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  • 1
    Electronic Resource
    Electronic Resource
    Growth pattern andβ-dimethylsulphoniopropionate (DMSP) content of green macroalgae at different irradiances (1991)
    Springer
    Marine biology 108 (1991), S. 151-155 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Growth rates and intracellularβ-dimethylsulphoniopropionate (DMSP) concentrations of five green algal species collected from different geographic regions in 1986 and 1989 were determined under four photon flux rates. InUlothrix implexa, U. subflaccida andAcrosiphonia arcta from Antarctica, growth was light-saturated at lower irradiances than in temperateUlva rigida from Southern Chile andBlidingia minima from Germany. The DMSP content ofUlothrix implexa, A. arcta andUlva rigida was directly correlated with the light factor: with increasing irradiance, algal DMSP level increased. In contrast, inUlothrix subflaccida andB. minima DMSP concentrations gradually decreased up to a photon flux rate of 30µmol m−2 s−1, then increased markedly under the highest photon flux rate tested. In non-growing, dark-incubatedA. arcta DMSP content was reduced by 35%, while the DMSP pool of all other species remained unchanged, at the level of pre-culture conditions. Under full darkness all plants exhibited a significantly higher DMSP concentration compared with algae grown at low photon flux rates of 2 to 30µmol m−2 s−1. These data show a correlation between growth pattern and DMSP biosynthesis, and may point to a species-specific minimum amount of light energy necessary for DMSP accumulation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01313483
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  • 2
    Electronic Resource
    Electronic Resource
    UV-radiation can affect depth-zonation of Antarctic macroalgae (1998)
    Springer
    Marine biology 131 (1998), S. 597-605 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Due to depletion of stratospheric ozone over polar regions of the Northern and Southern Hemispheres UV-B-radiation has increased at the surface of the earth. Measurements of variable chlorophyll fluorescence were conducted to document UV-induced photoinhibition of photosystem II in cultivated macroalgae with different depth distributions in Antarctica. The reactions during artificial UV-exposure were observed on a short time scale (hours) and in light–dark cycles over several days. The nine species of investigated macroalgae show great differences in UV-tolerance of the photosynthetic process. Photosynthesis of the studied green algae was inhibited to a minor degree, while the brown algae showed an intermediate inhibition of photosynthesis. The response of the studied red algae varied with species. The differences in the degree of inhibition and recovery of photosynthetic efficiency and capacity indicate that UV-radiation is one important factor affecting the vertical distribution of macroalgae in nature.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002270050351
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  • 3
    Electronic Resource
    Electronic Resource
    Arctic-Antarctic disjunctions in the benthic seaweeds Acrosiphonia arcta (Chlorophyta) and Desmarestia viridis/willii (Phaeophyta) are of recent origin (1993)
    Springer
    Marine biology 115 (1993), S. 381-386 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Two examples of the most extreme biogeographic disjunctions in benthic marine algae are found in Acrosiphonia arcta (Chlorophyta) and Desmarestia viridis/willii (Phaeophyta). Both species are members of the Arctic and Antarctic boreal and subboreal marine floras. Although both genera have temperate species, neither genus has subtropical or tropical representative. Comparisons of the fast-evolving ribosomal DNA internal transcribed spacer regions among isolates in each of the two species collected from both hemispheres showed an unexpected near sequence identity suggesting that these biogeographic disjunctions are of recent origin, possibly as recent as the last Pleistocene glacial maximum (18000 yr ago). Paleoclimatic explanations that rely on a much earlier transequatorial passage of cold-adapted species through a narrowed and cooler tropical belt during the Oligocene/Miocene (38 to 7 Ma ago) are unlikely. We hypothesize that despite the separated evolutionary histories of the northern and southern hemisphere coldwater marine floras, deep-water dispersal of microthalli has occurred and probably occurs on a regular basis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00349835
