@article{fdi:010072463,
  title = {{V}ariation of the isotopic composition of dissolved organic carbon during the runoff cycle in the {A}mazon {R}iver and the floodplains},
  author = {{A}lberic, {P}. and {P}erez, {M}. {A}. {P}. and {M}oreira {T}urcq, {P}atricia and {B}enedetti, {M}. {F}. and {B}ouillon, {S}. and {A}bril, {G}wena{\¨e}l},
  editor = {},
  language = {{ENG}},
  abstract = {{G}iven the relative scarcity of stable isotope data on dissolved organic carbon ({DOC}) in the {A}mazon {B}asin, we hypothesized that the variability in {DOC} sources may be underestimated in such major river basins. {T}o explore the links between the mainstem and tributaries and the floodplain, particular efforts were made during five distinct cruises at different stages of the hydrograph between {O}ctober 2008 and {J}anuary 2011, to document the spatial and temporal variation of {DOC} concentrations and delta {C}-13-{DOC} in the central {A}mazon {R}iver system ({B}razil). {B}ased on more than 200 data, the spatial and temporal variability of delta {C}-13-{DOC} values was found to be larger than previously reported in the same area. {A}lthough a small range of variation was observed throughout the hydrological cycle in the upper reach of the studied section (-29.2 to -29.5 parts per thousand in the {R}io {N}egro and -28.7 to -29.0 parts per thousand in the {R}io {S}olimoes), a much larger one (-28.0 to -34.6 parts per thousand) was found in the lower reach of the river, as the proportion of open lakes increased downstream in the floodplains. {T}he low variability in the upper reaches suggests constant and homogeneous {DOC} sources from upland soils and flooded forest, while lower delta {C}-13-{DOC} values recorded in the lower reach mainstem at high and falling waters can be attributed to a greater export of plankton-derived {C}-13-depleted {DOC} from flooded lakes. {N}oteworthy are the higher delta {C}-13-{DOC} values measured in the {R}io {M}adeira and the associated flooded lakes (-26.5 to -28.8 parts per thousand, which may reflect the imprint from upland headwaters and a weaker density of flooded forest in the watershed. {T}he higher delta {C}-13-{DOC} values observed in the lower reach during low waters are still not fully understood. {F}loating meadows principally consisting of {C}-4 macrophytes were found to increase delta {C}-13-{DOC} values by similar to 1.5 parts per thousand in their vicinity, but this impact was no longer noticeable at distances of similar to 10 m from the plant rafts. {T}his rather modest {C}-13-enrichment suggests rapid decomposition and/or dilution of this wetland-derived {DOC}.},
  keywords = {{DOC} ; {C}-13/{C}-12 ; {A}mazon {B}asin ; {R}unoff cycle ; {C}-4 plant raft ; {BRESIL} ; {AMAZONE} {BASSIN}},
  booktitle = {},
  journal = {{C}omptes {R}endus {G}eoscience},
  volume = {350},
  numero = {1-2},
  pages = {65--75},
  ISSN = {1631-0713},
  year = {2018},
  DOI = {10.1016/j.crte.2017.11.001},
  URL = {https://www.documentation.ird.fr/hor/fdi:010072463},
}