RiOMar.fr : Fate of organic carbon and nutrient at the interface between the Rhone river and the Mediterranean Sea
The coastal zone situated at the interface between ocean and continent is a vulnerable medium which undergoes a growing anthropogenic pressure due to the coastal population growth. Additionally, the continuous increase of agriculture in upstream regions associated to fertilizer use in temperate countries or deforestation in tropical regions, along with the development of hydro-electric power with dams and levees have brought important changes in the quantity and quality of dissolved and particulate matter carried by the rivers to the coastal ocean.
Yet, the fate of particulate organic carbon and nutrients delivered by the rivers in coastal zones dominated by river inputs is poorly known. This is mainly due to the large temporal and spatial variability present in these systems, including river floods which carry a large proportion of particulate material to the coastal zone.
Therefore, we have designed a programm called RiOMar.fr (for River-dominated Ocean Margin in France)in which an integrated study on the Rhone river and the adjacent shelf is planned : this includes continuous measurements of river fluxes of nutrients and organic carbon, investigations of river plume processes and nutrient utilisation, studies of carbon recycling in the sediments and lower water column, and an integration of these results in a coupled physical-biological model including the sedimnt compartment. This model will be used for investigation of scenarios of climate change (in terms of hydrology and particulate fluxes) and human inputs (such as nutrients, nutrient ratios, organic carbon).
Temporal variability will be tackled using a time series of river inputs and a newly designed benthic station which will be moored close to the river mouth and should be capable of measuring benthic recycling after flood events.
HyMeX – Hydrological cycle in the Mediterranean Experiment 2010-2020