Summary of Abstract Submission

Abstract Submission No. IO50-08-0016PresentationPoster

ABSORPTION AND FLUORESCENCE AS ESTUARINE WATER QUALITY INDICATORS

G. Chiranjeevulu*1, K.R. Mangalaa**2, Damien Cardinal2, V.V.S.S. Sarma3, Nittala S. Sarma1

1 Andhra University, India
2 Université Pierre et Marie Curie, France
3 National Institute of Oceanography Regional Center,Visakhapatnam , India

ABSTRACT :

The optical properties of dissolved organic matter (DOM) of natural and anthropogenic sources are distinctly different. The coloured DOM (CDOM) and fluorescent DOM (FDOM) can quantify DOM fluxes through simple linear models. The CDOM and FDOM were measured along salinity gradient in 18 major Indian monsoonal estuaries during discharge season. Ten of these estuaries are along the east coast and join the Bay of Bengal. Eight estuaries are along the west coast and join the Arabian Sea. The CDOM (absorption coefficient at 350 nm, a350) was in the sequence: Ponnaiyar> Vellar> Penna> Rushikulya> Haldia= Subernarekha> Krishna> Cauvery. The CDOM shows conservative behavior with salinity in the northeastern estuaries. The CDOM was positively correlated with salinity in west flowing rivers. The spectral slope ratio (SR= S275-295/S350-400), which is an inverse molecular weight indicator was higher in northwestern and southeastern estuaries compared to northeastern and southwestern estuaries. The CDOM clearly indicates that the lower molecular weight organic matter of the former estuaries is anthropogenic i.e., industrial effluents from the industrialized States of Gujarat and Tamil Nadu respectively. Four primary fluorescence components namely protein-like (T), and the humic likes (A > C > M; UV, Visible and Marine humic-like respectively) were observed in the estuarine water. The T fluorophore was enriched in estuaries of the northwest and southeast. On the contrary, humic fluorescence and high humification index (HIX) are enriched in the estuaries of the southwest and northeast. Absorption and fl