Light absorption and fluorescence properties of chromophoric dissolved organic matter (CDOM), in the ST. Lawrence Estuary
B. Niekea, R. Reuterb, R. Heuermannb, H. Wangc, M. Babind, and J. C. Therriaulte
aDrpartement de Biologie, Universit6 Laval, Sainte Foy, Qurbec GIK 7P4, Canada
bCarl von Ossietzky Universit~it Oldenburg, Fachbereich Physik, D-26111 Oldenburg, Germany
cPhysikalisch Technische Bundesanstalt, D-38100 Braunschweig, Germany
dLPCM, Universit6 Pierre et Marie Curie, F-06230 Viilefranche sur mer, France
eInstitut Maurice-Lamontagne, Ministrre des P~ches et des Ocrans, CP 1000, Mont-Joli, Qurbec G5H 3Z4, Canada
Summary
In this paper, light absorption by fluorescent dissolved organic matter has been discussed. The samples were collected from St. Lawrence Estuary. Chlorophyll a and chromophoric dissolved organic matter (CDOM) data of excitation emission matrix was obtained by fluorescence spectrophotometry. In this study, only three excitation wavelengths of 365, 388, and 480 nm were used. Against each wavelength emission was obtained between 380-550 nm, 410-550 nm, and 510-700 nm respectively. The spatial distribution of salinity, temperature, chlorophyll, CDOM adsorption and fluorescence were studied. It was found that the fluorescence and absorption can be used as tracers for water mass identification. Two cases of oceanic and coastal studies were carried out under the same conditions as described above. The first two excitation wavelengths and their results showed that the two cases can be identified. The difference between the relationships of fluorescence and absorption with salinity in the transition zone of the two cases was not observed. The relationship between fluorescence and absorption was consistent with the results of previous studies. The spatial distribution of the above mentioned water quality parameters has been shown in the following figure.
It was also proposed that lidar can be used to get more good results for absorption of CDOM.
Reviewer: Aamir Alaud Din