@article{fdi:010066347,
  title = {{I}ntra-skeletal calcite in a live-collected {P}orites sp. : impact on environmental proxies and potential formation process},
  author = {{L}azareth, {C}laire {E}. and {P}ereira, {C}. and {D}ouville, {E}. and {B}rahmi, {C}. and {D}issard, {D}elphine and {L}e {C}ornec, {F}lorence and {T}hil, {F}. and {G}onzalez-{R}oubaud, {C}. and {C}aquineau, {S}andrine and {C}abioch, {G}uy},
  editor = {},
  language = {{ENG}},
  abstract = {{G}eochemical proxies measured in the carbonate skeleton of tropical coral {P}orites sp. have commonly been used to reconstruct sea surface temperature ({SST}) and more recently seawater p{H}. {N}evertheless, both reconstructed {SST} and p{H} depend on the preservation state of the skeleton, here made of aragonite; i.e., diagenetic processes and its related effects should be limited. {I}n this study, we report on the impact of the presence of intra-skeletal calcite on the skeleton geochemistry of a live-collected {P}orites sp. {T}he {P}orites skeleton preservation state was analyzed using {X}-ray diffraction and scanning electron microscopy. {S}r/{C}a, {M}g/{C}a, {U}/{C}a, {B}a/{C}a, {L}i/{M}g, and {B}/{C}a ratios were measured at a monthly and yearly resolution using quadrupole {ICP}-{MS} and multi-collector {ICP}-{MS}. {T}he δ11{B} signatures and the calcite percentages were acquired at a yearly timescale. {T}he coral colony presents two parts, one with less than 3% calcite (referred to as "no-calcite" skeleton), the other one, corresponding to the skeleton formed during the last 4 years of growth, with calcite percentages varying from 13% to 32% (referred to as "with calcite" skeleton). {T}his intra-skeletal calcite replaces partly or completely numerous centers of calcification ({COC}s). {A}ll investigated geochemical tracers are significantly impacted by the presence of calcite. {T}he reconstructed {SST} decreases by about 0.1 °{C} per calcite-percent as inferred from the {S}r/{C}a ratio. {S}uch impact reaches up to 0.26 °{C} per calcite-percent for temperature deduced from the {L}i/{M}g ratio. {S}o, less than 5% of such intra-skeletal calcite does not prevent {SST} reconstructions using {S}r/{C}a ratio, but the percentage and type of calcite have to be determined before fine {SST} interpretation. {S}eawater p{H} reconstruction inferred from boron isotopes drop by about -0.011 p{H}-unit per calcite-percent. {S}uch sensitivity to calcite presence is particularly dramatic for fine paleo-p{H} reconstructions. {H}ere we suggest that after being brought to shallow waters following a cyclone, the studied coral was seasonally subjected to rainfall-related water freshening that could have mimicked a vadose environment like can be encountered on raised fossil coral reefs. {N}evertheless, the process of calcite precipitation remains to be determined.},
  keywords = {{PACIFIQUE} ; {VANUATU}},
  booktitle = {},
  journal = {{G}eochimica et {C}osmochimica {A}cta},
  volume = {176},
  numero = {},
  pages = {279--294},
  ISSN = {0016-7037},
  year = {2016},
  DOI = {10.1016/j.gca.2015.12.020},
  URL = {https://www.documentation.ird.fr/hor/fdi:010066347},
}