Colored Dissolved Organic Matter

Colored Dissolved Organic Matter (CDOM) is a measurement of the absorption of light in the UV and visible spectrum by the colored components of dissolved organic carbon. It is essentially the yellow substance in water as a result of decaying detritus. It is important to measure because it limits the amount of sunlight penetration, and thus restricts the growth of plankton populations. It is measured in a unit-less CDOM index. Data generated as part of CAFFs Circumpolar Biodiversity Monitoring Program (CAFF) and its Land Cover Change Initiative (LCC) Trends visible in the MODIS dataset show an overall decrease in the mean CDOM from 2003 to 2012, with a percent change of -31.7%. This trend can be seen in Figure 40. This decrease corresponds to the increase in total yearly primary productivity (Figure 30), as a decrease in the CDOM allows for sunlight to penetrate deeper into the water, boosting chlorophyll concentrations and thus primary productivity.