Chemical characterization of porewaters in an intertidal mudflat of the Seine estuary: relationship to erosion-deposition cycles.
A seasonal field study was carried out in the Seine estuary to determine the chemistry of sediment porewaters using the 'peeper' technique and changes in the elevation of the mudflats using the 'Altus' technique. This approach allowed us to evaluate the release of nutrients and to link these releases to the sediment hydrodynamics. Our results show that nutrient and organic matter cycling in a Seine estuary mudflat exhibits a seasonal behaviour, which is mainly influenced by variations in hydrodynamics. Sediments, rich organic matter, were input during floods and they were mineralized during summer and autumn, releasing nutrients and dissolved organic carbon into the sediment porewaters. The nutrient release, including ammonium, is mainly linked to the mineralization of organic matter, while the release of phosphate is delayed. The delay could be the result of phosphate association with organic matter and/or its co-precipitation with calcium and iron.
Bally
Gabriel
G
UMR CNRS 6143, Morphodynamique Continentale et Côtière, Département de Géologie, Université de Rouen, 76821 Mont-Saint-Aignan, France. gabriel.bally@univ-rouen.fr
Mesnage
Valérie
V
Deloffre
Julien
J
Clarisse
Olivier
O
Lafite
Robert
R
Dupont
Jean-Paul
JP
D017753:Ecosystem; D004784:Environmental Monitoring; D005602:France; D019015:Geologic Sediments / Q000737:chemistry*; D009584:Nitrogen / Q000032:analysis*; D009930:Organic Chemicals / Q000032:analysis; D010758:Phosphorus / Q000032:analysis*; D016062:Porosity; D045483:Rivers; D012621:Seasons; D014872:Water Movements
D009930:Organic Chemicals; D010758:Phosphorus; D009584:Nitrogen