@article{fdi:010055849,
  title = {{T}he puzzling presence of calcite in skeletons of modern solitary corals from the {M}editerranean {S}ea},
  author = {{G}offredo, {S}. and {C}aroselli, {E}. and {M}ezzo, {F}. and {L}aiolo, {L}. and {V}ergni, {P}. and {P}asquini, {L}. and {L}evy, {O}. and {Z}accanti, {F}. and {T}ribollet, {A}line and {D}ubinsky, {Z}. and {F}alini, {G}.},
  editor = {},
  language = {{ENG}},
  abstract = {{T}he skeleton of scleractinian corals is commonly believed to be composed entirely of aragonite due to the current {M}g/{C}a molar ratio of seawater, which thermodynamically favours the deposition of this polymorph of calcium carbonate ({C}a{CO}3). {H}owever, some studies have shown that other forms of {C}a{CO}3 such as calcite can be present in significant amount (1-20%) inside tropical coral skeletons, significantly impacting paleo-reconstructions of {SST} or other environmental parameters based on geochemical proxies. {T}his study aims at investigating for the first time, (1) the skeletal composition of two {M}editerranean solitary corals, the azooxanthellate {L}eptopsammia pruvoti and the zooxanthellate {B}alanophyllia europaea, across their life cycle, (2) the distribution of the different {C}a{CO}3 forms inside skeletons, and (3) their implications in paleoclimatology. {T}he origin of the different forms of {C}a{CO}3 observed inside studied coral skeletons and their relationships with the species' habitat and ecological strategies are also discussed. {C}a{CO}3 composition of {L}. pruvoti and {B}. europaea was investigated at six sites located along the {I}talian coasts. {S}keleton composition was studied by means of {X}-ray powder diffraction and {F}ourier transform infrared spectroscopy. {A} significant amount of calcite (1-23%) was found in more than 90% of the studied coral skeletons, in addition to aragonite. {T}his calcite was preferentially located in the basal and intermediate areas than at the oral pole of coral skeletons. {C}alcite was also mainly located in the epitheca that covered the exposed parts of the coral in its aboral region. {I}nterestingly in {B}. europaea, the calcite content was negatively correlated with skeleton size (age). {T}he presence of calcite in scleractinian corals may result from different mechanisms: (1) corals may biologically precipitate calcite crystals at their early stages in order to insure their settlement on the substrate of fixation, especially in surgy environments; (2) calcite presence may result from skeletons of other calcifying organisms such as crustose coralline algae; and/or (3) calcite may result from the infilling of galleries of boring microorganisms which are known to colonize coral skeletons. {W}e suggest that more than one of the above mentioned processes are involved.},
  keywords = {},
  booktitle = {},
  journal = {{G}eochimica et {C}osmochimica {A}cta},
  volume = {85},
  numero = {},
  pages = {187--199},
  ISSN = {0016-7037},
  year = {2012},
  DOI = {10.1016/j.gca.2012.02.014},
  URL = {https://www.documentation.ird.fr/hor/fdi:010055849},
}