@article{PAR00012576,
  title = {{B}iogenic silica dissolution in diatom aggregates : insights from reactive transport modelling},
  author = {{M}oriceau, {B}. and {L}aruelle, {G}. {G}. and {P}assow, {U}. and {V}an {C}appellen, {P}. and {R}agueneau, {O}livier},
  editor = {},
  language = {{ENG}},
  abstract = {{D}iatom aggregates contribute significantly to the vertical sinking flux of particulate matter in the ocean. {T}hese fragile structures form a specific microhabitat for the aggregated cells, but their internal chemical and physical characteristics remain largely unknown. {S}tudies on the impact of aggregation on the {S}i cycle led to apparent inconsistency. {D}espite a lower biogenic silica (b{S}i{O}(2)) dissolution rate and diffusion of the silicic acid (d{S}i) being similar in aggregates and in sea-water, d{S}i surprisingly accumulates in aggregates. {A} reaction-diffusion model helps to clarify this incoherence by reconstructing d{S}i accumulation measured during batch experiments with aggregated and non-aggregated {S}keletonema marinoi and {C}haetoceros decipiens. {T}he model calculates the effective b{S}i{O}(2) dissolution rate as opposed to the experimental apparent b{S}i{O}(2) dissolution rate, which is the results of the effective dissolution of b{S}i{O}(2) and transport of d{S}i out of the aggregate. {I}n the model, d{S}i transport out of the aggregate is modulated by alternatively considering retention (decrease of the d{S}i diffusion constant) and adsorption (reversible chemical bonds between d{S}i and the aggregate matrix) processes. {M}odelled b{S}i{O}(2) dissolution is modulated by the impact of d{S}i concentration inside aggregates and diatom viability, as enhanced persistence of metabolically active diatoms has been observed in aggregates. {A}dsorption better explains d{S}i accumulation within and outside aggregates, raising the possible importance of d{S}i travelling within aggregates to the deep sea (potentially representing 20% of the total silica flux). {T}he model indicates that b{S}i{O}(2) dissolution is effectively decreased in aggregates mainly due to higher diatom viability but also to other para meters discussed herein.},
  keywords = {{S}ilicic acid ; d{S}i accumulation ; d{S}i diffusion ; d{S}i adsorption ; {T}ransparent exopolymer particles ; {TEP} ; {V}iability ; {S}i cycle},
  booktitle = {},
  journal = {{M}arine {E}cology {P}rogress {S}eries},
  volume = {517},
  numero = {},
  pages = {35--49},
  ISSN = {0171-8630},
  year = {2014},
  DOI = {10.3354/meps11028},
  URL = {https://www.documentation.ird.fr/hor/{PAR}00012576},
}