Domart-Coulon I. auteur aut IRD Stolarski J. auteur aut IRD Brahmi Chloe auteur aut IRD Gutner-Hoch E. auteur aut IRD Janiszewska K. auteur aut IRD Shemesh A. auteur aut IRD Meibom A. auteur aut IRD text journalArticle eng text/pdf born digital access Using in situ (12 h) pulse-labeling of scleractinian coral aragonitic skeleton with stable 86Sr isotope, the diel pattern of skeletal extension was investigated in the massive Porites lobata species, grown at 5 m depth in the Gulf of Eilat Several microstructural aspects of coral biomineralization were elucidated, among which the most significant is simultaneous extension of the two basic microstructural components Rapid Accretion Deposits (RAD; also called Centers of Calcification) and Thickening Deposits (TD; also called fibers), both at night and during daytime. Increased thickness of the 86Sr-labeled growth-front in the RADs compared to the adjacent TDs revealed that in this species RADs extend on average twice as fast as TDs. At the level of the individual corallite, skeletal extension is spatially highly heterogeneous, with sporadic slowing or cessation depending on growth directions and skeletal structure morphology. Daytime photosynthesis by symbiotic dinoflagellates is widely acknowledged to substantially increase calcification rates at the colony and the corallite level in reef-building corals. However, in our study, the average night-time extension rate (visualized in three successive 12 h pulses) was similar to the average daytime extension (visualized in the initial 12 h pulse), in all growth directions and skeletal structures. This research provides a platform for further investigations into the temporal calibration of coral skeletal extension via cyclic growth increment deposition, which is a hallmark of coral biomineralization. specialized Coral skeleton Microstructure Linear extension Diel rythm Strontium labeling 034 020 185 1 79-88 2014 1047-8477 https://www.documentation.ird.fr/hor/fdi:010061501 10.1016/j.jsb.2013.10.012 1047-8477 [F B010061501] https://www.documentation.ird.fr/hor/fdi:010061501 https://www.documentation.ird.fr/intranet/publi/2014/02/010061501.pdf Accès réservé (Intranet de l'IRD) IRD - Base Horizon / Pleins textes 2014-03-03 2017-08-23 fdi:010061501 fre