@article{fdi:010084358,
  title = {{U}se of {R}a-223 and {R}a-224 as chronometers to estimate the residence time of {A}mazon waters on the {B}razilian continental shelf},
  author = {{L}eon, {M}. and van {B}eek, {P}. and {S}cholten, {J}. and {M}oore, {W}. {S}. and {S}ouhaut, {M}. and {D}e {O}liveira, {J}. and {J}eandel, {C}. and {S}eyler, {P}atrick and {J}ouanno, {J}ulien},
  editor = {},
  language = {{ENG}},
  abstract = {{W}hen rivers mix into the ocean, radium isotopes are released into the dissolved phase allowing us to apply these isotopes as powerful tracers of river plumes spreading into the ocean. {W}e report {R}a-223 and {R}a-224 radium activities that were determined in the {A}mazon {R}iver mouth and along the {A}mazon plume that extends off the coasts of {B}razil and {F}rench {G}uyana into the {A}tlantic {O}cean. {W}e summarize {R}a-223 and {R}a-224 data from {A}mas{S}eds (1991), {AMANDES} ({GEOTRACES} process study {GA}pr01; 2007-2008) and {M}147 (2018) projects, which were conducted in different seasons corresponding to different {A}mazon discharge rates. {W}e determined the {R}a-224(ex)/{R}a-223 activity ratios ({AR}) along the {A}mazon plume to derive apparent ages and to estimate the residence time of the {A}mazon waters on the {B}razilian continental shelf. {O}ur data suggest that it takes 9-14 d for the {A}mazon waters to reach the northern continental shelf off {F}rench {G}uyana and 12-21 d to reach the eastern part of the {B}razilian continental shelf. {T}hese time scales are in good agreement with those derived from a high-resolution numerical simulation of the regional ocean dynamics. {W}e do not find any relationship between the discharge rate of the {A}mazon {R}iver and the residence time of the waters on the {B}razilian continental shelf, suggesting that the residence time of the {A}mazon waters is primarily driven by the ambient northwestward current. {U}sing the apparent ages along the plume, we estimate an average velocity of 26 cm s(-1) for the northward transport of the {A}mazon waters on the continental shelf.},
  keywords = {{ATLANTIQUE} ; {BRESIL} ; {GUYANE} {FRANCAISE} ; {AMAZONIE}},
  booktitle = {},
  journal = {{L}imnology and {O}ceanography},
  volume = {[{E}arly access]},
  numero = {},
  pages = {[15 ]},
  ISSN = {0024-3590},
  year = {2022},
  DOI = {10.1002/lno.12010},
  URL = {https://www.documentation.ird.fr/hor/fdi:010084358},
}