. Therefore, the amount of Rubisco doesn�t appear to be the main reason for the increased Pmax in higher salinities.

  • 6.
    Gylle, A. Maria
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap, teknik och matematik.
    Nygård, Charlotta A
    Svan, I Carina
    Pocock, Tessa
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap, teknik och matematik.
    Ekelund, Nils GA
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap, teknik och matematik.
    Photosynthesis and relative amounts of photosynthetic proteins (D1, PsaA and Rubisco) in marine and brackish water ecotypes of Fucus vesiculosus and Fucus radicans (Phaeophyceae):  Photosynthesis and proteins in FucusManuskript (preprint) (Övrigt vetenskapligt)
    Abstract [en]

    This study investigated if the photosynthetic maximum capacity (Pmax) is related to the relative amounts of D1 (PsbA), PsaA proteins and ribulose-1.5-bisphosphate carboxylase/ oxygenase (Rubisco) in the marine, Norwegian Sea (34-35 practical salinity units, psu) and the brackish, Bothnian Sea (4-5 psu) ecotypes of Fucus vesiculosus and in Fucus radicans. The results revealed higher Pmax in the marine ecotype of F. vesiculosus compared to the brackish Fucus species. The relative amounts of PsaA proteins or D1/PsaA (photosystem II/photosystem I; PSII/PSI) ratio did not indicate any differences between the Fucus strains whereas the relative amount of D1 was higher in the marine F. vesiculosus compared to F. radicans. The PSII/PSI ratios confirm an overweight of PSI in all three Fucus strains. The analyses of the relative amount of Rubisco indicated a greater amount in both ecotypes of F. vesiculosus compared to F. radicans, whereas no differences could be detected between the two ecotypes of F. vesiculosus. Therefore, we suggest that the amount of Rubisco contributed to the differences of Pmax between the marine ecotype of F. vesiculosus and F. radicans. The lower Pmax in the brackish ecotype of F. vesiculosus compared to the marine ecotype however must have another origin and we suggest further investigations of the CO2 fixation rate of Rubisco. The study also included an investigation of the effects of salinity on Pmax and the relative amount of D1, PsaA and Rubisco in the brackish ecotype of F. vesiculosus. Treatment of the algae for one week in 5, 10, 20 and 35 psu resulted in a higher Pmax at higher salinities and a maximum at 10 psu. These results were not reflected in the amount of D1 or Rubisco whereas analyses of the amount of PsaA revealed the highest amount of PsaA in algae treated in 10 psu. We suggest a need of more ATP by cyclic ATP formation to supply a greater Rubisco activity as an explanation.

     

     

  • 7.
    Gylle, Maria
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Nygård, Charlotta
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Ekelund, Nils G. A.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Impacts of UV-radiation on photosynthesis of Fucus vesiculosus at low temperature and different salinities2002Ingår i: Internationale Vereinigung für theoretische und angewandte Limnologie, ISSN 0368-0770, Vol. 28, s. 242-245Artikel i tidskrift (Refereegranskat)
  • 8. Nyberg, M
    et al.
    Nygård, Charlotta
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Ekelund, Nils
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Impacts of UV-radiation on photosynthesis of Fucus vesiculosus at low temperature and different salinities2002Ingår i: The Proceedings of the International Association of Theoretical and Applied Limnology: 28th Congress in Melbourne, Melbourne (Australia), 4-10 Feb 2001, 2002, s. 242-245Konferensbidrag (Refereegranskat)
  • 9.
    Nygård, Charlotta A
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Ecophysiological responses of Baltic and Atlantic Fucus vesiculosus to environmental factors2005Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    The Baltic Sea is a species-poor ecosystem where marine species coexist with freshwater species. The Baltic Sea offers low salinity, low content of inorganic carbon, long cold winters and no tides.One of the few marine species that can be found in the Baltic, is the brown alga Fucus vesiculosus, which is regarded as ecologically the most important alga in this area. The aim of the present thesis was to examine physiological (photosynthesis and growth) differences between F. vesiculosus in the Bothnian Sea (northern Baltic) and the Atlantic. Measurements were performed with plants in their natural seawaters and under changed conditions of salinity, temperature, nutrients and inorganic carbon concentrations.

