Winter to Spring Variations of Chromophoric Dissolved Organic Matter in a temperate estuary (Po River, Northern Adriatic Sea)

D. Berto (1) , M. Giani (1, 2) , F. Savelli (1) , E. Centanni (3) , C.R. Ferrari , B. Pavoni (3)

1 ISPRA - Istituto Superiore per la Protezione e la Ricerca Ambientale
2 OGS - Istituto Nazionale di Oceanografia e di Geofisica Sperimentale
3 Dipartimento Scienze Ambientali

The light absorbing fraction of dissolved organic carbon (DOC), known as chromophoric dissolved organic matter (CDOM) showed wide seasonal variations in the temperate estuarine zone in front of the Po River mouth. DOC concentrations increased from winter through spring mainly as a seasonal response to increasing phytoplankton production and thermohaline stratification. The monthly dependence of the CDOM light absorption by salinity and chlorophyll concentrations was explored. In 2003, neither DOC nor CDOM were linearly correlated with salinity, due to an exceptionally low Po river inflow. Though the CDOM absorbance coefficients showed a higher content of chromophoric dissolved organic matter in 2004 with respect to 2003, the spectroscopic features confirmed that the qualitative nature of CDOM was quite similar in both years.

Mots clés: chromophoric dissolved organic matter; Po river; Northern Adriatic; estuary

D. Berto, M. Giani, F. Savelli, E. Centanni, C.R. Ferrari, et al.. Winter to Spring Variations of Chromophoric Dissolved Organic Matter in a temperate estuary (Po River, Northern Adriatic Sea). Marine Environmental Research, 2010, 70 (1), pp.73. ⟨10.1016/j.marenvres.2010.03.005⟩. ⟨hal-00598196⟩