@article{fdi:010057038,
  title = {{T}racing soil organic carbon in the lower {A}mazon {R}iver and its tributaries using {GDGT} distributions and bulk organic matter properties},
  author = {{K}im, {J}. {H}. and {Z}ell, {C}. and {T}urcq, {P}atricia and {P}erez, {M}. {A}. {P}. and {A}bril, {G}wena{\¨e}l and {M}ortillaro, {J}. {M}. and {W}eijers, {J}. {W}. {H}. and {M}eziane, {T}. and {D}amste, {J}. {S}. {S}.},
  editor = {},
  language = {{ENG}},
  abstract = {{I}n order to trace the transport of soil organic carbon ({OC}) in the lower {A}mazon basin, we investigated the distributions of crenarchaeol and branched glycerol dialkyl glycerol tetraethers ({GDGT}s) by analyzing riverbed sediments and river suspended particulate matter ({SPM}) collected in the {S}olimoes-{A}mazon {R}iver mainstem and its tributaries. {T}he {B}ranched and {I}soprenoid {T}etraether ({BIT}) index, a proxy for river-transported soil {OC} into the ocean, was determined from the distributions of these {GDGT}s. {T}he {GDGT}-derived parameters were compared with other bulk geochemical data (i.e. {C}:{N} ratio and stable carbon isotopic composition). {T}he {GDGT}-derived and bulk geochemical data indicate that riverine {SPM} and riverbed sediments in the lower {A}mazon {R}iver and its tributaries are a mixture of {C}-3 plant-derived soil {OC} and aquatic-derived {OC}. {T}he branched {GDGT}s in the {SPM} and riverbed sediments did not predominantly originate from the high {A}ndes soils (>2500 m in altitude) as was suggested previously. {H}owever, further constraint on the soil source area of branched {GDGT}s was hampered due to the deficiency of soil data from the lower montane forest areas in the {A}ndes. {O}ur study also revealed seasonal and interannual variation in {GDGT} composition as well as soil {OC} discharge, which was closely related to the hydrological cycle. {B}y way of a simple binary mixing model using the flux-weighted {BIT} values at {O}bidos, the last gauging station in the {A}mazon {R}iver, we estimated that 70-80% of the {POC} pool in the river was derived of soil {OC}. {H}owever, care should be taken to use the {BIT} index since it showed a non-conservative behaviour along the river continuum due to the aquatic production of crenarchaeol. {F}urther investigation using a continuous sampling strategy following the full hydrological cycle is required to fully understand how soil-derived {GDGT} signals are transformed in large tropical river systems through their transport pathway to the ocean.},
  keywords = {},
  booktitle = {},
  journal = {{G}eochimica et {C}osmochimica {A}cta},
  volume = {90},
  numero = {},
  pages = {163--180},
  ISSN = {0016-7037},
  year = {2012},
  DOI = {10.1016/j.gca.2012.05.014},
  URL = {https://www.documentation.ird.fr/hor/fdi:010057038},
}