Colored Dissolved Organic Matter

CDOM transmits yellow light (it is thus also referred as yellow substances) because it preferentially absorbs light at the blue end of the visible spectrum. As a consequence of its absorption characteristics, in certain oceanic situations, CDOM might outcompete with Chlorophyll-a in the absorption of blue light and thus might be responsible for photosynthesis limitation. CDOM is one of the products, which, together with Chlorophyll-a, can be extracted from Ocean Color Radiometry satellite. Because of analytical difficulties, its spatial and temporal distribution has not been up to now well documented. Further measurement efforts have thus to be undertaken.

2) How is it measured ?

Several methods exist to determine the oceanic CDOM concentration:

> In situ (sensor): fluorometry, spectrophotometry
> In vitro (in the lab), on discrete samples: spectrophotometry, fluorometry
> Space-based (satellite sensor): Ocean Color Radiometry.

3) Where is more information available?

IOCCG (2011). Bio-Optical Sensors on Argo Floats. Claustre, H. (ed.), Reports of the International Ocean-Colour Coordinating Group, No. 11, IOCCG, Darthmouth, Canada.

Xing et al. (2011). Combined processing and mutual interpretation of radiometry and fluorimetry from autonomous profiling Bio-Argo Floats. 2. The CDOM absorption retrieval. Journal of Geophysical Research, submitted.

Morel, A. & Gentili, B. (2009a). A simple band ratio technique to quantify the colored dissolved and detrital organic material from ocean color remotely sensed data. Remote Sens. Environ., 113, 998-1011, doi:10.1016/j.rse.2009.01.008.

Brown, C.A., Huot, Y., Werdell, P.J., Gentili, B. & Claustre, H. (2008). The origin and global distribution of second order variability in satellite ocean color and its potential applications to algorithm development, Remote Sens. Environ., 112, 4186-4203, doi:10.1016/j.rse.2008.06.008.

Nelson, N.B. & Siegel, D.A. (2002). Chromophoric DOM in the open ocean. In : Biogeochemistry of marine dissolved organic matter, D.A. Hansell and C.A. Carlson (Eds.), pp. 547-578, Academic Press, San Diego.

Siegel et al. (2002). Global distribution and dynamics of colored dissolved and detrital organic materials. J. Geophys. Res., 107, 3228, doi:10.1029/2001JC000965.