Biomineralisation in reef-building corals: from molecular mechanisms to environmental control

Corals from the Persian/Arabian Gulf as models for thermotolerant reef-builders: Prevalence of clade C3 Symbiodinium, host fluorescence and ex situ temperature tolerance

“…While other fields of (molecular) biology rely heavily on the thorough analysis of a few model organisms, at the moment there are not many coral models for laboratory studies (Weis et al, 2008). However, recent progress in coral culture enables the propagation of these organisms in excellent physiological conditions over many years or even decades Leewis and Janse, 2008) and experiments with laboratory strains have already yielded important insights into physiological processes in reef corals (Allemand et al, 2004;D'Angelo et al, , 2008Wiedenmann et al, 2012).…”

Reconsidering the role of carbonate ion concentration in calcification by marine organisms

“…As this ion is also the form used in the final precipitation reaction (Eq. 1), calcium does not need to be chemically transformed while being transported from seawater to the site of calcification (Allemand et al, 2004;Bentov et al, 2009;Mackinder et al, 2011). This is in clear contrast to CO 2− 3 , where the relation between ion source from seawater and ion sink during crystallization is considerably more complex since CO 2− 3 is in constant exchange with HCO − 3 and CO 2 .…”

“…Most studies assume that HCO − 3 rather than CO 2− 3 is the key inorganic carbon ion (e.g., Allemand et al, 2004;Mackinder et al, 2010;Stumpp et al, 2012;Taylor et al, 2012). However, proof of this assumption on a physiological level is still missing because attempts to unequivocally determine the inorganic carbon molecule transported by molecular transport systems have not been successful so far (Pushkin and Kurtz, 2006;Mackinder et al, 2010;Lee et al, 2013;Romero et al, 2013).…”

“…Still others found that the response is not controlled by a single carbonate system parameter, but by the interplay of two or more. In coccolithophores, for example, calcification rates were repeatedly shown to increase from low to intermediate DIC but decrease again above certain thresholds (Langer et al, 2006;Bach et al, 2011Bach et al, , 2015Sett et al, 2014). This optimumcurve response pattern was explained by the interaction between HCO − 3 and protons (H + ), where HCO − 3 stimulates calcification as substrate and H + functions as inhibitor (Bach et al, 2011(Bach et al, , 2013.…”

“…In coccolithophores, for example, calcification rates were repeatedly shown to increase from low to intermediate DIC but decrease again above certain thresholds (Langer et al, 2006;Bach et al, 2011Bach et al, , 2015Sett et al, 2014). This optimumcurve response pattern was explained by the interaction between HCO − 3 and protons (H + ), where HCO − 3 stimulates calcification as substrate and H + functions as inhibitor (Bach et al, 2011(Bach et al, , 2013. Similar conclusions have also been made in studies with bivalves (Thomsen et al, 2015) and corals (Jury et al, 2010), where it has been noted that the calcification response to changing carbonate chemistry could be the result of the opposing effects of and [H + ].…”