290 likes | 410 Views
SMIDDEST. Advantages of high frequency measurements of the water quality to the understanding of climatic impact in estuarine environment. Etcheber H., Castaing P., Chabaud G., Maneux E., Sautour B., Schmeltz M., Schmidt S., Sottolichio A. UMR 5805 EPOC
E N D
SMIDDEST Advantages of high frequency measurements of the water quality to the understanding of climatic impact in estuarine environment. Etcheber H.,Castaing P., Chabaud G., Maneux E., Sautour B., Schmeltz M., Schmidt S., Sottolichio A. UMR 5805 EPOC (Environnements et Paleo-environnements Océaniques) CNRS/University Bordeaux1
The GIRONDE Estuary Lower Estuary Central Estuary « salinity 0 » Guîtres Pessac « fluvial » Estuary La Réole 35 Salinity Gradient 0 Maximum Turbidity Zone(MTZ) « Bouchon vaseux »4-5 Mt SPM( > 1 g.L-1 in surface) Isle 0 Dordogne Garonne
SMIDDEST SOMLIT network (Service d’Observation en Milieu Littoral) Monthly data over 30 years. Biological , physical and geochemical data.
SMIDDEST • Topical questions: • - What are the daily and seasonal cycles of the suspended • particulate matter and dissolved oxygen contents? • - Is the Maximum Turbidity Zone moving upstream and getting larger? • - Is there a gradual annual deacrease of oxygen water • contents around Bordeaux?
SMIDDEST • Temperature • Salinity • Suspended matter content • Dissolved oxygen content • Measurements every 10 minutes (year: 2005)
SMIDDEST Transmetteurs Armoire électrique SEMC : SystèmeElectronique de Mesure et de Contrôle Chambre de mesure : sondes sur un circuit d’eau en continu Réservoir : de solution chlorée contre dépôts de biofilm.
SMIDDEST Example of recordeddata
SMIDDEST Evolution of salinity (A), temperature (B), turbidity (C) and O2 saturation rate (D) as a function of the tide. A C D B
SMIDDEST Temperature increase
F E K PK 13,5 F Salinity increases in the central estuary from one year to the other E K
SMIDDEST Evolution of salinity (A), temperature (B), turbidity (C) and O2 saturation rate (D) as a function of the tide. A C D B
Pleine Mer SMIDDEST Pleine Mer Pleine Mer Basse Mer Basse Mer
SMIDDEST Basse mer Pleine mer
SMIDDEST Daily cycle of O2 saturation rate in the Maximum Turbidity Zone during the summer drought in Bordeaux.
SMIDDEST • Major factors influencing the decrease of oxygen content in water during summer-time: • High water temperature • Organic load of water • Limited oscillations of waters due to the decrease of summer river discharge and the increase of marine intrusion.
SMIDDEST Oxygen saturation rate of the Garonne waters in Bordeaux during 2006 and 2007 Summers.
SMIDDEST Oxygen saturation rate of the Garonne waters in Bordeaux during 2006 summer. Dramatic consequences for alosa alevins.
SMIDDEST • Future evolution of Major Factors: • Increase of water Temperature • Increase of salinity • Decrease of summer river discharge inducing stagnancy (or low oscillations) of waters(better use of fluvial water) • Increase of the number of inhabitants inducing more water waste (better management of water waste treatment and inputs
SMIDDEST Future evolution : ETMOM MODEL (Estuarine Turbidity Maximum Oxygen Model) Bordeaux station
SMIDDEST ... car pour la terre, le soleil, les vents, ils ne sont point sujets à être emprisonnés, ni détournés, ni dérobés, tandis que cela peut arriver à l'eau, qui, pour de raison, a besoin que la loi vienne à son secours... L'eau est la seule chose la plus nécessaire à l'entretien de la vie, mais il est aisé de la corrompre « Les lois » Platon – IVe siècle avant Jésus-Christ « Eau, tu n’as ni couleur, ni arôme, on ne peut pas te définir, on te goûte sans te connaître. Tu n’es pas nécessaire à la vie, tu es la vie. » St Exupéry