Impact of phytoplankton and bacterial production on nutrient and DOM uptake in the Rhône River plume (NW Mediterranean)

2006 ◽  
Vol 315 ◽  
pp. 43-54 ◽  
Author(s):  
M Pujo-Pay ◽  
P Conan ◽  
F Joux ◽  
L Oriol ◽  
JJ Naudin ◽  
...  
Keyword(s):  
Bacterial Production ◽  
River Plume ◽  
Rhône River ◽  
Rhone River ◽  
Nw Mediterranean

scholarly journals Functioning of the planktonic ecosystem on the Gulf of Lions shelf (NW Mediterranean) during spring and its impact on the carbon deposition: a field data and 3-D modelling combined approach

2011 ◽  
Vol 8 (11) ◽  
pp. 3231-3261 ◽  
Author(s):  
P. A. Auger ◽  
F. Diaz ◽  
C. Ulses ◽  
C. Estournel ◽  
J. Neveux ◽  
...  
Keyword(s):  
Carbon Deposition ◽  
River Plume ◽  
Rhône River ◽  
Offshore Area ◽  
Good Opportunity ◽  
Gulf Of Lions ◽  
Rhone River ◽  
Nw Mediterranean ◽  
Living Organisms ◽  
Peak Discharges

Abstract. A coupled hydrodynamic-biogeochemical modelling is developed to address main mechanisms that drive the particulate organic carbon (POC) deposition in the Gulf of Lions (NW-Mediterranean). Low-salinity water (LSW, salinity <37.5) lenses detached from the Rhone River plume under specific wind conditions tend to favour the biological productivity and provide a good opportunity for validating a planktonic ecosystem modelling. A specific calibration dedicated to river plume ecosystems is then proposed and validated using in situ measurements within such LSW lens (BIOPRHOFI cruise – May 2006) and on the Gulf of Lions. During spring 2006, the POC deposition is maximal on the prodelta area and within the coastal area in the Gulf of Lions. Organic detritus mostly contribute to the total POC deposition (82–92%) whereas the contribution of living organisms (microphytoplankton) appears lower than 17%. Exploring both influences of terrestrial inputs from the Rhone River and planktonic ecosystems on the POC deposition on the shelf, we estimated that the contribution of terrestrial POM inputs to the total POC deposition is lower than 17% at the shelf scale during the study period, with maxima during peak discharges of the Rhone River. The main deposition area of terrestrial POC is found in the vicinity of the river mouth in agreement with sediment data. On the other hand, a remarkable influence of marine biological processes on the POC deposition is highlighted further on the shelf (from 60 to 80 m depth). A tight feedback between zooplankton and POM contents in the water column is proposed to explain the control of POC deposition by zooplankton: terrestrial POM inputs would favour the development of living organisms through photosynthesis and grazing processes increasing the retention of organic matter within the food web. By favouring the development of large-sized zooplankton, LSW lenses may have paradoxically a negative impact on the carbon deposition on the shelf. In the same way, peak discharges of the Rhone River finally increase the gradient of POC deposition between the prodelta and the offshore area in the Gulf of Lions. The biogenic elements from the Rhone River are then exported further offshore through advection of zooplankton communities on the Gulf of Lions shelf.

Zooplankton feeding on seston in the Rhone River plume area (NW Mediterranean Sea) in May 1988

Hydrobiologia ◽  
1990 ◽  
Vol 207 (1) ◽  
pp. 241-249 ◽  
Author(s):  
Raymond Gaudy ◽  
Marc Pagano ◽  
Fran�ois Lochet
Keyword(s):  
Mediterranean Sea ◽  
River Plume ◽  
Rhône River ◽  
Rhone River ◽  
Plume Area ◽  
Nw Mediterranean ◽  
Nw Mediterranean Sea

scholarly journals Occurrence of perfluoroalkyl substances in the Bay of Marseille (NW Mediterranean Sea) and the Rhône River

2019 ◽  
Vol 149 ◽  
pp. 110491 ◽  
Author(s):  
Natascha Schmidt ◽  
Vincent Fauvelle ◽  
Javier Castro-Jiménez ◽  
Katixa Lajaunie-Salla ◽  
Christel Pinazo ◽  
...  
Keyword(s):  
Mediterranean Sea ◽  
Perfluoroalkyl Substances ◽  
Rhône River ◽  
Rhone River ◽  
Nw Mediterranean ◽  
Nw Mediterranean Sea

scholarly journals Bacterial activity and genetic richness along an estuarine gradient (Rhone River plume, France)

