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  • PANGAEA  (52)
  • Springer  (8)
Publikationsart
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Verlag/Herausgeber
Erscheinungszeitraum
  • 1
    Digitale Medien
    Digitale Medien
    Photosynthesis of two Arctic macroalgae under different ambient radiation levels and their sensitivity to enhanced UV radiation (2000)
    Springer
    Polar biology 23 (2000), S. 257-264 
    Details
    ISSN: 1432-2056
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The change in optimal quantum efficiency (F v/F m) of the Arctic species Laminaria saccharina and Palmaria palmata was investigated in a long-term experiment in situ under different radiation levels during the summer of 1997 in the Kongsfjord (Ny-Ålesund, Spitsbergen, Norway, 78°55.5′N, 11°56.0′E). Whole plants were incubated in an open box system made of UV-transparent Perspex and exposed to solar radiation (λ〉295 nm), solar radiation excluding UVB (λ 〉 320 nm) and solar radiation excluding UVA + UVB (λ 〉 400 nm). Increasing radiation levels were simulated by transplantation of the pre-adapted algae from their growth depth at 2 m to a water depth of 1 m. Sensitivity to artificially increased UV radiation was determined by exposure of algae from the three treatments to 6 h of strong UV radiation. P. palmata was relatively insensitive to increasing UV radiation and recovered very fast and almost completely in 2 h. Even plants pre-cultured in ambient radiation levels excluding UVA + UVB or UVB only showed no photoinhibition after exposure to extra UV radiation in the laboratory. L. saccharina was, in comparison to P. palmata, more sensitive and showed photoinhibition under solar radiation and solar minus UVB radiation after transplantation from 2 to 1 m water depth. However, after 3 weeks at 1 m depth, F v/F m of L. saccharina was equal in all treatments and restored to the original values at the start of the experiment. Sensitivity to extra UV radiation in the laboratory increased in time, although recovery was also fast and occurred within 20 h.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s003000050442
    Standort Signatur Einschränkungen Verfügbarkeit
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    Artikel (Nationallizenzen)
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  • 2
    Digitale Medien
    Digitale Medien
    Acclimation of brown algal photosynthesis to ultraviolet radiation in Arctic coastal waters (Spitsbergen, Norway) (1998)
    Springer
    Polar biology 20 (1998), S. 388-395 
    Details
    ISSN: 1432-2056
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract In field studies conducted at the Kongsfjord (Spitsbergen) changes of the irradiance in the atmosphere and the sublittoral zone were monitored from the beginning of June until the end of August 1997, to register the minimum and maximum fluxes of ultraviolet and photosynthetically active radiation and to characterise the underwater light climate. Measurements of photosynthesis in three abundant brown algal species (Alaria esculenta, Laminaria saccharina, Saccorhiza dermatodea) were conducted to test whether their photosynthetic performance reflects changing light climate in accordance with depth. Plants sampled at various depths were exposed to controlled fluence rates of photosynthetically active radiation (400–700 nm), UV-A (320–400 nm) and UV-B (280–320 nm). Changes in photosynthetic performance during the treatments were monitored by measuring variable chlorophyll fluorescence of photosystem II. In each species, the degree of inhibition of photosynthesis was related to the original collection depth, i.e. shallow-water isolates were more resistant than plants from deeper waters. The results show that macroalgae acclimate effectively to increasing irradiance levels for both photosynthetically active and ultraviolet radiation. However, the kinetics of acclimation are different within the different species. It is shown that one important strategy to cope with higher irradiance levels in shallow waters is the capability for a faster recovery from high light stress compared to isolates from deeper waters.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s003000050319
    Standort Signatur Einschränkungen Verfügbarkeit
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    Artikel (Nationallizenzen)
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  • 3
    Digitale Medien
    Digitale Medien
    Effects of ultraviolet radiation on photosynthesis and related enzyme reactions of marine macroalgae (2000)
    Springer
    Planta 211 (2000), S. 555-562 
    Details
    ISSN: 1432-2048
