@article{PAR00010408,
  title = {{S}patio-temporal variability in benthic silica cycling in two macrotidal estuaries : causes and consequences for local to global studies},
  author = {{R}aimonet, {M}. and {R}agueneau, {O}livier and {A}ndrieux-{L}oyer, {F}. and {P}hilippon, {X}. and {K}erouel, {R}. and {L}e {G}off, {M}. and {M}emery, {L}.},
  editor = {},
  language = {{ENG}},
  abstract = {{T}he high heterogeneity of silica cycling in coastal margins and the lack of silica data (compared to nitrogen and phosphorus) prevent the estimation of global silica retention in estuaries. {I}n this study, the spatial and temporal variability of porewater silicic acid ({S}i({OH})(4)) profiles - that integrate benthic transport and reaction processes - was investigated at different spatial (metre, longitudinal and cross-section, intra-estuary) and temporal (tidal, seasonal) scales in two macrotidal estuaries, very close geographically but essentially differing in their shape. {S}tudying the spatial and temporal variability of {S}i({OH})(4) concentrations in porewaters provided evidence for the importance of transport processes, e.g. bio-irrigation, tidal pumping, resuspension and any combination of these processes, in affecting {S}i({OH})(4) concentrations and fluxes and therefore temporary or permanent retention along the land ocean continuum. {W}e confirm that a{S}i{O}(2) (amorphous silicate) transported by rivers and estuaries clearly needs to be better characterized as it provides an important source of reactive a{S}i{O}(2) to sediments. {T}his study allows us to: (1) interrogate spatial and temporal scales, although both are most often in complete interaction; (2) design the most appropriate sampling schemes to be representative of any given system and to extrapolate at the scale of the whole estuary; (3) quantify uncertainty associated to the estimations of {S}i({OH})(4) stocks and fluxes in this type of ecosystem, essential for budget calculations. {W}e showed that two adjacent small macrotidal estuaries, may exhibit different behaviours regarding {S}i retention. {T}emporary retention has been observed in the meanders of the {A}ulne {E}stuary and not along the more linear {E}lorn {E}stuary, demonstrating the importance of the morphology and hydrodynamic components of the estuarine filter. {R}esearch is needed in other systems and climatic zones, but our study suggests that the typology should not only account for the different types of land-ocean continuum (fjord, delta, mangrove...), but also incorporate the physical or biological attributes of the estuarine filter.},
  keywords = {heterogeneity ; season ; silicate ; sediment ; land-sea interface ; upscaling},
  booktitle = {},
  journal = {{E}stuarine {C}oastal and {S}helf {S}cience},
  volume = {119},
  numero = {},
  pages = {31--43},
  ISSN = {0272-7714},
  year = {2013},
  DOI = {10.1016/j.ecss.2012.12.008},
  URL = {https://www.documentation.ird.fr/hor/{PAR}00010408},
}