Physiological acclimation to gradients of solar irradiance within mats of the filamentous green macroalgaChaetomorpha linumfrom southern Spain

Chaetomorpha linum(Müller) Kützing is a dominant mat-forming green macroalgal species within eutrophic systems. Its structure, comprising thick mats of interwoven filaments, requires acclimation to either high or low irradiance along a steep gradient of light arising from self-shading. Occurring in...

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Bibliographic Details
Published in:Marine ecology. Progress series (Halstenbek) 2006-01, Vol.306, p.165-175
Main Authors: Bischof, Kai, Rautenberger, Ralf, Brey, Lena, Pérez-Lloréns, José Lucas
Format: Article
Language:English
Subjects:
Acclimatization
Algae
Irradiance
Oxidative stress
Oxygen
Photosynthesis
Photosynthetically active radiation
Pigments
Renewable energy
Solar radiation
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Summary:Chaetomorpha linum(Müller) Kützing is a dominant mat-forming green macroalgal species within eutrophic systems. Its structure, comprising thick mats of interwoven filaments, requires acclimation to either high or low irradiance along a steep gradient of light arising from self-shading. Occurring in high-light environments, such as that along the southern coast of Spain,C. linummats represent an excellent model system for studying spatial differences in photoacclimation and also the interactive effects of photosynthetically active and ultraviolet radiation on photoinhibition. This study was conducted in eutrophic brine-pond systems along the Bay of Cádiz (southern Spain). For periods of up to 1 wk,C. linummats were exposed to natural solar radiation under different cut-off filters to study the effects of different wavelength ranges on photosynthetic activity, pigment and protein composition, and the occurrence of oxidative stress and changes in enzymatic activity of superoxide dismutase (SOD). The results revealed a particularly high tolerance ofC. linumphotosynthesis to high light and UV exposure. Addition of the UV-B range (280 to 315 nm) to photosynthetically active radiation, resulted in inhibition of non-photochemical quenching, a delay in recovery from photoinhibition, and an increase in both lipid peroxidation and SOD activity. In contrast, pigment and protein data revealed acclimation to the high irradiances of photosynthetically active radiation, but no additional effect of UV radiation. The data suggest that even in a high-radiation environment such as southern Spain, UV-B radiation plays a minor role in photoacclimation ofC. linum, but is effective in increasing both the generation and scavenging of oxidative stress. The UV-induced increase in SOD activity represents an important physiological acclimation mechanism ofC. linum, enabling it to thrive under high UV radiation and high-light conditions.
ISSN:0171-8630
1616-1599