    Schlagwort(e): Key words: Macroalgae – Photosynthesis – Ribulose-1, 5-bisphosphate carboxylase/oxygenase – UV radiation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract.  Changes in physiological parameters related to photosynthesis were studied in five macroalgal species from Spitsbergen (Monostroma arcticum, Laminaria solidungula, Alaria esculenta, Palmaria palmata, Phycodrys rubens) during a 72-h exposure to UV radiation. Maximal quantum yield of photochemistry (Fv/Fm) and maximal electron transport rate (ETRmax) were measured with a pulse-amplitude-modulated fluorometer; the activity of the Calvin cycle enzymes ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) and glyceraldehyde-3-phosphate dehydrogenase (G3PDH) were estimated using a photometric test. Proteins of crude extracts were separated by SDS gel electrophoresis and changes in cellular concentrations of Rubisco were determined. Moreover, the concentration of chlorophyll a (Chl a), and protein content, were measured photometrically. In all species, Chl a content, maximal quantum yield as well as ETRmax decreased during the UV treatment. Changes in ETRmax were related to the changes in the overall activity of Rubisco. Analysis of SDS gels showed that in P. rubens, L. solidungula, M. arcticum and A. esculenta decreasing Rubisco activity partly resulted from a degradation of the enzyme. However, in A. esculenta, the formation of a high-molecular-weight polypeptide was observed. In all species, the activity of Rubisco was more strongly impaired than that of G3PDH. Exposure to UV resulted in loss of total protein only in the deepwater species L. solidungula and P. rubens. The different sensitivities to UV exposure of the species tested reflect their zonation pattern in the field.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s004250000313
    Standort Signatur Einschränkungen Verfügbarkeit
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    Artikel (Nationallizenzen)
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  • 4
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    Physiological responses of the calcifying rhodophyte, Corallina officinalis (L.), to future CO2 levels (2012)
    Springer
    In:  Marine Biology, 159 (4). pp. 783-792.
    Details
    Publikationsdatum: 2020-07-14
    Beschreibung: Future atmospheric CO2 levels will most likely have complex consequences for marine organisms, particulary photosynthetic calcifying organisms. Corallina officinalis L. is an erect calcifying macroalga found in the inter- and subtidal regions of temperate rocky coastlines and provides important substrate and refugia for marine meiofauna. The main goal of the current study was to determine the physiological responses of C. officinalis to increased CO2 concentrations expected to occur within the next century and beyond. Our results show that growth and production of inorganic material decreased under high CO2 levels, while carbonic anhydrase activity was stimulated and negatively correlated to algal inorganic content. Photosynthetic efficiency based on oxygen evolution was also negatively affected by increased CO2. The results of this study indicate that C. officinalis may become less competitive under future CO2 levels, which could result in structural changes in future temperate intertidal communities.
    Materialart: Article , PeerReviewed
    Format: text
    DOI: 10.1007/s00227-011-1854-9
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 5
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    Nutrient availability affects the response of the calcifying chlorophyte Halimeda opuntia (L.) J.V. Lamouroux to low pH (2014)
    Springer
    In:  Planta, 239 (1). pp. 231-242.
    Details
    Publikationsdatum: 2014-08-29
    Beschreibung: Atmospheric carbon dioxide emissions cause a decrease in the pH and aragonite saturation state of surface ocean water. As a result, calcifying organisms are expected to suffer under future ocean conditions, but their physiological responses may depend on their nutrient status. Because many coral reefs experience high inorganic nutrient loads or seasonal changes in nutrient availability, reef organisms in localized areas will have to cope with elevated carbon dioxide and changes in inorganic nutrients. Halimeda opuntia is a dominant calcifying primary producer on coral reefs that contributes to coral reef accretion. Therefore, we investigated the carbon and nutrient balance of H. opuntia exposed to elevated carbon dioxide and inorganic nutrients. We measured tissue nitrogen, phosphorus and carbon content as well as the activity of enzymes involved in inorganic carbon uptake and nitrogen assimilation (external carbonic anhydrase and nitrate reductase, respectively). Inorganic carbon content was lower in algae exposed to high CO2, but calcification rates were not significantly affected by CO2 or inorganic nutrients. Organic carbon was positively correlated to external carbonic anhydrase activity, while inorganic carbon showed the opposite correlation. Carbon dioxide had a significant effect on tissue nitrogen and organic carbon content, while inorganic nutrients affected tissue phosphorus and N:P ratios. Nitrate reductase activity was highest in algae grown under elevated CO2 and inorganic nutrient conditions and lowest when phosphate was limiting. In general, we found that enzymatic responses were strongly influenced by nutrient availability, indicating its important role in dictating the local responses of the calcifying primary producer H. opuntia to ocean acidification.
