@article{PAR00013320,
  title = {{S}patial and temporal variability of sediment organic matter recycling in two temperate eutrophicated estuaries},
  author = {{K}halil, {K}. and {R}aimonet, {M}. and {L}averman, {A}. {M}. and {Y}an, {C}. and {A}ndrieux-{L}oyer, {F}. and {V}iollier, {E}. and {D}eflandre, {B}. and {R}agueneau, {O}livier and {R}abouille, {C}.},
  editor = {},
  language = {{ENG}},
  abstract = {{T}his paper deals with the spatial and seasonal recycling of organic matter in sediments of two temperate small estuaries ({E}lorn and {A}ulne, {F}rance). {T}he spatio-temporal distribution of oxygen, nutrient and metal concentrations as well as the organic carbon and nitrogen contents in surficial sediments were determined and diffusive oxygen fluxes were calculated. {I}n order to assess the source of organic carbon ({OC}) in the two estuaries, the isotopic composition of carbon (delta {C}-13) was also measured. {T}he temporal variation of organic matter recycling was studied during four seasons in order to understand the driving forces of sediment mineralization and storage in these temperate estuaries. {L}ow spatial variability of vertical profiles of oxygen, nutrient, and metal concentrations and diffusive oxygen fluxes were monitored at the station scale (within meters of the exact location) and cross-section scale. {W}e observed diffusive oxygen fluxes around 15 mmol m(-2) day(-1) in the {E}lorn estuary and 10 mmol m(-2) day(-1) in the {A}ulne estuary. {T}he outer (marine) stations of the two estuaries displayed similar diffusive {O}-2 fluxes. {S}uboxic and anoxic mineralization was large in the sediments from the two estuaries as shown by the rapid removal of very high bottom water concentrations of {NO}x- (> 200 mu {M}) and the large {NH}4+ increase at depth at all stations. {OC} contents and {C}/{N} ratios were high in upstream sediments (11-15 % d.w. and 4-6, respectively) and decreased downstream to values around 2 % d.w. and {C}/{N} <= 10. delta {C}-13 values show that the organic matter has different origins in the two watersheds as exemplified by lower delta {C}-13 values in the {A}ulne watershed. {A} high increase of delta {C}-13 and {C}/{N} values was visible in the two estuaries from upstream to downstream indicating a progressive mixing of terrestrial with marine organic matter. {T}he {E}lorn estuary is influenced by human activities in its watershed (urban area, animal farming) which suggest the input of labile organic matter, whereas the {A}ulne estuary displays larger river primary production which can be either mineralized in the water column or transferred to the lower estuary, thus leaving a lower mineralization in {A}ulne than {E}lorn estuary. {T}his study highlights that (1) meter scale heterogeneity of benthic biogeochemical properties can be low in small and linear macrotidal estuaries, (2) two estuaries that are geographically close can show different pattern of organic matter origin and recycling related to human activities on watersheds, (3) small estuaries can have an important role in recycling and retention of organic matter.},
  keywords = {{S}patial and temporal variability ; {E}stuarine sediment ; {O}xygen ; {O}rganic carbon and isotopic composition ; {M}icroelectrode ; {O}rganic matter recycling ; {FRANCE}},
  booktitle = {},
  journal = {{A}quatic {G}eochemistry},
  volume = {19},
  numero = {5-6},
  pages = {517--542},
  ISSN = {1380-6165},
  year = {2013},
  DOI = {10.1007/s10498-013-9213-8},
  URL = {https://www.documentation.ird.fr/hor/{PAR}00013320},
}