Biogeochemistry and hydrology of a high-energy sandy beach : the Truc Vert beach : matter fluxes in intertidal sandy sediments
type: Dataset
contact point: Organization
  fn: CCSD
keyword: biogeochimie
keyword: intertidal-zone
keyword: sdustusciences-of-the-universe-physicsearth-sciences
keyword: plages-sableuses
keyword: permeable-sediments
keyword: zone-intertidale
keyword: theses
keyword: infoeu-reposemanticsdoctoralthesis
keyword: sandy-beaches
keyword: biogeochemistry
keyword: sediments-permeables
landing page: https://theses.hal.science/tel-00946913
description: Biogeochemical studies in permeable sandy sediments are recent: the role of these environments in biogeochemical cycles was neglected because of their poverty in organic matter and the complexity of transient processes affecting them. Sandy beaches are subject to various physical forcings like tide, waves and connexion with continental groundwaters. Advection is the leading mode of transport. Huge volumes of organic matter-bearing seawater are potentially filtered by permeable intertidal sediments. The main objective of this study was to characterize biogeochemical processes induced by seawater recirculation and groundwater discharge in the intertidal zone of an exposed beach: the Truc Vert beach.Seasonal monitoring of pore water properties showed that aerobic respiration processes occurred in the seawater recirculation plume. Extrapolated to the 240 km-long Aquitanian coast, these processes represent each year an annual release of 610 tons of nitrate and 4400 tons of dissolved inorganic carbon, i.e. the equivalent of the Leyre input, a small river draining a catchment area of 2000 km2 at the southeast part of the Arcachon lagoon.The benthic macrofauna is dominated by Crustaceans. These organisms have a low impact on biogeochemical cycles: the contribution of benthic macrofauna on oxygen deficits observed in the lower beach pore waters is insignificant (< 2%). Biogeochemical fluxes observed in the intertidal zone are mainly induced by the aerobic respiration of microorganisms living in the sediment. Supported by regular tidal inputs of dissolved oxygen on the pore space, these processes varied seasonnally with temperature and organic matter availability.The deployment of autonomous probes into the sediment of the intertidal zone allowed us to clarify the short-term variability of pore water properties. Extension of the intertidal saline plume evolved with the tidal amplitude. Oxygen levels measured at a given point of the beach varied slightly with the lunar cycle. …
identifier: NNT: 2013BOR14916
issued: 2026-05-06T09:31:45.686391
language: fr
modified: 2026-05-06T09:31:45.686396

test_moissonnage_selune
type: Agent

Biogeochemistry and hydrology of a high-energy sandy beach : the Truc Vert beach : matter fluxes in intertidal sandy sediments
type: Distribution
access URL: https://theses.hal.science/tel-00946913
format: HTML
issued: 2026-05-06T09:31:45.706271
modified: 2026-05-06T09:31:45.653783