    Materialart: Article , PeerReviewed
    Format: text
    DOI: 10.1007/s00425-013-1982-1
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 6
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    Unbekannt
    CO2 and inorganic nutrient enrichment affect the performance of a calcifying green alga and its noncalcifying epiphyte (2015)
    Springer
    In:  Oecologia, 177 (4). pp. 1157-1169.
    Details
    Publikationsdatum: 2015-06-30
    Beschreibung: Ocean acidification studies in the past decade have greatly improved our knowledge of how calcifying organisms respond to increased surface ocean CO2 levels. It has become evident that, for many organisms, nutrient availability is an important factor that influences their physiological responses and competitive interactions with other species. Therefore, we tested how simulated ocean acidification and eutrophication (nitrate and phosphate enrichment) interact to affect the physiology and ecology of a calcifying chlorophyte macroalga (Halimeda opuntia (L.) J.V. Lamouroux) and its common noncalcifying epiphyte (Dictyota sp.) in a 4-week fully crossed multifactorial experiment. Inorganic nutrient enrichment (+NP) had a strong influence on all responses measured with the exception of net calcification. Elevated CO2 alone significantly decreased electron transport rates of the photosynthetic apparatus and resulted in phosphorus limitation in both species, but had no effect on oxygen production or respiration. The combination of CO2 and +NP significantly increased electron transport rates in both species. While +NP alone stimulated H. opuntia growth rates, Dictyota growth was significantly stimulated by nutrient enrichment only at elevated CO2, which led to the highest biomass ratios of Dictyota to Halimeda. Our results suggest that inorganic nutrient enrichment alone stimulates several aspects of H. opuntia physiology, but nutrient enrichment at a CO2 concentration predicted for the end of the century benefits Dictyota sp. and hinders its calcifying basibiont H. opuntia.
    Materialart: Article , PeerReviewed
    Format: text
    DOI: 10.1007/s00442-015-3242-5
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 7
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    Unbekannt
    Hyposaline conditions affect UV susceptibility in the Arctic kelp Alaria esculenta (Phaeophyceae) - results of laboratory experiments at Kongsfjorden, June/July 2014 (2018)
    PANGAEA
    In:  Supplement to: Springer, Karin; Lütz, Cornelius; Lütz-Meindl, Ursula; Wendt, Angela; Bischof, Kai (2017): Hyposaline conditions affect UV susceptibility in the Arctic kelp Alaria esculenta (Phaeophyceae). Phycologia, 56(6), 675-685, https://doi.org/10.2216/16-122.1
    Details
    Publikationsdatum: 2023-03-23
    Beschreibung: The kelp Alaria esculenta represents a key species in high Arctic marine fjord ecosystems. However, the European Arctic is currently experiencing extensive environmental change. Glacial fjord systems, such as Kongsfjorden (Spitsbergen, Svalbard), are subjected to rising temperature, increased freshwater inflow from glaciers and melting snow and a changing ultraviolet (UV) radiation regime related to stratospheric ozone depletion. Thus, in addition to natural seasonality, sessile organisms require acclimation in order to adapt to an environment in transition. We examined the physiological and ultrastructural responses of A. esculenta to the combined exposure to hyposalinity and UV radiation. Photosynthetic quantum yield slightly decreased during a low-salinity treatment of 7 d. Exposure to UV radiation also lowered quantum yield, but specimens previously treated with hyposalinity were significantly less susceptible to UV than nontreated individuals. Concomitant with a loss of chlorophyll during the hyposaline treatment, phlorotannin and antioxidant contents were maintained, and samples treated with low salinities exhibited higher UV-screening characteristics as demonstrated by significantly higher absorption ratios at 300/680 nm. Ultrastructural analyses revealed a treatment-dependent swelling of cell walls and accumulations of phlorotannin-containing vesicles. Our findings point to a strategy by which kelps apply a fast and cost-efficient redistribution of phlorotannins rather than increased synthesis as a general stress response to different environmental drivers in contrast to stress-specific responses. The notion that acclimation to one stressor (low salinity) reflects increased tolerance towards a second stressor (UV radiation) supports the concept of 'cross-acclimation' as established for higher plants but not yet for seaweeds.
