@article{fdi:010087735,
  title = {{S}cale issue for organic and inorganic carbon exports to oceans : case study in the sub-tropical {T}hukela {R}iver {B}asin, {S}outh {A}frica},
  author = {{M}utema, {M}. and {F}iglan, {S}. and {C}haplot, {V}incent},
  editor = {},
  language = {{ENG}},
  abstract = {{D}espite carbon ({C}) exports from continents being crucial in the connection between terrestrial, atmospheric, and oceanic {C}, there is still limited understanding of the dynamics of {C} within river basins. {T}he objective of this work was to assess the changes in particulate ({POC}) and dissolved organic ({DOC}) and inorganic {C} ({PIC}: particulate inorganic carbon, {DIC}: dissolved inorganic carbon) content, quality, and fluxes within a river basin from its headwaters to its exit at the ocean. {A} survey was designed in the {T}hukela basin (from 2012 to 2013 and at six nested catchments ranging from similar to 10 to similar to 30,000 km(2)) in the east of {S}outh {A}frica to evaluate the content, fluxes, and quality ({UV} spectral slope, {C}-13, {CO}2 effluxes from runoff) of the transported {C} in conjunction with chemical elements ({S}i, {N}a) for discriminating between the water sources and estimating {C} dynamics during low flows. {T}otal carbon exports decreased continuously from 9.75 km(2) in the headwater (31.9 kg {C} km(-2) y(-1)) to ocean (4.7 kg {C} km(-2) y(-1)) with the highest decrease occurring between the catchment (7614 km(2)) and large catchment (14,478 km(2)). {A}bout 80% of {C} exports from the headwaters were {POC}, followed by {DIC} (10%) and {DOC} (10%), while at the ocean, the proportions were 31% ({POC}), 45% ({DIC}), 23% ({DOC}), and 0.7% ({PIC}). {M}oreover, there was a sharp decrease in the dissolved organic matter aromaticity from the headwater to ocean and for both {DOC} and {POC} that did not correspond to changes in water sources along the river (as indicated by a relatively constant {S}i/{N}a ratio). {T}his pointed to the decomposition in the river of the dissolved organic matter originating from soils and to the within-stream organic production. {F}urther in situ investigations need to be performed to quantify the within-stream inputs.},
  keywords = {organic compounds ; river ; chemistry ; {A}frica ; landscapes ; {AFRIQUE} {DU} {SUD}},
  booktitle = {},
  journal = {{L}and},
  volume = {12},
  numero = {4},
  pages = {815 [10 p.]},
  year = {2023},
  DOI = {10.3390/land12040815},
  URL = {https://www.documentation.ird.fr/hor/fdi:010087735},
}