@article{fdi:010063516,
  title = {{T}he isotopic fingerprint of {F}e cycling in an equatorial soil-plant-water system : {T}he {N}simi watershed, {S}outh {C}ameroon},
  author = {{A}kerman, {A}. and {P}oitrasson, {F}. and {O}liva, {P}. and {A}udry, {S}. and {P}runier, {J}. and {B}raun, {J}ean-{J}acques},
  editor = {},
  language = {{ENG}},
  abstract = {{F}ollowing an initial study of a tropical lateritic hillside system showing little iron isotope fractionation despite a strong accumulation within the soil profile, the present work investigates iron isotope signatures within the organic matter rich swamp system that represents 20% of the studied watershed surface (from {N}simi, {S}outh {C}ameroon). {T}his study considers the soil-plant-water continuum in order to better understand the {F}e elemental and isotopic transfer out of the ecosystem. {W}ithin the swamp system, the iron isotope compositions of gleysol samples (delta {F}e-57({IRMM}-14) similar to+ 0.6 parts per thousand) are significantly heavier than both the continental crust baseline and the reference lateritic soils from the hillslope (delta {F}e-57({IRMM}-14) = + 0.1 parts per thousand). {T}his enrichment towards heavy isotopes is attributed to a preferential removal of light iron isotopes during soil forming processes. {P}edogenic transformations (i.e., gleyzation, organic complexation of metal and leaching) are responsible for the reductimorphic features observed in ferralitic horizons (i.e., incomplete degradation of organic matter in surface and soil whitening favored by good draining conditions). {T}he organic carbon-rich waters of the swamp system are prone to redox processes and strong metal chelation. {T}he dissolved iron (i.e., fraction < 0.22 mu m) of the {M}engong stream shows positive delta {F}e-57 signatures, with a down-stream enrichment in heavy isotopes, from + 0.511 +/- 0.266 parts per thousand to + 1.076 +/- 0.240 parts per thousand. {T}he binding of iron ({F}e-{III}) with organic matter can explain the observed enrichment in heavy isotopes in the dissolved fraction. {O}n the contrary, plant leaves are significantly enriched in light {F}e (delta {F}e-57 of -0.665 +/- 0.035 and -1.119 +/- 0.080 parts per thousand) relative to (i) the litter compartment (-0.166 +/- 0.078 to -0.262 +/- 0.013% for delta {F}e-57) and (ii) the most superficial soils. {I}ron isotopic compositions in plants and litter vary as a function of both plant species and season. {H}ence, the differences in {F}e isotopic compositions between the various studied compartments suggest that {F}e isotopes can be used (i) to study elemental transfers during soil pedogenesis in tropical environment and (ii) to better appraise and constrain iron biogeochemical cycle between surface horizon of soils, surface waters and the vegetation.},
  keywords = {{I}ron isotopes ; {S}wamp zone soil ; {S}tream water ; {V}egetation ; {C}hemical weathering ; {L}ateritic regolith ; {CAMEROUN}},
  booktitle = {},
  journal = {{C}hemical {G}eology},
  volume = {385},
  numero = {},
  pages = {104--116},
  ISSN = {0009-2541},
  year = {2014},
  DOI = {10.1016/j.chemgeo.2014.07.003},
  URL = {https://www.documentation.ird.fr/hor/fdi:010063516},
}