2002 ◽  
Vol 28 ◽  
pp. 13-24 ◽  
Author(s):  
M Troussellier ◽  
H Schäfer ◽  
N Batailler ◽  
L Bernard ◽  
C Courties ◽  
...  
Keyword(s):  
River Plume ◽  
Bacterial Activity ◽  
Rhône River ◽  
Estuarine Gradient ◽  
Rhone River

scholarly journals Biogeochemical characterization of the riverine particulate organic matter transferred to the NW Mediterranean Sea

2014 ◽  
Vol 11 (1) ◽  
pp. 157-172 ◽  
Author(s):  
M. Higueras ◽  
P. Kerhervé ◽  
A. Sanchez-Vidal ◽  
A. Calafat ◽  
W. Ludwig ◽  
...  
Keyword(s):  
Organic Matter ◽  
Particulate Organic Matter ◽  
High Water ◽  
Terrestrial Organic Matter ◽  
Rhône River ◽  
Δ13c And Δ15n ◽  
Coastal Rivers ◽  
Rhone River ◽  
Nw Mediterranean ◽  
Nw Mediterranean Sea

Abstract. A large amount of terrestrial organic matter is annually delivered by rivers to the continental shelf, where this material is either degraded, buried or transferred to the deep sea by hydrodynamic processes such as storms. The relative amount of terrestrial organic matter in the marine sediments is often determined by analysing the stable isotopes (δ13C and δ15N) and the C / N ratio of organic matter because the various particulate organic matter (POM) sources have distinct isotopic compositions. With the objective to refine and better interpret POM sources in the marine environment, we have characterized monthly terrestrial POM delivered by eight rivers discharging to the NW Mediterranean Sea: the Rhône, Hérault, Orb, Aude, Têt, Fluvià, Ter and Tordera rivers. These rivers were simultaneously sampled from November 2008 to December 2009 and the concentrations of total suspended matter (TSM), particulate organic carbon (POC) and nitrogen (PN), as well as their stable isotopic ratios (δ13C and δ15N) were determined. During the survey, three rainstorm events with winds coming from the E–NE and the S–SE impacted the NW Mediterranean. Depending on the direction of incoming winds, the fluvial response (amount of water discharge and TSM) was different. Rivers draining the Alps (Rhône River) and Central Massif (Hérault, Orb, and Aude rivers) were mostly impacted by rainstorms associated with winds coming from the S–SE, while rivers draining the Pyrenees (Têt, Fluvià, and Ter rivers) and the Montseny Massif (Tordera River) were impacted by rainstorms associated with winds coming from the E–NE. In addition, the spatial evolution of water discharges shows a different hydrological regime of the Rhône River, with relatively constant and high water stages and TSM concentrations when compared to coastal rivers, characterized by long periods of low water stages. TSM concentrations are positively correlated to water discharges (high water flows resuspended riverbed sediments) but show an inverse relationship with POC and PN relative contents (mostly due to dilution and by low availability of light in river waters during flood events). TSM in most of the coastal rivers have on average 2.5–3 times higher POC and PN mean contents than the Rhône River (8.5 and 1.5%, respectively, for coastal rivers compared to 3.6 and 0.5%, respectively, for the Rhône River). This discrepancy may be caused by the long drought periods in small coastal Mediterranean watersheds that enhance the eutrophication in studied coastal rivers. The δ13C ratios of organic matter also reflect this discrepancy between high and low water stages with values ranging from −33.2 to −24.5‰. The enriched 13C values (−26.3 ± 0.4‰ for the Rhône River and −26.9 ± 1.2‰ for coastal rivers), measured during high water stages, express mostly a mixture of terrestrial source (plant remains and soils) whereas depleted 13C values (∼ −30‰) associated with low water stages exhibit a source with predominant freshwater algae. The high δ15N mean values (>8‰) found in Têt, Ter and Tordera rivers may underline the importance of denitrification processes as a consequence of the eutrophication and anthropogenic impact.

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