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  • 4
    Electronic Resource
    Electronic Resource
    Seasonal photosynthetic characteristics of Ascoseira mirabilis (Ascoseirales, Phaeophyceae) from King George Island, Antarctica (1995)
    Springer
    Marine biology 123 (1995), S. 167-172 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Monthly variation in photosynthesis, dark respiration, chlorophyll a content and carbon: nitrogen (C:N) ratios in different lamina sections of adult plants of Ascoseira mirabilis Skottsberg from King George Island, Antarctica, was investigated between September 1993 and February 1994. Light saturated net photosynthesis (P max) showed maximum values in September (12 to 25 μmol O2 g-1 fr wt h-1), and decreased towards the summer to values ranging between 2.0 and 5.0 μmol O2 g-1. In the distal section, however, a second optimum occurred in December (25 μmol O2 g-1 fr wt h-1). Dark respiration rates were also highest in October and November and decreased strongly in December to February (6.0 and 1.0 μmol O2 g-1 fr wt h-1, respectively). Gross photosynthesis exhibited high values between September and December. Concomitant with the seasonal decrease of photosynthetic efficiency (α) from mean values of 1.2 μmol O2 g-1 fr wt h-1 (μmol photons cm-2 s-1)-1 in September to 0.3 μmol O2 g-1 fr wt h-1 (μmol photons cm-2 s-1)-1 in January, the initial light saturating point (I k) gradually increased from 19 to 60 μmol photons m-2 s-1. Likewise C:N ratios were low in spring (12 to 13) and increased in summer (20). In general, the photosynthetic parameters P max, gross photosynthesis, α and Chl a concentrations were significantly higher in the distal section of the thallus. In contrast, C:N ratios were lower in the distal section of the lamina. The results show that photosynthesis obviously strongly supports growth of the alga in late winter to spring, as it does in some morphologically related brown algae from temperate and polar regions. The question whether growth is additionally powered
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00350336
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  • 5
    Electronic Resource
    Electronic Resource
    Temperature adaptation in strains of the amphi-equatorial green alga Urospora penicilliformis (Acrosiphoniales): biogeographical implications (1995)
    Springer
    Marine biology 122 (1995), S. 681-688 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The temperature requirements for growth and the upper survival temperatures (UST's) of the amiphi-equatorial green alga Urospora penicilliformis collected from several localities within its distribution area between 1986 and 1991 were determined. Ecotypic variation, both with regard to growth ranges and optima and to survival temperatures, was demonstrated. In the polar strains of U. penicilliformis, temperature growth ranges were narrower and the growth optima and UST's were at lower temperatures compared to cold-temperate strains. In particular, the polar strains grew between 0 and 15°C with optimal growth at 0 or 5°C, whereas the cold-temperate isolates grew between 0 and (15) 20°C with almost equal growth rates or a growth optimum between 5 and 15°C. The Arctic strains survived 23 to 24°C, and the Antarctic isolate only 19°C, while the UST's of the cold-temperate isolates were between (24) 25 to 26°C. The data strongly indicate that a cold water history of ca. 3 million yr in the Arctic can be sufficient for changes in the temperature growth ranges and optima as well as for small changes of UST as shown in the Arctic populations of U. penicilliformis. For stronger reduction of upper survival temperatures, longer time periods are necessary as exemplified in the isolate from Antarctica, where low temperatures have existed for at least 14 million yr. The significantly lower UST of the Antarctic strain, points to an early contact of the alga with the cold water of the Antarctic region and may indicate an origin of U. penicilliformis in the Southern Hemisphere. The UST's of the cold-temperate isolates (24 to 26°C) would have allowed a migration across the equator during Pleistocene lowerings of the seawater temperatures in the tropics. Growth, however, would not have been possible during the passage across the equator due to the narrow temperature-growth window. The nature of the geographical boundaries and the control of seasonal development of U. penicilliformis by the temperature conditions in the various geographical regions are discussed in relation to the present local temperature regime.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00350690
