Context Events Situation Limits Strategy Glider Observation of Suspended Particle Dynamics in the Gulf of Lions Gaël MANY 1, François Bourrin 1, Romaric Verney 2, David Le Berre 2, Matthias Jacquet 2 Kiel - COST Action, 6th EGO Glider Conference - June, 17th, AQUA-MODIS 01/21/2014

Context Events Situation Limits Strategy m 2000 m 0 m Main processes in the sediment transport ? River inputs (floods) Offshore Exports (storms) Sedimentation / erosion Atmospheric deposits 8 % of total ocean surface 90% of total ocean biodiversity LOICZ Key area Coastal area : an interface between continent and deep-sea Marine particles : - Food - Contaminant - Sediment Algal Bloom

Context Events Situation Limits Strategy Marine Wind Coastal Rivers Rhône Alongshore circulation Ulses et al., 2005 Importance of the Rhône (~80% of total material inputs) Courp et Monaco, 1990 Pro-deltas Preferential deposit areas + - Bourrin et al., 2006 Our study area : The Gulf of Lions 2

Context Events Situation Limits Strategy Marine Wind Coastal Rivers Rhône Fixed buoys Mooring lines Slocum Coastal Glider deployments 1 – Têt shelf = 1045 km, Spring 2013 > 26 Sections 2 – Rhône shelf = 450 km, Winter 2014 > 9 Sections TUCPA campaign - Water sampling (SSC, POC) - CTD profile - LISST measurements MODIS pictures 3 Limited by meteorological conditions Our Strategy

Context Events Situation Limits Strategy Objectives Main events involved in the particle dynamics of the Gulf of Lions Winter storm (Bourrin et al., In prep) Spring bloom period Winter flood event Optical sensors calibration Chl a (factory calibration) to Chl a (In Situ calibration) Turbidity (NTU units) to SSC (mg/L) done To do

Context Events Situation Limits Strategy GFF filtration = SSC (mg/L) samplingHACH turbidimeter (NTU) Turbidity / SSC calibration Glider NTU sensor calibration (bb 700nm) Filtration system 4

Context Events Situation Limits Strategy CDOM (ppm) Spring Bloom situation April 2013 CTD Stratified water Complex and small structure CDOM Noisy sensor signal SSC BNL ~ 2 to 0.5 mg/L (cross-shore) Thickness 15-30m mab Chl a surface ~ 1µg/L (Im. Sat.) subsurface >3µg/L (Glider) SSC (mg/L) Chl a (µg/L) SSC (mg/L) 5

Context Events Situation Limits Strategy Spring Bloom situation - Chl a (µg/L) spatio-temporal variability Depth (m) Depth (m) Depth (m) Distance to POEM Buoy (km) April, 10-15, 2013 Distance to POEM Buoy (km) May, 7-13,

Context Events Situation Limits Strategy SSC (mg/L) Chl a (µg/L) SSC (mg/L) Winter flood situation February 2014 Rhône river discharge > 4000m 3 /s Plume length = ~ 55km CTD Plume identification Length > 45km Thickness : 20-40m CDOM Plume vs BNL Chl a Low in plume (~1µg/L) Correlation with MODIS SSC 2 structures : plume / BNL 7

Context Events Situation Limits Strategy SSC (mg/L) Depth (m) Density Depth (m) Surface turbid cell 15-20km offshore 20m thickness SSC > 5 mg/L Density < 25 Detached from mouth Bottom turbid cell 50-90m depth SSC > 3mg/L Resuspension (?) Plume sedimentation (?) Winter flood situation 8

Context Events Situation Limits Strategy Rhône plume spatial variability - SSC (mg/L) Distance to Roustan-Sud buoy (km) /01/ Deployment /30/14 to 02/12/14

Context Events Situation Limits Strategy Pre-flood eventFlood event 30-31/01/ /01/ /01/2014 Plume length > 50km Plume length > 15km Rhône discharge m 3 /s ~4000m 3 /s Rhône River plume spatial variability Deployment ~2500m 3 /s

Context Events Situation Limits Strategy Glider problem and deployment limits Glider recovery by safety guards Ballast problem Emergency procedure 60km drift 11 14/02/2014

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