@article{fdi:010092600,
  title = {17{O}-excess of grass leaf phytoliths across the {N}orth {A}merican prairies records late-growing season daytime relative humidity},
  author = {{G}uo, {M}. {E}. and {A}lexandre, {A}. and {L}ongstaffe, {F}. {J}. and {P}eugeot, {C}hristophe and {W}ebb, {E}. {A}.},
  editor = {},
  language = {{ENG}},
  abstract = {{B}ecause it is an important climate parameter, an accurate proxy is required for the reconstruction of past {R}elative {H}umidity ({RH}). {T}riple oxygen isotopes of grass-leaf phytoliths have a high potential for this purpose. {A} strong correlation between {RH} and {O}-17-excess of grass leaf phytoliths has been previously demonstrated from calibration experiments in growth chambers and at natural {S}ub-{S}aharan {A}frican and {M}editerranean sites. {H}ere we focus on the potential of 17 {O}-excess of grass leaf phytoliths as a proxy of {RH} across the {N}orth {A}merican {G}reat {P}lains. {W}e tested the relationship between the {O}-17-excess of naturally grown {C}alamovilfa longifolia phytoliths and {RH} for different periods of the grass growing season. {T}he results show that {O}-17-excess of leaf phytoliths has a strong correlation with late-growing season ({J}uly-{A}ugust) daytime {RH}, which varies from 29 to 72 % across {N}orth {A}merica. {T}he correlation can be expressed as: {O}-17-excess leaf phytoliths = 4.14(+0.47) x {RH} (%) - 497(+26) ({R}-2 = 0.85, p-value<0.0001). {T}o use the {O}-17-excess of bulk phytoliths buried in soils and sediments as a quantitative proxy of past {RH}, future calibration studies on soil phytoliths are needed to evaluate the contribution of non-transpiring phytoliths. {T}he(17){O}-excess of stem water, which was determined by {O}-17-excess of stem phytoliths, shows similar values to the {O}-17-excess of precipitation in {N}orth {A}merica without evaporation, which therefore does not affect the {O}-17-excess of leaf phytoliths in {N}orth {A}merica. {T}hese results demonstrate that the {O}-17-excess of phytoliths is a promising proxy for regional growing season {RH}.},
  keywords = {{P}hytoliths ; {R}elative {H}umidity ; {T}ranspiration ; {N}orth {A}merican prairies ; {O}-17-excess ; {AMERIQUE} {DU} {NORD}},
  booktitle = {},
  journal = {{C}hemical {G}eology},
  volume = {671},
  numero = {},
  pages = {122484 [11 p.]},
  ISSN = {0009-2541},
  year = {2025},
  DOI = {10.1016/j.chemgeo.2024.122484},
  URL = {https://www.documentation.ird.fr/hor/fdi:010092600},
}