ABSTRACT
This chapter is based on some specific examples, how in situ measurements using ion microprobe (SIMS) have provided crucial key answers in understanding the mechanisms of calcication of living organisms. It focuses on the stable isotope geochemistry (C-O-B) of two deep-sea corals (DSCs), Lophelia pertusa and Madrepora oculata. Increasing human activities and their impacts on the environment require an accurate estimate of what could be the environmental conditions for the next decades or centuries. The organization with center of calcication or early biomineralization zones and the surrounding bers suggests that calcication is initiated by calcication centers and contributes to the lateral and vertical growth of the coral. The initiation of the vertical growth through the formation of an oor is still poorly understood and probably happens when the vertical growth of the theca and septa would become incompatible with the stretching of the polyp.