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  • 6
    Electronic Resource
    Electronic Resource
    Sensitivity of Laminariales zoospores from Helgoland (North Sea) to ultraviolet and photosynthetically active radiation: implications for depth distribution and seasonal reproduction (2005)
    Oxford, UK : Blackwell Science Ltd
    Plant, cell & environment 28 (2005), S. 0 
    Details
    ISSN: 1365-3040
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Depth distribution of kelp species in Helgoland (North Sea) is characterized by occurrence of Laminaria digitata in the upper sublittoral, whereas L. saccharina and L. hyperborea dominate the mid and lower sublittoral region. Laminaria digitata is fertile in summer whereas both other species are fertile in autumn/winter. To determine the light sensitivity of the propagules, zoospores of L. digitata, L. saccharina and L. hyperborea were exposed in the laboratory to different exposure times of photosynthetically active radiation (PAR; 400–700 nm), PAR + UVA radiation (UVAR; 320–400 nm) and PAR + UVAR + UVB radiation (UVBR; 280–320 nm). Optimum quantum yield of PSII and DNA damage were measured after exposure. Subsequently, recovery of photosynthetic efficiency and DNA damage repair, as well as germination rate were measured after 2 and 3 d cultivation in dim white light. Photosynthetic efficiency of all species was photoinhibited already at 20 µmol photons m−2 s−1 PAR, whereas UV radiation (UVR) had a significant additional effect on photoinhibition. Recovery of the PSII function was observed in all species but not in spores exposed to irradiation longer than 4 h of PAR + UVA + UVB and 8 h of PAR + UVA. The amount of UVB-induced DNA damage measured as cyclobutane–pyrimidine dimers (CPDs) increased with exposure time and highest damage was detected in the spores of lower subtidal L. hyperborea relative to the other two species. Significant removal of CPDs indicating repair of DNA damage was observed in all species after 2 d in low white light especially in the spores of upper subtidal L. digitata. Therefore, efficient DNA damage repair and recovery of PSII damage contributed to the germination success but not in spores exposed to 16 h of UVBR. UV absorption of zoospore suspension in L. digitata is based both on the absorption by the zoospores itself as well as by exudates in the medium. In contrast, the absorption of the zoospore suspension in L. saccharina and L. hyperborea is based predominantly on the absorption by the exudates in the medium. This study indicates that UVR sensitivity of zoospores is related to the seasonal zoospore production as well as the vertical distribution pattern of the large sporophytes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-3040.2005.01288.x
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  • 7
    Electronic Resource
    Electronic Resource
    The effect of light intensity and daylength on the β-dimethylsulphoniopropionate (DMSP) content of marine green macroalgae from Antarctica (1990)
    Oxford, UK : Blackwell Publishing Ltd
    Plant, cell & environment 13 (1990), S. 0 
    Details
    ISSN: 1365-3040
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Abstract. The β-dimethylsulphoniopropionate (DMSP) concentrations of 5 Antarctic green algae grown at 2, 30 and 55 μmol photons m−2 s−1 were determined during a period of one year, cultivated under fluctuating daylengths mimicking the conditions of the natural habitat at King George Island. Antarctica. The intracellular DMSP content of all species decreased simultaneously with decreasing daylengths and vice versa. Additionally, the DMSP level was affected by the light intensity: the higher the photon fluence rate the greater the algal DMSP concentration. Under conditions of darkness, there was a degradation of the DMSP pool in members of the Acrosiphoniales, while the DMSP content in members of the Ulvales did not change. The results indicate a light-dependent DMSP accumulation in algae. Therefore, they may help to explain the seasonal variability of DMSP and its cleavage product dimethylsulphide (DMS) in coastal waters.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-3040.1990.tb01991.x
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  • 8
    Electronic Resource
    Electronic Resource
    Calcium compartmentation in Antarctic brown algae
    Amsterdam : Elsevier
