@article{fdi:010076491,
  title = {{A}n estimate of thorium 234 partition coefficients through global inverse modeling},
  author = {{L}e {G}land, {G}. and {A}umont, {O}livier and {M}emery, {L}.},
  editor = {},
  language = {{ENG}},
  abstract = {{T}horium-234 ({T}h-234), an insoluble radioisotope scavenged by marine particles, can be used as a proxy of the biological carbon pump. {T}horium-234 observations can constrain biogeochemical models, but a necessary first step is to estimate the poorly known partition coefficients between particulate and dissolved phases. {I}n this study, the {T}h-234 partition coefficients for five particle types, differing in size and chemical composition, are estimated by fitting a global 3-{D} {T}h-234 model based on the coupled ocean general circulation-biogeochemistry model {NEMO}-{PISCES} (at a resolution of 2 degrees) to a global {T}h-234 data set (including {GEOTRACES} data). {S}urface partition coefficients are estimated between 0.79 and 16.7x10(6). {B}iogenic silica has the smallest partition coefficients. {S}mall particulate organic carbon and lithogenic dust have the largest. {T}horium-234 observations at depth cannot be recovered without allowing partition coefficients to increase by one order of magnitude from surface to 1,000m deep. {I}n our time-dependent global 3-{D} model, the biases introduced by three common assumptions made in biological carbon pump studies can be quantified. {F}irst, using the {C}:{T}h-234 ratio of large particles alone leads to an overestimation of carbon export at the base of the euphotic layer, by up to a factor 2. {F}urthermore, assuming steady state and neglecting transport by advection and diffusion can bias fluxes by as much as 50%, especially at high latitudes and in upwellings, with a sign and intensity depending on the season.},
  keywords = {thorium 234 ; inverse modeling ; partition coefficient ; biological carbon ; pump},
  booktitle = {},
  journal = {{J}ournal of {G}eophysical {R}esearch : {O}ceans},
  volume = {124},
  numero = {6},
  pages = {3575--3606},
  ISSN = {2169-9275},
  year = {2019},
  DOI = {10.1029/2018jc014668},
  URL = {https://www.documentation.ird.fr/hor/fdi:010076491},
}