Implementation of an automatic monitoring program with high frequency measurements (MAREL Carnot) in the eastern English Channel : a close watch on a potential problem area with regard to the eutrophication status A.Lefebvre - Laboratoire Environnement & Ressources Centre Ifremer Manche Mer du Nord, Boulogne/Mer

Once upon a time …Preliminary studies December 2001 – April 2002 Hydrology : main biological and physico-chemical parameters Courantology : ADCP Lefebvre A., Repecaud M., Facq J.-V., Lefebvre G. & B. Hitier, Projet dimplantation de la station De mesures automatisées MAREL dans le port de Boulogne sur mer - Mesures in situ et résultats du modèle dadvection-diffusion Mars 2D. Rapport Ifremer DEL/BL/RST/02/07, 51 pages. Hébert C. & A Lefebvre, Circulation des masses deau dans la rade de Boulogne sur Mer. Étude préalable à l implantation de la station de mesures automatisées MAREL Carnot. Rapport Ifremer DEL/BL/RST/04/08, 18 pages.

Sea wall « CARNOT » Location of the system Harbour English Channel MAREL Carnot

Building site End of the installation (18/12/2003) Understructure Installation of the tube : 12 m high, 2 m diameter et 15 t.

Instrumentation The buoyThe tube and the buoy

Studied parameters Seawater TemperatureAir temperature ConductivityRelative Humidity pH P.A.R. (Photosynthetically Active Radiation) TurbidityNitrate Dissolved oxygenPhosphate Chlorophyll (Fluorescence)Silicate Frequency :1 series / 20 minutes (to be adjusted if special needed)

Monthly percentages of acquire data in JanuaryFebruaryMarchAprilMayJune % données acquises 75,675,969,194,895,694,0 JulyAugustSeptemberOctoberNovemberDecember % données acquises 93,983,893,792,891,686,8 Main characteristics of the studied parameters Paramètres physico-chimiquesRangeUncertainty Temperature- 5 à + 30 °C0,1 °C Conductivité0 à 70 mS/cm0,3 mS/cm Dissolved oxygen0 à 20 mg/L0,2 mg/L PH6,5 à 8,5 UpH0,2 UpH Turbidity0 à 4000 NTU10 % Fluorescence0 à 50 FFU10 % Nitrate0,1 à 100 µmol/L5 % Phosphate0,1 à 100 µmol/L5 % Silicate0,1 à 100 µmol/L5 %

Access to data Quality Assurance on data series Free data and reports available on Dedicated web page

Expected results Improvement of the knowledge on the dynamic of a coastal system under marine and anthropogenic controls Region Of Freshwater Influence (ROFI) + riverine inputs Occurrence of regular and intense blooms of the foaming and noxious Prymnesiophyceae Phaeocystis globosa Eutrophication = Nutrient inputs + excessive algal growth + harmful consequences

Results Usual monitoring strategy: SRN Network* (monthly/bi-monthly frequencies) * Regional Nutrient Monitoring Network (Ifremer / Artois-Picardie Water Agency) The bloom in 2008 !? Well-fitted with the seasonal cycle but …

Results Fluorescence MAREL Carnot The same bloom with HF measurements !

Nutrients and phytoplanktonic dynamics Fluorescence Nitrat e Phosphate Silicate February – May 2007 (In Babin et al, modified from Dickey 1991) According to the objectives : ! Elementary knowledge o n time scale !

Diatoms Uptake of silicate by Diatoms Fluorescence Silicate Nutrients and phytoplanktonic dynamics March 2006 Complementarity between MAREL Carnot & S.R.N. : information on phytoplanktonic community involved

Fluorescence Nitrate Silicate Salinity February– May 2007 Nutrients and phytoplanktonic dynamics Early nutrient inputs => contribution to the main bloom

Fluorescence Nitrate Silicate Salinity February – June 2006 Late nutrient inputs => secondary blooms : noxious diatoms or flagellates ? Nutrients and phytoplanktonic dynamics

Role of the ammonium during the bloom Results from the S.R.N. CHEMINI In progress : Implementation of the CHEMINI system (CHEmical MINIaturized analyser)

Effect of the sampling strategy on fluorescence distribution and his P90 Use of 4 filters on the database: diurnal (7-19 h); diurnal et operationnal (Monday to Friday) ; diurnal et March-October ; diurnal, operationnal et March-October. Control on sampling frequency: Monthly ; F1 : monthly then bi-monthly in March-april and September-October; F2 : monthly then bi-monthly from March to May and from August to October; Bi-monthly ; Weekly. => BOOTSTRAP methodology applied for a given year (study of the annual variability) then for 6 years (WFD management plan)

P90 for simulated fluorescence for a 6 years management plan with diurnal and operationnal data, and for monthly, bi-monthly and weekly sampling frequencies Good assessment of the P90 => Good assessment of the P90 Effect of the sampling strategy on fluorescence distribution and his P90

Effect of the sampling strategy on fluorescence distribution and his P90 P90 for simulated fluorescence for a 6 years management plan with diurnal and operationnal data from March to October, and for monthly, F1, F2, bi-monthly and weekly sampling frequencies Over-estimation of the P90 => Over-estimation of the P90

Access to data via the Nausicaa browser within 24 h MAREL Carnot and satellite imagery: High frequency and meso-scale approach Sea Temperature: Marel Carnot vs. Pathfinder data February 2007 to February 2008 Water Framework Directive context Water Framework Directive context : chlorophyll, turbidity, sea surface temperature To be continued To be continued (offshore and ecosystemic approach) : Marine Strategy Framework Directive

Project Partners

MAREL Carnot 10 meters Thanks to the MAREL TEAM Michel Repecaud Renaud Vuillemin Karenn Bucas David Le Pivert Loïc Quémener Jean-Valery Facq Vincent Duquesne Camille Blondel Usual sampling conditions ! Who want to sample from a 5 meters long boat ? THANKS FOR YOUR ATTENTION