49
DOM through high temperature combustion (e.g., Del Castillo et al. 1999). Colored
dissolved organic matter (CDOM) is by definition the fraction of organic material
dissolved in natural waters that absorb visible light; the remaining dissolved organic
material is optically inactive and is mainly composed of small aliphatic molecules
that absorb only in the ultraviolet if at all. Colored substances profoundly affect the
penetration of light into natural waters bodies lending a tea-like tint to the water.
Black waters containing high CDOM concentrations are common in river plumes
and mangrove environments (Fig. 2.15).
Degradation of organic matter, particularly of terrestrial materials with high tannin contents, results in release to solution into coastal waters of globally significant
quantities of these chromophoric (optically active) substances characterized by
large molecular weight, polyphenolic content and variable chemical composition.
In situ photochemical condensation reactions are recognized as a less intense oceanic source. These materials are commonly known as humic substances. Hansell
and Carlson (2015) provide a detailed discussion of the composition, distribution,
optical activity, and global biogeochemical significance of CDOM.
Terrestrial runoff, mainly from large rivers with high humic content, can modulate optical properties of near-surface waters over ocean areas extending thousands
of kilometers from the river mouth. The Coriolis parameter, highest at high latitudes
Fig. 2.15 Black waters in
the buoyant Orinoco River
plume off the island of
Grenada
2.4 Electro-Optical Sensors for Measurement of Organic Matter in Seawater
DOM through high temperature combustion (e.g., Del Castillo et al. 1999). Colored
dissolved organic matter (CDOM) is by definition the fraction of organic material
dissolved in natural waters that absorb visible light; the remaining dissolved organic
material is optically inactive and is mainly composed of small aliphatic molecules
that absorb only in the ultraviolet if at all. Colored substances profoundly affect the
penetration of light into natural waters bodies lending a tea-like tint to the water.
Black waters containing high CDOM concentrations are common in river plumes
and mangrove environments (Fig. 2.15).
Degradation of organic matter, particularly of terrestrial materials with high tannin contents, results in release to solution into coastal waters of globally significant
quantities of these chromophoric (optically active) substances characterized by
large molecular weight, polyphenolic content and variable chemical composition.
In situ photochemical condensation reactions are recognized as a less intense oceanic source. These materials are commonly known as humic substances. Hansell
and Carlson (2015) provide a detailed discussion of the composition, distribution,
optical activity, and global biogeochemical significance of CDOM.
Terrestrial runoff, mainly from large rivers with high humic content, can modulate optical properties of near-surface waters over ocean areas extending thousands
of kilometers from the river mouth. The Coriolis parameter, highest at high latitudes
Fig. 2.15 Black waters in
the buoyant Orinoco River
plume off the island of
Grenada
2.4 Electro-Optical Sensors for Measurement of Organic Matter in Seawater