Depth-dependent responses to solar ultraviolet radiation and oxidative stress in the zooxanthellate coral Acropora microphthalma

Shick, J. Malcolm; Lesser, Michael P.; Dunlap, Walter C.; Stochaj, Wayne R.; Chalker, Bruce; Won, Jongho

doi:10.1007/bf00349276

Cited by 184 publications

(149 citation statements)

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“…Thus, deeper-growing species display a greater decrease of F v /F m in response to UVR exposure than do shallower-growing species. This type of relationship between photoinhibition and depth distribution has been reported previously for several species of marine macroalgae (Dring et al 1996;Hanelt et al 1997;Hanelt 1998;Bischof et al 2000b) and zooxanthellate corals (Shick et al 1995).…”

Section: Discussionsupporting

confidence: 84%

“…C. corallina was exposed during our experiments to UVR flux that is unrealistic in terms of the natural conditions it would encounter in the lake; however, the results demonstrate the link between the presence of UVR-absorbing compounds and UVR tolerance. Decreasing concentration of MAAs has previously been related to decreasing UVR exposure associated with increasing depth for a zooxanthellate coral (Shick et al 1995), plankton samples (Sommaruga and Garcia-Pichel 1999) and marine macroalgae (Bischof et al 2000b). Despite the same lack of UVR-absorbance by the two characeans in our experiments, the upper growth limit of C. fibrosa is 10 m shallower than that of C. corallina.…”

Section: Discussionsupporting

confidence: 42%

“…Zonation of marine macroalgae in upper and lower subtidal regions may be related to tolerance of inhibiting irradiance in general (Hanelt et al 1997;Hanelt 1998) and UVR in particular (Bischof et al 1998;Bischof et al 2000b). Differential sensitivity to UVR among marine macroalgae, as well as other organisms such as coral zooxanthellae, has been suggested to be due in part to the composition and concentration of the UVR-absorbing mycosporine-like amino acids (MAAs) within their tissues (Shick et al 1995;Bischof et al 2000b). Freshwater macrophytes also display zonation patterns along a depth gradient within the littoral zones of lakes (Wetzel 1983).…”

Section: Introductionmentioning

confidence: 99%

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Sensitivity of freshwater macrophytes to UV radiation: relationship to depth zonation in an oligotrophic New Zealand lake

Rae¹,

Hanelt

Hawes³

2001

Mar. Freshwater Res.

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Abstract. The ultraviolet radiation (UVR) responses of photosynthesis by two freshwater vascular plants, Potamogeton cheesemanii and Isoetes alpinus, and the characean algae Chara fibrosa and C. corallina in Lake Coleridge, New Zealand, were investigated. Experiments comprised 4-5 h of exposure to different UV wavelengths followed by 17 h of recovery in low light. Photosynthetic competence was assessed by pulse-amplitude-modulated fluorometry. The four species showed different sensitivities to UVR, which were consistent with their upper depth limits. The shallowest-growing species, P. cheesemanii, was uninhibited by UVR, whereas after 5 h of exposure to UVR, inhibition of 15%, 38% and 48% was measured for I. alpinus, C. fibrosa and C. corallina collected from 4 m, 6.2 m and 16.5 m, respectively. Not all plants recovered fully from UVR inhibition. Plants from upper and lower depths of their growth range did not generally differ in inhibition sustained or ability to recover photosynthesis. The species with greatest tolerance of UVR also contained the highest concentrations of UVR-absorbing pigments. Freshwater macrophytes have differing abilities to tolerate UVR exposure through repair and/or protection strategies and these may be related to their vertical zonation.

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Section: Discussionsupporting

confidence: 84%

Section: Discussionsupporting

confidence: 42%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Sensitivity of freshwater macrophytes to UV radiation: relationship to depth zonation in an oligotrophic New Zealand lake

Rae¹,

Hanelt

Hawes³

2001

Mar. Freshwater Res.

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“…Photosynthetic organisms have evolved defense mechanisms to reduce oxidative injury [33]. Various molecules such as carotenoids, tocopherols, ascorbate, and reduced glutathione provide protection against ROS.…”

Section: Introductionmentioning

confidence: 99%

Ultraviolet-B exposure induces photo-oxidative damage and subsequent repair strategies in a desert cyanobacterium Microcoleus vaginatus Gom.

