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- Brutemark, Andreas, et al.
(författare)
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Growth, toxicity and oxidative stress of a cultured cyanobacterium (Dolichospermum sp.) under different CO2/pH and temperature conditions
- 2015
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Ingår i: Phycological Research. - : Wiley. - 1322-0829 .- 1440-1835. ; 63:1, s. 56-63
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Tidskriftsartikel (refereegranskat)abstract
- Cyanobacteria blooms are a worldwide nuisance in fresh, brackish and marine waters. Changing environmental conditions due to upwelling, changed mixing conditions or climate change are likely to influence cyanobacteria growth and toxicity. In this study, the response of the toxic cyanobacterium Dolichospermum sp. to lowered pH (-0.4 units by adding CO2) and elevated temperature (+4 degrees C) in an experimental set-up was examined. Growth rate, microcystin concentration and oxidative stress were measured. The growth rate and intracellular toxin concentration increased significantly as a response to temperature. When Dolichospermum was exposed to the combination of elevated temperature and high CO2/low pH, lipid peroxidation increased and antioxidant levels decreased. Microcystin concentrations were significantly correlated with growth rates. Our results show, although oxidative stress increases when exposed to a combination of high CO2/low pH and high temperature, that growth and toxicity increase at high temperature, suggesting that the cyanobacterium in general seems to be fairly tolerant to changes in pH and temperature. Further progress in identifying biological responses and predicting climate change consequences in estuaries experiencing cyanobacteria blooms requires a better understanding of the interplay between stressors such as pH and temperature.
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| 2. |
- Gylle, Maria, et al.
(författare)
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Research note: Ecotype differentiation in qualitative content of water soluble organic compounds between marine and brackish Fucus vesiculosus L. (Phaeophyceae)
- 2009
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Ingår i: Phycological Research. - : Wiley. - 1322-0829 .- 1440-1835. ; 57:2, s. 127-130
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Tidskriftsartikel (refereegranskat)abstract
- In the present study we compared the contents of water soluble organic compounds of the marine intertidal ecotype of Fucus vesiculosus (Phaeophyceae) from the Norwegian Sea (34 practical salinity units, psu) with the sublittoral ecotype of F. vesiculosus from the brackish Bothnian Sea (5 psu). Nuclear magnetic resonance spectra revealed that marine F. vesiculosus had additional types of water soluble organic compounds compared with brackish F. vesiculosus. The results suggested that glycine betaine in the marine ecotype could be the reason for this ecotype differentiation. Furthermore, the qualitative differences between the ecotypes were the same after one week's treatment of marine algae in brackish water and of brackish algae in marine water. These suggest that the additional types of water soluble organic compounds in marine F. vesiculosus are not caused by the salinity conditions at the growth sites. Further research concerning other environmental factors that may influence ecotype differentiation of water soluble organic compounds qualitative content and adaptation in F. vesiculosus is recommended.
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| 3. |
- Müller, Ruth, et al.
(författare)
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UV-radiation and elevated temperatures induce formation of reactive oxygen species in gametophytes of cold-temperate/Arctic kelps (Laminariales, Phaeophyceae)
- 2012
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Ingår i: Phycological Research. - : Wiley. - 1322-0829 .- 1440-1835. ; 60:1, s. 27-36
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Tidskriftsartikel (refereegranskat)abstract
- Enhanced UV-radiation (UVR) through stratospheric ozone depletion and global warming are crucial stressors to marine macroalgae. Damages may arise through formation of reactive oxygen species (ROS) in gametophytes of ecologically important kelps, brown algae of the order Laminariales, Such stress-induced damages may have a negative impact on their fitness and further impact their following life stages. In our study, gametophytes of three kelp species Alaria esculenta (L.) Grev., Laminaria digitata (Huds.) Lamour., Saccharina latissima (L.) Lane, Mayes, Druehl, Saunders from the Arctic, and of L. hyperborea (Gunnerus) Foslie from the North Sea were exposed to photosynthetically active radiation, UV-A, and UV-B radiation and four temperatures (2-18°C). ROS are formed predominantly in the peripheral cytoplasm and in chloroplasts especially after exposure to UVR. Superoxide (O2*-) is additionally formed in small, globular cytoplasmic structures, possibly mitochondria. In the surrounding medium O2*--concentration increased markedly at elevated temperatures and under UV stress in some cases. Ultrastructural damage was negligible pointing to a high stress tolerance of this developmental stage. Our data indicate that stress tolerant gametophytes of three Arctic kelp species should sustain their crucial function as seed bank for kelp populations even under prospective rising environmental perturbations. © 2011 Japanese Society of Phycology.
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