    Schlagwort(e): Antioxidant capacity, in Trolox Equivalents; beta-Carotene; Chlorophyll a; Chlorophyll c1+c2; EXP; Experiment; Family; Fucoxanthin; Initial slope of rapid light curve; KongsfjordenOA; Light saturation point; Maximal electron transport rate; Maximum photochemical quantum yield of photosystem II; Phlorotannins; Ratio; Species; Treatment; Violaxanthin + Antheraxanthin + Zeaxanthin
    Materialart: Dataset
    Format: text/tab-separated-values, 96 data points
    Standort Signatur Einschränkungen Verfügbarkeit
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    DATA PANGAEA
  • 8
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    Responses of a natural phytoplankton community from the Drake Passage to two predicted climate change scenarios (2022)
    PANGAEA
    Details
    Publikationsdatum: 2023-04-05
    Beschreibung: Contrasting models predict two different climate change scenarios for the Southern Ocean (SO), forecasting either less or stronger vertical mixing of the water column. To investigate the responses of SO phytoplankton to these future conditions, we sampled a natural diatom dominated (63%) community from today's relatively moderately mixed Drake Passage waters with both low availabilities of iron (Fe) and light. The phytoplankton community was then incubated at these ambient open ocean conditions (low Fe and low light, moderate mixing treatment), representing a control treatment. In addition, the phytoplankton was grown under two future mixing scenarios based on current climate model predictions. Mixing was simulated by changes in light and Fe availabilities. The two future scenarios consisted of a low mixing scenario (low Fe and higher light, low mixing treatment) and a strong mixing scenario (high Fe and low light, strong mixing treatment). In addition, communities of each mixing scenario were exposed to ambient and low pH, the latter simulating ocean acidification (OA). The effects of the scenarios on particulate organic carbon (POC) production, trace metal to carbon ratios, photophysiology and the relative numerical contribution of diatoms and nanoflagellates were assessed. During the first growth phase, at ambient pH both future mixing scenarios promoted the numerical abundance of diatoms (~75%) relative to nanoflagellates. This positive effect, however, vanished in response to OA in the communities of both future mixing scenarios (~65%), with different effects for their productivity. At the end of the experiment, diatoms remained numerically the most abundant phytoplankton group across all treatments (~80%). In addition, POC production was increased in the two future mixing scenarios under OA. Overall, this study suggests a continued numerical dominance of diatoms as well as higher carbon fixation in response to both future mixing scenarios under OA, irrespective of different changes in light and Fe availability.
    Schlagwort(e): Carbon, organic, particulate, net production; Carbon, organic, particulate, net production, standard deviation; CO2; compiled data; diatoms; DrakePassage; Experiment/study setup; Experimental treatment; Growth phase; iron; Iron/Carbon ratio; Iron/Carbon ratio, standard deviation; Light; mixing; Multiple stressors; Ocean acidification; pH; Photochemical quantum yield; Photochemical quantum yield, standard deviation; Pigments, light harvesting/light protective ratio; Pigments, light harvesting/light protective ratio, standard deviation; Scenario; Southern Ocean
    Materialart: Dataset
    Format: text/tab-separated-values, 168 data points
    Standort Signatur Einschränkungen Verfügbarkeit
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    DATA PANGAEA
  • 9
    facet.materialart.
