@article{fdi:010068822,
  title = {{E}valuation of branched {GDGT}s and leaf wax n-alkane delta {H}-2 as (paleo) environmental proxies in {E}ast {A}frica [+ {C}orrigendum in {G}eochimica et {C}osmochimica {A}cta, 2020, vol. 271, p. 289-291]},
  author = {{C}offinet, {S}. and {H}uguet, {A}. and {P}edentchouk, {N}. and {B}ergonzini, {L}. and {O}muombo, {C}. and {W}illiamson, {D}avid and {A}nquetil, {C}. and {J}ones, {M}. and {M}ajule, {A}. and {W}agner, {T}. and {D}erenne, {S}.},
  editor = {},
  language = {{ENG}},
  abstract = {{T}he role of mountain evolution on local climate is poorly understood and potentially underestimated in climate models. {O}ne prominent example is {E}ast {A}frica, which underwent major geodynamic changes with the onset of the {E}ast {A}frican {R}ift {S}ystem ({EARS}) more than 250 {M}yr ago. {T}his study explores, at the regional {E}ast {A}frican scale, a molecular approach for terrestrially-based paleo-climatic reconstructions that takes into account both changes in temperature and in altitude, potentially leading to an improved concept in paleo-climatic reconstructions. {U}sing surface soils collected along pronounced altitudinal gradients in {M}t. {R}ungwe (n = 40; {S}outhwest {T}anzania) and {M}t. {K}enya (n = 20; {C}entral {K}enya), we investigate the combination of 2 terrestrial proxies, leaf wax n-alkane delta {H}-2 (delta {H}-2(wax)) and branched glycerol dialkyl glycerol tetraether (br {GDGT}) membrane lipids, as (paleo) elevation and (paleo) temperature proxies, respectively. {A}t the mountain scale, a weak link between delta {H}-2(wax) and altitude ({R}-2 = 0.33) is observed at {M}t. {K}enya, but no relationship is observed at {M}t. {R}ungwe. {I}t is likely that additional parameters, such as decreasing relative humidity ({RH}) or vegetation changes with altitude, are outcompeting the expected {H}-2-depletion trend along {M}t. {R}ungwe. {I}n contrast, br {GDGT}-derived absolute mean annual air temperature ({MAAT}) and temperature lapse rate (0.65 degrees {C}/100 m) for both mountains are in good agreement with direct field measurements, further supporting the robustness of this molecular proxy for (paleo) temperature reconstructions. {A}t the regional scale, estimated and observed d 2 {H} data in precipitation along 3 mountains in {E}ast {A}frica ({M}ts. {R}ungwe, {K}enya and {K}ilimanjaro) highlight a strong spatial heterogeneity, preventing the establishment of a regional based calibration of delta {H}-2(wax) for paeloaltitudinal reconstructions. {D}ifferent from that, an improved regional soil calibration is developed between br {GDGT} distribution and {MAAT} by combining the data from this study ({M}ts. {R}ungwe and {K}enya) with previous results from {E}ast {A}frican surface soils along {M}ts. {K}ilimanjaro ({T}anzania) and {R}wenzori ({U}ganda). {T}his new regional calibration, based on 105 samples, improves both the {R}-2 (0.77) and {RMSE} (root mean square error; 2.4 degrees {C}) of br {GDGT}-derived {MAAT} over the global soil calibrations previously established ({R}-2 = 0.56; {RMSE} = 4.2 degrees {C}) and leads to more accurate (paleo) temperature reconstructions in the region.},
  keywords = {{B}ranched {GDGT}s ; delta {H}-2(wax) ; {E}ast {A}frica ; {P}aleo-altitude ; {P}aleo-temperature ; {S}oils n-alkanes ; {M}ountain transects ; {AFRIQUE} {DE} {L}'{EST} ; {KENYA} ; {TANZANIE} ; {OUGANDA}},
  booktitle = {},
  journal = {{G}eochimica et {C}osmochimica {A}cta},
  volume = {198},
  numero = {},
  pages = {182--193 [+ {C}orrigendum in {G}eochimica et {C}osmochimica {A}cta, 2020, vol. 271, p. 289--291]},
  ISSN = {0016-7037},
  year = {2017},
  DOI = {10.1016/j.gca.2016.11.020},
  URL = {https://www.documentation.ird.fr/hor/fdi:010068822},
}