The estuarine mixing behavior of colored dissolved organic matter (CDOM) absorbance was investigated in combined field and laboratory studies. From February to October 1998, surface water samples were collected along 9 transects in the Tyne estuary. Northeast England, from the tidal limit into the coastal North Sea. In 8 of these transects, mixing plots of absorbance vs. salinity indicated substantial removal of CDOM absorbance (average: 32%) in the upper estuary. Results from laboratory studies under simulated estuarine conditions suggest that an average of 21% (range: 9--39%) of riverine CDOM may be removed by adsorption onto suspended sediment, while CDOM flocculation accounted for an average removal of only 6% (range: 0--18%). We propose that adsorptive removal exerts a major control on CDOM in estuaries with elevated turbidity levels. ¿ 2001 American Geophysical Union