    Unbekannt
    Nitrate and silicate responses of a natural phytoplankton community from the Drake Passage to different climate change scenarios (2022)
    PANGAEA
    Details
    Publikationsdatum: 2023-04-05
    Beschreibung: Contrasting models predict two different climate change scenarios for the Southern Ocean (SO), forecasting either less or stronger vertical mixing of the water column. To investigate the responses of SO phytoplankton to these future conditions, we sampled a natural diatom dominated (63%) community from today's relatively moderately mixed Drake Passage waters with both low availabilities of iron (Fe) and light. The phytoplankton community was then incubated at these ambient open ocean conditions (low Fe and low light, moderate mixing treatment), representing a control treatment. In addition, the phytoplankton was grown under two future mixing scenarios based on current climate model predictions. Mixing was simulated by changes in light and Fe availabilities. The two future scenarios consisted of a low mixing scenario (low Fe and higher light, low mixing treatment) and a strong mixing scenario (high Fe and low light, strong mixing treatment). In addition, communities of each mixing scenario were exposed to ambient and low pH, the latter simulating ocean acidification (OA). The effects of the scenarios on particulate organic carbon (POC) production, trace metal to carbon ratios, photophysiology and the relative numerical contribution of diatoms and nanoflagellates were assessed. During the first growth phase, at ambient pH both future mixing scenarios promoted the numerical abundance of diatoms (~75%) relative to nanoflagellates. This positive effect, however, vanished in response to OA in the communities of both future mixing scenarios (~65%), with different effects for their productivity. At the end of the experiment, diatoms remained numerically the most abundant phytoplankton group across all treatments (~80%). In addition, POC production was increased in the two future mixing scenarios under OA. Overall, this study suggests a continued numerical dominance of diatoms as well as higher carbon fixation in response to both future mixing scenarios under OA, irrespective of different changes in light and Fe availability.
    Schlagwort(e): CO2; compiled data; diatoms; DrakePassage; Experimental treatment; Incubation duration; iron; Light; mixing; Multiple stressors; Nitrate; Nitrate, standard deviation; Ocean acidification; pH; Silicate; Silicate, standard deviation; Southern Ocean
    Materialart: Dataset
    Format: text/tab-separated-values, 343 data points
    Standort Signatur Einschränkungen Verfügbarkeit
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    DATA PANGAEA
  • 10
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    Unbekannt
    Coping with a changing Arctic: mechanisms of acclimation in the brown seaweed Saccharina latissima from Spitsbergen - raw data to 2-factor experiments with field material from Kongsfjorden, June/July 2019 (2021)
    PANGAEA
    Details
    Publikationsdatum: 2023-01-30
    Beschreibung: Polar Regions are facing rapid temperature increase. Combined with other factors temperature increase might have a strong impact on foundation species in Arctic shallow-water coastal ecosystems, such as the abundant kelp Saccharina latissima. We ran two short-term 2-factor experiments with field samples from Kongsfjorden (Svalbard) to reveal the impact of temperature increase in summer combined with hyposalinity (temperature × salinity) or nutrient enrichment (temperature × nutrients) and analyzed different biochemical and physiological parameters. The experiments were conducted with field samples at AWIPEV Station in Ny-Ålesund, Svalbard (Spitsbergen) in June/July 2019. As physiological parameter, size and the maximum photosynthetic quantum yield of photosystem II (Fv/Fm; Imaging-PAM, Walz GmbH Mess- und Regeltechnik, Effeltrich, Germany) were monitored every second day. For growth, the size of the algal discs was analyzed with ImageJ (Version 1.52a). For better comparison of the physiological parameters, Fv/Fm and growth the initial size of the different treatments was adjusted to 100% and size of each sample as % of initial was calculated. The C:N ratio, total nitrogen and total carbon content were analyzed with an elemental analyzer. Mannitol, as well as absolute pigment concentrations were analyzed using a HPLC. The de-expoxidation state of the xanthophyll cycle (DPS) and chlorophyll a : accessory pigment ratio calculated afterwards. Phlorotannins were analyzed using the photometric Folin-Ciocalteu method.
    Schlagwort(e): C:N; interactive effects; kelp; Mannitol; nutrients; pigments; Salinity; Temperature
    Materialart: Dataset
    Format: application/zip, 12 datasets
    Standort Signatur Einschränkungen Verfügbarkeit
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    DATA PANGAEA
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