In situ oxygen uptake rates by coastal sediments under the influence of the Rhone River (NW Mediterranean Sea)
type: Dataset
description: The influence of riverine inputs on biogeochemical cycling and organic matter recycling in sediments on the continental shelf off the Rhone River mouth (NW Mediterranean Sea) was investigated by measuring sediment oxygen uptake rates using a combination of in situ and laboratory techniques. Four stations were investigated during two cruises in June 2001 and June 2002, with depths ranging from 9 to 192 m and over a distance to the Rhone River mouth ranging from 4 to 36 km. Diffusive oxygen uptake (DOU) rates were determined using an in situ sediment microprofiler and total oxygen uptake (TOU) rates were measured using sediment core incubations. There 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 Rhone River mouth. Sediment oxygen uptake rates mostly decreased with increasing depth and with distance from the Rhone mouth. The highest oxygen uptake rate was observed at 63 m on the Rhone prodelta, corresponding to intense remineralization of organic matter. This 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 Rhone River inputs. This 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. Sediments of the Rhone prodelta are enriched in organic carbon (2-2.2%) relative to the continental shelf sediments (< 1%) and showed C/N ratios exceeding Redfield stoichiometry for fresh marine organic matter. A positive exponential correlation was found between DOU and TOC contents (r(2) = 0.98, n = 4). South-westward of the Rhone River mouth, sediments contained highly degraded organic matter of both terres…
issued: 2026-05-20T16:39:22.238442
language: en
modified: 2026-05-20T16:39:22.238447
contact point: Organization
  fn: CCSD
keyword: benthic-boundary-layer
keyword: continental-margin-sediments
keyword: fluxes
keyword: gulf-of-lions
keyword: infoeu-reposemanticsarticle
keyword: journal-articles
keyword: marine-sediments
keyword: matter
keyword: mediterranean-sea
keyword: microelectrodes
keyword: ocean
keyword: organic-carbon
keyword: organic-carbon-preservation
keyword: oxygen-uptake-rate
keyword: remineralization
keyword: rhone-river
keyword: sduoceansciences-of-the-universe-physicsocean-atmosphere
keyword: sediment
keyword: spatial-variability
keyword: water-interface
landing page: 0278-4343

In situ oxygen uptake rates by coastal sediments under the influence of the Rhone River (NW Mediterranean Sea)
type: Distribution
format: HTML
issued: 2026-05-20T16:39:22.275330
modified: 2026-05-20T16:39:22.183048
access URL: https://hal.science/hal-00691682

test_moissonnage_selune
type: Agent