  • 10.
    Nygård, Charlotta
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap, teknik och matematik.
    Dring, Matthew J
    Influence of salinity, temperature, dissolved inorganic carbon and nutrient concentration on the photosynthesis and growth of Fucus vesiculosus from the Baltic and Irish Seas2008Ingår i: European journal of phycology, ISSN 0967-0262, E-ISSN 1469-4433, Vol. 43, nr 3, s. 253-262Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Fucus vesiculosus from the northern Baltic Sea (5 psu) and from the Irish Sea (35 psu) were cultivated at different temperatures, salinities and dissolved inorganic carbon (DIC) concentrations with the addition of different nutrient concentrations. The influence of these abiotic factors was assessed by measuring photosynthesis as electron transport rate (ETR) and growth as relative growth rate (RGR). The maximal ETR and the RGR of the Irish Sea plants in their natural seawater (50.8 mol electrons m(-2) s-1; 0.024 g g(-1) day(-1)) were significantly higher than those of the Baltic plants in their natural seawater (21.9 mol electrons m-2 s(-1); 0.007 g g(-1) day(-1)). When Baltic F. vesiculosus was cultivated at a DIC concentration similar to that of the Irish Sea, the ETR as well as RGR increased, but never equalled the rates of the marine F. vesiculosus from the Irish Sea. Cultivation at different salinities showed that F. vesiculosus from the Baltic has a higher ETRmax and RGR at low salinities (5-10 psu) than F. vesiculosus from the Irish Sea, whose ETR and RGR decreased sharply in salinities below 20 psu. Plants from both sites grown at high nutrient concentrations, however, performed better at low salinities than those grown under low nutrient conditions. Salinity had the greatest impact on differences in ETR and RGR between the two populations, followed by differences in DIC and nutrient concentrations. There was a highly significant correlation between ETRmax and RGR in plants from both sites and across the full range of culture conditions, indicating that the same amount of energy from photosynthesis is used for growth in both varieties of the species at different salinities. The photosynthesis of F. vesiculosus in the northern Baltic is close to the minimum demand for growth, which may account for their small size. The temperature optimum for F. vesiculosus from the Baltic was 4-10 degrees C, while that for F. vesiculosus from the Irish Sea was 15-20 degrees C. The photosynthesis of Irish Sea plants was less strongly affected by exposure to high irradiances than that of plants from the Baltic.

  • 11.
    Nygård, Charlotta
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Ekelund, Nils
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Effects of lead (PbCl2) on photosynthesis and respiration of the bladderwrack, Fucus vesiculosus, in relation to different salinities.1999Ingår i: Water, Air and Soil Pollution, ISSN 0049-6979, E-ISSN 1573-2932, Vol. 116, nr 3-4, s. 549-565Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The photosynthetic and respiratoric capacity of Fucus vesiculosus grown at three different levels of salinity (4.5, 8 and 20‰) was studied in the presence of different concentrations of lead (5, 10, 15, 20, 25, and 30 mg PbCl2 L-1). The studies were performed by using a light-pipette, which has a precisely defined light source of photosynthetic active radiation (PAR, 400-700 nm). The photosynthetic and respiratoric capacity of the algae were measured when exposed to light pulses with increasing irradiance and after 24 hr in seawater with the addition of lead. The results indicate that the photosynthetic capacity of F. visiculosus from 20‰ is more sensitive to lead compared to those from 8 and 4.5‰. The photosynthetic capacity was reduced by 69% at 30 mg PbCl2 L-1 compared to the control alga. The photosynthetic capacity of F vesiculosus from 8 and 4.5‰ was reduced by 38 and 15%. The respiratoric capacity of F. vesiculosus from 20‰ was reduced by 41% at 30 mg PbCl2 L-1. However, the respiratoric capacity of the algae from 4.5‰ increased by 55% at the same concentration of PbCl2. The results indicate that lead showed inhibitory effects on photosynthesis but a stimulatory effect on respiration of F versiculosus grown at low levels of salinity.

  • 12.
    Nygård, Charlotta
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Ekelund, Nils
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Photosynthesis and UV-B tolerance of the marine alga Fucus vesiculosus at different sea water salinities2006Ingår i: Journal of Applied Phycology, ISSN 0921-8971, E-ISSN 1573-5176, Vol. 18, nr 3-5, s. 461-467Artikel i tidskrift (Refereegranskat)
  • 13.
    Nygård, Charlotta
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Ekelund, Nils
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Photosynthetic properties of Fucus vesiculosus (Phaeophyceae) from different depths and sites in the Bothnian Sea.Manuskript (preprint) (Övrigt vetenskapligt)
1 - 13 av 13
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