@article{fdi:010066661,
  title = {{L}eaky savannas : the significance of lateral carbon fluxes in the seasonal tropics},
  author = {{T}weed, {S}. and {L}eblanc, {M}arc and {B}ass, {A}. and {H}arrington, {G}. {A}. and {M}unksgaard, {N}. and {B}ird, {M}. {I}.},
  editor = {},
  language = {{ENG}},
  abstract = {{G}lobally, dissolved inorganic carbon ({DIC}) accounts for more than half the annual flux of carbon exported from terrestrial ecosystems via rivers. {H}ere, we assess the relative influences of biogeochemical and hydrological processes on {DIC} fluxes exported from a tropical river catchment characterized by distinct land cover, climate and geology transition from the wet tropical mountains to the low-lying savanna plains. {P}rocesses controlling changes in river {DIC} were investigated using dissolved organic carbon, particulate organic carbon and {DIC} concentrations and stable isotope ratios of {DIC} ({C}-13({DIC})) at two time scales: seasonal and diel. {T}he recently developed {I}sotopic {C}ontinuous {D}issolved {I}norganic {C}arbon {A}nalyser was used to measure diel {DIC} concentration and {C}-13({DIC}) changes at a 15-min temporal resolution. {R}esults highlight the predominance of biologically mediated processes (photosynthesis and respiration) controlling diel changes in {DIC}. {T}hese resulted in {DIC} concentrations varying between 3.55 and 3.82mg/l and {C}-13({DIC}) values ranging from -19.7 +/- 0.31 parts per thousand to -17.1 +/- 0.08 parts per thousand. {I}n contrast, at the seasonal scale, we observed wet season {DIC} variations predominantly from mixing processes and dry season {DIC} variations due to both mixing processes and biological processes. {T}he observed wet season increases in {DIC} concentrations (by 6.81mg/l) and {C}-13({DIC}) values of river water (by 5.4 parts per thousand) largely result from proportional increases in subsurface inflows from the savanna plains ({C}-4 vegetation) region relative to inflows from the rainforest ({C}-3 vegetation) highlands. {T}he high {DIC} river load during the wet season resulted in the transfer of 97% of the annual river carbon load. {T}herefore, in this gaining river, there are significant seasonal variations in both the hydrological and carbon cycles, and there is evidence of substantial coupling between the carbon cycles of the terrestrial and the fluvial environments. {R}ecent identification of a substantial carbon sink in the savannas of northern {A}ustralia during wetter years in the recent past does not take into account the possibility of a substantial, rapid, lateral flux of carbon to rivers and back to the atmosphere.},
  keywords = {dissolved inorganic carbon ; diel ; seasonal ; carbon cycle ; tropics ; savanna ; {AUSTRALIE} ; {ZONE} {TROPICALE}},
  booktitle = {},
  journal = {{H}ydrological {P}rocesses},
  volume = {30},
  numero = {6},
  pages = {873--887},
  ISSN = {0885-6087},
  year = {2016},
  DOI = {10.1002/hyp.10640},
  URL = {https://www.documentation.ird.fr/hor/fdi:010066661},
}