@article{fdi:010042691,
  title = {{I}n situ oxygen uptake rates by coastal sediments under the influence of the {R}hone {R}iver ({NW} {M}editerranean {S}ea)},
  author = {{L}ansard, {B}. and {R}abouille, {C}. and {D}enis, {L}. and {G}renz, {C}hristian},
  editor = {},
  language = {{ENG}},
  abstract = {{T}he influence of riverine inputs on biogeochemical cycling and organic matter recycling in sediments on the continental shelf off the {R}hone {R}iver mouth ({NW} {M}editerranean {S}ea) was investigated by measuring sediment oxygen uptake rates using a combination of in situ and laboratory techniques. {F}our stations were investigated during two cruises in {J}une 2001 and {J}une 2002, with depths ranging from 9 to 192 m and over a distance to the {R}hone {R}iver mouth ranging from 4 to 36 km. {D}iffusive oxygen uptake ({DOU}) rates were determined using an in situ sediment microprofiler and total oxygen uptake ({TOU}) rates were measured using sediment core incubations. {T}here was good agreement between these two techniques which indicates that the non-diffusive fraction of the oxygen flux was minimal at the investigated stations. {DOU} rates ranged from 3.7 +/- 0.4 mmol {O}-2 m(-2) d(-1) at the continental shelf break to 19.3 +/- 0.5 mmol {O}-2 m(-2) d(-1) in front of the {R}hone {R}iver mouth. {S}ediment oxygen uptake rates mostly decreased with increasing depth and with distance from the {R}hone mouth. {T}he highest oxygen uptake rate was observed at 63 m on the {R}hone prodelta, corresponding to intense remineralization of organic matter. {T}his oxygen uptake rate was much larger than expected for the increasing bathymetry, which indicates that biogeochemical cycles and benthic deposition are largely influenced by the {R}hone {R}iver inputs. {T}his functioning was also supported by the detailed spatial distribution of total organic carbon ({TOC}), total nitrogen ({TN}) and {C}/{N} atomic ratio in surficial sediments. {S}ediments of the {R}hone prodelta are enriched in organic carbon (2-2.2%) relative to the continental shelf sediments (< 1%) and showed {C}/{N} ratios exceeding {R}edfield stoichiometry for fresh marine organic matter. {A} positive exponential correlation was found between {DOU} and {TOC} contents (r(2) = 0.98, n = 4). {S}outh-westward of the {R}hone {R}iver mouth, sediments contained highly degraded organic matter of both terrestrial and marine origin, due to direct inputs from the {R}hone {R}iver, sedimentation of marine organic matter and organic material redeposition after resuspension events.},
  keywords = {{S}ediment ; {O}xygen uptake rate ; {M}icroelectrodes ; {O}rganic carbon ; {R}emineralization ; {M}editerranean sea ; {G}ulf of lions ; {R}hone river},
  booktitle = {},
  journal = {{C}ontinental {S}helf {R}esearch},
  volume = {28},
  numero = {12},
  pages = {1501--1510},
  ISSN = {0278-4343},
  year = {2008},
  DOI = {10.1016/j.csr.2007.10.010},
  URL = {https://www.documentation.ird.fr/hor/fdi:010042691},
}