@article {460,
	title = {Growth and photosynthesis of two Mediterranean corals, Cladocora caespitosa and Oculina patagonica, under normal and elevated temperature},
	journal = {The Journal of Experimental Biology},
	volume = {209},
	year = {2006},
	abstract = {<p>The Ligurian Sea (NW Mediterranean) experienced warm summers in 1998,  1999 and from 2003 to 2005. The temperature was 1-3\&deg;C higher than the  mean summer value (24\&deg;C) and remained high over a long period. During  these summers, mass-mortality events, affecting several sessile benthic  species, were reported. In the present study, we tested the long-term  (3-7 weeks) effect of different temperatures (20\&deg;C measured in spring  and autumn, 24\&deg;C observed in summer, and 26\&deg;C and 28\&deg;C abnormal summer  values) on two Mediterranean corals, Cladocora caespitosa and Oculina  patagonica. Growth rate, photosynthetic efficiency (Fv/Fm), relative  electron transport rate (ETR), zooxanthellae and chlorophyll (chl)  contents were measured during 48 days incubation. At 20\&deg;C, all  parameters remained constant during the whole experiment for both  species. At higher temperatures, most physiological parameters were  affected by only 2-5 weeksat 24\&deg;C, and were severely depressed at higher  temperatures. Small replicate samples (nubbins) of O. patagonica  significantly decreased their zooxanthellae and chl concentrations at  all temperatures, after 2 weeks of incubation. Their Fv/Fm values, as  well as their growth rates, were also gradually reduced during the  incubation at all temperatures. However, only a few nubbinsmaintained at  28\&deg;C showed signs of tissue necrosis after 34 days, and these gradually  recovered tissue when temperature was returned to normal. In nubbins of  C. caespitosa, chl and zooxanthellae concentrations decreased only  after 34 days of incubation at 26\&deg;C and 28\&deg;C. At the same time, tissue  necrosis was observed, explaining the loss of the symbionts. Fv/Fm was  reduced only after 34 days of incubation at the different temperatures,  and growth rate was first enhanced, before collapsing by 30\% at 24\&deg;C and  by 90-100\% at 26\&deg;C and 28\&deg;C. All samples maintained at 26\&deg;C and 28\&deg;C  had died, due to tissue necrosis, by the end of the experiment. Results  obtained suggest that O. patagonica is more able than C. caespitosa to  resist high temperature conditions because of its rapid bleaching  capacity. In contrast, it seems that C. caespitosa is living close to  its thermal limit during the summer period; therefore, a long-term  increase at 24\&deg;C or above could be lethal for this coral, just as was  observed in situ during the recent warm summers.</p>},
	keywords = {benthos, biodiversit{\'e}, biodiversity, blanchiment, bleaching, Cladocora caespitosa, climate change, corail, coral, g{\`e}ne, Genoa, injury, Italie, Italy, La Spezia, Ligurian Sea, mass mortality, Mediterranean sea, M{\'e}diterran{\'e}e nord-occidentale, M{\'e}diterrann{\'e}e occidentale, Mer Ligure, Mer M{\'e}diterran{\'e}e, mortalit{\'e} massive, n{\'e}crose, north-western Mediterranean, Oculina patagonica, photosynth{\`e}se, photosynthesis, physiologie, r{\'e}chauffement, scleractinian, sea water temperature, temperature, temp{\'e}rature de l{\textquoteright}eau de mer, thermotolerance, transport, warming, western Mediterranean, zooxanthellae, zooxanthelle},
	author = {R. Rodolfo-Metalpa and C. Richard and D. Allemand and C. Ferrier-Pag{\`e}s}
}
