Ultraviolet radiation shapes seaweed communities

Bischof, Kai; Gómez, Iván; Molis, Markus; Hanelt, Dieter; Karsten, Ulf; Lüder, Ulrike; Roleda, Michael Y.; Zacher, Katharina; Wiencke, Christian

doi:10.1007/s11157-006-0002-3

Cited by 202 publications

(131 citation statements)

References 183 publications

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“…Macroalgae regulate their biochemical composition to changes in solar radiation (Bischof et al, 2006;Figueroa et al, 2014a,b). Whilst light obviously affects photosynthesis, other variables such pH, nutrients and the availability of different DIC species all have the potential to affect photosynthetic rates .…”

Section: Discussionmentioning

confidence: 99%

Macroalgal responses to ocean acidification depend on nutrient and light levels

et al. 2015

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Ocean acidification may benefit algae that are able to capitalize on increased carbon availability for photosynthesis, but it is expected to have adverse effects on calcified algae through dissolution. Shifts in dominance between primary producers will have knock-on effects on marine ecosystems and will likely vary regionally, depending on factors such as irradiance (light vs. shade) and nutrient levels (oligotrophic vs. eutrophic). Thus experiments are needed to evaluate interactive effects of combined stressors in the field. In this study, we investigated the physiological responses of macroalgae near a CO 2 seep in oligotrophic waters off Vulcano (Italy). The algae were incubated in situ at 0.2 m depth using a combination of three mean CO 2 levels (500, 700-800 and 1200 μatm CO 2 ), two light levels (100 and 70% of surface irradiance) and two nutrient levels of N, P, and K (enriched vs. non-enriched treatments) in the non-calcified macroalga Cystoseira compressa (Phaeophyceae, Fucales) and calcified Padina pavonica (Phaeophyceae, Dictyotales). A suite of biochemical assays and in vivo chlorophyll a fluorescence parameters showed that elevated CO 2 levels benefitted both of these algae, although their responses varied depending on light and nutrient availability. In C. compressa, elevated CO 2 treatments resulted in higher carbon content and antioxidant activity in shaded conditions both with and without nutrient enrichment-they had more Chla, phenols and fucoxanthin with nutrient enrichment and higher quantum yield (F v /F m ) and photosynthetic efficiency (α ETR ) without nutrient enrichment. In P. pavonica, elevated CO 2 treatments had higher carbon content, F v /F m , α ETR , and Chla regardless of nutrient levels-they had higher concentrations of phenolic compounds in nutrient enriched, fully-lit conditions and more antioxidants in shaded, nutrient enriched conditions. Nitrogen content increased significantly in fertilized treatments, confirming that these algae were nutrient limited in this oligotrophic part of the Mediterranean. Our findings strengthen evidence that brown algae can be expected to proliferate as the oceans acidify where physicochemical conditions, such as nutrient levels and light, permit.

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Section: Discussionmentioning

confidence: 99%

Macroalgal responses to ocean acidification depend on nutrient and light levels

et al. 2015

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“…The high irradiance and transparency of shallow water in this region suggest that macroalgae have de-veloped efficient photoprotection mechanisms to tolerate light stress (Figueroa and Gómez 2001). In fact, intertidal macroalgae subject to high solar irradiance and desiccation can survive and grow under the stressful conditions of the intertidal system due to active photoprotection mechanisms such as dynamic photoinhibition, accumulation of UV screen substances and increase in antioxidant capacity (Häder and Figueroa 1997, Korbee et al 2006, Bischof et al 2006, Hanelt and Figueroa 2012.…”

Section: Introductionmentioning

confidence: 99%

Seasonal photoacclimation patterns in the intertidal macroalga <em>Cystoseira tamariscifolia</em> (Ochrophyta)

et al. 2014

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Summary: Cystoseira tamariscifolia thalli collected from rocky shores and rockpools in winter and summer in Southern Spain were incubated for 7 days in UV transparent cylindrical vessels under outdoor conditions. Photosynthetic activity estimated as in vivo chlorophyll a fluorescence of photosystem II, photosynthetic pigments, antioxidant activity (DPPH assay), phenolic compounds and total internal C and N contents were determined after short-term (3 d) and mid-term (7 d) periods. Maximum quantum yield of PSII (F v /F m ) was significantly higher in field-collected algae and after 7 d incubation in winter than in summer. In rocky shores and rockpools thalli, maximum electron transport rate (ETR max ) and photosynthetic efficiency (a ETR ) were much higher in summer than in winter. ETR of outdoor-grown thalli (in situ ETR) showed a daily pattern, with a decrease at noon in both winter and summer (3 rd and 7 th days). We found much higher antioxidant activity in thalli collected in summer than in winter. However, the concentration of internal UV screen substances (polyphenols) was higher in winter than in summer, whereas the release of phenolic compounds was lower. The highest capacity of acclimation in C. tamariscifolia found in summer and RS with emersion periods was explained by the highest dynamic photoinhibition, energy dissipation (non-photochemical quenching) and antioxidant activity (EC 50 ).Keywords: antioxidant activity; Cystoseira tamariscifolia; phenolic compounds; photoinhibition; photoprotection. Patrones estacionales de fotoaclimatación en el alga intermareal, Cystoseira tamariscifolia (Ochrophyta)Resumen: Talos de Cystoseira tamariscifolia recolectados en pozas y plataformas rocosas intermareales (Sur de España) en invierno y en verano se incubaron bajo radiación solar durante 7 días en recipientes cilíndricos de metacrilato transparentes a la radiación UV. Se estimó la actividad fotosintética a través de la fluorescencia de la clorofila a asociada al fotosistema II, el contenido de pigmentos fotosintéticos y compuestos fenólicos, actividad antioxidante y el contenido total en C y N internos tras 3 y 7 días de incubación. Los valores iniciales del rendimiento cuántico máximo (F v /F m ) fueron significativamente mayores en algas recolectadas en invierno que en verano mientras que la tasa de transporte electrónico máximo (ETR max ) y la eficiencia fotosintética fueron mayores en verano que en invierno en ambas zonas. Por otra parte, la tasa de transporte electrónico determinada bajo radiación solar presentó un patrón diario, con una disminución a mediodía, tanto en invierno como en los períodos de verano. La actividad antioxidante fue mayor en algas recogidas en verano; sin embargo, la concentración interna de compuestos fenólicos fue mayor en invierno que en verano, mientras que en la tasa de excreción se observó lo contrario. La alta capacidad de aclimatación en C. tamariscifolia en algas sometidas a emersión en las plataformas rocosas en verano se explica por su alta fotoinhibición dinámica, su c...

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“…As more CO 2 dissolves in seawater, changes in the speciation of inorganic carbon occur, resulting in more bicarbonate ions (HCO 3 − ), more protons (H + ) and fewer carbonate ions (CO 3 drop by 0.3 to 0.5 units (Caldeira & Wickett 2003, Feely et al 2004, Orr et al 2005 due to increasing concentrations of atmospheric CO 2 that could reach up to 970 ppm CO 2 (Houghton et al 2001). In addition, both ocean temperature increases due to global warming and increased UVR due to the development of ozone holes may represent a real threat for all sessile marine organisms (Bischof et al 2006).…”

Section: Introductionmentioning

confidence: 99%