کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
4395906 1618440 2012 9 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Thermal priming affects symbiont photosynthesis but does not alter bleaching susceptibility in Acropora millepora
موضوعات مرتبط
علوم زیستی و بیوفناوری علوم کشاورزی و بیولوژیک علوم آبزیان
پیش نمایش صفحه اول مقاله
Thermal priming affects symbiont photosynthesis but does not alter bleaching susceptibility in Acropora millepora
چکیده انگلیسی

This study experimentally investigated the effect of an early summer short-term summer thermal anomaly in November on Heron Reef (Great Barrier Reef), on the performance of the coral–algal symbiosis during a subsequent, thermally induced bleaching event (defined by loss of symbionts) in February 2009. Fragments of the reef flat coral, Acropora millepora, exposed to the two heating events lost 78% of their symbionts and showed a 64% decline in dark adapted quantum yield (Fv/Fm) to values less than 0.25. Whereas corals that were only heated in the second event lost 57% symbionts and displayed a 75% decline in Fv/Fm to values less than 0.2. Coral in both pre-stressed and non pre-stressed treatments at 34 °C had net photosynthetic rates significantly less than zero (Pnet max < 0), suggesting that daytime O2 respiration rates were significantly greater than rates of O2 evolution through photosynthesis. Increases in the daily light field and/or increases in temperature led to the observation of dark-adapted xanthophyll de-epoxidation suggesting that the potential for non-photochemical quenching is maintained into the dark (after 1 h dark adaption). Pre-stressed corals were also found to have de-epoxidation ratios three times greater than non pre-stressed corals at 34 °C and xanthophyll pool to Chl a, much greater than non pre-stressed corals. Combined, these results indicate that symbionts in pre-stressed corals have a greater ability to dump incoming light energy as heat. We conclude that whilst differences were observed between pre-stressed and non pre-stressed populations in measurements of photosynthetic productivity, photosynthetic pigments and areal protein, thermal bleaching as defined by symbiont loss did not vary between treatments.


► We examine the effect of a thermal priming event on subsequent coral bleaching.
► The onset of thermal bleaching was not altered by the priming event.
► Photosynthetic productivity and pigments were altered by the priming event.
► Pre-stressed corals were able to dump greater amounts of light energy as heat.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Experimental Marine Biology and Ecology - Volumes 432–433, 30 November 2012, Pages 64–72
نویسندگان
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