Xie

Wang

Liu

et al. 2009

European Journal of Soil Biology

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“…However, not all corals within a reef are equally susceptible to elevated temperature stress (5,6). Although elevated temperatures often lead to a reduction in the quantum yield of photochemistry, a concomitant increase in the rate of protein turnover in oxygen-generating reaction center, photosystem (PS)II (7)(8)(9), and an increase in the production of reactive oxygen species (ROS) (10)(11)(12), no mechanism has been elucidated. Here we show that thermal sensitivity in isolated clones of zooxanthellae and in symbiotic animal hosts is correlated with the degree of saturation of the lipids in the thylakoid membranes in the algal plastids.…”

mentioning

confidence: 99%

Membrane lipids of symbiotic algae are diagnostic of sensitivity to thermal bleaching in corals

Tchernov

Gorbunov

Vargas

et al. 2004

Proc. Natl. Acad. Sci. U.S.A.

555

587

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Over the past three decades, massive bleaching events of zooxanthellate corals have been documented across the range of global distribution. Although the phenomenon is correlated with relatively small increases in sea-surface temperature and enhanced light intensity, the underlying physiological mechanism remains unknown. In this article we demonstrate that thylakoid membrane lipid composition is a key determinate of thermal-stress sensitivity in symbiotic algae of cnidarians. Analyses of thylakoid membranes reveal that the critical threshold temperature separating thermally tolerant from sensitive species of zooxanthellae is determined by the saturation of the lipids. The lipid composition is potentially diagnostic of the differential nature of thermally induced bleaching found in scleractinian corals. Measurements of variable chlorophyll fluorescence kinetic transients indicate that thermally damaged membranes are energetically uncoupled but remain capable of splitting water. Consequently, a fraction of the photosynthetically produced oxygen is reduced by photosystem I through the Mehler reaction to form reactive oxygen species, which rapidly accumulate at high irradiance levels and trigger death and expulsion of the endosymbiotic algae. Differential sensitivity to thermal stress among the various species of Symbiodinium seems to be distributed across all clades. A clocked molecular phylogenetic analysis suggests that the evolutionary history of symbiotic algae in cnidarians selected for a reduced tolerance to elevated temperatures in the latter portion of the Cenozoic.C oral bleaching on a global scale is a growing concern because of both the reduction in essential ecological services provided by zooxanthellate corals within reef communities (1, 2) and the potentially devastating economic impacts accompanying the phenomenon (3). Small, positive deviations in temperature of Ͻ2°C can trigger massive losses of symbiotic algae, Symbiodinium spp., from their cnidarian host cells (4). However, not all corals within a reef are equally susceptible to elevated temperature stress (5, 6). Although elevated temperatures often lead to a reduction in the quantum yield of photochemistry, a concomitant increase in the rate of protein turnover in oxygen-generating reaction center, photosystem (PS)II (7-9), and an increase in the production of reactive oxygen species (ROS) (10-12), no mechanism has been elucidated. Here we show that thermal sensitivity in isolated clones of zooxanthellae and in symbiotic animal hosts is correlated with the degree of saturation of the lipids in the thylakoid membranes in the algal plastids. Our results provide a mechanistic basis for understanding and diagnosing coral bleaching patterns in nature. Materials and MethodsCultures and Corals. Cultures of Symbiodinium spp., obtained from culture collections or isolated from hosts, were grown in F͞2 medium under a 10͞14-h light͞dark cycle and illuminated with 100 mol quanta m Ϫ2 ⅐s Ϫ1 . Corals were grown at 26°C in 800 liters of aquaria with running ...

show abstract

Depth-dependent responses to solar ultraviolet radiation and oxidative stress in the zooxanthellate coral Acropora microphthalma

Cited by 184 publications

References 45 publications

Sensitivity of freshwater macrophytes to UV radiation: relationship to depth zonation in an oligotrophic New Zealand lake

Sensitivity of freshwater macrophytes to UV radiation: relationship to depth zonation in an oligotrophic New Zealand lake

Ultraviolet-B exposure induces photo-oxidative damage and subsequent repair strategies in a desert cyanobacterium Microcoleus vaginatus Gom.

Membrane lipids of symbiotic algae are diagnostic of sensitivity to thermal bleaching in corals

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