DICASE

Type Oceanographic cruise
Ship Téthys II
Ship owner CNRS
Dates 02/06/2014 (Port-Saint-Louis-du-Rhône) - 11/06/2014 (Port-Saint-Louis-du-Rhône)
Chief scientist(s) LANSARD Bruno

LABORATOIRE SCIENCES DU CLIMAT ET DE L'ENVIRONNEMENT (LSCE)

UMR 8212, CNRS-CEA-UVSQ

LSCE-Vallée, Bat.12

Avenue de la Terrasse

91198 GIF-SUR-YVETTE

+33(0)1 69.82 35 23

contact@lsce.ipsl.fr

http://www.lsce.ipsl.fr/

DOI 10.17600/14007100
Objective The DICASE cruise looked at the spatial variability of benthic recycling of organic matter and its interactions with carbonates. So it focused on organic and inorganic carbon dynamics at the interface between bottom water and sediments and provided some elements of response about the spatial variability of CO2 fluxes at the water-sediment interface. In sediments, organic carbon is mainly mineralized, whereas carbonates are either preserved or dissolved depending on the sediments' pH. Therefore the amount of carbon stored in sediments depends on the rate at which terrigenous and marine organic matter is deposited, on the intensity of organic carbon recycling and on the pH conditions. The cruise provided an initial integrated study of carbonate dissolution in Rhone delta sediments by measuring pH profiles in situ and ex situ, total alkalinity, DIC, Ca2+ and Mg2+ in order to highlight any dissolution of carbonates in these sediments. The related project is MERMEX.

Bibliography

Rassmann Jens, Lansard Bruno, Pozzato Lara, Rabouille Christophe (2016). Carbonate chemistry in sediment porewaters of the Rhône River delta driven by early diagenesis (northwestern Mediterranean). Biogeosciences, 13(18), 5379-5394. http://doi.org/10.5194/bg-13-5379-2016

Rassmann Jens, Lansard Bruno, Pozzato Lara, Rabouille Christophe (2016). Carbonate chemistry in sediment pore waters of the Rhône River delta driven by early diagenesis (NW Mediterranean). Biogeosciences, 13(18), 5379-5394. http://doi.org/10.5194/bg-2016-212