@article{fdi:010083275,
  title = {{T}he triple oxygen isotope composition of phytoliths, a new proxy of atmospheric relative humidity : controls of soil water isotope composition, temprature, {CO}2 concentration and relative humidity},
  author = {{O}utrequin, {C}. and {A}lexandre, {A}. and {V}allet-{C}oulomb, {C}. and {P}iel, {C}. and {D}evidal, {S}. and {L}andais, {A}. and {C}ouapel, {M}artine and {M}azur, {J}. {C}. and {P}eugeot, {C}hristophe and {P}ierre, {M}. and {P}rie, {F}. and {R}oy, {J}. and {S}onzogni, {C}. and {V}oigt, {C}.},
  editor = {},
  language = {{ENG}},
  abstract = {{C}ontinental atmospheric relative humidity is a major climate parameter whose variability is poorly understood by global climate models. {M}odels' improvement relies on model-data comparisons for past periods. {H}owever, there are no truly quantitative indicators of relative humidity for the pre-instrumental period. {P}revious studies highlighted a quantitative relationship between the triple oxygen isotope composition of phytoliths, particularly the {O}-17 excess of phytoliths, and atmospheric relative humidity. {H}ere, as part of a series of calibrations, we examine the respective controls of soil water isotope composition, temperature, {CO}2 concentration and relative humidity on phytolith {O}-17 excess. {F}or that purpose, the grass species {F}estuca arundinacea was grown in growth chambers where these parameters were varying. {T}he setup was designed to control the evolution of the triple oxygen isotope composition of phytoliths and all the water compartments of the soil-plant-atmosphere continuum. {D}ifferent analytical techniques (cavity ring-down spectroscopy and isotope ratio mass spectrometry) were used to analyze water and silica. {A}n inter-laboratory comparison allowed to strengthen the isotope data matching. {W}ater and phytolith isotope compositions were compared to previous datasets obtained from growth chamber and natural tropical sites. {T}he results show that the delta {O}-1(8) value of the source water governs the starting point from which the triple oxygen isotope composition of leaf water, phytolith-forming water and phytoliths evolves. {H}owever, since the 17 0 excess varies little in the growth chamber and natural source waters, this has no impact on the strong relative humidity dependency of the {O}-17 excess of phytoliths, demonstrated for the 40 %-80% relative humidity range. {T}his relative humidity dependency is not impacted by changes in air temperature or {CO}2 concentration either. {A} relative humidity proxy equation is proposed. {E}ach per meg of change in phytolith {O}-17 excess reflects a change in atmospheric relative humidity of ca. 0.2 %. {T}he +/- 15 per meg reproducibility on the measurement of phytolith {O}-17 excess corresponds to a +/- 3.6 % precision on the reconstructed relative humidity. {T}he low sensitivity of phytolith {O}-17 excess to climate parameters other than relative humidity makes it particularly suitable for quantitative reconstructions of continental relative humidity changes in the past.},
  keywords = {},
  booktitle = {},
  journal = {{C}limate of the {P}ast},
  volume = {17},
  numero = {5},
  pages = {1881--1902},
  ISSN = {1814-9324},
  year = {2021},
  DOI = {10.5194/cp-17-1881-2021},
  URL = {https://www.documentation.ird.fr/hor/fdi:010083275},
}