    Ultramicroscopy 32 (1990), S. 7-11 
    Details
    ISSN: 0304-3991
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Electrical Engineering, Measurement and Control Technology , Natural Sciences in General , Physics
    Type of Medium: Electronic Resource
    URL: http://linkinghub.elsevier.com/retrieve/pii/0304-3991(90)90087-3
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  • 9
    Electronic Resource
    Electronic Resource
    Incomplete turgor adjustment in Cladophora rupestrisunder fluctuating salinity regimes
    Amsterdam : Elsevier
    Estuarine, Coastal and Shelf Science 34 (1992), S. 413-427 
    Details
    ISSN: 0272-7714
    Keywords: Cladophora rupestris ; North Wales ; amino acids ; fluctuating salinity ; glycine betaine ; inorganic ions ; turgor pressure
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology , Geography , Geosciences
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1016/S0272-7714(05)80079-4
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  • 10
    Electronic Resource
    Electronic Resource
    Seasonality of brown macroalgae from Antarctica—a long-term culture study under fluctuating Antarctic daylengths (1990)
    Springer
    Polar biology 10 (1990), S. 589-600 
    Details
    ISSN: 1432-2056
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The seasonal development of the endemic Antarctic Desmarestiales Himantothallus grandifolius, Phaeurus antarcticus, Desmarestia anceps, of a ligulate Desmarestia sp., of the Antarctic cold-temperate Adenocystis utricularis (Dictyosiphonales) and of the endemic Antarctic Ascoseira mirabilis (Ascoseirales) was monitored in a 2-year culture study under fluctuating daylengths mimicking the daylength conditions on King George Island (Antarctica). Temperature was kept constant at 0° C and nutrient levels were maintained at 0.6 moles m−3 nitrate and 0.025 moles m −3 phosphate. Sporophytes were initiated between (April-) June and July in all Desmarestiales. This event was controlled either by induction of gametophyte fertility (in H. grandifolius and D. anceps) or by induction of spore formation (in Desmarestia sp. and P. antarcticus). Young sporophytes of all species showed a growth optimum from September to December (-February). Desmarestia sp. and P. antarcticus produced spores and degenerated subsequently after one year of culture at ≥3 μmol photons m−2 s−1 or after 22 months of culture at 2 μmol m−2 s−1. In D. anceps spores were released without degeneration of the mother plants after 20 and 19 months of culture at 3 and 10 μolm−2 s−1, respectively. In H. grandifolius spore formation was not observed. Adult one year old plants of the latter two perennial species showed growth optima between September and November. Microthalli of A. utricularis were the dominant life phase of this alga in winter. Macrothalli started to develop from June onwards at ≥3 μmol m−2 s−1 or from August to September at 2 μmol m−2 s−1. Growth rates of macrothalli cultivated at ≥9 μmol m−2 s−1 showed a growth optimum from September to November. The macrothalli released spores from January to February. Macrothalli cultivated at ≥3 μmol m−2 s−1 maximally grew in January. They became fertile after almost 2 years of culture at 3 μmol m−2 s−1 and remained vegetative at 2 μmol m−2 s−1. A. mirabilis exhibited a prominent growth optimum from August to October, at photon fluence rates between 2 and 47 μmol m−2 s−1. A second optimum was evident from January to March in plants cultivated at ≥9 μmol m−2 s−1. The results closely correspond to available field data and indicate that the phenology of the studied species can be controlled in the laboratory solely by simulating Antarctic daylengths conditions. The light requirements for growth were very low in microthalli and in juvenile macrothalli and growth was mostly light saturated at 4–12 μmol m−2 s−1. Few-celled sporophytes of H. grandifolius and D. anceps tolerated at least 8 and 11 months of darkness. The minimum light demands for completion of the life cycle are 31.4 mol m−2 year−1 in Desmarestia sp., P. antarcticus and probably also in the 2 perennial Desmarestiales; 47.1 mol m−2 year−1 are needed in A. utricularis and probably also in A. mirabilis. These values predict a lower distribution limit of the investigated species at 53±23 m or 48±21 m in clear offshore waters and at 28±5 m or 26±5 m, respectively, in inshore fjords of the Antarctic Peninsula region.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00239370
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